selfTest.cpp

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#include "CollisionDetection.h"
#define DOCTEST_CONFIG_IMPLEMENT
#include <chrono>
#include <cmath>
#include <doctest.h>
#include <iostream>
#include "doctest_utils.h"
#include "global.h"
 
using namespace helios;
 
int CollisionDetection::selfTest(int argc, char **argv) {
    return helios::runDoctestWithValidation(argc, argv);
}
 
namespace CollisionTests {
 
    std::vector<uint> generateSeparatedTriangles(Context *context, int count, float separation = 5.0f) {
        std::vector<uint> uuids;
        for (int i = 0; i < count; i++) {
            float x = i * separation;
            uint uuid = context->addTriangle(make_vec3(x, -1, 0), make_vec3(x + 1, -1, 0), make_vec3(x + 0.5f, 1, 0));
            uuids.push_back(uuid);
        }
        return uuids;
    }
 
    std::vector<uint> generateOverlappingCluster(Context *context, int count, vec3 center = make_vec3(0, 0, 0)) {
        std::vector<uint> uuids;
        for (int i = 0; i < count; i++) {
            float angle = (2.0f * M_PI * i) / count;
            float radius = 0.5f; // Overlapping radius
            float x = center.x + radius * cos(angle);
            float y = center.y + radius * sin(angle);
 
            uint uuid = context->addTriangle(make_vec3(x - 0.5f, y - 0.5f, center.z), make_vec3(x + 0.5f, y - 0.5f, center.z), make_vec3(x, y + 0.5f, center.z));
            uuids.push_back(uuid);
        }
        return uuids;
    }
 
    std::vector<uint> createParallelWallsWithGap(Context *context, vec3 gap_center, float gap_width, float wall_height = 2.0f, float wall_distance = 3.0f) {
        std::vector<uint> uuids;
        float half_gap = gap_width * 0.5f;
        float half_height = wall_height * 0.5f;
 
        // Left wall (before gap)
        float left_wall_end = gap_center.x - half_gap;
        if (left_wall_end > -5.0f) {
            uint uuid1 = context->addTriangle(make_vec3(-5.0f, gap_center.y - half_height, wall_distance), make_vec3(left_wall_end, gap_center.y - half_height, wall_distance), make_vec3(-5.0f, gap_center.y + half_height, wall_distance));
            uint uuid2 = context->addTriangle(make_vec3(left_wall_end, gap_center.y - half_height, wall_distance), make_vec3(left_wall_end, gap_center.y + half_height, wall_distance), make_vec3(-5.0f, gap_center.y + half_height, wall_distance));
            uuids.push_back(uuid1);
            uuids.push_back(uuid2);
        }
 
        // Right wall (after gap)
        float right_wall_start = gap_center.x + half_gap;
        if (right_wall_start < 5.0f) {
            uint uuid3 = context->addTriangle(make_vec3(right_wall_start, gap_center.y - half_height, wall_distance), make_vec3(5.0f, gap_center.y - half_height, wall_distance), make_vec3(right_wall_start, gap_center.y + half_height, wall_distance));
            uint uuid4 = context->addTriangle(make_vec3(5.0f, gap_center.y - half_height, wall_distance), make_vec3(5.0f, gap_center.y + half_height, wall_distance), make_vec3(right_wall_start, gap_center.y + half_height, wall_distance));
            uuids.push_back(uuid3);
            uuids.push_back(uuid4);
        }
 
        return uuids;
    }
 
    vec3 calculateGapCenterDirection(vec3 apex, vec3 gap_center) {
        vec3 direction = gap_center - apex;
        return direction.normalize();
    }
 
    float measureAngularError(vec3 actual, vec3 expected) {
        // Ensure both vectors are normalized
        actual = actual.normalize();
        expected = expected.normalize();
 
        // Calculate dot product and clamp to valid range for acos
        float dot = std::max(-1.0f, std::min(1.0f, actual * expected));
        return acosf(dot);
    }
 
    std::vector<uint> createSymmetricTwinGaps(Context *context, float gap_separation, float gap_width, float wall_distance = 3.0f) {
        std::vector<uint> uuids;
        float half_separation = gap_separation * 0.5f;
 
        // Create left gap
        auto left_wall = createParallelWallsWithGap(context, make_vec3(-half_separation, 0, 0), gap_width, 2.0f, wall_distance);
        uuids.insert(uuids.end(), left_wall.begin(), left_wall.end());
 
        // Create right gap
        auto right_wall = createParallelWallsWithGap(context, make_vec3(half_separation, 0, 0), gap_width, 2.0f, wall_distance);
        uuids.insert(uuids.end(), right_wall.begin(), right_wall.end());
 
        return uuids;
    }
 
} // namespace CollisionTests
 
DOCTEST_TEST_CASE("CollisionDetection Plugin Initialization") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test basic initialization
    DOCTEST_CHECK_NOTHROW(collision.disableMessages());
    DOCTEST_CHECK_NOTHROW(collision.enableMessages());
    collision.disableMessages(); // Re-disable to suppress subsequent output
 
    // Test GPU acceleration capabilities based on actual hardware availability
    try {
        // Try to enable GPU acceleration and see if it actually works (capture any warnings)
        bool gpu_enabled;
        {
            helios::capture_cerr capture;
            collision.enableGPUAcceleration();
            gpu_enabled = collision.isGPUAccelerationEnabled();
        } // Capture destroyed before assertions
 
        // Create minimal test geometry to verify GPU functionality
        uint test_uuid = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
        collision.buildBVH();
 
        // If we reach here without exception, GPU may be available
        DOCTEST_INFO("GPU acceleration capability test - actual hardware dependent");
        if (gpu_enabled) {
            DOCTEST_WARN("GPU acceleration is available and enabled on this system");
        } else {
            DOCTEST_WARN("GPU acceleration requested but not available - using CPU fallback");
        }
 
        // Test that we can successfully disable GPU acceleration
        DOCTEST_CHECK_NOTHROW(collision.disableGPUAcceleration());
        DOCTEST_CHECK(collision.isGPUAccelerationEnabled() == false);
 
    } catch (std::exception &e) {
        // GPU initialization failure is acceptable - GPU may not be available
        DOCTEST_WARN((std::string("GPU acceleration test failed (expected on non-NVIDIA systems): ") + e.what()).c_str());
 
        // Ensure CPU mode works regardless
        DOCTEST_CHECK_NOTHROW(collision.disableGPUAcceleration());
        DOCTEST_CHECK(collision.isGPUAccelerationEnabled() == false);
    }
}
 
 
DOCTEST_TEST_CASE("CollisionDetection GPU Availability Query") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // isGPUAvailable() must not throw and must be deterministic across calls.
    bool available_first = false;
    DOCTEST_CHECK_NOTHROW(available_first = CollisionDetection::isGPUAvailable());
    bool available_second = CollisionDetection::isGPUAvailable();
    DOCTEST_CHECK(available_first == available_second);
 
    // Enabling GPU acceleration succeeds if and only if a usable GPU is available.
    {
        helios::capture_cerr capture; // suppress the no-GPU warning on CPU-only systems
        collision.enableGPUAcceleration();
    }
    DOCTEST_CHECK(collision.isGPUAccelerationEnabled() == available_first);
 
    // Disabling always lands in CPU mode regardless of availability.
    DOCTEST_CHECK_NOTHROW(collision.disableGPUAcceleration());
    DOCTEST_CHECK(collision.isGPUAccelerationEnabled() == false);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection BVH Construction") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create some simple triangles
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
    uint UUID2 = context.addTriangle(make_vec3(2, -1, 0), make_vec3(4, -1, 0), make_vec3(3, 1, 0));
    uint UUID3 = context.addTriangle(make_vec3(-0.5, -0.5, 1), make_vec3(1.5, -0.5, 1), make_vec3(0.5, 1.5, 1));
 
    // Build BVH
    collision.buildBVH();
 
    DOCTEST_CHECK(collision.isBVHValid() == true);
    DOCTEST_CHECK(collision.getPrimitiveCount() == 3);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Basic Collision Detection") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration(); // Use CPU for deterministic results
 
    // Create overlapping triangles
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
    uint UUID2 = context.addTriangle(make_vec3(-0.5, -0.5, 0), make_vec3(1.5, -0.5, 0), make_vec3(0.5, 1.5, 0));
 
    // Create non-overlapping triangle
    uint UUID3 = context.addTriangle(make_vec3(10, -1, 0), make_vec3(11, -1, 0), make_vec3(10.5, 1, 0));
 
    collision.buildBVH();
 
    // Test collision between overlapping triangles
    std::vector<uint> collisions1 = collision.findCollisions(UUID1);
 
    // UUID1 should collide with UUID2 but not UUID3
    bool found_UUID2 = std::find(collisions1.begin(), collisions1.end(), UUID2) != collisions1.end();
    bool found_UUID3 = std::find(collisions1.begin(), collisions1.end(), UUID3) != collisions1.end();
 
    DOCTEST_CHECK(found_UUID2 == true);
    DOCTEST_CHECK(found_UUID3 == false);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection BVH Statistics") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create a larger set of primitives
    for (int i = 0; i < 20; i++) {
        context.addTriangle(make_vec3(i, -1, 0), make_vec3(i + 1, -1, 0), make_vec3(i + 0.5f, 1, 0));
    }
 
    collision.buildBVH();
 
    size_t node_count, leaf_count, max_depth;
    collision.getBVHStatistics(node_count, leaf_count, max_depth);
 
    DOCTEST_CHECK(node_count > 0);
    DOCTEST_CHECK(leaf_count > 0);
    // Small geometry sets may result in single leaf (depth 0) which is valid optimization
    DOCTEST_CHECK(max_depth >= 0);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Empty Geometry Handling") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Try to build BVH with no primitives
    collision.buildBVH();
 
    // Should handle gracefully
    DOCTEST_CHECK(collision.getPrimitiveCount() == 0);
 
    // Try collision detection with empty BVH
    std::vector<uint> collisions = collision.findCollisions(std::vector<uint>{});
 
    DOCTEST_CHECK(collisions.empty() == true);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Invalid UUID Handling") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
 
    // Try collision detection with invalid UUID - should throw std::runtime_error
    DOCTEST_CHECK_THROWS_AS(collision.findCollisions(999999), std::runtime_error);
 
    // Also verify the exception message contains relevant information
    try {
        collision.findCollisions(999999);
        DOCTEST_FAIL("Expected exception was not thrown");
    } catch (const std::runtime_error &e) {
        std::string error_msg = e.what();
        bool has_relevant_content = error_msg.find("UUID") != std::string::npos || error_msg.find("invalid") != std::string::npos;
        DOCTEST_CHECK(has_relevant_content);
    }
}
 
 
DOCTEST_TEST_CASE("CollisionDetection GPU/CPU Mode Switching") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
    uint UUID2 = context.addTriangle(make_vec3(-0.5, -0.5, 0), make_vec3(1.5, -0.5, 0), make_vec3(0.5, 1.5, 0));
 
    collision.buildBVH();
 
    // Test with GPU enabled (capture any warnings)
    std::vector<uint> gpu_results;
    {
        helios::capture_cerr capture;
        collision.enableGPUAcceleration();
        gpu_results = collision.findCollisions(UUID1);
    }
 
    // Test with GPU disabled
    collision.disableGPUAcceleration();
    std::vector<uint> cpu_results = collision.findCollisions(UUID1);
 
    // Results should be equivalent (though may be in different order)
    std::sort(gpu_results.begin(), gpu_results.end());
    std::sort(cpu_results.begin(), cpu_results.end());
 
    DOCTEST_CHECK(gpu_results == cpu_results);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Null Context Error Handling") {
    // Should throw std::runtime_error when context is null
    DOCTEST_CHECK_THROWS_AS(CollisionDetection collision(nullptr), std::runtime_error);
 
    // Also verify the exception message contains relevant information
    try {
        CollisionDetection collision(nullptr);
        DOCTEST_FAIL("Expected exception was not thrown");
    } catch (const std::runtime_error &e) {
        std::string error_msg = e.what();
        bool has_relevant_content = error_msg.find("context") != std::string::npos || error_msg.find("Context") != std::string::npos || error_msg.find("null") != std::string::npos;
        DOCTEST_CHECK(has_relevant_content);
    }
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Invalid UUIDs in BuildBVH") {
    Context context;
 
    // Suppress all initialization messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Try to build BVH with invalid UUIDs - should throw std::runtime_error
    std::vector<uint> invalid_UUIDs = {999999, 888888};
 
    DOCTEST_CHECK_THROWS_AS(collision.buildBVH(invalid_UUIDs), std::runtime_error);
 
    // Also verify the exception message contains relevant information
    try {
        collision.buildBVH(invalid_UUIDs);
        DOCTEST_FAIL("Expected exception was not thrown");
    } catch (const std::runtime_error &e) {
        std::string error_msg = e.what();
        bool has_relevant_content = error_msg.find("UUID") != std::string::npos || error_msg.find("invalid") != std::string::npos;
        DOCTEST_CHECK(has_relevant_content);
    }
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Primitive/Object Collision Detection") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create some primitives
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
    uint UUID2 = context.addTriangle(make_vec3(-0.5, -0.5, 0), make_vec3(1.5, -0.5, 0), make_vec3(0.5, 1.5, 0));
 
    // Create a compound object
    uint objID = context.addTileObject(make_vec3(0, 0, 1), make_vec2(2, 2), make_SphericalCoord(0, 0), make_int2(1, 1));
 
    collision.buildBVH();
 
    // Test mixed primitive/object collision detection
    std::vector<uint> primitive_UUIDs = {UUID1};
    std::vector<uint> object_IDs = {objID};
 
    DOCTEST_CHECK_NOTHROW(collision.findCollisions(primitive_UUIDs, object_IDs));
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Empty Input Handling") {
    Context context;
 
    // Suppress all initialization messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test empty primitive vector
    std::vector<uint> empty_primitives;
    std::vector<uint> collisions1 = collision.findCollisions(empty_primitives);
 
    // Test empty mixed input
    std::vector<uint> empty_objects;
    std::vector<uint> collisions2 = collision.findCollisions(empty_primitives, empty_objects);
 
    DOCTEST_CHECK(collisions1.empty() == true);
    DOCTEST_CHECK(collisions2.empty() == true);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Invalid Object ID Error Handling") {
    Context context;
 
    // Suppress all initialization messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Try collision detection with invalid object ID - should throw std::runtime_error
    std::vector<uint> empty_primitives;
    std::vector<uint> invalid_objects = {999999};
 
    DOCTEST_CHECK_THROWS_AS(collision.findCollisions(empty_primitives, invalid_objects), std::runtime_error);
 
    // Also verify the exception message contains relevant information
    try {
        collision.findCollisions(empty_primitives, invalid_objects);
        DOCTEST_FAIL("Expected exception was not thrown");
    } catch (const std::runtime_error &e) {
        std::string error_msg = e.what();
        bool has_relevant_content = error_msg.find("object") != std::string::npos || error_msg.find("Object") != std::string::npos || error_msg.find("999999") != std::string::npos || error_msg.find("exist") != std::string::npos ||
                                    error_msg.find("invalid") != std::string::npos;
        DOCTEST_CHECK(has_relevant_content);
    }
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Manual BVH Rebuild") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create initial geometry
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
    collision.buildBVH();
 
    size_t initial_count = collision.getPrimitiveCount();
 
    // Add more geometry
    uint UUID2 = context.addTriangle(make_vec3(2, -1, 0), make_vec3(4, -1, 0), make_vec3(3, 1, 0));
 
    // Force rebuild
    collision.rebuildBVH();
 
    size_t final_count = collision.getPrimitiveCount();
 
    DOCTEST_CHECK(final_count == 2);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Message Control") {
    Context context;
 
    // Suppress initialization messages (we're testing message control itself)
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test message disabling/enabling
    DOCTEST_CHECK_NOTHROW(collision.disableMessages());
    DOCTEST_CHECK_NOTHROW(collision.enableMessages());
    collision.disableMessages(); // Re-disable to suppress subsequent output
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Large Geometry Handling") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create many primitives to stress test BVH
    for (int i = 0; i < 50; i++) {
        context.addTriangle(make_vec3(i, -1, 0), make_vec3(i + 1, -1, 0), make_vec3(i + 0.5f, 1, 0));
    }
 
    collision.buildBVH();
 
    // Test collision detection with large BVH
    uint UUID = context.getAllUUIDs()[0];
    std::vector<uint> collisions = collision.findCollisions(UUID);
 
    // Verify BVH statistics make sense
    size_t node_count, leaf_count, max_depth;
    collision.getBVHStatistics(node_count, leaf_count, max_depth);
 
    DOCTEST_CHECK(collision.getPrimitiveCount() == 50);
    DOCTEST_CHECK(node_count > 0);
    // Small geometry sets may result in single leaf (depth 0) which is valid optimization
    DOCTEST_CHECK(max_depth >= 0);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Single Primitive Edge Case") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create single primitive
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
 
    collision.buildBVH();
 
    // Test collision with itself (should return empty since self is removed)
    std::vector<uint> collisions = collision.findCollisions(UUID1);
 
    // Verify BVH handles single primitive correctly
    size_t node_count, leaf_count, max_depth;
    collision.getBVHStatistics(node_count, leaf_count, max_depth);
 
    DOCTEST_CHECK(collision.getPrimitiveCount() == 1);
    DOCTEST_CHECK(collision.isBVHValid() == true);
}
 
DOCTEST_TEST_CASE("CollisionDetection Texture Transparency Rejection") {
    // A ray that strikes a transparent texel of a textured primitive must pass through (miss),
    // while a ray striking an opaque texel must register a hit. disk_texture.png is a solid disk
    // (opaque center, transparent corners) so the center is solid and the corners are transparent.
    const char *texture = "lib/images/disk_texture.png";
 
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // 2x2 patch in the z=0 plane centered at the origin, textured with the disk.
    uint patch = context.addPatch(make_vec3(0, 0, 0), make_vec2(2, 2), nullrotation, texture);
    DOCTEST_CHECK(context.primitiveTextureHasTransparencyChannel(patch));
 
    collision.buildBVH();
 
    // Ray straight down through the center of the patch -> opaque texel -> HIT.
    CollisionDetection::HitResult center_hit = collision.castRay(CollisionDetection::RayQuery(make_vec3(0, 0, 5), make_vec3(0, 0, -1), 10.0f));
    DOCTEST_CHECK(center_hit.hit == true);
    DOCTEST_CHECK(center_hit.primitive_UUID == patch);
    DOCTEST_CHECK(center_hit.distance == doctest::Approx(5.0f));
 
    // Ray straight down through a corner of the patch -> transparent texel -> MISS (passes through).
    CollisionDetection::HitResult corner_hit = collision.castRay(CollisionDetection::RayQuery(make_vec3(0.95f, 0.95f, 5), make_vec3(0, 0, -1), 10.0f));
    DOCTEST_CHECK(corner_hit.hit == false);
 
    // A second, opaque patch placed behind the transparent corner must be hit through the gap,
    // confirming the ray continues past the transparent texel rather than terminating.
    uint backing = context.addPatch(make_vec3(0.95f, 0.95f, -2), make_vec2(1, 1));
    collision.buildBVH();
    CollisionDetection::HitResult through_hit = collision.castRay(CollisionDetection::RayQuery(make_vec3(0.95f, 0.95f, 5), make_vec3(0, 0, -1), 10.0f));
    DOCTEST_CHECK(through_hit.hit == true);
    DOCTEST_CHECK(through_hit.primitive_UUID == backing);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Overlapping AABB Primitives") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create primitives with overlapping AABBs
    // These triangles are tilted so their AABBs will overlap in Z
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0.2f));
    uint UUID2 = context.addTriangle(make_vec3(-1, -1, 0.1f), make_vec3(1, -1, 0.1f), make_vec3(0, 1, -0.1f));
 
    collision.buildBVH();
 
    // These should collide (overlapping AABBs)
    std::vector<uint> collisions = collision.findCollisions(UUID1);
 
    bool found_collision = std::find(collisions.begin(), collisions.end(), UUID2) != collisions.end();
 
    DOCTEST_CHECK(found_collision == true);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection BVH Validity Persistence") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Initially invalid (no BVH built)
    DOCTEST_CHECK(collision.isBVHValid() == false);
 
    // Create geometry and build
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
    collision.buildBVH();
 
    // Should be valid after building
    DOCTEST_CHECK(collision.isBVHValid() == true);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Soft/Hard Detection Integration - BVH Sharing") {
    Context context;
 
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create test geometry - obstacle and some primitives for "soft" collision testing
    uint obstacle = context.addPatch(make_vec3(0, 0, 1), make_vec2(2, 2)); // Obstacle at height 1m
    uint soft_prim1 = context.addTriangle(make_vec3(-0.5, -0.5, 0.5), make_vec3(0.5, -0.5, 0.5), make_vec3(0, 0.5, 0.5)); // Below obstacle
    uint soft_prim2 = context.addTriangle(make_vec3(-1.5, -1.5, 1.5), make_vec3(-0.5, -1.5, 1.5), make_vec3(-1, -0.5, 1.5)); // Above obstacle
 
    // Build BVH with all geometry for initial soft collision detection
    std::vector<uint> all_geometry = {obstacle, soft_prim1, soft_prim2};
    collision.buildBVH(all_geometry);
 
    // Verify initial BVH state
    DOCTEST_CHECK(collision.isBVHValid() == true);
    size_t initial_node_count, initial_leaf_count, initial_max_depth;
    collision.getBVHStatistics(initial_node_count, initial_leaf_count, initial_max_depth);
 
    // Simulate soft collision detection (standard findCollisions)
    std::vector<uint> soft_collisions = collision.findCollisions({soft_prim1, soft_prim2});
    bool soft_detection_completed = true; // Mark that soft detection has run
 
    // Now test hard detection using the same BVH
    vec3 test_origin = make_vec3(0, 0, 0.5);
    vec3 test_direction = make_vec3(0, 0, 1); // Pointing up toward obstacle
    float distance;
    vec3 obstacle_direction;
 
    // This should use the SAME BVH that was built for soft detection
    bool hard_hit = collision.findNearestSolidObstacleInCone(test_origin, test_direction, 0.52f, 1.0f, {obstacle}, distance, obstacle_direction);
 
    // Verify both detections work correctly despite sharing BVH
    DOCTEST_CHECK(soft_detection_completed == true);
    DOCTEST_CHECK(hard_hit == true);
    DOCTEST_CHECK(distance < 1.0f); // Should detect obstacle before 1m
 
    // Verify BVH state wasn't corrupted by interleaved usage
    size_t final_node_count, final_leaf_count, final_max_depth;
    collision.getBVHStatistics(final_node_count, final_leaf_count, final_max_depth);
 
    DOCTEST_CHECK(initial_node_count == final_node_count);
    DOCTEST_CHECK(initial_leaf_count == final_leaf_count);
    DOCTEST_CHECK(collision.isBVHValid() == true);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Soft/Hard Detection Integration - Sequential Calls") {
    Context context;
 
    CollisionDetection collision(&context);
    collision.disableMessages(); // Suppress console output during testing
    collision.disableGPUAcceleration();
 
    // Create a more complex scene
    uint ground = context.addPatch(make_vec3(0, 0, 0), make_vec2(4, 4));
    uint wall = context.addPatch(make_vec3(1, 0, 0.5), make_vec2(0.1, 2), make_SphericalCoord(0.5 * M_PI, 0.5 * M_PI)); // Vertical wall
    uint plant_stem = context.addTriangle(make_vec3(-0.02, 0, 0), make_vec3(0.02, 0, 0), make_vec3(0, 0, 0.8));
 
    std::vector<uint> all_obstacles = {ground, wall};
    std::vector<uint> plant_parts = {plant_stem};
 
    collision.buildBVH(all_obstacles);
 
    // Test 1: Soft collision detection between plant and obstacles
    std::vector<uint> soft_collisions = collision.findCollisions(plant_parts, {}, all_obstacles, {});
 
    // Test 2: Hard detection for plant growth (cone-based)
    vec3 growth_tip = make_vec3(0, 0, 0.8);
    vec3 growth_direction = make_vec3(0.5, 0, 0.2); // Angled toward wall
    growth_direction.normalize();
 
 
    float distance;
    vec3 obstacle_direction;
    bool hard_hit = collision.findNearestSolidObstacleInCone(growth_tip, growth_direction, 0.35f, 2.0f, // Increased height to 2.0m
                                                             all_obstacles, distance, obstacle_direction);
 
    // Test 3: Repeat soft detection to ensure no state corruption
    std::vector<uint> soft_collisions_2 = collision.findCollisions(plant_parts, {}, all_obstacles, {});
 
    // Test 4: Repeat hard detection with different parameters
    vec3 growth_direction_2 = make_vec3(-0.3, 0, 0.3);
    growth_direction_2.normalize();
 
    bool hard_hit_2 = collision.findNearestSolidObstacleInCone(growth_tip, growth_direction_2, 0.35f, 0.5f, all_obstacles, distance, obstacle_direction);
 
    // Verify consistency - repeated calls should give same results
    DOCTEST_CHECK(soft_collisions.size() == soft_collisions_2.size());
    DOCTEST_CHECK(hard_hit == true); // Should detect wall
    DOCTEST_CHECK(collision.isBVHValid() == true);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Soft/Hard Detection Integration - Different Geometry Sets") {
    Context context;
 
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create separate geometry sets for soft and hard detection
    uint hard_obstacle_1 = context.addPatch(make_vec3(1, 0, 1), make_vec2(1, 1)); // For hard detection only
    uint hard_obstacle_2 = context.addPatch(make_vec3(-1, 0, 1), make_vec2(1, 1)); // For hard detection only
 
    uint soft_object_1 = context.addTriangle(make_vec3(0, 1, 1.0), make_vec3(0.5, 1.5, 1.0), make_vec3(-0.5, 1.5, 1.0)); // For soft detection only
    uint soft_object_2 = context.addTriangle(make_vec3(0, -1, 0.5), make_vec3(0.5, -1.5, 0.5), make_vec3(-0.5, -1.5, 0.5)); // For soft detection only
 
    uint shared_object = context.addPatch(make_vec3(0, 0, 2), make_vec2(0.5, 0.5)); // Used by both detection types
 
    // Build BVH with ALL geometry (this is typical in plant architecture)
    std::vector<uint> all_geometry = {hard_obstacle_1, hard_obstacle_2, soft_object_1, soft_object_2, shared_object};
    collision.buildBVH(all_geometry);
 
    // Test hard detection using only hard obstacles
    vec3 test_origin = make_vec3(0, 0, 0.5);
    vec3 test_direction = make_vec3(1, 0, 0.3); // Toward hard_obstacle_1
    test_direction.normalize();
 
    std::vector<uint> hard_only = {hard_obstacle_1, hard_obstacle_2, shared_object};
    float distance;
    vec3 obstacle_direction;
 
    bool hard_hit = collision.findNearestSolidObstacleInCone(test_origin, test_direction, 0.4f, 2.0f, hard_only, distance, obstacle_direction);
 
    // Test soft detection using only soft objects
    std::vector<uint> soft_only = {soft_object_1, soft_object_2, shared_object};
    std::vector<uint> soft_collisions = collision.findCollisions(soft_only);
 
    // Test with mixed queries to ensure BVH handles subset filtering correctly
    vec3 test_direction_2 = make_vec3(0, 1, 0.3); // Toward soft_object_1
    test_direction_2.normalize();
 
    bool hard_hit_2 = collision.findNearestSolidObstacleInCone(test_origin, test_direction_2, 0.4f, 10.0f, // Very generous height for detection
                                                               soft_only, distance, obstacle_direction); // Using soft objects for hard detection
 
    // Verify that detection works correctly with different geometry subsets
    DOCTEST_CHECK(hard_hit == true); // Should detect hard obstacle
    DOCTEST_CHECK(hard_hit_2 == true); // Should also detect soft object when used as hard obstacle
    DOCTEST_CHECK(collision.isBVHValid() == true);
 
    // Verify BVH efficiency - primitive count should match total geometry
    DOCTEST_CHECK(collision.getPrimitiveCount() == all_geometry.size());
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Soft/Hard Detection Integration - BVH Rebuild Behavior") {
    Context context;
 
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Initial geometry
    uint obstacle1 = context.addPatch(make_vec3(0, 0, 1), make_vec2(1, 1));
    std::vector<uint> initial_geometry = {obstacle1};
 
    collision.buildBVH(initial_geometry);
 
    // Test initial state
    vec3 test_origin = make_vec3(0, 0, 0.5);
    vec3 test_direction = make_vec3(0, 0, 1);
    float distance;
    vec3 obstacle_direction;
 
    bool hit_initial = collision.findNearestSolidObstacleInCone(test_origin, test_direction, 0.3f, 1.0f, initial_geometry, distance, obstacle_direction);
 
    // Add more geometry (this might trigger BVH rebuild internally)
    uint obstacle2 = context.addPatch(make_vec3(1, 1, 1), make_vec2(1, 1));
    uint obstacle3 = context.addPatch(make_vec3(-1, -1, 1), make_vec2(1, 1));
 
    std::vector<uint> expanded_geometry = {obstacle1, obstacle2, obstacle3};
 
    // This should trigger a BVH rebuild
    collision.buildBVH(expanded_geometry);
 
    // Test that both detection methods still work after rebuild
    std::vector<uint> soft_collisions = collision.findCollisions(expanded_geometry);
 
    bool hit_after_rebuild = collision.findNearestSolidObstacleInCone(test_origin, test_direction, 0.3f, 1.0f, expanded_geometry, distance, obstacle_direction);
 
    // Test detection with different geometry subset after rebuild
    vec3 test_direction_2 = make_vec3(1, 1, 0.2);
    test_direction_2.normalize();
 
    bool hit_subset = collision.findNearestSolidObstacleInCone(test_origin, test_direction_2, 0.5f, 2.0f, {obstacle2}, distance, obstacle_direction); // Only test against obstacle2
 
    // Verify all detection methods work correctly after BVH rebuild
    DOCTEST_CHECK(hit_initial == true);
    DOCTEST_CHECK(hit_after_rebuild == true);
    DOCTEST_CHECK(hit_subset == true);
    DOCTEST_CHECK(collision.isBVHValid() == true);
    DOCTEST_CHECK(collision.getPrimitiveCount() == expanded_geometry.size());
}
 
 
DOCTEST_TEST_CASE("CollisionDetection GPU Acceleration") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test geometry
    for (int i = 0; i < 5; i++) {
        context.addTriangle(make_vec3(i, -1, 0), make_vec3(i + 1, -1, 0), make_vec3(i + 0.5f, 1, 0));
    }
 
    // Test GPU vs CPU equivalence (if GPU available)
    try {
        collision.disableGPUAcceleration();
        collision.buildBVH();
        uint UUID = context.getAllUUIDs()[0];
        std::vector<uint> cpu_results = collision.findCollisions(UUID);
 
        std::vector<uint> gpu_results;
        {
            helios::capture_cerr capture;
            collision.enableGPUAcceleration();
            collision.buildBVH(); // This should transfer to GPU
            gpu_results = collision.findCollisions(UUID);
        } // Capture destroyed before assertions
 
        // Compare results (allowing for different orders)
        std::sort(cpu_results.begin(), cpu_results.end());
        std::sort(gpu_results.begin(), gpu_results.end());
 
        // Check if results match (GPU may not be available, so we use INFO instead of CHECK)
        DOCTEST_INFO("GPU/CPU result comparison - GPU may not be available on this system");
        if (cpu_results.size() == gpu_results.size()) {
            bool results_match = true;
            for (size_t i = 0; i < cpu_results.size(); i++) {
                if (cpu_results[i] != gpu_results[i]) {
                    results_match = false;
                    break;
                }
            }
            // Only warn if results don't match - this is acceptable if no GPU
            if (!results_match) {
                DOCTEST_WARN("GPU/CPU results differ - may be expected if no CUDA device");
            }
        }
    } catch (std::exception &e) {
        // GPU test failure is acceptable - GPU may not be available
        DOCTEST_WARN((std::string("GPU test failed (may be expected): ") + e.what()).c_str());
    }
}
 
 
DOCTEST_TEST_CASE("CollisionDetection GPU/CPU Message Display") {
    Context context;
 
    // Suppress initialization message, then create collision detection object and test geometry
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
    uint UUID2 = context.addTriangle(make_vec3(-0.5, -0.5, 0), make_vec3(1.5, -0.5, 0), make_vec3(0.5, 1.5, 0));
    collision.buildBVH(); // Build once to avoid BVH construction messages later
 
    // Test that messages are displayed when enabled
    collision.enableMessages();
    collision.disableGPUAcceleration();
 
    // Capture traversal messages using capture_cout (these are the specific messages we want to test)
    std::string cpu_output;
    std::vector<uint> cpu_results;
    {
        helios::capture_cout capture_cpu;
        cpu_results = collision.findCollisions(UUID1);
        cpu_output = capture_cpu.get_captured_output();
    } // capture destroyed here
 
    // Check that some CPU message was displayed (the exact message may vary)
    // DOCTEST_INFO("CPU output: " << cpu_output);
    // For now, just check that collision detection worked (test is mainly about message suppression)
    DOCTEST_CHECK(true); // Placeholder - the main goal is testing message suppression below
 
    // Test GPU message (if available)
    std::string gpu_output;
    std::vector<uint> gpu_results;
    {
        helios::capture_cerr capture_err;
        helios::capture_cout capture_gpu;
        collision.enableGPUAcceleration();
        gpu_results = collision.findCollisions(UUID1);
        gpu_output = capture_gpu.get_captured_output();
    } // Capture destroyed before assertions
 
    // Should contain either GPU or CPU message depending on availability
    // For now, just check basic functionality (the main test is message suppression below)
    DOCTEST_CHECK(true); // Placeholder - the main goal is testing message suppression below
 
    // Test message suppression
    collision.disableMessages();
 
    std::string silent_output;
    std::vector<uint> silent_results;
    {
        helios::capture_cout capture_silent;
        silent_results = collision.findCollisions(UUID1);
        silent_output = capture_silent.get_captured_output();
    } // capture destroyed here
 
    // Should not contain traversal messages when disabled
    DOCTEST_CHECK(silent_output.find("Using GPU acceleration") == std::string::npos);
    DOCTEST_CHECK(silent_output.find("Using CPU traversal") == std::string::npos);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Automatic BVH Building") {
    Context context;
 
    // Suppress all initialization and automatic BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration(); // Use CPU for predictable behavior
 
    // Create initial geometry
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
 
    // BVH should be invalid initially (not built)
    DOCTEST_CHECK(collision.isBVHValid() == false);
 
    // Calling findCollisions should automatically build BVH
    std::vector<uint> results = collision.findCollisions(UUID1);
 
    // BVH should now be valid
    DOCTEST_CHECK(collision.isBVHValid() == true);
    DOCTEST_CHECK(collision.getPrimitiveCount() == 1);
 
    // Add more geometry and mark it dirty in context
    uint UUID2 = context.addTriangle(make_vec3(2, -1, 0), make_vec3(4, -1, 0), make_vec3(3, 1, 0));
 
    // BVH should now be invalid because there's a new primitive not in the BVH
    DOCTEST_CHECK(collision.isBVHValid() == false);
 
    // But calling findCollisions should detect the new geometry and rebuild
    results = collision.findCollisions(UUID1);
 
    // BVH should now include both primitives
    DOCTEST_CHECK(collision.getPrimitiveCount() == 2);
    DOCTEST_CHECK(collision.isBVHValid() == true);
 
    // Test that repeated calls don't unnecessarily rebuild
    size_t count_before = collision.getPrimitiveCount();
    results = collision.findCollisions(UUID1);
    size_t count_after = collision.getPrimitiveCount();
 
    // Should be the same (no unnecessary rebuild)
    DOCTEST_CHECK(count_before == count_after);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Restricted Geometry - UUIDs Only") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create test geometry: 3 overlapping triangles
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
    uint UUID2 = context.addTriangle(make_vec3(-0.5, -0.5, 0), make_vec3(1.5, -0.5, 0), make_vec3(0.5, 1.5, 0));
    // UUID3 overlaps in z-dimension to ensure AABB collision
    uint UUID3 = context.addTriangle(make_vec3(-0.5, -0.5, -0.1f), make_vec3(1.5, -0.5, -0.1f), make_vec3(0.5, 1.5, 0.1f));
 
    // Test unrestricted collision detection (should find all collisions)
    std::vector<uint> all_results = collision.findCollisions(UUID1);
 
    // UUID1 should collide with both UUID2 and UUID3
    bool found_UUID2_all = std::find(all_results.begin(), all_results.end(), UUID2) != all_results.end();
    bool found_UUID3_all = std::find(all_results.begin(), all_results.end(), UUID3) != all_results.end();
 
    DOCTEST_CHECK(found_UUID2_all == true);
    DOCTEST_CHECK(found_UUID3_all == true);
 
    // Test restricted collision detection - only target UUID2
    std::vector<uint> query_UUIDs = {UUID1};
    std::vector<uint> query_objects = {};
    std::vector<uint> target_UUIDs = {UUID2}; // Only target UUID2
    std::vector<uint> target_objects = {};
 
    std::vector<uint> restricted_results = collision.findCollisions(query_UUIDs, query_objects, target_UUIDs, target_objects);
 
    // Should only find collision with UUID2, not UUID3
    bool found_UUID2_restricted = std::find(restricted_results.begin(), restricted_results.end(), UUID2) != restricted_results.end();
    bool found_UUID3_restricted = std::find(restricted_results.begin(), restricted_results.end(), UUID3) != restricted_results.end();
 
    DOCTEST_CHECK(found_UUID2_restricted == true);
    DOCTEST_CHECK(found_UUID3_restricted == false);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Restricted Geometry - Object IDs") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create individual primitives
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
 
    // Create compound objects
    uint objID1 = context.addTileObject(make_vec3(0, 0, 0.5f), make_vec2(2, 2), make_SphericalCoord(0, 0), make_int2(1, 1));
    uint objID2 = context.addTileObject(make_vec3(10, 0, 0), make_vec2(2, 2), make_SphericalCoord(0, 0), make_int2(1, 1));
 
    // Test collision detection restricted to specific object
    std::vector<uint> query_UUIDs = {UUID1};
    std::vector<uint> query_objects = {};
    std::vector<uint> target_UUIDs = {};
    std::vector<uint> target_objects = {objID1}; // Only target objID1
 
    DOCTEST_CHECK_NOTHROW(collision.findCollisions(query_UUIDs, query_objects, target_UUIDs, target_objects));
 
    // Test mixed UUID/Object ID restriction
    std::vector<uint> mixed_target_UUIDs = {UUID1};
    std::vector<uint> mixed_target_objects = {objID1};
 
    DOCTEST_CHECK_NOTHROW(collision.findCollisions(query_UUIDs, query_objects, mixed_target_UUIDs, mixed_target_objects));
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Restricted Geometry - Error Handling") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create valid geometry
    uint UUID1 = context.addTriangle(make_vec3(-1, -1, 0), make_vec3(1, -1, 0), make_vec3(0, 1, 0));
 
    // Test error handling for invalid query UUIDs - should throw std::runtime_error
    std::vector<uint> invalid_query_UUIDs = {999999};
    std::vector<uint> query_objects = {};
    std::vector<uint> valid_target_UUIDs = {UUID1};
    std::vector<uint> target_objects = {};
 
    DOCTEST_CHECK_THROWS_AS(collision.findCollisions(invalid_query_UUIDs, query_objects, valid_target_UUIDs, target_objects), std::runtime_error);
 
    // Test error handling for invalid target UUIDs - should throw std::runtime_error
    std::vector<uint> valid_query_UUIDs = {UUID1};
    std::vector<uint> invalid_target_UUIDs = {999999};
 
    DOCTEST_CHECK_THROWS_AS(collision.findCollisions(valid_query_UUIDs, query_objects, invalid_target_UUIDs, target_objects), std::runtime_error);
 
    // Test error handling for invalid query object IDs - should throw std::runtime_error
    std::vector<uint> invalid_query_objects = {999999};
 
    DOCTEST_CHECK_THROWS_AS(collision.findCollisions(valid_query_UUIDs, invalid_query_objects, valid_target_UUIDs, target_objects), std::runtime_error);
 
    // Test error handling for invalid target object IDs - should throw std::runtime_error
    std::vector<uint> invalid_target_objects = {999999};
 
    DOCTEST_CHECK_THROWS_AS(collision.findCollisions(valid_query_UUIDs, query_objects, valid_target_UUIDs, invalid_target_objects), std::runtime_error);
 
    // Additional verification - test that the exception messages are meaningful
    try {
        collision.findCollisions(invalid_query_UUIDs, query_objects, valid_target_UUIDs, target_objects);
        DOCTEST_FAIL("Expected exception was not thrown");
    } catch (const std::runtime_error &e) {
        std::string error_msg = e.what();
        bool has_relevant_content = error_msg.find("UUID") != std::string::npos || error_msg.find("invalid") != std::string::npos;
        DOCTEST_CHECK(has_relevant_content);
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection findOptimalConePath Basic Functionality") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create a simple test scene with obstacles
    // Add a few triangles that will create obstacles in certain directions
    uint triangle1 = context.addTriangle(make_vec3(2, -1, -1), make_vec3(2, 1, -1), make_vec3(2, 0, 1));
    uint triangle2 = context.addTriangle(make_vec3(-2, -1, -1), make_vec3(-2, 1, -1), make_vec3(-2, 0, 1));
 
    // Test with cone pointing towards obstacles
    vec3 apex = make_vec3(0, 0, -5);
    vec3 central_axis = make_vec3(0, 0, 1); // Pointing toward obstacles
    float half_angle = M_PI / 4.0f; // 45 degrees
 
    // Test 1: Basic functionality with default parameters
    CollisionDetection::OptimalPathResult result = collision.findOptimalConePath(apex, central_axis, half_angle);
 
    DOCTEST_CHECK(result.direction.magnitude() > 0.9f); // Should be normalized
    DOCTEST_CHECK(result.direction.magnitude() < 1.1f);
    DOCTEST_CHECK(result.confidence >= 0.0f);
    DOCTEST_CHECK(result.confidence <= 1.0f);
    DOCTEST_CHECK(result.collisionCount >= 0);
}
 
DOCTEST_TEST_CASE("CollisionDetection findOptimalConePath Gap Detection") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test geometry with obstacles in a specific pattern
    // Add obstacle directly in front (along central axis)
    context.addTriangle(make_vec3(-0.5f, -0.5f, 0), make_vec3(0.5f, -0.5f, 0), make_vec3(0, 0.5f, 0));
    // Add fewer obstacles to the side (at an angle from central axis)
    context.addTriangle(make_vec3(3, -0.2f, 0), make_vec3(3, 0.2f, 0), make_vec3(3, 0, 0.5f));
 
    vec3 apex = make_vec3(0, 0, -2);
    vec3 central_axis = make_vec3(0, 0, 1); // Pointing toward main obstacle
    float half_angle = M_PI / 3.0f; // 60 degrees - wide cone
 
    // Test 1: Default behavior - should find optimal gap-based path
    CollisionDetection::OptimalPathResult gap_result = collision.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 64);
 
    // Test 2: Higher sample count for better gap detection
    CollisionDetection::OptimalPathResult dense_result = collision.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 256);
 
    // Test 3: Lower sample count
    CollisionDetection::OptimalPathResult sparse_result = collision.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 32);
 
    // Verify results are reasonable
    DOCTEST_CHECK(gap_result.direction.magnitude() > 0.9f);
    DOCTEST_CHECK(dense_result.direction.magnitude() > 0.9f);
    DOCTEST_CHECK(sparse_result.direction.magnitude() > 0.9f);
 
    // All should have valid confidence scores
    DOCTEST_CHECK(gap_result.confidence >= 0.0f);
    DOCTEST_CHECK(gap_result.confidence <= 1.0f);
    DOCTEST_CHECK(dense_result.confidence >= 0.0f);
    DOCTEST_CHECK(dense_result.confidence <= 1.0f);
    DOCTEST_CHECK(sparse_result.confidence >= 0.0f);
    DOCTEST_CHECK(sparse_result.confidence <= 1.0f);
 
    // Results should be valid directions
    float gap_deviation = acosf(std::max(-1.0f, std::min(1.0f, gap_result.direction * central_axis)));
    float dense_deviation = acosf(std::max(-1.0f, std::min(1.0f, dense_result.direction * central_axis)));
 
    DOCTEST_CHECK(gap_deviation >= 0.0f); // Should be valid angle
    DOCTEST_CHECK(dense_deviation >= 0.0f); // Should be valid angle
}
 
DOCTEST_TEST_CASE("CollisionDetection findOptimalConePath Edge Cases") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    vec3 apex = make_vec3(0, 0, 0);
    vec3 central_axis = make_vec3(0, 0, 1);
 
    // Test 1: Invalid parameters
    {
        // Zero samples
        CollisionDetection::OptimalPathResult result = collision.findOptimalConePath(apex, central_axis, M_PI / 4.0f, 0.0f, 0);
        DOCTEST_CHECK(result.direction * central_axis > 0.9f); // Should default to central axis
    }
 
    // Test 2: Zero half-angle
    {
        CollisionDetection::OptimalPathResult result = collision.findOptimalConePath(apex, central_axis, 0.0f, 0.0f, 16);
        DOCTEST_CHECK(result.direction * central_axis > 0.9f); // Should default to central axis
    }
 
    // Test 3: Empty scene (no geometry)
    {
        CollisionDetection::OptimalPathResult result = collision.findOptimalConePath(apex, central_axis, M_PI / 4.0f, 0.0f, 16);
        DOCTEST_CHECK(result.direction * central_axis > 0.9f); // Should prefer central axis
        DOCTEST_CHECK(result.collisionCount == 0); // No collisions in empty scene
        DOCTEST_CHECK(result.confidence == 1.0f); // High confidence with no obstacles
    }
 
    // Test 4: Single sample
    {
        // Add some geometry
        context.addTriangle(make_vec3(-1, -1, 1), make_vec3(1, -1, 1), make_vec3(0, 1, 1));
 
        CollisionDetection::OptimalPathResult result = collision.findOptimalConePath(apex, central_axis, M_PI / 4.0f, 0.0f, 1);
        DOCTEST_CHECK(result.direction.magnitude() > 0.9f); // Should be normalized
        DOCTEST_CHECK(result.confidence == 1.0f); // Perfect confidence with single sample
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Finite Cone Height") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create obstacles at different distances
    // Close obstacle
    context.addTriangle(make_vec3(-0.5f, -0.5f, 1), make_vec3(0.5f, -0.5f, 1), make_vec3(0, 0.5f, 1));
    // Far obstacle
    context.addTriangle(make_vec3(-0.5f, -0.5f, 5), make_vec3(0.5f, -0.5f, 5), make_vec3(0, 0.5f, 5));
 
    vec3 apex = make_vec3(0, 0, 0);
    vec3 central_axis = make_vec3(0, 0, 1);
    float half_angle = M_PI / 6.0f; // 30 degrees
 
    // Test 1: Short cone - should only see close obstacle
    CollisionDetection::OptimalPathResult short_result = collision.findOptimalConePath(apex, central_axis, half_angle, 2.0f, 16);
 
    // Test 2: Long cone - should see both obstacles
    CollisionDetection::OptimalPathResult long_result = collision.findOptimalConePath(apex, central_axis, half_angle, 10.0f, 16);
 
    // Both should produce valid results
    DOCTEST_CHECK(short_result.direction.magnitude() > 0.9f);
    DOCTEST_CHECK(long_result.direction.magnitude() > 0.9f);
    DOCTEST_CHECK(short_result.collisionCount >= 0);
    DOCTEST_CHECK(long_result.collisionCount >= 0);
}
 
// ================================================================
// ACCURACY TEST CASES FOR findOptimalConePath
// ================================================================
 
DOCTEST_TEST_CASE("CollisionDetection findOptimalConePath Accuracy - Single Gap Tests") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    vec3 apex = make_vec3(0, 0, -3);
    vec3 central_axis = make_vec3(0, 0, 1);
    float half_angle = M_PI / 4.0f; // 45 degrees
 
    // Test 1: Center gap - optimal path should point straight ahead
    {
        CollisionTests::createParallelWallsWithGap(&context, make_vec3(0, 0, 0), 1.0f, 2.0f, 3.0f);
 
        CollisionDetection::OptimalPathResult result = collision.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 128);
        vec3 expected_direction = CollisionTests::calculateGapCenterDirection(apex, make_vec3(0, 0, 3.0f));
        float angular_error = CollisionTests::measureAngularError(result.direction, expected_direction);
 
        DOCTEST_CHECK(result.direction.magnitude() > 0.9f);
        DOCTEST_CHECK(result.direction.magnitude() < 1.1f);
        DOCTEST_CHECK(angular_error < 0.1f); // Less than ~5.7 degrees
        DOCTEST_CHECK(result.confidence > 0.5f); // Should have reasonable confidence
    }
 
    // Test 2: Off-center gap - should point toward gap center
    {
        Context context_reset;
        CollisionDetection collision_reset(&context_reset);
        collision_reset.disableMessages();
 
        vec3 gap_center = make_vec3(0.5f, 0, 0);
        CollisionTests::createParallelWallsWithGap(&context_reset, gap_center, 0.8f, 2.0f, 3.0f);
 
        CollisionDetection::OptimalPathResult result = collision_reset.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 128);
        vec3 expected_direction = CollisionTests::calculateGapCenterDirection(apex, make_vec3(gap_center.x, gap_center.y, 3.0f));
        float angular_error = CollisionTests::measureAngularError(result.direction, expected_direction);
 
        DOCTEST_CHECK(angular_error < 0.15f); // Less than ~8.6 degrees
        DOCTEST_CHECK(result.confidence > 0.3f);
    }
 
    // Test 3: Narrow gap - should still find it but with lower confidence
    {
        Context context_reset;
        CollisionDetection collision_reset(&context_reset);
        collision_reset.disableMessages();
 
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(0, 0, 0), 0.3f, 2.0f, 3.0f);
 
        CollisionDetection::OptimalPathResult result = collision_reset.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 256);
        vec3 expected_direction = CollisionTests::calculateGapCenterDirection(apex, make_vec3(0, 0, 3.0f));
        float angular_error = CollisionTests::measureAngularError(result.direction, expected_direction);
 
        DOCTEST_CHECK(angular_error < 0.2f); // Less than ~11.5 degrees (more tolerance for narrow gap)
        DOCTEST_CHECK(result.confidence >= 0.0f); // Valid confidence
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection findOptimalConePath Accuracy - Symmetric Twin Gaps") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    vec3 apex = make_vec3(0, 0, -3);
    vec3 central_axis = make_vec3(0, 0, 1);
    float half_angle = M_PI / 3.0f; // 60 degrees - wide enough to see both gaps
 
    // Test 1: Identical gaps equidistant from center - should prefer center alignment
    {
        CollisionTests::createSymmetricTwinGaps(&context, 2.0f, 0.8f, 3.0f);
 
        CollisionDetection::OptimalPathResult result = collision.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 256);
 
        // Should prefer the more centrally aligned solution
        float deviation_from_center = fabsf(acosf(std::max(-1.0f, std::min(1.0f, result.direction * central_axis))));
        DOCTEST_CHECK(deviation_from_center < M_PI / 6.0f); // Less than 30 degrees from center
        DOCTEST_CHECK(result.confidence > 0.4f);
    }
 
    // Test 2: Different sized gaps - should prefer larger gap
    {
        Context context_reset;
        CollisionDetection collision_reset(&context_reset);
        collision_reset.disableMessages();
 
        // Create small left gap and large right gap
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(-1.0f, 0, 0), 0.5f, 2.0f, 3.0f);
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(1.0f, 0, 0), 1.5f, 2.0f, 3.0f);
 
        CollisionDetection::OptimalPathResult result = collision_reset.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 256);
 
        // Should prefer the larger gap (right side)
        vec3 expected_direction = CollisionTests::calculateGapCenterDirection(apex, make_vec3(1.0f, 0, 3.0f));
        float angular_error = CollisionTests::measureAngularError(result.direction, expected_direction);
 
        DOCTEST_CHECK(angular_error < 0.3f); // Should point roughly toward larger gap
        DOCTEST_CHECK(result.confidence > 0.3f);
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection findOptimalConePath Accuracy - Angular Precision") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    vec3 apex = make_vec3(0, 0, -2);
    vec3 central_axis = make_vec3(0, 0, 1);
    float half_angle = M_PI / 4.0f; // 45 degrees
 
    // Test different gap positions at known angles
    struct TestCase {
        vec3 gap_position;
        float expected_angle_from_center; // in radians
        std::string description;
    };
 
    std::vector<TestCase> test_cases = {
            {make_vec3(0, 0, 0), 0.0f, "Center gap"},
            {make_vec3(0.5f, 0, 0), 0.245f, "15 degree gap"}, // atan(0.5/2) ≈ 0.245 rad
            {make_vec3(-0.7f, 0, 0), -0.334f, "Negative 19 degree gap"}, // atan(-0.7/2) ≈ -0.334 rad
            {make_vec3(0, 0.8f, 0), 0.381f, "Vertical 22 degree gap"} // atan(0.8/2) ≈ 0.381 rad
    };
 
    for (const auto &test_case: test_cases) {
        // Reset context for each test
        Context context_fresh;
        CollisionDetection collision_fresh(&context_fresh);
        collision_fresh.disableMessages();
 
        // Create gap at specific position
        CollisionTests::createParallelWallsWithGap(&context_fresh, test_case.gap_position, 0.6f, 2.0f, 2.0f);
 
        CollisionDetection::OptimalPathResult result = collision_fresh.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 512);
 
        // Calculate expected direction
        vec3 gap_center_3d = make_vec3(test_case.gap_position.x, test_case.gap_position.y, 2.0f);
        vec3 expected_direction = CollisionTests::calculateGapCenterDirection(apex, gap_center_3d);
        float angular_error = CollisionTests::measureAngularError(result.direction, expected_direction);
 
        // Verify angular accuracy
        DOCTEST_CHECK_MESSAGE(angular_error < 0.35f, test_case.description.c_str()); // Less than 20 degrees (realistic tolerance)
        DOCTEST_CHECK_MESSAGE(result.confidence > 0.1f, test_case.description.c_str());
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection findOptimalConePath Accuracy - Distance-Based Priority") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    vec3 apex = make_vec3(0, 0, -4);
    vec3 central_axis = make_vec3(0, 0, 1);
    float half_angle = M_PI / 3.0f; // 60 degrees
 
    // Test 1: Large far gap vs small near gap - fish-eye metric should prefer larger angular gap
    {
        // Near small gap (at distance 2.0)
        CollisionTests::createParallelWallsWithGap(&context, make_vec3(-1.0f, 0, 0), 0.4f, 2.0f, 2.0f);
 
        // Far large gap (at distance 6.0)
        CollisionTests::createParallelWallsWithGap(&context, make_vec3(1.0f, 0, 0), 2.0f, 2.0f, 6.0f);
 
        CollisionDetection::OptimalPathResult result = collision.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 256);
 
        // Fish-eye metric should make closer objects appear larger
        // The closer small gap should have larger angular size than the far large gap
        vec3 near_direction = CollisionTests::calculateGapCenterDirection(apex, make_vec3(-1.0f, 0, 2.0f));
        float angular_error_near = CollisionTests::measureAngularError(result.direction, near_direction);
 
        DOCTEST_CHECK(angular_error_near < 0.5f); // Should be closer to near gap
        DOCTEST_CHECK(result.confidence > 0.2f);
    }
 
    // Test 2: Same-sized gaps at different distances
    {
        Context context_reset;
        CollisionDetection collision_reset(&context_reset);
        collision_reset.disableMessages();
 
        // Near gap at distance 2.0
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(-0.8f, 0, 0), 0.8f, 2.0f, 2.0f);
 
        // Far gap at distance 5.0
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(0.8f, 0, 0), 0.8f, 2.0f, 5.0f);
 
        CollisionDetection::OptimalPathResult result = collision_reset.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 256);
 
        // Should prefer the closer gap due to larger angular size
        vec3 near_direction = CollisionTests::calculateGapCenterDirection(apex, make_vec3(-0.8f, 0, 2.0f));
        float angular_error_near = CollisionTests::measureAngularError(result.direction, near_direction);
 
        DOCTEST_CHECK(angular_error_near < 0.4f); // Should prefer closer gap
        DOCTEST_CHECK(result.confidence > 0.2f);
    }
 
    // Test 3: Gap size vs distance trade-off verification
    {
        Context context_reset;
        CollisionDetection collision_reset(&context_reset);
        collision_reset.disableMessages();
 
        // Create scenario where angular sizes are roughly similar
        // Near small gap (angular size ≈ gap_width / distance)
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(-0.5f, 0, 0), 0.5f, 2.0f, 2.5f); // Angular size ≈ 0.2 rad
 
        // Far medium gap
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(0.5f, 0, 0), 1.0f, 2.0f, 5.0f); // Angular size ≈ 0.2 rad
 
        CollisionDetection::OptimalPathResult result = collision_reset.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 512);
 
        // Both gaps should have similar scoring - result should be reasonable for either
        DOCTEST_CHECK(result.direction.magnitude() > 0.9f);
        DOCTEST_CHECK(result.direction.magnitude() < 1.1f);
        DOCTEST_CHECK(result.confidence > 0.1f);
 
        // Direction should point toward one of the gaps (not somewhere random)
        vec3 near_dir = CollisionTests::calculateGapCenterDirection(apex, make_vec3(-0.5f, 0, 2.5f));
        vec3 far_dir = CollisionTests::calculateGapCenterDirection(apex, make_vec3(0.5f, 0, 5.0f));
        float error_near = CollisionTests::measureAngularError(result.direction, near_dir);
        float error_far = CollisionTests::measureAngularError(result.direction, far_dir);
 
        DOCTEST_CHECK((error_near < 0.3f || error_far < 0.3f)); // Should point toward one of the gaps
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection findOptimalConePath Accuracy - Edge Case Geometry") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    vec3 apex = make_vec3(0, 0, -2);
    vec3 central_axis = make_vec3(0, 0, 1);
 
    // Test 1: Very narrow gap - algorithm should handle gracefully
    {
        float half_angle = M_PI / 6.0f; // 30 degrees
        CollisionTests::createParallelWallsWithGap(&context, make_vec3(0, 0, 0), 0.1f, 2.0f, 2.0f); // Very narrow gap
 
        CollisionDetection::OptimalPathResult result = collision.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 512);
 
        DOCTEST_CHECK(result.direction.magnitude() > 0.9f);
        DOCTEST_CHECK(result.direction.magnitude() < 1.1f);
        DOCTEST_CHECK(result.confidence >= 0.0f);
        DOCTEST_CHECK(result.confidence <= 1.0f);
 
        // Should still point roughly toward the gap
        vec3 expected_direction = CollisionTests::calculateGapCenterDirection(apex, make_vec3(0, 0, 2.0f));
        float angular_error = CollisionTests::measureAngularError(result.direction, expected_direction);
        DOCTEST_CHECK(angular_error < 0.5f); // Reasonable accuracy even for narrow gap
    }
 
    // Test 2: Gap at edge of cone - testing cone boundary conditions
    {
        Context context_reset;
        CollisionDetection collision_reset(&context_reset);
        collision_reset.disableMessages();
 
        float half_angle = M_PI / 4.0f; // 45 degrees
        // Place gap near the edge of the cone
        float edge_angle = half_angle * 0.8f; // 80% toward cone edge
        float gap_x = 2.0f * tan(edge_angle); // Distance * tan(angle) gives x position
 
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(gap_x, 0, 0), 0.6f, 2.0f, 2.0f);
 
        CollisionDetection::OptimalPathResult result = collision_reset.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 256);
 
        DOCTEST_CHECK(result.direction.magnitude() > 0.9f);
        DOCTEST_CHECK(result.direction.magnitude() < 1.1f);
 
        // Should find the gap at the cone edge
        vec3 expected_direction = CollisionTests::calculateGapCenterDirection(apex, make_vec3(gap_x, 0, 2.0f));
        float angular_error = CollisionTests::measureAngularError(result.direction, expected_direction);
        DOCTEST_CHECK(angular_error < 0.4f); // More tolerance for edge case (less than 23 degrees)
    }
 
    // Test 3: Partially occluded gap - realistic scenario
    {
        Context context_reset;
        CollisionDetection collision_reset(&context_reset);
        collision_reset.disableMessages();
 
        float half_angle = M_PI / 3.0f; // 60 degrees
 
        // Create main gap
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(0, 0, 0), 1.2f, 2.0f, 3.0f);
 
        // Add partial obstruction in front of the gap
        context_reset.addTriangle(make_vec3(-0.3f, -0.4f, 1.5f), make_vec3(0.3f, -0.4f, 1.5f), make_vec3(0, 0.2f, 1.5f));
 
        CollisionDetection::OptimalPathResult result = collision_reset.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 512);
 
        // Should still find a reasonable path despite partial occlusion
        DOCTEST_CHECK(result.direction.magnitude() > 0.9f);
        DOCTEST_CHECK(result.direction.magnitude() < 1.1f);
        DOCTEST_CHECK(result.confidence >= 0.0f); // Valid confidence
 
        // Should point roughly toward gap region (allowing for avoidance of occlusion)
        vec3 gap_direction = CollisionTests::calculateGapCenterDirection(apex, make_vec3(0, 0, 3.0f));
        float angular_error = CollisionTests::measureAngularError(result.direction, gap_direction);
        DOCTEST_CHECK(angular_error < 0.6f); // More tolerance due to occlusion
    }
 
    // Test 4: Multiple competing gaps - stress test for decision making
    {
        Context context_reset;
        CollisionDetection collision_reset(&context_reset);
        collision_reset.disableMessages();
 
        float half_angle = M_PI / 2.5f; // 72 degrees - very wide cone
 
        // Create multiple gaps at various positions
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(-1.5f, 0, 0), 0.7f, 2.0f, 4.0f);
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(0, 0, 0), 0.5f, 2.0f, 3.0f);
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(1.2f, 0, 0), 0.8f, 2.0f, 3.5f);
        CollisionTests::createParallelWallsWithGap(&context_reset, make_vec3(0, 1.0f, 0), 0.6f, 2.0f, 3.2f);
 
        CollisionDetection::OptimalPathResult result = collision_reset.findOptimalConePath(apex, central_axis, half_angle, 0.0f, 512);
 
        // Should make a reasonable choice among the gaps
        DOCTEST_CHECK(result.direction.magnitude() > 0.9f);
        DOCTEST_CHECK(result.direction.magnitude() < 1.1f);
        DOCTEST_CHECK(result.confidence > 0.1f); // Should have some confidence in the choice
 
        // Direction should be within the cone
        float deviation_from_center = acosf(std::max(-1.0f, std::min(1.0f, result.direction * central_axis)));
        DOCTEST_CHECK(deviation_from_center <= half_angle + 0.01f); // Within cone bounds (small tolerance)
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Scale Test - 1000 Primitives") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Generate 1000 separated triangles
    auto uuids = CollisionTests::generateSeparatedTriangles(&context, 1000);
 
    // Should not crash during BVH construction
    DOCTEST_CHECK_NOTHROW(collision.buildBVH());
 
    DOCTEST_CHECK(collision.isBVHValid() == true);
    DOCTEST_CHECK(collision.getPrimitiveCount() == 1000);
}
 
DOCTEST_TEST_CASE("CollisionDetection Scale Test - 10000 Primitives") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Generate 10,000 separated triangles - should stress memory allocation
    auto uuids = CollisionTests::generateSeparatedTriangles(&context, 10000);
 
    // This would have caught the original memory allocation bug
    DOCTEST_CHECK_NOTHROW(collision.buildBVH());
 
    DOCTEST_CHECK(collision.isBVHValid() == true);
    DOCTEST_CHECK(collision.getPrimitiveCount() == 10000);
}
 
// =================== CPU vs GPU VALIDATION ===================
 
DOCTEST_TEST_CASE("CollisionDetection CPU vs GPU Consistency - Small Scale") {
    Context context;
 
    // Suppress all initialization and BVH building messages
 
    // Create test scenario - overlapping and non-overlapping primitives
    auto overlapping = CollisionTests::generateOverlappingCluster(&context, 5, make_vec3(0, 0, 0));
    auto separated = CollisionTests::generateSeparatedTriangles(&context, 5, 10.0f);
 
    // Test with CPU
    CollisionDetection cpu_collision(&context);
    cpu_collision.disableMessages();
    cpu_collision.disableGPUAcceleration();
    cpu_collision.buildBVH();
 
    // Test with GPU
    CollisionDetection gpu_collision(&context);
    gpu_collision.disableMessages();
    gpu_collision.enableGPUAcceleration();
    gpu_collision.buildBVH();
 
    // Compare results for each primitive
    for (uint uuid: overlapping) {
        auto cpu_results = cpu_collision.findCollisions(uuid);
        auto gpu_results = gpu_collision.findCollisions(uuid);
 
        // Sort for comparison
        std::sort(cpu_results.begin(), cpu_results.end());
        std::sort(gpu_results.begin(), gpu_results.end());
 
        DOCTEST_CHECK(cpu_results == gpu_results);
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection CPU vs GPU Consistency - Large Scale") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Generate 1000 primitives with known collision pattern
    auto cluster1 = CollisionTests::generateOverlappingCluster(&context, 10, make_vec3(0, 0, 0));
    auto cluster2 = CollisionTests::generateOverlappingCluster(&context, 10, make_vec3(20, 0, 0));
    auto separated = CollisionTests::generateSeparatedTriangles(&context, 980, 2.0f);
 
    // Test CPU results
    collision.disableGPUAcceleration();
    collision.buildBVH();
    auto cpu_results = collision.findCollisions(cluster1[0]);
 
    // Test GPU results
    std::vector<uint> gpu_results;
    {
        helios::capture_cerr capture;
        collision.enableGPUAcceleration();
        collision.buildBVH();
        gpu_results = collision.findCollisions(cluster1[0]);
    } // Capture destroyed before assertions
 
    // Sort for comparison
    std::sort(cpu_results.begin(), cpu_results.end());
    std::sort(gpu_results.begin(), gpu_results.end());
 
    // This would have caught the original GPU false positive bug
    DOCTEST_CHECK(cpu_results == gpu_results);
}
 
// =================== NEGATIVE TESTING ===================
 
DOCTEST_TEST_CASE("CollisionDetection Negative Test - Well Separated Primitives") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create primitives that definitely should not intersect
    uint triangle1 = context.addTriangle(make_vec3(0, 0, 0), make_vec3(1, 0, 0), make_vec3(0.5f, 1, 0));
    uint triangle2 = context.addTriangle(make_vec3(10, 10, 10), make_vec3(11, 10, 10), make_vec3(10.5f, 11, 10));
    uint patch = context.addPatch(make_vec3(20, 20, 20), make_vec2(1, 1));
 
    collision.buildBVH();
 
    // Test CPU
    collision.disableGPUAcceleration();
    auto cpu_collisions = collision.findCollisions(triangle1);
 
    // Test GPU
    std::vector<uint> gpu_collisions;
    {
        helios::capture_cerr capture;
        collision.enableGPUAcceleration();
        gpu_collisions = collision.findCollisions(triangle1);
    } // Capture destroyed before assertions
 
    // Should find 0 collisions (not counting self)
    DOCTEST_CHECK(cpu_collisions.size() == 0);
    DOCTEST_CHECK(gpu_collisions.size() == 0);
}
 
DOCTEST_TEST_CASE("CollisionDetection Negative Test - Patch vs Distant Model") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create a cluster of triangles far from origin
    auto distant_triangles = CollisionTests::generateOverlappingCluster(&context, 20, make_vec3(50, 50, 50));
 
    // Create patch at origin
    uint patch = context.addPatch(make_vec3(0, 0, 0), make_vec2(1, 1));
 
    collision.buildBVH();
 
    // Test both CPU and GPU
    collision.disableGPUAcceleration();
    auto cpu_collisions = collision.findCollisions(patch);
 
    std::vector<uint> gpu_collisions;
    {
        helios::capture_cerr capture;
        collision.enableGPUAcceleration();
        gpu_collisions = collision.findCollisions(patch);
    } // Capture destroyed before assertions
 
    // Should find 0 collisions
    DOCTEST_CHECK(cpu_collisions.size() == 0);
    DOCTEST_CHECK(gpu_collisions.size() == 0);
    DOCTEST_CHECK(cpu_collisions == gpu_collisions);
}
 
// =================== EDGE CASE TESTING ===================
 
DOCTEST_TEST_CASE("CollisionDetection Edge Case - Boundary Touching") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create primitives that exactly touch at boundaries
    uint triangle1 = context.addTriangle(make_vec3(0, 0, 0), make_vec3(1, 0, 0), make_vec3(0.5f, 1, 0));
    uint triangle2 = context.addTriangle(make_vec3(1, 0, 0), make_vec3(2, 0, 0), make_vec3(1.5f, 1, 0)); // Shares edge
 
    collision.buildBVH();
 
    // Test CPU vs GPU consistency
    collision.disableGPUAcceleration();
    auto cpu_results = collision.findCollisions(triangle1);
 
    std::vector<uint> gpu_results;
    {
        helios::capture_cerr capture;
        collision.enableGPUAcceleration();
        gpu_results = collision.findCollisions(triangle1);
    } // Capture destroyed before assertions
 
    std::sort(cpu_results.begin(), cpu_results.end());
    std::sort(gpu_results.begin(), gpu_results.end());
 
    DOCTEST_CHECK(cpu_results == gpu_results);
}
 
DOCTEST_TEST_CASE("CollisionDetection Edge Case - Very Small Overlaps") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create primitives with tiny overlaps (precision testing)
    uint triangle1 = context.addTriangle(make_vec3(0, 0, 0), make_vec3(1, 0, 0), make_vec3(0.5f, 1, 0));
    uint triangle2 = context.addTriangle(make_vec3(0.99f, 0, 0), make_vec3(1.99f, 0, 0), make_vec3(1.49f, 1, 0));
 
    collision.buildBVH();
 
    // Test CPU vs GPU consistency for precision
    collision.disableGPUAcceleration();
    auto cpu_results = collision.findCollisions(triangle1);
 
    std::vector<uint> gpu_results;
    {
        helios::capture_cerr capture;
        collision.enableGPUAcceleration();
        gpu_results = collision.findCollisions(triangle1);
    } // Capture destroyed before assertions
 
    std::sort(cpu_results.begin(), cpu_results.end());
    std::sort(gpu_results.begin(), gpu_results.end());
 
    DOCTEST_CHECK(cpu_results == gpu_results);
}
 
// =================== REAL GEOMETRY TESTING ===================
 
DOCTEST_TEST_CASE("CollisionDetection Real Geometry - PLY File Loading") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // This would test with actual PLY files if available
    // For now, simulate complex real geometry
    std::vector<uint> complex_model;
 
    // Generate a "complex model" with varying triangle sizes and orientations
    for (int i = 0; i < 1000; i++) {
        float scale = 0.1f + (i % 10) * 0.05f; // Varying sizes
        float angle = (i * 0.1f);
        float x = cos(angle) * (i * 0.01f);
        float y = sin(angle) * (i * 0.01f);
        float z = (i % 100) * 0.001f; // Varying heights
 
        uint uuid = context.addTriangle(make_vec3(x - scale, y - scale, z), make_vec3(x + scale, y - scale, z), make_vec3(x, y + scale, z));
        complex_model.push_back(uuid);
    }
 
    // Test patch at various positions
    uint patch_intersecting = context.addPatch(make_vec3(0, 0, 0.05f), make_vec2(0.5f, 0.5f));
    uint patch_non_intersecting = context.addPatch(make_vec3(100, 100, 100), make_vec2(1, 1));
 
    collision.buildBVH();
 
    // Test CPU vs GPU with complex geometry
    collision.disableGPUAcceleration();
    auto cpu_intersecting = collision.findCollisions(patch_intersecting);
    auto cpu_non_intersecting = collision.findCollisions(patch_non_intersecting);
 
    std::vector<uint> gpu_intersecting, gpu_non_intersecting;
    {
        helios::capture_cerr capture;
        collision.enableGPUAcceleration();
        gpu_intersecting = collision.findCollisions(patch_intersecting);
        gpu_non_intersecting = collision.findCollisions(patch_non_intersecting);
    } // Capture destroyed before assertions
 
    // Sort for comparison
    std::sort(cpu_intersecting.begin(), cpu_intersecting.end());
    std::sort(gpu_intersecting.begin(), gpu_intersecting.end());
    std::sort(cpu_non_intersecting.begin(), cpu_non_intersecting.end());
    std::sort(gpu_non_intersecting.begin(), gpu_non_intersecting.end());
 
    DOCTEST_CHECK(cpu_intersecting == gpu_intersecting);
    DOCTEST_CHECK(cpu_non_intersecting == gpu_non_intersecting);
    DOCTEST_CHECK(cpu_non_intersecting.size() == 0); // Should be empty
}
 
// =================== PERFORMANCE REGRESSION TESTING ===================
 
DOCTEST_TEST_CASE("CollisionDetection Performance - BVH Construction Time") {
    Context context;
 
    // Suppress all initialization messages - but we want to time BVH construction itself
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Generate substantial geometry
    auto uuids = CollisionTests::generateSeparatedTriangles(&context, 5000);
 
    // End suppression for timing the actual BVH construction (but keep it silent)
    // Time BVH construction
    auto start = std::chrono::high_resolution_clock::now();
    collision.buildBVH();
    auto end = std::chrono::high_resolution_clock::now();
 
    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end - start);
 
    // Should complete within reasonable time (adjust threshold as needed)
    DOCTEST_CHECK(duration.count() < 5000); // 5 seconds max
    DOCTEST_CHECK(collision.isBVHValid() == true);
}
 
// =================== MEMORY STRESS TESTING ===================
 
DOCTEST_TEST_CASE("CollisionDetection Memory Stress - Progressive Loading") {
    Context context;
 
    // Suppress all initialization and BVH building messages
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Progressively add more primitives to test memory allocation patterns
    std::vector<uint> all_uuids;
 
    for (int batch = 0; batch < 10; batch++) {
        // Add 1000 more primitives each batch
        auto batch_uuids = CollisionTests::generateSeparatedTriangles(&context, 1000, 5.0f + batch * 50.0f);
        all_uuids.insert(all_uuids.end(), batch_uuids.begin(), batch_uuids.end());
 
        // Rebuild BVH each time (stress test memory management)
        DOCTEST_CHECK_NOTHROW(collision.buildBVH());
        DOCTEST_CHECK(collision.isBVHValid() == true);
        DOCTEST_CHECK(collision.getPrimitiveCount() == all_uuids.size());
    }
}
 
// =================== RAY DISTANCE TESTING ===================
 
DOCTEST_TEST_CASE("CollisionDetection findNearestPrimitiveDistance - Basic Functionality") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create a simple scene with triangles at known distances
    uint triangle1 = context.addTriangle(make_vec3(5, -1, -1), make_vec3(5, 1, -1), make_vec3(5, 0, 1));
    uint triangle2 = context.addTriangle(make_vec3(10, -1, -1), make_vec3(10, 1, -1), make_vec3(10, 0, 1));
    uint triangle3 = context.addTriangle(make_vec3(15, -1, -1), make_vec3(15, 1, -1), make_vec3(15, 0, 1));
 
    // Test 1: Ray hitting the nearest triangle
    vec3 origin = make_vec3(0, 0, 0);
    vec3 direction = make_vec3(1, 0, 0); // Pointing along +X axis
    std::vector<uint> candidate_UUIDs = {triangle1, triangle2, triangle3};
    float distance;
    vec3 obstacle_direction;
 
    bool result = collision.findNearestPrimitiveDistance(origin, direction, candidate_UUIDs, distance, obstacle_direction);
    DOCTEST_CHECK(result == true);
    DOCTEST_CHECK(distance >= 4.0f); // Should be approximately 5.0, but AABB might be slightly smaller
    DOCTEST_CHECK(distance <= 6.0f);
 
    // Test 2: Ray missing all triangles
    vec3 direction_miss = make_vec3(0, 1, 0); // Pointing along +Y axis
    bool result_miss = collision.findNearestPrimitiveDistance(origin, direction_miss, candidate_UUIDs, distance, obstacle_direction);
    DOCTEST_CHECK(result_miss == false);
 
    // Test 3: Ray with subset of candidates
    std::vector<uint> subset_UUIDs = {triangle2, triangle3}; // Exclude nearest triangle
    bool result_subset = collision.findNearestPrimitiveDistance(origin, direction, subset_UUIDs, distance, obstacle_direction);
    DOCTEST_CHECK(result_subset == true);
    DOCTEST_CHECK(distance >= 9.0f); // Should be approximately 10.0
    DOCTEST_CHECK(distance <= 11.0f);
}
 
DOCTEST_TEST_CASE("CollisionDetection findNearestPrimitiveDistance - Edge Cases") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test geometry
    uint triangle1 = context.addTriangle(make_vec3(5, -1, -1), make_vec3(5, 1, -1), make_vec3(5, 0, 1));
    vec3 origin = make_vec3(0, 0, 0);
    vec3 direction = make_vec3(1, 0, 0);
    float distance;
 
    // Test 1: Empty candidate list
    std::vector<uint> empty_UUIDs;
    vec3 obstacle_direction_unused;
    bool result_empty = collision.findNearestPrimitiveDistance(origin, direction, empty_UUIDs, distance, obstacle_direction_unused);
    DOCTEST_CHECK(result_empty == false);
 
    // Test 2: Non-normalized direction vector (should return false with warning)
    vec3 non_normalized_dir = make_vec3(2, 0, 0); // Magnitude = 2
    std::vector<uint> valid_UUIDs = {triangle1};
    bool result_non_norm = collision.findNearestPrimitiveDistance(origin, non_normalized_dir, valid_UUIDs, distance, obstacle_direction_unused);
    DOCTEST_CHECK(result_non_norm == false);
 
    // Test 3: Invalid UUID in candidate list
    std::vector<uint> invalid_UUIDs = {999999}; // Non-existent UUID
    bool result_invalid = collision.findNearestPrimitiveDistance(origin, direction, invalid_UUIDs, distance, obstacle_direction_unused);
    DOCTEST_CHECK(result_invalid == false);
 
    // Test 4: Mixed valid and invalid UUIDs
    std::vector<uint> mixed_UUIDs = {triangle1, 999999};
    bool result_mixed = collision.findNearestPrimitiveDistance(origin, direction, mixed_UUIDs, distance, obstacle_direction_unused);
    DOCTEST_CHECK(result_mixed == true); // Should still find the valid triangle
    DOCTEST_CHECK(distance >= 4.0f);
    DOCTEST_CHECK(distance <= 6.0f);
}
 
DOCTEST_TEST_CASE("CollisionDetection findNearestPrimitiveDistance - Complex Scenarios") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create overlapping geometry
    auto cluster = CollisionTests::generateOverlappingCluster(&context, 10, make_vec3(5, 0, 0));
 
    // Test 1: Ray through dense cluster
    vec3 origin = make_vec3(0, 0, 0);
    vec3 direction = make_vec3(1, 0, 0);
    float distance;
    vec3 obstacle_direction_unused;
 
    bool result = collision.findNearestPrimitiveDistance(origin, direction, cluster, distance, obstacle_direction_unused);
    // Updated expectation: ray traveling in +X direction should NOT hit triangles in XY plane (parallel)
    DOCTEST_CHECK(result == false);
 
    // Test 2: Ray from near the cluster edge
    // Note: Ray parallel to triangles should not detect intersection
    vec3 origin_near = make_vec3(3.5, 0, 0); // Just outside the cluster
    vec3 direction_out = make_vec3(1, 0, 0);
    bool result_near = collision.findNearestPrimitiveDistance(origin_near, direction_out, cluster, distance, obstacle_direction_unused);
    DOCTEST_CHECK(result_near == false); // Ray parallel to triangles - no hit expected
 
    // Test 3: Test with ray that can actually hit the triangles (perpendicular approach)
    vec3 origin_above = make_vec3(5, 0, 1); // Above the cluster center
    vec3 direction_down = make_vec3(0, 0, -1); // Growing downward toward triangles
    bool result_perpendicular = collision.findNearestPrimitiveDistance(origin_above, direction_down, cluster, distance, obstacle_direction_unused);
    DOCTEST_CHECK(result_perpendicular == true); // Should hit triangles when approaching perpendicularly
    DOCTEST_CHECK(distance >= 0.9f); // Distance from z=1 to z=0 (approximately)
    DOCTEST_CHECK(distance <= 1.1f);
}
 
DOCTEST_TEST_CASE("CollisionDetection findNearestPrimitiveDistance - Directional Testing") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create triangles in different directions
    uint triangle_x = context.addTriangle(make_vec3(5, -1, -1), make_vec3(5, 1, -1), make_vec3(5, 0, 1));
    uint triangle_y = context.addTriangle(make_vec3(-1, 5, -1), make_vec3(1, 5, -1), make_vec3(0, 5, 1));
    uint triangle_z = context.addTriangle(make_vec3(-1, -1, 5), make_vec3(1, -1, 5), make_vec3(0, 1, 5));
    uint triangle_neg_x = context.addTriangle(make_vec3(-5, -1, -1), make_vec3(-5, 1, -1), make_vec3(-5, 0, 1));
 
    std::vector<uint> all_triangles = {triangle_x, triangle_y, triangle_z, triangle_neg_x};
    vec3 origin = make_vec3(0, 0, 0);
    float distance;
 
    // Test different ray directions
    struct DirectionTest {
        vec3 direction;
        float expected_min;
        float expected_max;
        bool should_hit;
    };
 
    std::vector<DirectionTest> tests = {
            {make_vec3(1, 0, 0), 4.0f, 6.0f, true}, // +X direction
            {make_vec3(0, 1, 0), 4.0f, 6.0f, true}, // +Y direction
            {make_vec3(0, 0, 1), 4.0f, 6.0f, true}, // +Z direction
            {make_vec3(-1, 0, 0), 4.0f, 6.0f, true}, // -X direction
            {make_vec3(0.707f, 0.707f, 0), 6.0f, 8.0f, false}, // Diagonal XY (should miss)
    };
 
    vec3 obstacle_direction_unused;
    for (const auto &test: tests) {
        bool result = collision.findNearestPrimitiveDistance(origin, test.direction, all_triangles, distance, obstacle_direction_unused);
        DOCTEST_CHECK(result == test.should_hit);
        if (result && test.should_hit) {
            DOCTEST_CHECK(distance >= test.expected_min);
            DOCTEST_CHECK(distance <= test.expected_max);
        }
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection - findNearestPrimitiveDistance front/back face detection") {
    helios::Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create a horizontal patch at z=1.0 (normal pointing up in +Z direction)
    vec3 patch_center = make_vec3(0, 0, 1);
    vec2 patch_size = make_vec2(2, 2);
    uint horizontal_patch = context.addPatch(patch_center, patch_size);
 
    std::vector<uint> candidates = {horizontal_patch};
    float distance;
    vec3 obstacle_direction;
 
    // Test 1: Approaching from below (should get +Z direction - toward surface)
    vec3 origin_below = make_vec3(0, 0, 0.5f);
    vec3 direction_up = make_vec3(0, 0, 1); // Growing upward
 
    bool found_below = collision.findNearestPrimitiveDistance(origin_below, direction_up, candidates, distance, obstacle_direction);
    DOCTEST_CHECK(found_below == true);
    DOCTEST_CHECK(distance >= 0.49f);
    DOCTEST_CHECK(distance <= 0.51f);
    // When approaching from below, obstacle_direction should point upward (+Z)
    DOCTEST_CHECK(obstacle_direction.z > 0.9f);
    DOCTEST_CHECK(std::abs(obstacle_direction.x) < 0.1f);
    DOCTEST_CHECK(std::abs(obstacle_direction.y) < 0.1f);
 
    // Test 2: Approaching from above (should get -Z direction - toward surface)
    vec3 origin_above = make_vec3(0, 0, 1.5f);
    vec3 direction_down = make_vec3(0, 0, -1); // Growing downward
 
    bool found_above = collision.findNearestPrimitiveDistance(origin_above, direction_down, candidates, distance, obstacle_direction);
    DOCTEST_CHECK(found_above == true);
    DOCTEST_CHECK(distance >= 0.49f);
    DOCTEST_CHECK(distance <= 0.51f);
    // When approaching from above, obstacle_direction should point downward (-Z)
    DOCTEST_CHECK(obstacle_direction.z < -0.9f);
    DOCTEST_CHECK(std::abs(obstacle_direction.x) < 0.1f);
    DOCTEST_CHECK(std::abs(obstacle_direction.y) < 0.1f);
 
    // Test 3: Growing away from surface (should not detect obstacle)
    vec3 origin_below2 = make_vec3(0, 0, 0.5f);
    vec3 direction_away = make_vec3(0, 0, -1); // Growing away from obstacle
 
    bool found_away = collision.findNearestPrimitiveDistance(origin_below2, direction_away, candidates, distance, obstacle_direction);
    DOCTEST_CHECK(found_away == false); // Should not detect surface behind growth direction
}
 
// =================== CONE-BASED OBSTACLE DETECTION TESTS ===================
 
DOCTEST_TEST_CASE("CollisionDetection Cone-Based Obstacle Detection - Basic Functionality") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create a horizontal patch obstacle at z=1.0
    uint obstacle_uuid = context.addPatch(make_vec3(0, 0, 1), make_vec2(2, 2));
    std::vector<uint> obstacles = {obstacle_uuid};
    collision.buildBVH(obstacles);
 
    // Test 1: Ray from below, directly toward obstacle
    vec3 apex = make_vec3(0, 0, 0.5f);
    vec3 axis = make_vec3(0, 0, 1); // Straight up
    float half_angle = deg2rad(30.0f); // 30 degree half-angle
    float height = 1.0f; // 1 meter detection range
 
    float distance;
    vec3 obstacle_direction;
 
    bool found = collision.findNearestSolidObstacleInCone(apex, axis, half_angle, height, obstacles, distance, obstacle_direction);
 
    DOCTEST_CHECK(found == true);
    DOCTEST_CHECK(distance >= 0.49f);
    DOCTEST_CHECK(distance <= 0.51f); // Should be ~0.5m from apex to obstacle
    DOCTEST_CHECK(obstacle_direction.z > 0.9f); // Direction should be mostly upward
 
    // Test 2: Ray from far away - should not detect
    vec3 apex_far = make_vec3(0, 0, -2.0f);
    bool found_far = collision.findNearestSolidObstacleInCone(apex_far, axis, half_angle, height, obstacles, distance, obstacle_direction);
    DOCTEST_CHECK(found_far == false); // Too far away
 
    // Test 3: Narrow cone that misses obstacle
    float narrow_angle = deg2rad(5.0f); // Very narrow cone
    vec3 axis_offset = make_vec3(3.0f, 0, 1); // Aimed well to the side to clearly miss the 2x2 patch
    axis_offset.normalize();
 
    bool found_narrow = collision.findNearestSolidObstacleInCone(apex, axis_offset, narrow_angle, height, obstacles, distance, obstacle_direction);
    DOCTEST_CHECK(found_narrow == false); // Should miss the obstacle
}
 
DOCTEST_TEST_CASE("CollisionDetection Cone-Based vs Legacy Method Comparison") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test obstacle
    uint obstacle_uuid = context.addPatch(make_vec3(0, 0, 1), make_vec2(1, 1));
    std::vector<uint> obstacles = {obstacle_uuid};
    collision.buildBVH(obstacles);
 
    // Test parameters
    vec3 origin = make_vec3(0, 0, 0.2f);
    vec3 direction = make_vec3(0, 0, 1);
 
    // Legacy method
    float legacy_distance;
    vec3 legacy_obstacle_direction;
    bool legacy_found = collision.findNearestPrimitiveDistance(origin, direction, obstacles, legacy_distance, legacy_obstacle_direction);
 
    // New cone method
    float cone_distance;
    vec3 cone_obstacle_direction;
    float half_angle = deg2rad(30.0f);
    float height = 2.0f;
    bool cone_found = collision.findNearestSolidObstacleInCone(origin, direction, half_angle, height, obstacles, cone_distance, cone_obstacle_direction);
 
    // Both should find the obstacle
    DOCTEST_CHECK(legacy_found == true);
    DOCTEST_CHECK(cone_found == true);
 
    // Both methods should produce reasonable distance measurements (within 5% of expected 0.8m)
    DOCTEST_CHECK(std::abs(cone_distance - 0.8f) < 0.04f); // Within 4cm of expected distance
    DOCTEST_CHECK(std::abs(legacy_distance - 0.8f) < 0.04f); // Within 4cm of expected distance
 
    // Both should have reasonable direction vectors
    DOCTEST_CHECK(legacy_obstacle_direction.magnitude() > 0.9f);
    DOCTEST_CHECK(cone_obstacle_direction.magnitude() > 0.9f);
}
 
DOCTEST_TEST_CASE("CollisionDetection Cone-Based Triangle vs Patch Intersection") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test triangle intersection
    uint triangle_uuid = context.addTriangle(make_vec3(-0.5f, -0.5f, 1.0f), make_vec3(0.5f, -0.5f, 1.0f), make_vec3(0, 0.5f, 1.0f));
 
    // Test patch intersection
    uint patch_uuid = context.addPatch(make_vec3(2, 0, 1), make_vec2(1, 1));
 
    std::vector<uint> triangle_obstacles = {triangle_uuid};
    std::vector<uint> patch_obstacles = {patch_uuid};
 
    collision.buildBVH({triangle_uuid, patch_uuid});
 
    vec3 apex = make_vec3(0, 0, 0.5f);
    vec3 axis = make_vec3(0, 0, 1);
    float half_angle = deg2rad(30.0f);
    float height = 1.0f;
    float distance;
    vec3 obstacle_direction;
 
    // Test triangle intersection
    bool triangle_found = collision.findNearestSolidObstacleInCone(apex, axis, half_angle, height, triangle_obstacles, distance, obstacle_direction);
    DOCTEST_CHECK(triangle_found == true);
    DOCTEST_CHECK(distance > 0.4f);
    DOCTEST_CHECK(distance < 0.6f);
 
    // Test patch intersection
    vec3 apex_patch = make_vec3(2, 0, 0.5f);
    bool patch_found = collision.findNearestSolidObstacleInCone(apex_patch, axis, half_angle, height, patch_obstacles, distance, obstacle_direction);
    DOCTEST_CHECK(patch_found == true);
    DOCTEST_CHECK(distance > 0.4f);
    DOCTEST_CHECK(distance < 0.6f);
}
 
DOCTEST_TEST_CASE("CollisionDetection Cone-Based Parameter Validation") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    uint obstacle_uuid = context.addPatch(make_vec3(0, 0, 1), make_vec2(1, 1));
    std::vector<uint> obstacles = {obstacle_uuid};
    collision.buildBVH(obstacles);
 
    vec3 apex = make_vec3(0, 0, 0.5f);
    vec3 axis = make_vec3(0, 0, 1);
    float distance;
    vec3 obstacle_direction;
 
    // Test invalid parameters
    bool result1 = collision.findNearestSolidObstacleInCone(apex, axis, -0.1f, 1.0f, obstacles, distance, obstacle_direction); // Negative angle
    DOCTEST_CHECK(result1 == false);
 
    bool result2 = collision.findNearestSolidObstacleInCone(apex, axis, M_PI, 1.0f, obstacles, distance, obstacle_direction); // Too large angle
    DOCTEST_CHECK(result2 == false);
 
    bool result3 = collision.findNearestSolidObstacleInCone(apex, axis, deg2rad(30.0f), -1.0f, obstacles, distance, obstacle_direction); // Negative height
    DOCTEST_CHECK(result3 == false);
 
    // Test empty candidate list
    std::vector<uint> empty_obstacles;
    bool result4 = collision.findNearestSolidObstacleInCone(apex, axis, deg2rad(30.0f), 1.0f, empty_obstacles, distance, obstacle_direction);
    DOCTEST_CHECK(result4 == false);
 
    // Test valid parameters - should work
    bool result5 = collision.findNearestSolidObstacleInCone(apex, axis, deg2rad(30.0f), 1.0f, obstacles, distance, obstacle_direction);
    DOCTEST_CHECK(result5 == true);
}
 
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Basic Functionality") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Set up simple voxel grid
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(10, 10, 10);
    int3 grid_divisions(2, 2, 2);
 
    // Create simple rays through the grid
    std::vector<vec3> ray_origins;
    std::vector<vec3> ray_directions;
 
    // Ray going straight through the grid center
    ray_origins.push_back(make_vec3(-10, 0, 0));
    ray_directions.push_back(make_vec3(1, 0, 0));
 
    // Ray going diagonally through multiple voxels
    ray_origins.push_back(make_vec3(-10, -10, -10));
    ray_directions.push_back(normalize(make_vec3(1, 1, 1)));
 
    // Calculate voxel ray path lengths
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
    // Test transmission probability access
    int P_denom, P_trans;
    collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), P_denom, P_trans);
    DOCTEST_CHECK(P_denom >= 0);
    DOCTEST_CHECK(P_trans >= 0);
    DOCTEST_CHECK(P_trans <= P_denom);
 
    // Test r_bar access
    float r_bar = collision.getVoxelRbar(make_int3(0, 0, 0));
    DOCTEST_CHECK(r_bar >= 0.0f);
 
    // Clear data should work without error
    collision.clearVoxelData();
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Edge Cases") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test with empty ray vectors
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(5, 5, 5);
    int3 grid_divisions(1, 1, 1);
 
    std::vector<vec3> empty_origins;
    std::vector<vec3> empty_directions;
 
    // Should handle empty input gracefully
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, empty_origins, empty_directions);
 
    // Test invalid voxel indices
    int P_denom, P_trans;
 
    // Test boundary cases - should handle gracefully or throw appropriate error
    {
        capture_cerr capture;
        try {
            collision.getVoxelTransmissionProbability(make_int3(-1, 0, 0), P_denom, P_trans);
        } catch (const std::exception &e) {
            // Expected behavior - invalid indices should be handled
        }
 
        try {
            collision.getVoxelTransmissionProbability(make_int3(1, 0, 0), P_denom, P_trans);
        } catch (const std::exception &e) {
            // Expected behavior - out of bounds indices
        }
    } // capture destroyed here
 
    // Assertions after capture is destroyed
    DOCTEST_CHECK(true);
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Data Consistency") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(6, 6, 6);
    int3 grid_divisions(3, 3, 3);
 
    // Create systematic ray pattern
    std::vector<vec3> ray_origins;
    std::vector<vec3> ray_directions;
 
    // Grid of parallel rays
    for (int i = -1; i <= 1; i++) {
        for (int j = -1; j <= 1; j++) {
            ray_origins.push_back(make_vec3(i * 1.5f, j * 1.5f, -10));
            ray_directions.push_back(make_vec3(0, 0, 1));
        }
    }
 
    // Calculate path lengths
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
    // Verify data consistency
    bool found_data = false;
    for (int i = 0; i < grid_divisions.x; i++) {
        for (int j = 0; j < grid_divisions.y; j++) {
            for (int k = 0; k < grid_divisions.z; k++) {
                int P_denom, P_trans;
                collision.getVoxelTransmissionProbability(make_int3(i, j, k), P_denom, P_trans);
 
                if (P_denom > 0) {
                    found_data = true;
                    // Transmission count should never exceed total count
                    DOCTEST_CHECK(P_trans <= P_denom);
 
                    // R_bar should be positive when rays are present
                    float r_bar = collision.getVoxelRbar(make_int3(i, j, k));
                    DOCTEST_CHECK(r_bar > 0.0f);
                }
            }
        }
    }
 
    DOCTEST_CHECK(found_data); // Should have found at least some ray intersections
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Manual Data Setting") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(4, 4, 4);
    int3 grid_divisions(2, 2, 2);
 
    // Initialize with minimal calculation to set up data structures
    std::vector<vec3> init_origins;
    std::vector<vec3> init_directions;
    init_origins.push_back(make_vec3(0, 0, -10)); // Outside the grid
    init_directions.push_back(make_vec3(0, 0, 1));
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, init_origins, init_directions);
 
    // Test manual data setting
    int3 test_voxel(0, 0, 0);
    collision.setVoxelTransmissionProbability(100, 75, test_voxel);
    collision.setVoxelRbar(2.5f, test_voxel);
 
    // Verify the data was set correctly
    int P_denom, P_trans;
    collision.getVoxelTransmissionProbability(test_voxel, P_denom, P_trans);
    DOCTEST_CHECK(P_denom == 100);
    DOCTEST_CHECK(P_trans == 75);
 
    float r_bar = collision.getVoxelRbar(test_voxel);
    DOCTEST_CHECK(std::abs(r_bar - 2.5f) < 1e-6f);
 
    // Test another voxel
    int3 test_voxel2(1, 1, 1);
    collision.setVoxelTransmissionProbability(200, 150, test_voxel2);
    collision.setVoxelRbar(3.7f, test_voxel2);
 
    collision.getVoxelTransmissionProbability(test_voxel2, P_denom, P_trans);
    DOCTEST_CHECK(P_denom == 200);
    DOCTEST_CHECK(P_trans == 150);
 
    r_bar = collision.getVoxelRbar(test_voxel2);
    DOCTEST_CHECK(std::abs(r_bar - 3.7f) < 1e-6f);
 
    // Verify first voxel data is still intact
    collision.getVoxelTransmissionProbability(test_voxel, P_denom, P_trans);
    DOCTEST_CHECK(P_denom == 100);
    DOCTEST_CHECK(P_trans == 75);
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Different Grid Sizes") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test various grid sizes
    std::vector<int3> test_grids = {
            make_int3(1, 1, 1), // Single voxel
            make_int3(2, 1, 1), // Linear arrangement
            make_int3(4, 4, 4), // Cubic arrangement
            make_int3(5, 3, 2) // Asymmetric arrangement
    };
 
    for (const auto &grid_div: test_grids) {
        vec3 grid_center(0, 0, 0);
        vec3 grid_size(10, 10, 10);
 
        std::vector<vec3> ray_origins;
        std::vector<vec3> ray_directions;
 
        // Single test ray
        ray_origins.push_back(make_vec3(0, 0, -10));
        ray_directions.push_back(make_vec3(0, 0, 1));
 
        collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_div, ray_origins, ray_directions);
 
        // Verify that valid indices work
        bool found_valid_voxel = false;
        for (int i = 0; i < grid_div.x; i++) {
            for (int j = 0; j < grid_div.y; j++) {
                for (int k = 0; k < grid_div.z; k++) {
                    int P_denom, P_trans;
                    collision.getVoxelTransmissionProbability(make_int3(i, j, k), P_denom, P_trans);
                    float r_bar = collision.getVoxelRbar(make_int3(i, j, k));
 
                    // Should not crash and should give reasonable values
                    DOCTEST_CHECK(P_denom >= 0);
                    DOCTEST_CHECK(P_trans >= 0);
                    DOCTEST_CHECK(r_bar >= 0.0f);
                    found_valid_voxel = true;
                }
            }
        }
        DOCTEST_CHECK(found_valid_voxel);
 
        collision.clearVoxelData();
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Ray Direction Variations") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(8, 8, 8);
    int3 grid_divisions(2, 2, 2);
 
    // Test rays with different directions
    std::vector<vec3> test_directions = {
            make_vec3(1, 0, 0), // X-axis
            make_vec3(0, 1, 0), // Y-axis
            make_vec3(0, 0, 1), // Z-axis
            normalize(make_vec3(1, 1, 1)), // Diagonal
            normalize(make_vec3(1, -1, 0)), // Diagonal in XY plane
            normalize(make_vec3(-1, 0, 1)) // Negative X, positive Z
    };
 
    for (const auto &direction: test_directions) {
        std::vector<vec3> ray_origins;
        std::vector<vec3> ray_directions;
 
        // Start ray from outside grid
        vec3 start_point = grid_center - direction * 10.0f;
        ray_origins.push_back(start_point);
        ray_directions.push_back(direction);
 
        collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
        // Should find intersections for most directions through the center
        bool found_intersections = false;
        for (int i = 0; i < grid_divisions.x; i++) {
            for (int j = 0; j < grid_divisions.y; j++) {
                for (int k = 0; k < grid_divisions.z; k++) {
                    int P_denom, P_trans;
                    collision.getVoxelTransmissionProbability(make_int3(i, j, k), P_denom, P_trans);
                    if (P_denom > 0) {
                        found_intersections = true;
                        float r_bar = collision.getVoxelRbar(make_int3(i, j, k));
                        DOCTEST_CHECK(r_bar > 0.0f);
                    }
                }
            }
        }
 
        DOCTEST_CHECK(found_intersections);
        collision.clearVoxelData();
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - GPU/CPU Consistency") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(6, 6, 6);
    int3 grid_divisions(3, 3, 3);
 
    // Create test rays
    std::vector<vec3> ray_origins;
    std::vector<vec3> ray_directions;
 
    for (int i = 0; i < 5; i++) {
        ray_origins.push_back(make_vec3(i - 2.0f, 0, -10));
        ray_directions.push_back(make_vec3(0, 0, 1));
    }
 
    // Test CPU implementation first
    collision.disableGPUAcceleration();
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
    // Store CPU results
    std::vector<std::vector<std::vector<std::pair<int, float>>>> cpu_results(grid_divisions.x);
    for (int i = 0; i < grid_divisions.x; i++) {
        cpu_results[i].resize(grid_divisions.y);
        for (int j = 0; j < grid_divisions.y; j++) {
            cpu_results[i][j].resize(grid_divisions.z);
            for (int k = 0; k < grid_divisions.z; k++) {
                int P_denom, P_trans;
                collision.getVoxelTransmissionProbability(make_int3(i, j, k), P_denom, P_trans);
                float r_bar = collision.getVoxelRbar(make_int3(i, j, k));
                cpu_results[i][j][k] = std::make_pair(P_denom, r_bar);
            }
        }
    }
 
    // Test GPU implementation
    {
        helios::capture_cerr capture;
        collision.enableGPUAcceleration();
        collision.clearVoxelData();
        collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
    } // Capture destroyed before assertions
 
    // Compare GPU results with CPU results
    for (int i = 0; i < grid_divisions.x; i++) {
        for (int j = 0; j < grid_divisions.y; j++) {
            for (int k = 0; k < grid_divisions.z; k++) {
                int P_denom_gpu, P_trans_gpu;
                collision.getVoxelTransmissionProbability(make_int3(i, j, k), P_denom_gpu, P_trans_gpu);
                float r_bar_gpu = collision.getVoxelRbar(make_int3(i, j, k));
 
                int P_denom_cpu = cpu_results[i][j][k].first;
                float r_bar_cpu = cpu_results[i][j][k].second;
 
                // Results should match within reasonable tolerance
                // Allow some tolerance for different algorithms (GPU brute-force vs CPU DDA)
                DOCTEST_CHECK(abs(P_denom_gpu - P_denom_cpu) <= 1);
                if (r_bar_cpu > 0 && r_bar_gpu > 0) {
                    DOCTEST_CHECK(std::abs(r_bar_gpu - r_bar_cpu) < 1e-4f);
                }
            }
        }
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Parameter Validation") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test 1: Negative grid size
    vec3 grid_center(0, 0, 0);
    vec3 negative_size(-5, 5, 5);
    int3 grid_divisions(2, 2, 2);
    std::vector<vec3> ray_origins = {make_vec3(0, 0, -10)};
    std::vector<vec3> ray_directions = {make_vec3(0, 0, 1)};
 
    // Should handle gracefully without crashing
    try {
        collision.calculateVoxelRayPathLengths(grid_center, negative_size, grid_divisions, ray_origins, ray_directions);
        // If it doesn't throw, verify voxel data is still accessible
        int P_denom, P_trans;
        collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), P_denom, P_trans);
        DOCTEST_CHECK(P_denom >= 0);
        DOCTEST_CHECK(P_trans >= 0);
    } catch (const std::exception &e) {
        // Exception is acceptable for invalid parameters
        DOCTEST_CHECK(true);
    }
 
    // Test 2: Zero grid divisions
    int3 zero_divisions(0, 2, 2);
    try {
        collision.calculateVoxelRayPathLengths(grid_center, make_vec3(5, 5, 5), zero_divisions, ray_origins, ray_directions);
        // If no exception, verify it handles gracefully by checking voxel access behavior
        int P_denom_zero, P_trans_zero;
        try {
            collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), P_denom_zero, P_trans_zero);
            // Either returns valid data or the getter throws - both are acceptable
            DOCTEST_CHECK(P_denom_zero >= 0);
        } catch (const std::exception &inner_e) {
            // Exception on voxel access is acceptable for zero divisions
            DOCTEST_CHECK(true);
        }
    } catch (const std::exception &e) {
        DOCTEST_CHECK(true); // Exception is also expected behavior
    }
 
    // Test 3: Mismatched ray vector sizes
    std::vector<vec3> mismatched_directions = {make_vec3(0, 0, 1), make_vec3(1, 0, 0)};
    try {
        collision.calculateVoxelRayPathLengths(grid_center, make_vec3(5, 5, 5), make_int3(2, 2, 2), ray_origins, mismatched_directions);
        DOCTEST_CHECK(false); // Should throw an exception
    } catch (const std::exception &e) {
        DOCTEST_CHECK(true); // Expected behavior
    }
 
    // Test 4: Invalid P_trans > P_denom
    vec3 valid_grid_size(4, 4, 4);
    int3 valid_divisions(2, 2, 2);
    collision.calculateVoxelRayPathLengths(grid_center, valid_grid_size, valid_divisions, ray_origins, ray_directions);
 
    // This should be allowed - implementation may handle it gracefully
    collision.setVoxelTransmissionProbability(10, 15, make_int3(0, 0, 0)); // P_trans > P_denom
    int test_P_denom, test_P_trans;
    collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), test_P_denom, test_P_trans);
    DOCTEST_CHECK(test_P_denom == 10);
    DOCTEST_CHECK(test_P_trans == 15);
 
    // Test 5: Negative values for transmission probability
    collision.setVoxelTransmissionProbability(-5, -3, make_int3(0, 0, 0));
    collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), test_P_denom, test_P_trans);
    DOCTEST_CHECK(test_P_denom == -5);
    DOCTEST_CHECK(test_P_trans == -3);
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Mathematical Validation") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test 1: Single ray through single voxel - analytical solution
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(2, 2, 2); // 2x2x2 cube
    int3 grid_divisions(1, 1, 1); // Single voxel
 
    // Ray passes straight through center
    std::vector<vec3> ray_origins = {make_vec3(0, 0, -5)};
    std::vector<vec3> ray_directions = {make_vec3(0, 0, 1)};
 
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
    float r_bar = collision.getVoxelRbar(make_int3(0, 0, 0));
 
    // Expected path length through 2x2x2 cube should be 2.0 (cube height)
    DOCTEST_CHECK(std::abs(r_bar - 2.0f) < 0.1f);
 
    // Test 2: Diagonal ray through cubic voxel
    collision.clearVoxelData();
    std::vector<vec3> diagonal_origins = {make_vec3(-2, -2, -2)};
    std::vector<vec3> diagonal_directions = {normalize(make_vec3(1, 1, 1))};
 
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, diagonal_origins, diagonal_directions);
 
    float diagonal_r_bar = collision.getVoxelRbar(make_int3(0, 0, 0));
 
    // Expected diagonal through 2x2x2 cube should be sqrt(3)*2 = ~3.46
    float expected_diagonal = std::sqrt(3.0f) * 2.0f;
    DOCTEST_CHECK(std::abs(diagonal_r_bar - expected_diagonal) < 0.2f);
 
    // Test 3: Multiple rays, verify statistical consistency
    collision.clearVoxelData();
    std::vector<vec3> multi_origins;
    std::vector<vec3> multi_directions;
 
    // Create 4 parallel rays through same voxel
    for (int i = 0; i < 4; i++) {
        multi_origins.push_back(make_vec3(0.5f * i - 0.75f, 0, -5));
        multi_directions.push_back(make_vec3(0, 0, 1));
    }
 
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, multi_origins, multi_directions);
 
    int P_denom, P_trans;
    collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), P_denom, P_trans);
    float multi_r_bar = collision.getVoxelRbar(make_int3(0, 0, 0));
 
    // Should have 4 rays hitting the voxel
    DOCTEST_CHECK(P_denom == 4);
    // All rays should pass through (assuming no geometry), so P_trans should equal P_denom
    DOCTEST_CHECK(P_trans == P_denom);
    // Average path length should still be ~2.0
    DOCTEST_CHECK(std::abs(multi_r_bar - 2.0f) < 0.1f);
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Numerical Precision") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test 1: Very small grid (precision test)
    vec3 tiny_center(0, 0, 0);
    vec3 tiny_size(0.001f, 0.001f, 0.001f);
    int3 tiny_divisions(1, 1, 1);
 
    std::vector<vec3> tiny_origins = {make_vec3(0, 0, -0.01f)};
    std::vector<vec3> tiny_directions = {make_vec3(0, 0, 1)};
 
    collision.calculateVoxelRayPathLengths(tiny_center, tiny_size, tiny_divisions, tiny_origins, tiny_directions);
    float tiny_r_bar = collision.getVoxelRbar(make_int3(0, 0, 0));
 
    // Should handle small values without underflow
    DOCTEST_CHECK(tiny_r_bar > 0.0f);
    DOCTEST_CHECK(tiny_r_bar < 0.1f); // Should be on order of tiny_size
 
    // Test 2: Large grid (overflow test)
    vec3 large_center(0, 0, 0);
    vec3 large_size(1000.0f, 1000.0f, 1000.0f);
    int3 large_divisions(2, 2, 2);
 
    std::vector<vec3> large_origins = {make_vec3(0, 0, -2000)};
    std::vector<vec3> large_directions = {make_vec3(0, 0, 1)};
 
    collision.calculateVoxelRayPathLengths(large_center, large_size, large_divisions, large_origins, large_directions);
    float large_r_bar = collision.getVoxelRbar(make_int3(1, 1, 1)); // Center voxel
 
    // Should handle large values without overflow
    DOCTEST_CHECK(large_r_bar > 0.0f);
    DOCTEST_CHECK(large_r_bar < 2000.0f); // Should be reasonable
 
    // Test 3: CPU/GPU precision comparison with tight tolerance
    collision.clearVoxelData();
    vec3 precision_center(0, 0, 0);
    vec3 precision_size(10, 10, 10);
    int3 precision_divisions(5, 5, 5);
 
    std::vector<vec3> precision_origins;
    std::vector<vec3> precision_directions;
    for (int i = 0; i < 10; i++) {
        precision_origins.push_back(make_vec3(i - 5.0f, 0, -20));
        precision_directions.push_back(make_vec3(0, 0, 1));
    }
 
    // CPU calculation
    collision.disableGPUAcceleration();
    collision.calculateVoxelRayPathLengths(precision_center, precision_size, precision_divisions, precision_origins, precision_directions);
 
    // Store CPU results with higher precision
    std::vector<float> cpu_rbars;
    for (int i = 0; i < precision_divisions.x; i++) {
        for (int j = 0; j < precision_divisions.y; j++) {
            for (int k = 0; k < precision_divisions.z; k++) {
                cpu_rbars.push_back(collision.getVoxelRbar(make_int3(i, j, k)));
            }
        }
    }
 
    // GPU calculation
    {
        helios::capture_cerr capture;
        collision.enableGPUAcceleration();
        collision.clearVoxelData();
        collision.calculateVoxelRayPathLengths(precision_center, precision_size, precision_divisions, precision_origins, precision_directions);
    } // Capture destroyed before assertions
 
    // Compare with tighter tolerance than existing test
    int idx = 0;
    for (int i = 0; i < precision_divisions.x; i++) {
        for (int j = 0; j < precision_divisions.y; j++) {
            for (int k = 0; k < precision_divisions.z; k++) {
                float gpu_rbar = collision.getVoxelRbar(make_int3(i, j, k));
                float cpu_rbar = cpu_rbars[idx++];
 
                if (cpu_rbar > 0 && gpu_rbar > 0) {
                    float relative_error = std::abs(gpu_rbar - cpu_rbar) / std::max(cpu_rbar, gpu_rbar);
                    DOCTEST_CHECK(relative_error < 1e-5f); // Tighter precision requirement
                }
            }
        }
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Error Recovery and State Management") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test 1: API calls before initialization should handle gracefully
    try {
        int P_denom, P_trans;
        collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), P_denom, P_trans);
        // Should return zeros for uninitialized data
        DOCTEST_CHECK(P_denom == 0);
        DOCTEST_CHECK(P_trans == 0);
    } catch (const std::exception &e) {
        // Exception is also acceptable
        DOCTEST_CHECK(true);
    }
 
    try {
        float r_bar = collision.getVoxelRbar(make_int3(0, 0, 0));
        // Should return zero for uninitialized data
        DOCTEST_CHECK(r_bar == 0.0f);
    } catch (const std::exception &e) {
        // Exception is also acceptable
        DOCTEST_CHECK(true);
    }
 
    // Test 2: Multiple initialization cycles
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(4, 4, 4);
    int3 grid_divisions(2, 2, 2);
    std::vector<vec3> ray_origins = {make_vec3(0, 0, -10)};
    std::vector<vec3> ray_directions = {make_vec3(0, 0, 1)};
 
    // Initialize multiple times - should handle gracefully
    for (int cycle = 0; cycle < 3; cycle++) {
        collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
        // Verify data is accessible
        int P_denom, P_trans;
        collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), P_denom, P_trans);
        DOCTEST_CHECK(P_denom >= 0);
 
        float r_bar = collision.getVoxelRbar(make_int3(0, 0, 0));
        DOCTEST_CHECK(r_bar >= 0);
 
        // Clear and reinitialize
        collision.clearVoxelData();
    }
 
    // Test 3: State consistency after errors
    try {
        // Attempt invalid operation
        collision.setVoxelTransmissionProbability(10, 5, make_int3(-1, 0, 0)); // Invalid index
        DOCTEST_CHECK(false); // Should throw
    } catch (const std::exception &e) {
        // After error, system should still be usable
        collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
        int P_denom, P_trans;
        collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), P_denom, P_trans);
        DOCTEST_CHECK(P_denom >= 0);
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Memory and Performance Stress") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test 1: Moderately large grid (memory test)
    vec3 stress_center(0, 0, 0);
    vec3 stress_size(50, 50, 50);
    int3 stress_divisions(10, 10, 10); // 1000 voxels
 
    // Create many rays
    std::vector<vec3> stress_origins;
    std::vector<vec3> stress_directions;
    for (int i = 0; i < 100; i++) {
        for (int j = 0; j < 10; j++) {
            stress_origins.push_back(make_vec3(i - 50.0f, j - 5.0f, -100));
            stress_directions.push_back(make_vec3(0, 0, 1));
        }
    }
 
    // Should handle 1000 rays x 1000 voxels without issues
    auto start_time = std::chrono::high_resolution_clock::now();
    collision.calculateVoxelRayPathLengths(stress_center, stress_size, stress_divisions, stress_origins, stress_directions);
    auto end_time = std::chrono::high_resolution_clock::now();
    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end_time - start_time);
 
    // Verify computation completed successfully
    bool found_data = false;
    for (int i = 0; i < stress_divisions.x && !found_data; i++) {
        for (int j = 0; j < stress_divisions.y && !found_data; j++) {
            for (int k = 0; k < stress_divisions.z && !found_data; k++) {
                int P_denom, P_trans;
                collision.getVoxelTransmissionProbability(make_int3(i, j, k), P_denom, P_trans);
                if (P_denom > 0) {
                    found_data = true;
                    DOCTEST_CHECK(P_trans <= P_denom);
                    float r_bar = collision.getVoxelRbar(make_int3(i, j, k));
                    DOCTEST_CHECK(r_bar > 0.0f);
                }
            }
        }
    }
    DOCTEST_CHECK(found_data);
 
    // Test 2: Memory cleanup validation
    collision.clearVoxelData();
 
    // After clear, should return default values
    int P_denom, P_trans;
    collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), P_denom, P_trans);
    DOCTEST_CHECK(P_denom == 0);
    DOCTEST_CHECK(P_trans == 0);
 
    float r_bar = collision.getVoxelRbar(make_int3(0, 0, 0));
    DOCTEST_CHECK(r_bar == 0.0f);
 
    // Test 3: Repeated allocation/deallocation cycles
    for (int cycle = 0; cycle < 5; cycle++) {
        vec3 cycle_size(8 + cycle * 2, 8 + cycle * 2, 8 + cycle * 2);
        int3 cycle_divisions(2 + cycle, 2 + cycle, 2 + cycle);
 
        std::vector<vec3> cycle_origins = {make_vec3(0, 0, -20)};
        std::vector<vec3> cycle_directions = {make_vec3(0, 0, 1)};
 
        collision.calculateVoxelRayPathLengths(stress_center, cycle_size, cycle_divisions, cycle_origins, cycle_directions);
 
        // Verify some data exists
        collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), P_denom, P_trans);
        DOCTEST_CHECK(P_denom >= 0);
 
        collision.clearVoxelData();
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Integration with BVH") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create some geometry to ensure BVH is built
    std::vector<uint> sphere_UUIDs = context.addSphere(10, make_vec3(0, 0, 0), 1.0f);
 
    // Build BVH before calling voxel calculations to avoid thread safety issues
    collision.buildBVH(sphere_UUIDs);
 
    // Test 1: Voxel calculations with existing geometry
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(10, 10, 10);
    int3 grid_divisions(5, 5, 5);
 
    std::vector<vec3> ray_origins;
    std::vector<vec3> ray_directions;
    for (int i = 0; i < 8; i++) {
        ray_origins.push_back(make_vec3(i - 4.0f, 0, -15));
        ray_directions.push_back(make_vec3(0, 0, 1));
    }
 
    // Should work normally even with geometry in context
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
    // Verify data is accessible
    bool found_voxel_data = false;
    for (int i = 0; i < grid_divisions.x; i++) {
        for (int j = 0; j < grid_divisions.y; j++) {
            for (int k = 0; k < grid_divisions.z; k++) {
                int P_denom, P_trans;
                collision.getVoxelTransmissionProbability(make_int3(i, j, k), P_denom, P_trans);
                if (P_denom > 0) {
                    found_voxel_data = true;
                    DOCTEST_CHECK(P_trans >= 0);
                    DOCTEST_CHECK(P_trans <= P_denom);
 
                    float r_bar = collision.getVoxelRbar(make_int3(i, j, k));
                    DOCTEST_CHECK(r_bar >= 0.0f);
                }
            }
        }
    }
    DOCTEST_CHECK(found_voxel_data);
 
    // Test 2: Verify collision detection still works after voxel calculations
    std::vector<uint> collision_results = collision.findCollisions(sphere_UUIDs[0]);
    DOCTEST_CHECK(collision_results.size() >= 0); // Should execute without error
 
    // Test 3: Interleaved operations
    collision.clearVoxelData();
 
    // Add more geometry
    std::vector<uint> triangle_UUIDs;
    triangle_UUIDs.push_back(context.addTriangle(make_vec3(5, 0, 0), make_vec3(6, 1, 0), make_vec3(6, 0, 1)));
 
    // Recalculate voxels
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
    // Find collisions with new geometry
    std::vector<uint> new_collisions = collision.findCollisions(triangle_UUIDs);
    DOCTEST_CHECK(new_collisions.size() >= 0);
 
    // Verify voxel data is still valid
    int final_P_denom, final_P_trans;
    collision.getVoxelTransmissionProbability(make_int3(2, 2, 2), final_P_denom, final_P_trans);
    DOCTEST_CHECK(final_P_denom >= 0);
    DOCTEST_CHECK(final_P_trans >= 0);
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Ray Path Length - Edge Case Ray Geometries") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(4, 4, 4);
    int3 grid_divisions(2, 2, 2);
 
    // Test 1: Ray parallel to voxel face (grazing)
    std::vector<vec3> grazing_origins = {make_vec3(-3, 2.0f, 0)}; // At grid boundary
    std::vector<vec3> grazing_directions = {make_vec3(1, 0, 0)}; // Parallel to face
 
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, grazing_origins, grazing_directions);
 
    // Should handle gracefully - may or may not intersect
    bool found_grazing_intersection = false;
    for (int i = 0; i < grid_divisions.x; i++) {
        for (int j = 0; j < grid_divisions.y; j++) {
            for (int k = 0; k < grid_divisions.z; k++) {
                int P_denom, P_trans;
                collision.getVoxelTransmissionProbability(make_int3(i, j, k), P_denom, P_trans);
                if (P_denom > 0) {
                    found_grazing_intersection = true;
                    float r_bar = collision.getVoxelRbar(make_int3(i, j, k));
                    DOCTEST_CHECK(r_bar >= 0.0f);
                }
            }
        }
    }
 
    // Test 2: Ray touching corner/edge
    collision.clearVoxelData();
    std::vector<vec3> corner_origins = {make_vec3(-3, -3, -3)};
    std::vector<vec3> corner_directions = {normalize(make_vec3(1, 1, 1))};
 
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, corner_origins, corner_directions);
 
    bool found_corner_intersection = false;
    for (int i = 0; i < grid_divisions.x; i++) {
        for (int j = 0; j < grid_divisions.y; j++) {
            for (int k = 0; k < grid_divisions.z; k++) {
                int P_denom, P_trans;
                collision.getVoxelTransmissionProbability(make_int3(i, j, k), P_denom, P_trans);
                if (P_denom > 0) {
                    found_corner_intersection = true;
                    float r_bar = collision.getVoxelRbar(make_int3(i, j, k));
                    DOCTEST_CHECK(r_bar >= 0.0f);
                }
            }
        }
    }
 
    // Test 3: Rays with very small direction components (near-zero)
    collision.clearVoxelData();
    std::vector<vec3> near_zero_origins = {make_vec3(0, 0, -5)};
    std::vector<vec3> near_zero_directions = {normalize(make_vec3(1e-6f, 1e-6f, 1.0f))};
 
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, near_zero_origins, near_zero_directions);
 
    // Should handle without numerical issues
    bool found_near_zero_intersection = false;
    for (int i = 0; i < grid_divisions.x; i++) {
        for (int j = 0; j < grid_divisions.y; j++) {
            for (int k = 0; k < grid_divisions.z; k++) {
                int P_denom, P_trans;
                collision.getVoxelTransmissionProbability(make_int3(i, j, k), P_denom, P_trans);
                if (P_denom > 0) {
                    found_near_zero_intersection = true;
                    float r_bar = collision.getVoxelRbar(make_int3(i, j, k));
                    DOCTEST_CHECK(r_bar >= 0.0f);
                    DOCTEST_CHECK(std::isfinite(r_bar)); // Check for NaN/inf
                }
            }
        }
    }
}
 
// -------- GENERIC RAY-TRACING TESTS --------
 
DOCTEST_TEST_CASE("CollisionDetection Generic Ray Casting - Basic Functionality") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create simple test geometry - triangle
    vec3 v0 = make_vec3(0, 0, 0);
    vec3 v1 = make_vec3(1, 0, 0);
    vec3 v2 = make_vec3(0.5f, 0, 1);
    uint triangle_uuid = context.addTriangle(v0, v1, v2);
 
    // Test 1: Hit test - ray intersecting triangle
    vec3 ray_origin = make_vec3(0.5f, -1, 0.5f);
    vec3 ray_direction = normalize(make_vec3(0, 1, 0));
 
    CollisionDetection::CollisionDetection::HitResult result = collision.castRay(ray_origin, ray_direction);
 
    DOCTEST_CHECK(result.hit == true);
    DOCTEST_CHECK(result.primitive_UUID == triangle_uuid);
    DOCTEST_CHECK(result.distance > 0.9f);
    DOCTEST_CHECK(result.distance < 1.1f);
 
    // Check intersection point is reasonable
    DOCTEST_CHECK(result.intersection_point.x > 0.4f);
    DOCTEST_CHECK(result.intersection_point.x < 0.6f);
    DOCTEST_CHECK(std::abs(result.intersection_point.y) < 1e-5f);
    DOCTEST_CHECK(result.intersection_point.z > 0.4f);
    DOCTEST_CHECK(result.intersection_point.z < 0.6f);
 
    // Test 2: Miss test - ray not intersecting triangle
    vec3 miss_origin = make_vec3(2, -1, 0.5f);
    vec3 miss_direction = normalize(make_vec3(0, 1, 0));
 
    CollisionDetection::HitResult miss_result = collision.castRay(miss_origin, miss_direction);
    DOCTEST_CHECK(miss_result.hit == false);
    DOCTEST_CHECK(miss_result.distance < 0);
 
    // Test 3: Max distance constraint
    vec3 limited_origin = make_vec3(0.5f, -2, 0.5f);
    vec3 limited_direction = normalize(make_vec3(0, 1, 0));
    float max_distance = 1.5f; // Ray would need ~2 units to reach triangle
 
    CollisionDetection::HitResult limited_result = collision.castRay(limited_origin, limited_direction, max_distance);
    DOCTEST_CHECK(limited_result.hit == false);
}
 
DOCTEST_TEST_CASE("CollisionDetection Generic Ray Casting - CollisionDetection::RayQuery Structure") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test geometry
    uint triangle1 = context.addTriangle(make_vec3(0, 0, 0), make_vec3(1, 0, 0), make_vec3(0.5f, 0, 1));
    uint triangle2 = context.addTriangle(make_vec3(2, 0, 0), make_vec3(3, 0, 0), make_vec3(2.5f, 0, 1));
 
    // Test 1: CollisionDetection::RayQuery with default constructor
    CollisionDetection::RayQuery query1;
    query1.origin = make_vec3(0.5f, -1, 0.5f);
    query1.direction = normalize(make_vec3(0, 1, 0));
 
    CollisionDetection::HitResult result1 = collision.castRay(query1);
    DOCTEST_CHECK(result1.hit == true);
 
    // Test 2: CollisionDetection::RayQuery with full constructor
    CollisionDetection::RayQuery query2(make_vec3(2.5f, -1, 0.5f), normalize(make_vec3(0, 1, 0)), -1.0f, {triangle2});
 
    CollisionDetection::HitResult result2 = collision.castRay(query2);
    DOCTEST_CHECK(result2.hit == true);
    DOCTEST_CHECK(result2.primitive_UUID == triangle2);
 
    // Test 3: Target UUID filtering - should only hit triangle1
    CollisionDetection::RayQuery query3(make_vec3(0.5f, -1, 0.5f), normalize(make_vec3(0, 1, 0)), -1.0f, {triangle1});
 
    CollisionDetection::HitResult result3 = collision.castRay(query3);
    DOCTEST_CHECK(result3.hit == true);
    DOCTEST_CHECK(result3.primitive_UUID == triangle1);
 
    // Test 4: Target UUID filtering with non-intersecting primitive
    CollisionDetection::RayQuery query4(make_vec3(0.5f, -1, 0.5f), normalize(make_vec3(0, 1, 0)), -1.0f, {triangle2});
 
    CollisionDetection::HitResult result4 = collision.castRay(query4);
    DOCTEST_CHECK(result4.hit == false);
}
 
DOCTEST_TEST_CASE("CollisionDetection Batch Ray Casting") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test geometry
    uint triangle = context.addTriangle(make_vec3(-1, 0, -1), make_vec3(1, 0, -1), make_vec3(0, 0, 1));
 
 
    // Create multiple ray queries
    std::vector<CollisionDetection::RayQuery> queries;
    queries.push_back(CollisionDetection::RayQuery(make_vec3(0, -1, 0), normalize(make_vec3(0, 1, 0)))); // Hit
    queries.push_back(CollisionDetection::RayQuery(make_vec3(2, -1, 0), normalize(make_vec3(0, 1, 0)))); // Miss
    queries.push_back(CollisionDetection::RayQuery(make_vec3(-0.5f, -1, 0), normalize(make_vec3(0, 1, 0)))); // Hit
    queries.push_back(CollisionDetection::RayQuery(make_vec3(0.5f, -1, 0), normalize(make_vec3(0, 1, 0)))); // Hit
 
    // Test batch casting with statistics
    CollisionDetection::RayTracingStats stats;
    std::vector<CollisionDetection::HitResult> results = collision.castRays(queries, &stats);
 
 
    DOCTEST_CHECK(results.size() == 4);
    DOCTEST_CHECK(stats.total_rays_cast == 4);
    DOCTEST_CHECK(stats.total_hits == 3);
    DOCTEST_CHECK(stats.average_ray_distance > 0);
 
    // Verify individual results
    DOCTEST_CHECK(results[0].hit == true); // Center hit
    DOCTEST_CHECK(results[1].hit == false); // Miss
    DOCTEST_CHECK(results[2].hit == true); // Left hit
    DOCTEST_CHECK(results[3].hit == true); // Right hit
 
    // All hits should be on the same triangle
    for (const auto &result: results) {
        if (result.hit) {
            DOCTEST_CHECK(result.primitive_UUID == triangle);
            DOCTEST_CHECK(result.distance > 0);
        }
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection SoA Batch Ray Casting Equivalence") {
    // The low-memory SoA batch cast (castRaysSoA writing into caller arrays) must produce results identical to the
    // reference vector-based castRays() for the same scene and rays.
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    uint triangle = context.addTriangle(make_vec3(-1, 0, -1), make_vec3(1, 0, -1), make_vec3(0, 0, 1));
    uint sphere_first = context.addSphere(8, make_vec3(0, 4, 0), 1.0f).front(); // second target to exercise multiple primitives
 
    // Same ray set as the reference batch test, plus one aimed at the sphere.
    std::vector<helios::vec3> origins = {make_vec3(0, -1, 0), make_vec3(2, -1, 0), make_vec3(-0.5f, -1, 0), make_vec3(0.5f, -1, 0), make_vec3(0, -1, 0)};
    std::vector<helios::vec3> directions = {normalize(make_vec3(0, 1, 0)), normalize(make_vec3(0, 1, 0)), normalize(make_vec3(0, 1, 0)), normalize(make_vec3(0, 1, 0)), normalize(make_vec3(0, 1, 0))};
    const size_t count = origins.size();
    const float max_distance = -1.0f;
 
    // Reference path.
    std::vector<CollisionDetection::RayQuery> queries;
    queries.reserve(count);
    for (size_t i = 0; i < count; i++) {
        queries.emplace_back(origins[i], directions[i], max_distance);
    }
    std::vector<CollisionDetection::HitResult> ref_results = collision.castRays(queries);
 
    // SoA path writing into caller-owned arrays.
    constexpr uint MISS_UUID = 0xFFFFFFFFu;
    std::vector<float> soa_distance(count, -1.0f);
    std::vector<helios::vec3> soa_normal(count);
    std::vector<uint> soa_uuid(count, MISS_UUID);
    CollisionDetection::RayTracingStats soa_stats;
    DOCTEST_CHECK_NOTHROW(collision.castRaysSoA(origins.data(), directions.data(), count, max_distance, soa_distance.data(), soa_normal.data(), soa_uuid.data(), &soa_stats));
 
    DOCTEST_CHECK(soa_stats.total_rays_cast == count);
 
    size_t soa_hits = 0;
    for (size_t i = 0; i < count; i++) {
        bool soa_hit = (soa_uuid[i] != MISS_UUID);
        DOCTEST_CHECK(soa_hit == ref_results[i].hit); // same hit/miss classification ray-for-ray
        if (soa_hit) {
            soa_hits++;
            DOCTEST_CHECK(soa_uuid[i] == ref_results[i].primitive_UUID);
            DOCTEST_CHECK(soa_distance[i] == doctest::Approx(ref_results[i].distance));
            DOCTEST_CHECK(soa_normal[i].x == doctest::Approx(ref_results[i].normal.x));
            DOCTEST_CHECK(soa_normal[i].y == doctest::Approx(ref_results[i].normal.y));
            DOCTEST_CHECK(soa_normal[i].z == doctest::Approx(ref_results[i].normal.z));
        }
    }
    DOCTEST_CHECK(soa_stats.total_hits == soa_hits);
 
    // Zero-count is a valid no-op (must not touch the output arrays or crash).
    DOCTEST_CHECK_NOTHROW(collision.castRaysSoA(origins.data(), directions.data(), 0, max_distance, soa_distance.data(), soa_normal.data(), soa_uuid.data(), nullptr));
 
    (void) triangle;
    (void) sphere_first;
}
 
DOCTEST_TEST_CASE("CollisionDetection SoA Packet Ray Casting Equivalence") {
    // The coherent packet cast (castRaysSoA_packets) must produce results bit-for-bit identical to the per-ray
    // castRaysSoA() for the same scene and rays, for any packet size. We build a moderately complex scene and a set of
    // coherent ray packets (clusters of near-parallel rays sharing an origin, mimicking LiDAR pulse sub-rays) plus some
    // axis-aligned rays (which exercise the parallel-slab AABB handling), then compare ray-for-ray.
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Diverse geometry: a ground patch, a tessellated sphere, and a tilted triangle.
    context.addPatch(make_vec3(0, 0, 0), make_vec2(6, 6));
    context.addSphere(10, make_vec3(0, 0, 2.0f), 0.75f);
    context.addTriangle(make_vec3(-2, -2, 1), make_vec3(2, -2, 1), make_vec3(0, 2, 3));
 
    // Build coherent packets: each packet shares an origin and fans out within a small cone (like a pulse's sub-rays).
    const size_t packet_size = 12;
    const std::vector<helios::vec3> packet_origins = {make_vec3(0, 0, 6), make_vec3(1.5f, -1.0f, 5), make_vec3(-2.0f, 1.0f, 4), make_vec3(0.2f, 0.2f, 8)};
    std::vector<helios::vec3> origins;
    std::vector<helios::vec3> directions;
    for (const helios::vec3 &po: packet_origins) {
        for (size_t p = 0; p < packet_size; p++) {
            const float a = 0.02f * float(p); // small angular spread -> coherent packet
            origins.push_back(po);
            directions.push_back(normalize(make_vec3(std::sin(a), 0.5f * std::sin(a), -1.0f)));
        }
    }
    // Append one packet of exactly-axis-aligned downward rays (z-parallel) to exercise the NaN-safe slab path.
    for (size_t p = 0; p < packet_size; p++) {
        origins.push_back(make_vec3(-0.4f + 0.06f * float(p), 0.0f, 7.0f));
        directions.push_back(make_vec3(0, 0, -1));
    }
    const size_t count = origins.size();
    const float max_distance = -1.0f;
 
    constexpr uint MISS_UUID = 0xFFFFFFFFu;
 
    // Per-ray reference.
    std::vector<float> ref_d(count, -1.0f);
    std::vector<helios::vec3> ref_n(count);
    std::vector<uint> ref_u(count, MISS_UUID);
    DOCTEST_CHECK_NOTHROW(collision.castRaysSoA(origins.data(), directions.data(), count, max_distance, ref_d.data(), ref_n.data(), ref_u.data()));
 
    // Packet path.
    std::vector<float> pkt_d(count, -1.0f);
    std::vector<helios::vec3> pkt_n(count);
    std::vector<uint> pkt_u(count, MISS_UUID);
    CollisionDetection::RayTracingStats pkt_stats;
    DOCTEST_CHECK_NOTHROW(collision.castRaysSoA_packets(origins.data(), directions.data(), count, packet_size, max_distance, pkt_d.data(), pkt_n.data(), pkt_u.data(), &pkt_stats));
 
    DOCTEST_CHECK(pkt_stats.total_rays_cast == count);
 
    size_t pkt_hits = 0;
    for (size_t i = 0; i < count; i++) {
        const bool ref_hit = (ref_u[i] != MISS_UUID);
        const bool pkt_hit = (pkt_u[i] != MISS_UUID);
        DOCTEST_CHECK(pkt_hit == ref_hit); // identical hit/miss classification ray-for-ray
        if (ref_hit && pkt_hit) {
            pkt_hits++;
            // The closest-hit DISTANCE is the order-independent invariant and must match exactly. The hit primitive
            // (and its normal) is only uniquely defined when no other primitive lies at the same distance: when two
            // coincident facets share an edge a ray grazes, the per-ray and packet traversals legitimately tie-break
            // to different (equally valid) primitives because they visit nodes in a different order. So only require
            // the UUID/normal to agree when the distances are NOT an exact tie candidate.
            DOCTEST_CHECK(pkt_d[i] == doctest::Approx(ref_d[i]));
            if (pkt_u[i] == ref_u[i]) {
                DOCTEST_CHECK(pkt_n[i].x == doctest::Approx(ref_n[i].x));
                DOCTEST_CHECK(pkt_n[i].y == doctest::Approx(ref_n[i].y));
                DOCTEST_CHECK(pkt_n[i].z == doctest::Approx(ref_n[i].z));
            } else {
                // Different primitive returned -> must be a genuine equal-distance tie, not a wrong/farther hit.
                DOCTEST_CHECK(pkt_d[i] == doctest::Approx(ref_d[i]).epsilon(1e-4));
            }
        }
    }
    DOCTEST_CHECK(pkt_stats.total_hits == pkt_hits);
 
    // packet_size == 1 must degenerate to the per-ray path and still match.
    std::vector<float> p1_d(count, -1.0f);
    std::vector<helios::vec3> p1_n(count);
    std::vector<uint> p1_u(count, MISS_UUID);
    DOCTEST_CHECK_NOTHROW(collision.castRaysSoA_packets(origins.data(), directions.data(), count, 1, max_distance, p1_d.data(), p1_n.data(), p1_u.data()));
    for (size_t i = 0; i < count; i++) {
        DOCTEST_CHECK((p1_u[i] != MISS_UUID) == (ref_u[i] != MISS_UUID));
        if (ref_u[i] != MISS_UUID) {
            DOCTEST_CHECK(p1_u[i] == ref_u[i]);
            DOCTEST_CHECK(p1_d[i] == doctest::Approx(ref_d[i]));
        }
    }
 
    // A packet size larger than the internal MAX_PACKET_RAYS (256) must still match (forces sub-packet splitting).
    {
        const size_t big = 600;
        std::vector<helios::vec3> bo(big), bd(big);
        for (size_t i = 0; i < big; i++) {
            bo[i] = make_vec3(-2.5f + 5.0f * float(i) / float(big - 1), 0.0f, 7.0f);
            bd[i] = make_vec3(0, 0, -1);
        }
        std::vector<float> rd(big, -1.0f), kd(big, -1.0f);
        std::vector<helios::vec3> rn(big), kn(big);
        std::vector<uint> ru(big, MISS_UUID), ku(big, MISS_UUID);
        collision.castRaysSoA(bo.data(), bd.data(), big, max_distance, rd.data(), rn.data(), ru.data());
        collision.castRaysSoA_packets(bo.data(), bd.data(), big, big, max_distance, kd.data(), kn.data(), ku.data());
        for (size_t i = 0; i < big; i++) {
            DOCTEST_CHECK((ku[i] != MISS_UUID) == (ru[i] != MISS_UUID));
            if (ru[i] != MISS_UUID) {
                // Distance is the order-independent invariant; UUID may differ only on an exact equal-distance tie.
                DOCTEST_CHECK(kd[i] == doctest::Approx(rd[i]));
            }
        }
    }
 
    // Zero-count is a valid no-op.
    DOCTEST_CHECK_NOTHROW(collision.castRaysSoA_packets(origins.data(), directions.data(), 0, packet_size, max_distance, pkt_d.data(), pkt_n.data(), pkt_u.data(), nullptr));
}
 
DOCTEST_TEST_CASE("CollisionDetection SoA Batch Ray Casting GPU/CPU Equivalence") {
    // The SoA batch cast must produce identical results on the GPU and CPU paths. The GPU dispatch is forced by
    // exceeding the 1M-ray batch threshold on a >=500-primitive resident scene (see shouldUseGPU); we then compare the
    // GPU SoA result against the CPU SoA result ray-for-ray. On a non-CUDA build both runs execute on the CPU and the
    // comparison is trivially satisfied, so this test is safe everywhere.
    Context context;
 
    // A grid of 5041 SEPARATED triangles at x=0 (>= MIN_PRIMITIVES_FOR_GPU). One triangle per cell, inset with gaps so
    // no two triangles share an edge or are otherwise coplanar-adjacent. Because each ray (below) is aimed at exactly
    // one triangle's interior centroid, the closest hit is unambiguous and its UUID/distance/normal are identical
    // between CPU and GPU (no coplanar tie-break to disagree on). Centroids are recorded for ray targeting.
    const int grid = 71;
    const float extent = 2.0f;
    const float c = extent / float(grid); // cell size
    std::vector<helios::vec3> centroids;
    centroids.reserve(size_t(grid) * size_t(grid));
    for (int a = 0; a < grid; a++) {
        for (int b = 0; b < grid; b++) {
            float by = -extent / 2.0f + a * c;
            float bz = -extent / 2.0f + b * c;
            vec3 v0(0, by + 0.2f * c, bz + 0.2f * c);
            vec3 v1(0, by + 0.8f * c, bz + 0.2f * c);
            vec3 v2(0, by + 0.5f * c, bz + 0.8f * c);
            context.addTriangle(v0, v1, v2);
            centroids.push_back(make_vec3(0.0f, by + 0.5f * c, bz + 0.4f * c)); // interior point (avg of the three)
        }
    }
    const size_t num_tri = centroids.size();
 
    // 1,102,500 rays (> 1M threshold) shooting +x. Each ray targets one triangle's interior centroid, so it hits that
    // triangle and only that triangle. A sparse subset is shifted far off the grid to force genuine misses.
    const int rays_per_dim = 1050;
    const size_t count = size_t(rays_per_dim) * size_t(rays_per_dim);
    std::vector<helios::vec3> origins(count), directions(count);
    for (size_t idx = 0; idx < count; idx++) {
        const helios::vec3 &target = centroids[idx % num_tri];
        bool make_miss = (idx % 53 == 0);
        origins[idx] = make_vec3(-2.0f, make_miss ? target.y + 100.0f : target.y, target.z);
        directions[idx] = make_vec3(1.0f, 0.0f, 0.0f);
    }
    const float max_distance = 10.0f;
    constexpr uint MISS_UUID = 0xFFFFFFFFu;
 
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // CPU SoA reference (GPU disabled forces the OpenMP traversal regardless of batch size).
    collision.disableGPUAcceleration();
    collision.buildBVH();
    std::vector<float> cpu_d(count, -1.0f);
    std::vector<helios::vec3> cpu_n(count);
    std::vector<uint> cpu_u(count, MISS_UUID);
    DOCTEST_CHECK_NOTHROW(collision.castRaysSoA(origins.data(), directions.data(), count, max_distance, cpu_d.data(), cpu_n.data(), cpu_u.data()));
 
    // GPU SoA: enabling GPU + buildBVH uploads the resident scene; the >1M batch then dispatches to the device.
    collision.enableGPUAcceleration();
    collision.buildBVH();
    std::vector<float> gpu_d(count, -1.0f);
    std::vector<helios::vec3> gpu_n(count);
    std::vector<uint> gpu_u(count, MISS_UUID);
    CollisionDetection::RayTracingStats gpu_stats;
    DOCTEST_CHECK_NOTHROW(collision.castRaysSoA(origins.data(), directions.data(), count, max_distance, gpu_d.data(), gpu_n.data(), gpu_u.data(), &gpu_stats));
    DOCTEST_CHECK(gpu_stats.total_rays_cast == count);
 
    // HELIOS_CUDA_AVAILABLE is a *compile-time* flag (the CUDA toolkit was present at build time); it does NOT guarantee a
    // usable device at *runtime*. When the toolkit is compiled in but no working GPU exists (e.g. a dead/absent NVIDIA
    // driver on a CI runner), allocateGPUMemory() correctly logs a warning and flips gpu_acceleration_enabled back to
    // false, and the cast above transparently falls back to the CPU traversal. In that case the "GPU" run below is really
    // a second CPU run, so the CPU/GPU equivalence comparison is trivially satisfied and still meaningful — we just can't
    // claim the device path was exercised. Only assert the GPU path was genuinely taken when GPU acceleration survived
    // the buildBVH() upload (i.e. a working device was actually present).
#ifdef HELIOS_CUDA_AVAILABLE
    if (collision.isGPUAccelerationEnabled()) {
        DOCTEST_MESSAGE("GPU path exercised (working CUDA device present)");
    } else {
        DOCTEST_MESSAGE("SKIPPED GPU-path assertion: no usable CUDA device at runtime; comparison ran CPU-vs-CPU");
    }
#endif
 
    // Aggregate the per-ray comparison (1.1M rays => count discrepancies rather than emit a check per ray).
    size_t cpu_hits = 0, gpu_hits = 0, classify_mismatch = 0, uuid_mismatch = 0, dist_mismatch = 0, normal_mismatch = 0;
    for (size_t i = 0; i < count; i++) {
        bool ch = (cpu_u[i] != MISS_UUID);
        bool gh = (gpu_u[i] != MISS_UUID);
        if (ch)
            cpu_hits++;
        if (gh)
            gpu_hits++;
        if (ch != gh) {
            classify_mismatch++;
            continue;
        }
        if (ch) {
            if (gpu_u[i] != cpu_u[i])
                uuid_mismatch++;
            if (std::fabs(gpu_d[i] - cpu_d[i]) > 1e-3f)
                dist_mismatch++;
            if ((gpu_n[i] - cpu_n[i]).magnitude() > 1e-3f)
                normal_mismatch++;
        }
    }
    DOCTEST_CHECK(cpu_hits > 0);
    DOCTEST_CHECK(gpu_hits == cpu_hits);
    DOCTEST_CHECK(classify_mismatch == 0);
    DOCTEST_CHECK(uuid_mismatch == 0);
    DOCTEST_CHECK(dist_mismatch == 0);
    DOCTEST_CHECK(normal_mismatch == 0);
}
 
DOCTEST_TEST_CASE("CollisionDetection Grid Ray Intersection") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test geometry - triangle in center
    uint triangle = context.addTriangle(make_vec3(-0.5f, 0, -0.5f), make_vec3(0.5f, 0, -0.5f), make_vec3(0, 0, 0.5f));
 
    // Set up grid parameters
    vec3 grid_center = make_vec3(0, 0, 0);
    vec3 grid_size = make_vec3(4, 4, 4);
    int3 grid_divisions = make_int3(2, 2, 2);
 
    // Create rays hitting different voxels
    std::vector<CollisionDetection::RayQuery> rays;
    rays.push_back(CollisionDetection::RayQuery(make_vec3(0, -2, 0), normalize(make_vec3(0, 1, 0)))); // Center voxel
    rays.push_back(CollisionDetection::RayQuery(make_vec3(-0.8f, -2, 0), normalize(make_vec3(0, 1, 0)))); // Different voxel
    rays.push_back(CollisionDetection::RayQuery(make_vec3(2, -2, 0), normalize(make_vec3(0, 1, 0)))); // Miss entirely
 
    auto grid_results = collision.performGridRayIntersection(grid_center, grid_size, grid_divisions, rays);
 
    DOCTEST_CHECK(grid_results.size() == 2); // x-divisions
    DOCTEST_CHECK(grid_results[0].size() == 2); // y-divisions
    DOCTEST_CHECK(grid_results[0][0].size() == 2); // z-divisions
 
    // Count total hits across all voxels
    int total_hits = 0;
    for (int i = 0; i < 2; i++) {
        for (int j = 0; j < 2; j++) {
            for (int k = 0; k < 2; k++) {
                total_hits += grid_results[i][j][k].size();
            }
        }
    }
    DOCTEST_CHECK(total_hits >= 1); // At least one hit should be recorded
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Path Lengths Detailed") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test geometry
    uint triangle = context.addTriangle(make_vec3(-1, 0, -1), make_vec3(1, 0, -1), make_vec3(0, 0, 1));
 
    // Set up test parameters
    vec3 grid_center = make_vec3(0, 0, 0);
    vec3 grid_size = make_vec3(4, 4, 4);
    int3 grid_divisions = make_int3(2, 2, 2);
 
    std::vector<vec3> ray_origins = {
            make_vec3(0, -2, 0), make_vec3(0.5f, -2, 0), make_vec3(2, -2, 0) // This should miss
    };
 
    std::vector<vec3> ray_directions = {normalize(make_vec3(0, 1, 0)), normalize(make_vec3(0, 1, 0)), normalize(make_vec3(0, 1, 0))};
 
    std::vector<CollisionDetection::HitResult> hit_results;
    collision.calculateRayPathLengthsDetailed(grid_center, grid_size, grid_divisions, ray_origins, ray_directions, hit_results);
 
    DOCTEST_CHECK(hit_results.size() == 3);
 
    // First two rays should hit
    DOCTEST_CHECK(hit_results[0].hit == true);
    DOCTEST_CHECK(hit_results[1].hit == true);
    DOCTEST_CHECK(hit_results[2].hit == false);
 
    // Hit distances should be reasonable
    DOCTEST_CHECK(hit_results[0].distance > 1.5f);
    DOCTEST_CHECK(hit_results[0].distance < 2.5f);
    DOCTEST_CHECK(hit_results[1].distance > 1.5f);
    DOCTEST_CHECK(hit_results[1].distance < 2.5f);
 
    // Verify that existing voxel data is also updated
    int P_denom, P_trans;
    collision.getVoxelTransmissionProbability(make_int3(0, 0, 0), P_denom, P_trans);
    DOCTEST_CHECK(P_denom >= 0);
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Casting - Normal Calculation") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test 1: Triangle normal calculation
    vec3 v0 = make_vec3(0, 0, 0);
    vec3 v1 = make_vec3(1, 0, 0);
    vec3 v2 = make_vec3(0, 1, 0);
    uint triangle = context.addTriangle(v0, v1, v2);
 
    vec3 ray_origin = make_vec3(0.3f, 0.3f, -1);
    vec3 ray_direction = normalize(make_vec3(0, 0, 1));
 
    CollisionDetection::CollisionDetection::HitResult result = collision.castRay(ray_origin, ray_direction);
 
    DOCTEST_CHECK(result.hit == true);
 
    // Normal should point in +Z direction (calculated from cross product)
    vec3 expected_normal = normalize(make_vec3(0, 0, 1));
    float dot_product = result.normal.x * expected_normal.x + result.normal.y * expected_normal.y + result.normal.z * expected_normal.z;
    DOCTEST_CHECK(std::abs(dot_product) > 0.9f); // Should be nearly parallel
 
    // Test 2: Patch normal calculation
    uint patch = context.addPatch(make_vec3(0, 0, 2), make_vec2(1, 1));
 
    vec3 patch_ray_origin = make_vec3(0, 0, 1);
    vec3 patch_ray_direction = normalize(make_vec3(0, 0, 1));
 
    CollisionDetection::HitResult patch_result = collision.castRay(patch_ray_origin, patch_ray_direction);
 
    DOCTEST_CHECK(patch_result.hit == true);
    DOCTEST_CHECK(patch_result.primitive_UUID == patch);
 
    // Patch normal should also be reasonable
    DOCTEST_CHECK(patch_result.normal.magnitude() > 0.9f);
    DOCTEST_CHECK(patch_result.normal.magnitude() < 1.1f);
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Casting - Edge Cases and Error Handling") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test triangle
    uint triangle = context.addTriangle(make_vec3(0, 0, 0), make_vec3(1, 0, 0), make_vec3(0.5f, 0, 1));
 
    // Test 1: Zero direction vector (should be handled)
    vec3 zero_direction = make_vec3(0, 0, 0);
    CollisionDetection::HitResult zero_result = collision.castRay(make_vec3(0, -1, 0), zero_direction);
    DOCTEST_CHECK(zero_result.hit == false); // Should handle gracefully
 
    // Test 2: Very small direction vector (should normalize)
    vec3 tiny_direction = make_vec3(1e-8f, 1e-8f, 1e-8f);
    CollisionDetection::HitResult tiny_result = collision.castRay(make_vec3(0.5f, -1, 0.5f), tiny_direction);
    // Should either hit or miss gracefully, not crash
 
    // Test 3: Infinite max distance
    CollisionDetection::HitResult inf_result = collision.castRay(make_vec3(0.5f, -1, 0.5f), normalize(make_vec3(0, 1, 0)), std::numeric_limits<float>::infinity());
    DOCTEST_CHECK(inf_result.hit == true);
 
    // Test 4: Negative max distance (should be treated as infinite)
    CollisionDetection::HitResult neg_result = collision.castRay(make_vec3(0.5f, -1, 0.5f), normalize(make_vec3(0, 1, 0)), -5.0f);
    DOCTEST_CHECK(neg_result.hit == true);
 
    // Test 5: Empty target UUIDs (should use all primitives)
    std::vector<uint> empty_targets;
    CollisionDetection::HitResult empty_result = collision.castRay(make_vec3(0.5f, -1, 0.5f), normalize(make_vec3(0, 1, 0)), -1.0f, empty_targets);
    DOCTEST_CHECK(empty_result.hit == true);
 
    // Test 6: Invalid target UUIDs (should be filtered out)
    std::vector<uint> invalid_targets = {99999, triangle, 88888};
    CollisionDetection::HitResult invalid_result = collision.castRay(make_vec3(0.5f, -1, 0.5f), normalize(make_vec3(0, 1, 0)), -1.0f, invalid_targets);
    DOCTEST_CHECK(invalid_result.hit == true);
    DOCTEST_CHECK(invalid_result.primitive_UUID == triangle);
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Casting - Performance and Scalability") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create larger set of test geometry
    std::vector<uint> triangles;
    for (int i = 0; i < 100; i++) {
        float x = i * 0.1f;
        uint triangle = context.addTriangle(make_vec3(x, 0, -0.5f), make_vec3(x + 0.05f, 0, -0.5f), make_vec3(x + 0.025f, 0, 0.5f));
        triangles.push_back(triangle);
    }
 
    // Test batch casting with large number of rays - align with triangle centers
    std::vector<CollisionDetection::RayQuery> many_rays;
    for (int i = 0; i < 200; i++) {
        float x = (i % 100) * 0.1f + 0.025f; // Align with triangle centers
        many_rays.push_back(CollisionDetection::RayQuery(make_vec3(x, -1, 0), normalize(make_vec3(0, 1, 0))));
    }
 
    auto start_time = std::chrono::high_resolution_clock::now();
 
    CollisionDetection::RayTracingStats stats;
    std::vector<CollisionDetection::HitResult> results = collision.castRays(many_rays, &stats);
 
    auto end_time = std::chrono::high_resolution_clock::now();
    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end_time - start_time);
 
    DOCTEST_CHECK(results.size() == 200);
    DOCTEST_CHECK(stats.total_rays_cast == 200);
    DOCTEST_CHECK(stats.total_hits >= 100); // Should hit many triangles
 
    // Performance should be reasonable (less than 1 second for 200 rays)
    DOCTEST_CHECK(duration.count() < 1000);
 
    // Performance info available in stats but not printed during normal test runs
    // Uncomment for performance benchmarking:
    // std::cout << "Batch ray casting performance: " << duration.count() << " ms for " << many_rays.size() << " rays (" << stats.total_hits << " hits)" << std::endl;
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Casting - Integration with Existing BVH") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test geometry
    uint triangle1 = context.addTriangle(make_vec3(0, 0, 0), make_vec3(1, 0, 0), make_vec3(0.5f, 0, 1));
    uint triangle2 = context.addTriangle(make_vec3(2, 0, 0), make_vec3(3, 0, 0), make_vec3(2.5f, 0, 1));
 
    // Test that ray casting works with manually built BVH
    collision.buildBVH();
 
    CollisionDetection::HitResult result1 = collision.castRay(make_vec3(0.5f, -1, 0.5f), normalize(make_vec3(0, 1, 0)));
    DOCTEST_CHECK(result1.hit == true);
    DOCTEST_CHECK(result1.primitive_UUID == triangle1);
 
    CollisionDetection::HitResult result2 = collision.castRay(make_vec3(2.5f, -1, 0.5f), normalize(make_vec3(0, 1, 0)));
    DOCTEST_CHECK(result2.hit == true);
    DOCTEST_CHECK(result2.primitive_UUID == triangle2);
 
    // Test that ray casting works with automatic BVH rebuilds
    collision.enableAutomaticBVHRebuilds();
 
    // Add new geometry after BVH was built
    uint triangle3 = context.addTriangle(make_vec3(4, 0, 0), make_vec3(5, 0, 0), make_vec3(4.5f, 0, 1));
 
    // Should automatically rebuild BVH and find new triangle
    CollisionDetection::HitResult result3 = collision.castRay(make_vec3(4.5f, -1, 0.5f), normalize(make_vec3(0, 1, 0)));
    DOCTEST_CHECK(result3.hit == true);
    DOCTEST_CHECK(result3.primitive_UUID == triangle3);
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Casting - Compatibility with Other Plugin Methods") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create overlapping test geometry
    auto triangles = CollisionTests::generateOverlappingCluster(&context, 5);
 
    // Test that ray casting and collision detection can coexist
    auto collisions = collision.findCollisions(triangles[0]);
    DOCTEST_CHECK(collisions.size() > 0);
 
    // Test that existing collision detection methods still work
    DOCTEST_CHECK(triangles.size() == 5);
 
    // Test cone intersection functionality
    auto cone_result = collision.findOptimalConePath(make_vec3(0, -2, 0), make_vec3(0, 1, 0), M_PI / 6, 3.0f);
 
    // Verify that both collision detection and ray casting infrastructure coexist
    // This test mainly verifies compatibility, not specific ray hits
    DOCTEST_CHECK(collisions.size() > 0); // Collision detection works
    DOCTEST_CHECK(true); // Ray casting infrastructure is available (compilation test)
}
 
// ================================================================
// OPTIMIZATION TEST CASES
// ================================================================
 
DOCTEST_TEST_CASE("CollisionDetection - BVH Optimization Mode Management") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test geometry to trigger BVH construction
    uint triangle = context.addTriangle(make_vec3(0, 0, 0), make_vec3(1, 0, 0), make_vec3(0.5f, 0, 1));
    auto sphere_uuids = context.addSphere(10, make_vec3(2, 0, 0.5f), 0.5f);
 
    // Test 1: Default mode should be SOA_UNCOMPRESSED
    DOCTEST_CHECK(collision.getBVHOptimizationMode() == CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
 
    // Test 2: Mode switching (only SOA_UNCOMPRESSED available now)
    DOCTEST_CHECK_NOTHROW(collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED));
    DOCTEST_CHECK(collision.getBVHOptimizationMode() == CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
 
    // Test 4: Build BVH to populate memory statistics
    collision.buildBVH();
 
    // Test 5: Convert between optimization modes to populate all memory structures
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
 
    // Test 6: Memory usage comparison
    auto memory_stats = collision.getBVHMemoryUsage();
    DOCTEST_CHECK(memory_stats.soa_memory_bytes > 0);
 
    // With quantized mode removed, quantized_memory_bytes should be 0
    DOCTEST_CHECK(memory_stats.quantized_memory_bytes == 0);
    DOCTEST_CHECK(memory_stats.quantized_reduction_percent == 0.0f);
}
 
DOCTEST_TEST_CASE("CollisionDetection - Optimized Ray Casting Correctness") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create diverse test geometry with known positions
    uint triangle = context.addTriangle(make_vec3(0, 0, 0), make_vec3(1, 0, 0), make_vec3(0.5f, 0, 1));
    auto sphere_uuids = context.addSphere(8, make_vec3(3, 0, 0.5f), 0.5f);
 
    // Create test rays with known expected outcomes
    std::vector<CollisionDetection::RayQuery> rays;
    rays.push_back(CollisionDetection::RayQuery(make_vec3(0.5f, -1, 0.5f), make_vec3(0, 1, 0))); // Should hit triangle
    rays.push_back(CollisionDetection::RayQuery(make_vec3(3, -1, 0.5f), make_vec3(0, 1, 0))); // Should hit sphere
    rays.push_back(CollisionDetection::RayQuery(make_vec3(10, -1, 0), make_vec3(0, 1, 0))); // Should miss both
 
    // Test legacy and optimized (SoA) modes produce consistent results
    std::vector<CollisionDetection::HitResult> legacy_results, soa_results;
 
    // Legacy mode
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
    legacy_results = collision.castRays(rays);
 
    // SOA optimized mode
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
    soa_results = collision.castRaysOptimized(rays);
 
    // Verify both modes produce equivalent results
    DOCTEST_REQUIRE(legacy_results.size() == 3);
    DOCTEST_REQUIRE(soa_results.size() == 3);
 
    for (size_t i = 0; i < legacy_results.size(); i++) {
        // Hit/miss should be consistent across both modes
        DOCTEST_CHECK(legacy_results[i].hit == soa_results[i].hit);
 
        if (legacy_results[i].hit) {
            // Primitive UUID should match
            DOCTEST_CHECK(legacy_results[i].primitive_UUID == soa_results[i].primitive_UUID);
 
            // Distance should be very close
            DOCTEST_CHECK(std::abs(legacy_results[i].distance - soa_results[i].distance) < 0.001f);
        }
    }
 
    // Verify expected hit pattern: ray 0 and 1 should hit, ray 2 should miss
    DOCTEST_CHECK(legacy_results[0].hit == true); // Triangle hit
    DOCTEST_CHECK(legacy_results[1].hit == true); // Sphere hit
    DOCTEST_CHECK(legacy_results[2].hit == false); // Miss
}
 
DOCTEST_TEST_CASE("CollisionDetection - Ray Streaming Interface") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
 
    // Create test geometry grid
    for (int i = 0; i < 5; i++) {
        float x = i * 2.0f;
        context.addTriangle(make_vec3(x, 0, 0), make_vec3(x + 1, 0, 0), make_vec3(x + 0.5f, 0, 1));
    }
 
    // Test ray streaming interface
    CollisionDetection::RayStream stream;
    std::vector<CollisionDetection::RayQuery> batch;
 
    // Create batch of rays
    for (int i = 0; i < 50; i++) {
        float x = (i % 5) * 2.0f + 0.5f; // Align with triangles
        batch.push_back(CollisionDetection::RayQuery(make_vec3(x, -1, 0.5f), make_vec3(0, 1, 0)));
    }
    stream.addRays(batch);
 
    DOCTEST_CHECK(stream.total_rays == 50);
    DOCTEST_CHECK(stream.packets.size() > 0);
 
    // Process stream
    CollisionDetection::RayTracingStats stats;
    bool success = collision.processRayStream(stream, &stats);
    DOCTEST_CHECK(success == true);
    DOCTEST_CHECK(stats.total_rays_cast == 50);
 
    // Verify results
    auto results = stream.getAllResults();
    DOCTEST_CHECK(results.size() == 50);
 
    // All rays should hit (they're aligned with triangles)
    size_t hit_count = 0;
    for (const auto &result: results) {
        if (result.hit)
            hit_count++;
    }
    DOCTEST_CHECK(hit_count > 40); // Most rays should hit the triangles
}
 
DOCTEST_TEST_CASE("CollisionDetection - BVH Layout Conversion Methods") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test geometry
    uint triangle1 = context.addTriangle(make_vec3(0, 0, 0), make_vec3(2, 0, 0), make_vec3(1, 0, 2));
    auto sphere_uuids = context.addSphere(12, make_vec3(5, 0, 1), 0.8f);
    uint triangle2 = context.addTriangle(make_vec3(-2, 1, 0), make_vec3(0, 1, 0), make_vec3(-1, 1, 1.5f));
 
    // Build BVH
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
    collision.buildBVH();
 
    // Test rays
    std::vector<CollisionDetection::RayQuery> test_rays = {
            CollisionDetection::RayQuery(make_vec3(1, -1, 1), make_vec3(0, 1, 0)), // Should hit triangle1
            CollisionDetection::RayQuery(make_vec3(5, -1, 1), make_vec3(0, 1, 0)), // Should hit sphere
            CollisionDetection::RayQuery(make_vec3(-1, 0, 0.75f), make_vec3(0, 1, 0)) // Should hit triangle2
    };
 
    // Test legacy and SoA modes
    auto legacy_results = collision.castRays(test_rays);
    auto soa_results = collision.castRaysOptimized(test_rays);
    auto memory_stats = collision.getBVHMemoryUsage();
 
    // Validation
    DOCTEST_REQUIRE(legacy_results.size() == 3);
    DOCTEST_REQUIRE(soa_results.size() == 3);
 
    // Count hits to verify consistency
    size_t legacy_hits = 0, soa_hits = 0;
    for (size_t i = 0; i < 3; i++) {
        if (legacy_results[i].hit)
            legacy_hits++;
        if (soa_results[i].hit)
            soa_hits++;
    }
 
    // SoA should produce consistent results with legacy mode
    DOCTEST_CHECK(legacy_hits == soa_hits);
 
    // Memory usage verification (without quantized mode)
    DOCTEST_CHECK(memory_stats.soa_memory_bytes > 0);
    DOCTEST_CHECK(memory_stats.quantized_memory_bytes == 0); // No quantized mode
    DOCTEST_CHECK(memory_stats.quantized_reduction_percent == 0.0f);
}
 
DOCTEST_TEST_CASE("CollisionDetection - RayPacket Edge Cases and Functionality") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test 1: Empty RayPacket behavior
    CollisionDetection::RayPacket empty_packet;
    DOCTEST_CHECK(empty_packet.ray_count == 0);
    DOCTEST_CHECK(empty_packet.getMemoryUsage() == 0);
    DOCTEST_CHECK(empty_packet.toRayQueries().empty());
 
    // Clear empty packet should not crash
    DOCTEST_CHECK_NOTHROW(empty_packet.clear());
 
    // Test 2: RayPacket capacity management
    CollisionDetection::RayPacket capacity_packet;
    capacity_packet.reserve(100);
 
    // Add rays up to and beyond initial capacity
    std::vector<CollisionDetection::RayQuery> test_queries;
    for (int i = 0; i < 150; i++) {
        float x = i * 0.1f;
        CollisionDetection::RayQuery query(make_vec3(x, 0, 0), make_vec3(0, 0, 1));
        test_queries.push_back(query);
        capacity_packet.addRay(query);
    }
 
    DOCTEST_CHECK(capacity_packet.ray_count == 150);
    DOCTEST_CHECK(capacity_packet.origins.size() == 150);
    DOCTEST_CHECK(capacity_packet.directions.size() == 150);
    DOCTEST_CHECK(capacity_packet.results.size() == 150);
 
    // Test 3: RayPacket conversion accuracy
    auto converted_queries = capacity_packet.toRayQueries();
    DOCTEST_REQUIRE(converted_queries.size() == 150);
 
    for (size_t i = 0; i < 150; i++) {
        DOCTEST_CHECK(converted_queries[i].origin.magnitude() == test_queries[i].origin.magnitude());
        DOCTEST_CHECK(converted_queries[i].direction.magnitude() == test_queries[i].direction.magnitude());
        DOCTEST_CHECK(converted_queries[i].max_distance == test_queries[i].max_distance);
    }
 
    // Test 4: Memory usage calculation
    size_t expected_memory = (150 * 2) * sizeof(helios::vec3) + // origins + directions
                             150 * sizeof(float) + // max_distances
                             150 * sizeof(CollisionDetection::HitResult); // results
    size_t actual_memory = capacity_packet.getMemoryUsage();
    DOCTEST_CHECK(actual_memory >= expected_memory); // Account for target_UUIDs overhead
 
    // Test 5: Clear functionality
    capacity_packet.clear();
    DOCTEST_CHECK(capacity_packet.ray_count == 0);
    DOCTEST_CHECK(capacity_packet.origins.empty());
    DOCTEST_CHECK(capacity_packet.directions.empty());
    DOCTEST_CHECK(capacity_packet.results.empty());
    DOCTEST_CHECK(capacity_packet.getMemoryUsage() == 0);
}
 
DOCTEST_TEST_CASE("CollisionDetection - RayStream Batch Management") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
 
    // Create test geometry
    for (int i = 0; i < 3; i++) {
        float x = i * 3.0f;
        context.addTriangle(make_vec3(x, 0, 0), make_vec3(x + 1, 0, 0), make_vec3(x + 0.5f, 0, 1));
    }
 
    // Test 1: Large ray stream with multiple packets
    CollisionDetection::RayStream large_stream;
    std::vector<CollisionDetection::RayQuery> large_batch;
 
    // Create more rays than fit in a single packet
    size_t total_rays = CollisionDetection::RAY_BATCH_SIZE * 2.5; // 2.5 packets worth
    for (size_t i = 0; i < total_rays; i++) {
        float x = (i % 3) * 3.0f + 0.5f;
        large_batch.push_back(CollisionDetection::RayQuery(make_vec3(x, -1, 0.5f), make_vec3(0, 1, 0)));
    }
 
    large_stream.addRays(large_batch);
    DOCTEST_CHECK(large_stream.total_rays == total_rays);
    DOCTEST_CHECK(large_stream.packets.size() == 3); // Should create 3 packets
 
    // Test 2: Stream processing and memory usage
    size_t stream_memory_before = large_stream.getMemoryUsage();
    DOCTEST_CHECK(stream_memory_before > 0);
 
    CollisionDetection::RayTracingStats large_stats;
    bool large_success = collision.processRayStream(large_stream, &large_stats);
    DOCTEST_CHECK(large_success == true);
    DOCTEST_CHECK(large_stats.total_rays_cast == total_rays);
 
    // Test 3: Results aggregation
    auto all_results = large_stream.getAllResults();
    DOCTEST_CHECK(all_results.size() == total_rays);
 
    // Verify reasonable hit rate (rays are aligned with triangles)
    size_t hit_count = 0;
    for (const auto &result: all_results) {
        if (result.hit)
            hit_count++;
    }
    float hit_rate = float(hit_count) / float(total_rays);
    DOCTEST_CHECK(hit_rate > 0.8f); // Expect high hit rate
 
    // Test 4: Empty stream handling
    CollisionDetection::RayStream empty_stream;
    DOCTEST_CHECK(empty_stream.total_rays == 0);
    DOCTEST_CHECK(empty_stream.packets.empty());
    DOCTEST_CHECK(empty_stream.getMemoryUsage() == 0);
 
    CollisionDetection::RayTracingStats empty_stats;
    bool empty_success = collision.processRayStream(empty_stream, &empty_stats);
    DOCTEST_CHECK(empty_success == true);
    DOCTEST_CHECK(empty_stats.total_rays_cast == 0);
 
    // Test 5: Stream clear and reuse
    large_stream.clear();
    DOCTEST_CHECK(large_stream.total_rays == 0);
    DOCTEST_CHECK(large_stream.packets.empty());
    DOCTEST_CHECK(large_stream.current_packet == 0);
    DOCTEST_CHECK(large_stream.getMemoryUsage() == 0);
}
 
DOCTEST_TEST_CASE("CollisionDetection - SoA Precision Validation") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test geometry
    uint triangle1 = context.addTriangle(make_vec3(0, 0, 0), make_vec3(2, 0, 0), make_vec3(1, 0, 2));
    uint triangle2 = context.addTriangle(make_vec3(10, 0, 0), make_vec3(12, 0, 0), make_vec3(11, 0, 2));
    auto sphere_uuids = context.addSphere(12, make_vec3(5, 5, 1), 1.0f);
 
    // Build BVH
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
    collision.buildBVH();
 
    std::vector<CollisionDetection::RayQuery> precision_test_rays = {// Ray hitting first triangle
                                                                     CollisionDetection::RayQuery(make_vec3(1, -1, 1), make_vec3(0, 1, 0)),
                                                                     // Ray hitting second triangle
                                                                     CollisionDetection::RayQuery(make_vec3(11, -1, 1), make_vec3(0, 1, 0)),
                                                                     // Ray hitting sphere
                                                                     CollisionDetection::RayQuery(make_vec3(5, 3, 1), make_vec3(0, 1, 0)),
                                                                     // Miss rays
                                                                     CollisionDetection::RayQuery(make_vec3(20, -1, 0), make_vec3(0, 1, 0)), CollisionDetection::RayQuery(make_vec3(-5, -1, 0), make_vec3(0, 1, 0))};
 
    auto legacy_results = collision.castRays(precision_test_rays);
    auto soa_results = collision.castRaysOptimized(precision_test_rays);
 
    DOCTEST_REQUIRE(legacy_results.size() == precision_test_rays.size());
    DOCTEST_REQUIRE(soa_results.size() == precision_test_rays.size());
 
    // SoA should exactly match legacy results (no precision loss)
    for (size_t i = 0; i < precision_test_rays.size(); i++) {
        DOCTEST_CHECK(legacy_results[i].hit == soa_results[i].hit);
 
        if (legacy_results[i].hit && soa_results[i].hit) {
            DOCTEST_CHECK(legacy_results[i].primitive_UUID == soa_results[i].primitive_UUID);
            DOCTEST_CHECK(std::abs(legacy_results[i].distance - soa_results[i].distance) < 0.001f);
        }
    }
 
    // Memory usage verification (no quantized mode)
    auto memory_stats = collision.getBVHMemoryUsage();
    DOCTEST_CHECK(memory_stats.soa_memory_bytes > 0);
    DOCTEST_CHECK(memory_stats.quantized_memory_bytes == 0);
    DOCTEST_CHECK(memory_stats.quantized_reduction_percent == 0.0f);
}
 
DOCTEST_TEST_CASE("CollisionDetection - Error Handling and Edge Cases") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test 1: Mode conversion with empty BVH should not crash
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
    DOCTEST_CHECK_NOTHROW(collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED));
    DOCTEST_CHECK_NOTHROW(collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED));
 
    // Test 2: Repeated mode setting should be handled efficiently
    auto initial_mode = collision.getBVHOptimizationMode();
    DOCTEST_CHECK_NOTHROW(collision.setBVHOptimizationMode(initial_mode)); // No-op
    DOCTEST_CHECK(collision.getBVHOptimizationMode() == initial_mode);
 
    // Test 3: Memory usage queries with empty structures
    auto empty_memory_stats = collision.getBVHMemoryUsage();
    DOCTEST_CHECK(empty_memory_stats.soa_memory_bytes == 0);
    DOCTEST_CHECK(empty_memory_stats.quantized_memory_bytes == 0);
 
    // Test 4: Ray casting on empty BVH structures
    std::vector<CollisionDetection::RayQuery> empty_test_rays = {CollisionDetection::RayQuery(make_vec3(0, 0, 0), make_vec3(0, 0, 1))};
 
    DOCTEST_CHECK_NOTHROW(collision.castRays(empty_test_rays));
    DOCTEST_CHECK_NOTHROW(collision.castRaysOptimized(empty_test_rays));
 
    auto empty_results = collision.castRaysOptimized(empty_test_rays);
    DOCTEST_CHECK(empty_results.size() == 1);
    DOCTEST_CHECK(empty_results[0].hit == false);
 
    // Test 5: Stream processing with empty stream
    CollisionDetection::RayStream empty_stream;
    CollisionDetection::RayTracingStats empty_stats;
    DOCTEST_CHECK_NOTHROW(collision.processRayStream(empty_stream, &empty_stats));
 
    // Add geometry and test normal operation recovery
    uint recovery_triangle = context.addTriangle(make_vec3(0, 0, 0), make_vec3(1, 0, 0), make_vec3(0.5f, 0, 1));
    collision.buildBVH();
 
    std::vector<CollisionDetection::RayQuery> recovery_rays = {CollisionDetection::RayQuery(make_vec3(0.5f, -1, 0.5f), make_vec3(0, 1, 0))};
 
    auto recovery_results = collision.castRaysOptimized(recovery_rays);
    DOCTEST_CHECK(recovery_results.size() == 1);
    DOCTEST_CHECK(recovery_results[0].hit == true); // Should now hit the triangle
}
 
DOCTEST_TEST_CASE("CollisionDetection - Memory and Statistics Validation") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create a reasonable amount of test geometry for meaningful statistics
    for (int i = 0; i < 8; i++) {
        float x = i * 2.0f;
        float y = (i % 2) * 2.0f;
        context.addTriangle(make_vec3(x, y, 0), make_vec3(x + 1, y, 0), make_vec3(x + 0.5f, y, 1));
    }
    auto sphere_uuids = context.addSphere(16, make_vec3(10, 10, 1), 1.5f);
 
    // Build BVH in all modes and collect statistics
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
    collision.buildBVH();
    auto legacy_memory = collision.getBVHMemoryUsage();
 
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
    auto memory_stats = collision.getBVHMemoryUsage();
 
    // Test memory usage statistics accuracy (without quantized mode)
    DOCTEST_CHECK(memory_stats.soa_memory_bytes > 0);
    DOCTEST_CHECK(memory_stats.quantized_memory_bytes == 0);
    DOCTEST_CHECK(memory_stats.quantized_reduction_percent == 0.0f);
 
    // Test ray tracing statistics collection
    std::vector<CollisionDetection::RayQuery> stat_test_rays;
    for (int i = 0; i < 20; i++) {
        float x = (i % 4) * 2.0f + 0.5f;
        float y = (i / 4) * 2.0f + 0.5f;
        stat_test_rays.push_back(CollisionDetection::RayQuery(make_vec3(x, y, -1), make_vec3(0, 0, 1)));
    }
 
    CollisionDetection::RayTracingStats stats;
    auto stat_results = collision.castRaysOptimized(stat_test_rays, &stats);
 
    // Validate statistics collection
    DOCTEST_CHECK(stats.total_rays_cast == 20);
    DOCTEST_CHECK(stat_results.size() == 20);
    DOCTEST_CHECK(stats.total_hits <= stats.total_rays_cast); // Hits can't exceed rays
 
    if (stats.total_hits > 0) {
        DOCTEST_CHECK(stats.average_ray_distance > 0.0f);
        DOCTEST_CHECK(stats.bvh_nodes_visited > 0); // Should visit at least some BVH nodes
    }
 
    // Test stream processing statistics
    CollisionDetection::RayStream stats_stream;
    stats_stream.addRays(stat_test_rays);
 
    CollisionDetection::RayTracingStats stream_stats;
    bool stream_success = collision.processRayStream(stats_stream, &stream_stats);
    DOCTEST_CHECK(stream_success == true);
    DOCTEST_CHECK(stream_stats.total_rays_cast == 20);
 
    // Stream stats should be consistent with direct ray casting
    DOCTEST_CHECK(stream_stats.total_hits == stats.total_hits);
    DOCTEST_CHECK(std::abs(stream_stats.average_ray_distance - stats.average_ray_distance) < 0.01f);
}
 
// ============================================================================
// VOXEL PRIMITIVE INTERSECTION TESTS
// ============================================================================
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Primitive Intersection - Basic Ray-AABB Tests") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration(); // Test CPU implementation first
 
    // Create a simple 2x2x2 voxel at origin
    uint voxel_uuid = context.addVoxel(make_vec3(0, 0, 0), make_vec3(2, 2, 2));
 
    collision.buildBVH();
 
    // Test 1: Ray hitting voxel center (should hit)
    {
        CollisionDetection::RayQuery ray;
        ray.origin = make_vec3(0, 0, -5);
        ray.direction = make_vec3(0, 0, 1);
        ray.max_distance = 10.0f;
 
        auto results = collision.castRays({ray});
        DOCTEST_CHECK(results.size() == 1);
        DOCTEST_CHECK(results[0].hit == true);
        DOCTEST_CHECK(results[0].distance > 3.9f);
        DOCTEST_CHECK(results[0].distance < 4.1f); // Distance ~4 to reach voxel face
        DOCTEST_CHECK(results[0].primitive_UUID == voxel_uuid);
    }
 
    // Test 2: Ray missing voxel (should miss)
    {
        CollisionDetection::RayQuery ray;
        ray.origin = make_vec3(5, 0, -5);
        ray.direction = make_vec3(0, 0, 1);
        ray.max_distance = 10.0f;
 
        auto results = collision.castRays({ray});
        DOCTEST_CHECK(results.size() == 1);
        DOCTEST_CHECK(results[0].hit == false);
    }
 
    // Test 3: Ray starting inside voxel (should hit exit face)
    {
        CollisionDetection::RayQuery ray;
        ray.origin = make_vec3(0, 0, 0); // Inside voxel
        ray.direction = make_vec3(0, 0, 1);
        ray.max_distance = 10.0f;
 
        auto results = collision.castRays({ray});
        DOCTEST_CHECK(results.size() == 1);
        DOCTEST_CHECK(results[0].hit == true);
        DOCTEST_CHECK(results[0].distance > 0.9f);
        DOCTEST_CHECK(results[0].distance < 1.1f); // Distance ~1 to exit face
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Primitive Intersection - Multiple Voxels") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create a line of 3 voxels
    uint voxel1 = context.addVoxel(make_vec3(-4, 0, 0), make_vec3(2, 2, 2));
    uint voxel2 = context.addVoxel(make_vec3(0, 0, 0), make_vec3(2, 2, 2));
    uint voxel3 = context.addVoxel(make_vec3(4, 0, 0), make_vec3(2, 2, 2));
 
    collision.buildBVH();
 
    // Test 1: Ray hitting first voxel only
    {
        CollisionDetection::RayQuery ray;
        ray.origin = make_vec3(-4, 0, -5);
        ray.direction = make_vec3(0, 0, 1);
        ray.max_distance = 10.0f;
 
        auto results = collision.castRays({ray});
        DOCTEST_CHECK(results.size() == 1);
        DOCTEST_CHECK(results[0].hit == true);
        DOCTEST_CHECK(results[0].primitive_UUID == voxel1);
    }
 
    // Test 2: Ray passing through multiple voxels (should hit closest)
    {
        CollisionDetection::RayQuery ray;
        ray.origin = make_vec3(-8, 0, 0);
        ray.direction = make_vec3(1, 0, 0);
        ray.max_distance = 20.0f;
 
        auto results = collision.castRays({ray});
        DOCTEST_CHECK(results.size() == 1);
        DOCTEST_CHECK(results[0].hit == true);
        DOCTEST_CHECK(results[0].primitive_UUID == voxel1); // Should hit first voxel
        DOCTEST_CHECK(results[0].distance > 2.9f);
        DOCTEST_CHECK(results[0].distance < 3.1f); // Distance ~3 to first voxel
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Voxel Primitive Intersection - GPU vs CPU Consistency") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create test scene with various sized voxels
    std::vector<uint> voxel_uuids;
    voxel_uuids.push_back(context.addVoxel(make_vec3(-3, -3, 0), make_vec3(1, 1, 1))); // Small voxel
    voxel_uuids.push_back(context.addVoxel(make_vec3(0, 0, 0), make_vec3(2, 2, 2))); // Medium voxel
    voxel_uuids.push_back(context.addVoxel(make_vec3(4, 2, 1), make_vec3(3, 3, 3))); // Large voxel
 
    // Create diverse set of test rays
    std::vector<CollisionDetection::RayQuery> test_rays;
 
    // Rays from different angles and positions
    for (int i = 0; i < 5; i++) {
        for (int j = 0; j < 3; j++) {
            CollisionDetection::RayQuery ray;
            ray.origin = make_vec3(i * 2.0f - 4.0f, j * 2.0f - 2.0f, -8.0f);
            ray.direction = normalize(make_vec3(0.1f * i, 0.1f * j, 1.0f));
            ray.max_distance = 20.0f;
            test_rays.push_back(ray);
        }
    }
 
    collision.buildBVH();
 
    // Test CPU implementation
    collision.disableGPUAcceleration();
    auto cpu_results = collision.castRays(test_rays);
 
    // Test GPU implementation
    std::vector<CollisionDetection::HitResult> gpu_results;
    {
        helios::capture_cerr capture;
        collision.enableGPUAcceleration();
        gpu_results = collision.castRays(test_rays);
    } // Capture destroyed before assertions
 
    // Compare results
    DOCTEST_CHECK(cpu_results.size() == gpu_results.size());
    DOCTEST_CHECK(cpu_results.size() == test_rays.size());
 
    for (size_t i = 0; i < cpu_results.size(); i++) {
        DOCTEST_CHECK(cpu_results[i].hit == gpu_results[i].hit);
 
        if (cpu_results[i].hit && gpu_results[i].hit) {
            // Check distance consistency (allow small floating point differences)
            DOCTEST_CHECK(std::abs(cpu_results[i].distance - gpu_results[i].distance) < 0.01f);
            DOCTEST_CHECK(cpu_results[i].primitive_UUID == gpu_results[i].primitive_UUID);
        }
    }
}
 
// -------- ENHANCED MATHEMATICAL ACCURACY VALIDATION TESTS --------
 
DOCTEST_TEST_CASE("CollisionDetection Mathematical Accuracy - Ray-Triangle Intersection Algorithms") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration(); // Use CPU for deterministic results
 
    // Test 1: Known analytical triangle intersection
    vec3 v0 = make_vec3(0, 0, 0);
    vec3 v1 = make_vec3(1, 0, 0);
    vec3 v2 = make_vec3(0, 1, 0);
    uint triangle_uuid = context.addTriangle(v0, v1, v2);
 
    // Ray hitting center of triangle at (1/3, 1/3, 0)
    vec3 ray_origin = make_vec3(1.0f / 3.0f, 1.0f / 3.0f, -1.0f);
    vec3 ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult result = collision.castRay(ray_origin, ray_direction);
 
    DOCTEST_CHECK(result.hit == true);
    DOCTEST_CHECK(result.primitive_UUID == triangle_uuid);
 
    // Mathematical validation: distance should be exactly 1.0
    DOCTEST_CHECK(std::abs(result.distance - 1.0f) < 1e-6f);
 
    // Intersection point should be exactly at (1/3, 1/3, 0)
    DOCTEST_CHECK(std::abs(result.intersection_point.x - 1.0f / 3.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(result.intersection_point.y - 1.0f / 3.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(result.intersection_point.z - 0.0f) < 1e-6f);
 
    // Normal should be (0, 0, 1) for this triangle
    vec3 expected_normal = normalize(cross(v1 - v0, v2 - v0));
    float normal_dot = result.normal.x * expected_normal.x + result.normal.y * expected_normal.y + result.normal.z * expected_normal.z;
    DOCTEST_CHECK(std::abs(normal_dot - 1.0f) < 1e-6f);
}
 
DOCTEST_TEST_CASE("CollisionDetection Mathematical Accuracy - Edge Case Intersections") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Test 1: Ray hitting triangle edge
    vec3 v0 = make_vec3(0, 0, 0);
    vec3 v1 = make_vec3(2, 0, 0);
    vec3 v2 = make_vec3(1, 2, 0);
    uint triangle_uuid = context.addTriangle(v0, v1, v2);
 
    // Ray hitting midpoint of edge v0-v1 at (1, 0, 0)
    vec3 ray_origin = make_vec3(1, 0, -1);
    vec3 ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult result = collision.castRay(ray_origin, ray_direction);
 
    DOCTEST_CHECK(result.hit == true);
    DOCTEST_CHECK(std::abs(result.intersection_point.x - 1.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(result.intersection_point.y - 0.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(result.intersection_point.z - 0.0f) < 1e-6f);
 
    // Test 2: Ray hitting triangle vertex (may miss due to numerical precision)
    vec3 vertex_ray_origin = make_vec3(0, 0, -1);
    vec3 vertex_ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult vertex_result = collision.castRay(vertex_ray_origin, vertex_ray_direction);
 
    // Vertex hits can be numerically challenging - allow miss but check consistency
    if (vertex_result.hit) {
        DOCTEST_CHECK(std::abs(vertex_result.intersection_point.x - 0.0f) < 1e-3f);
        DOCTEST_CHECK(std::abs(vertex_result.intersection_point.y - 0.0f) < 1e-3f);
        DOCTEST_CHECK(std::abs(vertex_result.intersection_point.z - 0.0f) < 1e-3f);
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Mathematical Accuracy - Barycentric Coordinate Validation") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create equilateral triangle for precise barycentric testing
    float sqrt3 = std::sqrt(3.0f);
    vec3 v0 = make_vec3(-1, -sqrt3 / 3.0f, 0);
    vec3 v1 = make_vec3(1, -sqrt3 / 3.0f, 0);
    vec3 v2 = make_vec3(0, 2.0f * sqrt3 / 3.0f, 0);
    uint triangle_uuid = context.addTriangle(v0, v1, v2);
 
    // Test centroid hit (barycentric coordinates: 1/3, 1/3, 1/3)
    vec3 centroid = (v0 + v1 + v2) * (1.0f / 3.0f);
    vec3 ray_origin = make_vec3(centroid.x, centroid.y, -1);
    vec3 ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult result = collision.castRay(ray_origin, ray_direction);
 
    DOCTEST_CHECK(result.hit == true);
    DOCTEST_CHECK(std::abs(result.intersection_point.x - centroid.x) < 1e-6f);
    DOCTEST_CHECK(std::abs(result.intersection_point.y - centroid.y) < 1e-6f);
 
    // Test points with known barycentric coordinates
    vec3 midpoint_v0_v1 = (v0 + v1) * 0.5f; // (0.5, 0.5, 0) barycentric
    vec3 midpoint_ray_origin = make_vec3(midpoint_v0_v1.x, midpoint_v0_v1.y, -1);
 
    CollisionDetection::HitResult midpoint_result = collision.castRay(midpoint_ray_origin, ray_direction);
 
    DOCTEST_CHECK(midpoint_result.hit == true);
    DOCTEST_CHECK(std::abs(midpoint_result.intersection_point.x - midpoint_v0_v1.x) < 1e-6f);
    DOCTEST_CHECK(std::abs(midpoint_result.intersection_point.y - midpoint_v0_v1.y) < 1e-6f);
}
 
// -------- COMPREHENSIVE GPU-SPECIFIC TESTS --------
 
DOCTEST_TEST_CASE("CollisionDetection GPU-Specific - Direct castRaysGPU Testing") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create diverse test geometry
    std::vector<uint> uuids;
    uuids.push_back(context.addTriangle(make_vec3(0, 0, 0), make_vec3(1, 0, 0), make_vec3(0.5f, 1, 0)));
    uuids.push_back(context.addTriangle(make_vec3(2, 0, 0), make_vec3(3, 0, 0), make_vec3(2.5f, 1, 0)));
    uuids.push_back(context.addPatch(make_vec3(5, 0, 0), make_vec2(1, 1)));
 
    // Create comprehensive ray set
    std::vector<CollisionDetection::RayQuery> queries;
    for (int i = 0; i < 100; i++) {
        CollisionDetection::RayQuery query;
        query.origin = make_vec3(i * 0.1f - 2, -1, 0.5f);
        query.direction = normalize(make_vec3(0, 1, 0));
        query.max_distance = 5.0f;
        queries.push_back(query);
    }
 
    // Test GPU functionality if available
    try {
        collision.enableGPUAcceleration();
#ifdef HELIOS_CUDA_AVAILABLE
        if (collision.isGPUAccelerationEnabled()) {
            CollisionDetection::RayTracingStats gpu_stats;
            std::vector<CollisionDetection::HitResult> gpu_results = collision.castRaysGPU(queries, gpu_stats);
 
            DOCTEST_CHECK(gpu_results.size() == queries.size());
            DOCTEST_CHECK(gpu_stats.total_rays_cast == queries.size());
 
            // Test against CPU reference
            collision.disableGPUAcceleration();
            CollisionDetection::RayTracingStats cpu_stats;
            std::vector<CollisionDetection::HitResult> cpu_results = collision.castRays(queries, &cpu_stats);
 
            // Compare results
            DOCTEST_CHECK(cpu_results.size() == gpu_results.size());
 
            int consistent_hits = 0;
            for (size_t i = 0; i < cpu_results.size(); i++) {
                if (cpu_results[i].hit == gpu_results[i].hit) {
                    consistent_hits++;
                    if (cpu_results[i].hit) {
                        // Allow small floating-point differences in GPU vs CPU
                        DOCTEST_CHECK(std::abs(cpu_results[i].distance - gpu_results[i].distance) < 0.001f);
                        DOCTEST_CHECK(cpu_results[i].primitive_UUID == gpu_results[i].primitive_UUID);
                    }
                }
            }
 
            // Should have high consistency (allow for some GPU/CPU differences)
            DOCTEST_CHECK(consistent_hits >= (int) (0.95f * queries.size()));
 
        } else {
            DOCTEST_WARN("GPU acceleration not available - skipping direct GPU tests");
        }
#endif
    } catch (std::exception &e) {
        DOCTEST_WARN((std::string("GPU test failed (expected on non-NVIDIA systems): ") + e.what()).c_str());
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection GPU-Specific - Error Handling and Edge Cases") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    try {
        collision.enableGPUAcceleration();
#ifdef HELIOS_CUDA_AVAILABLE
        if (collision.isGPUAccelerationEnabled()) {
 
            // Test 1: Empty ray queries
            std::vector<CollisionDetection::RayQuery> empty_queries;
            CollisionDetection::RayTracingStats stats;
            std::vector<CollisionDetection::HitResult> results = collision.castRaysGPU(empty_queries, stats);
            DOCTEST_CHECK(results.empty());
            DOCTEST_CHECK(stats.total_rays_cast == 0);
 
            // Test 2: Large batch processing
            std::vector<CollisionDetection::RayQuery> large_batch;
            for (int i = 0; i < 10000; i++) {
                CollisionDetection::RayQuery query;
                query.origin = make_vec3(0, 0, i * 0.001f);
                query.direction = make_vec3(0, 0, 1);
                query.max_distance = 1.0f;
                large_batch.push_back(query);
            }
 
            CollisionDetection::RayTracingStats large_stats;
            std::vector<CollisionDetection::HitResult> large_results = collision.castRaysGPU(large_batch, large_stats);
            DOCTEST_CHECK(large_results.size() == large_batch.size());
            DOCTEST_CHECK(large_stats.total_rays_cast == large_batch.size());
 
            // Test 3: Degenerate rays
            std::vector<CollisionDetection::RayQuery> degenerate_queries;
            CollisionDetection::RayQuery degenerate;
            degenerate.origin = make_vec3(0, 0, 0);
            degenerate.direction = make_vec3(0, 0, 0); // Zero direction
            degenerate_queries.push_back(degenerate);
 
            CollisionDetection::RayTracingStats degenerate_stats;
            std::vector<CollisionDetection::HitResult> degenerate_results = collision.castRaysGPU(degenerate_queries, degenerate_stats);
            DOCTEST_CHECK(degenerate_results.size() == 1);
            DOCTEST_CHECK(degenerate_results[0].hit == false); // Should handle gracefully
 
        } else {
            DOCTEST_WARN("GPU acceleration not available - skipping GPU error handling tests");
        }
#endif
    } catch (std::exception &e) {
        DOCTEST_WARN((std::string("GPU error handling test failed: ") + e.what()).c_str());
    }
}
 
// -------- FLOATING-POINT PRECISION EDGE CASE TESTS --------
 
DOCTEST_TEST_CASE("CollisionDetection Floating-Point Precision - Extreme Values") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Test 1: Very small triangles
    float epsilon = 1e-6f;
    vec3 v0_small = make_vec3(0, 0, 0);
    vec3 v1_small = make_vec3(epsilon, 0, 0);
    vec3 v2_small = make_vec3(epsilon / 2.0f, epsilon, 0);
    uint small_triangle = context.addTriangle(v0_small, v1_small, v2_small);
 
    vec3 ray_origin = make_vec3(epsilon / 3.0f, epsilon / 3.0f, -epsilon);
    vec3 ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult small_result = collision.castRay(ray_origin, ray_direction);
    // Should either hit or miss consistently, not produce NaN/inf
    DOCTEST_CHECK(std::isfinite(small_result.distance));
    DOCTEST_CHECK(std::isfinite(small_result.intersection_point.x));
    DOCTEST_CHECK(std::isfinite(small_result.intersection_point.y));
    DOCTEST_CHECK(std::isfinite(small_result.intersection_point.z));
 
    // Test 2: Very large triangles
    float large_scale = 1e6f;
    vec3 v0_large = make_vec3(-large_scale, -large_scale, 0);
    vec3 v1_large = make_vec3(large_scale, -large_scale, 0);
    vec3 v2_large = make_vec3(0, large_scale, 0);
    uint large_triangle = context.addTriangle(v0_large, v1_large, v2_large);
 
    vec3 large_ray_origin = make_vec3(0, 0, -large_scale);
    vec3 large_ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult large_result = collision.castRay(large_ray_origin, large_ray_direction);
    DOCTEST_CHECK(std::isfinite(large_result.distance));
    if (large_result.hit) {
        DOCTEST_CHECK(std::isfinite(large_result.intersection_point.x));
        DOCTEST_CHECK(std::isfinite(large_result.intersection_point.y));
        DOCTEST_CHECK(std::isfinite(large_result.intersection_point.z));
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Floating-Point Precision - Near-Parallel Rays") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create triangle in XY plane
    vec3 v0 = make_vec3(0, 0, 0);
    vec3 v1 = make_vec3(1, 0, 0);
    vec3 v2 = make_vec3(0.5f, 1, 0);
    uint triangle_uuid = context.addTriangle(v0, v1, v2);
 
    // Test rays nearly parallel to triangle plane
    float tiny_angle = 1e-6f;
    vec3 near_parallel_origin = make_vec3(0.5f, 0.5f, -1);
    vec3 near_parallel_direction = normalize(make_vec3(0, tiny_angle, 1));
 
    CollisionDetection::HitResult near_parallel_result = collision.castRay(near_parallel_origin, near_parallel_direction);
 
    // Should handle gracefully without numerical instability
    DOCTEST_CHECK(std::isfinite(near_parallel_result.distance));
    if (near_parallel_result.hit) {
        DOCTEST_CHECK(std::isfinite(near_parallel_result.intersection_point.x));
        DOCTEST_CHECK(std::isfinite(near_parallel_result.intersection_point.y));
        DOCTEST_CHECK(std::isfinite(near_parallel_result.intersection_point.z));
        DOCTEST_CHECK(near_parallel_result.distance > 0);
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Floating-Point Precision - Boundary Conditions") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create unit triangle
    vec3 v0 = make_vec3(0, 0, 0);
    vec3 v1 = make_vec3(1, 0, 0);
    vec3 v2 = make_vec3(0, 1, 0);
    uint triangle_uuid = context.addTriangle(v0, v1, v2);
 
    // Test rays just outside triangle boundaries
    float boundary_offset = 1e-8f;
 
    std::vector<vec3> boundary_origins = {
            make_vec3(-boundary_offset, 0.5f, -1), // Just outside left edge
            make_vec3(1 + boundary_offset, 0.5f, -1), // Just outside right edge
            make_vec3(0.5f, -boundary_offset, -1), // Just outside bottom edge
            make_vec3(0.5f + boundary_offset, 0.5f + boundary_offset, -1) // Just outside diagonal edge
    };
 
    for (const auto &origin: boundary_origins) {
        vec3 ray_direction = make_vec3(0, 0, 1);
        CollisionDetection::HitResult result = collision.castRay(origin, ray_direction);
 
        // Results should be consistent and not produce artifacts
        DOCTEST_CHECK(std::isfinite(result.distance));
        if (result.hit) {
            DOCTEST_CHECK(std::isfinite(result.intersection_point.x));
            DOCTEST_CHECK(std::isfinite(result.intersection_point.y));
            DOCTEST_CHECK(std::isfinite(result.intersection_point.z));
        }
    }
}
 
// -------- COMPLEX GEOMETRY ACCURACY VALIDATION TESTS --------
 
DOCTEST_TEST_CASE("CollisionDetection Complex Geometry - Multi-Primitive Accuracy") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create complex scene with overlapping and adjacent primitives
    std::vector<uint> uuids;
 
    // Grid of triangles with known intersection patterns
    for (int i = 0; i < 5; i++) {
        for (int j = 0; j < 5; j++) {
            float x = i * 0.8f;
            float y = j * 0.8f;
            uint uuid = context.addTriangle(make_vec3(x, y, 0), make_vec3(x + 0.5f, y, 0), make_vec3(x + 0.25f, y + 0.5f, 0));
            uuids.push_back(uuid);
        }
    }
 
    // Test systematic ray grid
    int correct_predictions = 0;
    int total_predictions = 0;
 
    for (int i = 0; i < 10; i++) {
        for (int j = 0; j < 10; j++) {
            float x = i * 0.4f;
            float y = j * 0.4f;
 
            vec3 ray_origin = make_vec3(x, y, -1);
            vec3 ray_direction = make_vec3(0, 0, 1);
 
            CollisionDetection::HitResult result = collision.castRay(ray_origin, ray_direction);
 
            // Manually determine if this point should hit any triangle
            bool should_hit = false;
            for (int ti = 0; ti < 5; ti++) {
                for (int tj = 0; tj < 5; tj++) {
                    float tx = ti * 0.8f;
                    float ty = tj * 0.8f;
 
                    // Simple point-in-triangle test for validation
                    vec3 p = make_vec3(x, y, 0);
                    vec3 a = make_vec3(tx, ty, 0);
                    vec3 b = make_vec3(tx + 0.5f, ty, 0);
                    vec3 c = make_vec3(tx + 0.25f, ty + 0.5f, 0);
 
                    // Barycentric coordinate test
                    vec3 v0 = c - a;
                    vec3 v1 = b - a;
                    vec3 v2 = p - a;
 
                    float dot00 = v0.x * v0.x + v0.y * v0.y + v0.z * v0.z;
                    float dot01 = v0.x * v1.x + v0.y * v1.y + v0.z * v1.z;
                    float dot02 = v0.x * v2.x + v0.y * v2.y + v0.z * v2.z;
                    float dot11 = v1.x * v1.x + v1.y * v1.y + v1.z * v1.z;
                    float dot12 = v1.x * v2.x + v1.y * v2.y + v1.z * v2.z;
 
                    float inv_denom = 1.0f / (dot00 * dot11 - dot01 * dot01);
                    float u = (dot11 * dot02 - dot01 * dot12) * inv_denom;
                    float v = (dot00 * dot12 - dot01 * dot02) * inv_denom;
 
                    // Use epsilon tolerance for floating-point edge cases
                    const float EPSILON = 1e-6f;
                    if ((u >= -EPSILON) && (v >= -EPSILON) && (u + v <= 1 + EPSILON)) {
                        should_hit = true;
                        break;
                    }
                }
                if (should_hit)
                    break;
            }
 
            if (result.hit == should_hit) {
                correct_predictions++;
            }
            total_predictions++;
        }
    }
 
    // Should have perfect accuracy in complex geometry with proper floating-point handling
    float accuracy = (float) correct_predictions / (float) total_predictions;
    DOCTEST_CHECK(accuracy == 1.0f);
}
 
DOCTEST_TEST_CASE("CollisionDetection Complex Geometry - Stress Test Validation") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create stress test geometry - many small overlapping triangles
    std::vector<uint> stress_uuids;
    for (int i = 0; i < 1000; i++) {
        float x = (rand() % 100) * 0.01f;
        float y = (rand() % 100) * 0.01f;
        float z = (rand() % 10) * 0.01f;
        float size = 0.1f + (rand() % 10) * 0.01f;
 
        uint uuid = context.addTriangle(make_vec3(x, y, z), make_vec3(x + size, y, z), make_vec3(x + size / 2.0f, y + size, z));
        stress_uuids.push_back(uuid);
    }
 
    // Test random rays for consistency and correctness
    std::vector<CollisionDetection::RayQuery> stress_queries;
    for (int i = 0; i < 500; i++) {
        CollisionDetection::RayQuery query;
        query.origin = make_vec3((rand() % 200) * 0.01f - 1.0f, (rand() % 200) * 0.01f - 1.0f, -1.0f);
        query.direction = normalize(make_vec3(0, 0, 1));
        query.max_distance = 10.0f;
        stress_queries.push_back(query);
    }
 
    CollisionDetection::RayTracingStats stats;
    std::vector<CollisionDetection::HitResult> stress_results = collision.castRays(stress_queries, &stats);
 
    DOCTEST_CHECK(stress_results.size() == stress_queries.size());
    DOCTEST_CHECK(stats.total_rays_cast == stress_queries.size());
 
    // Validate all results are mathematically sound
    int valid_results = 0;
    for (const auto &result: stress_results) {
        if (std::isfinite(result.distance) && std::isfinite(result.intersection_point.x) && std::isfinite(result.intersection_point.y) && std::isfinite(result.intersection_point.z) && (result.hit ? result.distance >= 0 : true)) {
            valid_results++;
        }
    }
 
    DOCTEST_CHECK(valid_results == (int) stress_results.size());
}
 
// -------- PERFORMANCE REGRESSION TESTS --------
 
DOCTEST_TEST_CASE("CollisionDetection Performance Regression - BVH Construction Timing") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create large geometry set
    std::vector<uint> large_geometry;
    for (int i = 0; i < 5000; i++) {
        float x = i * 0.1f;
        uint uuid = context.addTriangle(make_vec3(x, -0.5f, 0), make_vec3(x + 0.05f, -0.5f, 0), make_vec3(x + 0.025f, 0.5f, 0));
        large_geometry.push_back(uuid);
    }
 
    // Measure BVH construction time
    auto start_time = std::chrono::high_resolution_clock::now();
    collision.buildBVH();
    auto end_time = std::chrono::high_resolution_clock::now();
 
    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end_time - start_time);
 
    // BVH construction should complete in reasonable time (< 5 seconds for 5k primitives)
    DOCTEST_CHECK(duration.count() < 5000);
 
    // Verify BVH validity after construction
    DOCTEST_CHECK(collision.isBVHValid() == true);
    DOCTEST_CHECK(collision.getPrimitiveCount() == large_geometry.size());
 
    size_t node_count, leaf_count, max_depth;
    collision.getBVHStatistics(node_count, leaf_count, max_depth);
 
    // Sanity checks on BVH structure
    DOCTEST_CHECK(node_count > 0);
    DOCTEST_CHECK(leaf_count > 0);
    DOCTEST_CHECK(max_depth > 0);
    DOCTEST_CHECK(max_depth < 50); // Should not be excessively deep
}
 
DOCTEST_TEST_CASE("CollisionDetection Performance Regression - Ray Casting Throughput") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create moderate complexity scene
    for (int i = 0; i < 1000; i++) {
        float x = (i % 50) * 0.2f;
        float y = (i / 50) * 0.2f;
        uint uuid = context.addTriangle(make_vec3(x, y, 0), make_vec3(x + 0.1f, y, 0), make_vec3(x + 0.05f, y + 0.1f, 0));
    }
 
    // Create large ray batch
    std::vector<CollisionDetection::RayQuery> throughput_queries;
    for (int i = 0; i < 10000; i++) {
        CollisionDetection::RayQuery query;
        query.origin = make_vec3((i % 100) * 0.1f, (i / 100) * 0.1f, -1.0f);
        query.direction = normalize(make_vec3(0, 0, 1));
        throughput_queries.push_back(query);
    }
 
    // Measure ray casting performance
    auto start_time = std::chrono::high_resolution_clock::now();
    CollisionDetection::RayTracingStats stats;
    std::vector<CollisionDetection::HitResult> results = collision.castRays(throughput_queries, &stats);
    auto end_time = std::chrono::high_resolution_clock::now();
 
    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end_time - start_time);
 
    // Should process 10k rays in reasonable time (< 2 seconds)
    DOCTEST_CHECK(duration.count() < 2000);
 
    // Verify results quality
    DOCTEST_CHECK(results.size() == throughput_queries.size());
    DOCTEST_CHECK(stats.total_rays_cast == throughput_queries.size());
 
    // Calculate rays per second
    float rays_per_second = (float) throughput_queries.size() / (duration.count() / 1000.0f);
    DOCTEST_CHECK(rays_per_second > 1000.0f); // Should achieve at least 1k rays/sec
}
 
DOCTEST_TEST_CASE("CollisionDetection Performance Regression - Memory Usage Validation") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test memory efficiency with different BVH modes
    for (int i = 0; i < 2000; i++) {
        float x = i * 0.05f;
        uint uuid = context.addTriangle(make_vec3(x, -0.25f, 0), make_vec3(x + 0.025f, -0.25f, 0), make_vec3(x + 0.0125f, 0.25f, 0));
    }
 
    // Test different optimization modes
    collision.setBVHOptimizationMode(CollisionDetection::BVHOptimizationMode::SOA_UNCOMPRESSED);
    collision.buildBVH();
 
    auto memory_stats = collision.getBVHMemoryUsage();
 
    // Memory usage should be reasonable (< 100MB for 2k primitives)
    DOCTEST_CHECK(memory_stats.soa_memory_bytes < 100 * 1024 * 1024);
    DOCTEST_CHECK(memory_stats.soa_memory_bytes > 0);
 
    // Test ray streaming memory efficiency
    CollisionDetection::RayStream stream;
    std::vector<CollisionDetection::RayQuery> stream_queries;
 
    for (int i = 0; i < 5000; i++) {
        CollisionDetection::RayQuery query;
        query.origin = make_vec3(i * 0.01f, 0, -1);
        query.direction = normalize(make_vec3(0, 0, 1));
        stream_queries.push_back(query);
    }
 
    stream.addRays(stream_queries);
 
    // Stream memory usage should be reasonable
    size_t stream_memory = stream.getMemoryUsage();
    DOCTEST_CHECK(stream_memory < 50 * 1024 * 1024); // < 50MB for 5k rays
    DOCTEST_CHECK(stream_memory > 0);
}
 
// -------- RAY-PATCH MATHEMATICAL ACCURACY TESTS --------
 
DOCTEST_TEST_CASE("CollisionDetection Mathematical Accuracy - Ray-Patch Intersection") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration(); // Use CPU for deterministic results
 
    // Test 1: Known analytical patch intersection
    vec3 v0 = make_vec3(0, 0, 0); // Bottom-left
    vec3 v1 = make_vec3(1, 0, 0); // Bottom-right
    vec3 v2 = make_vec3(0, 1, 0); // Top-left
    vec3 v3 = make_vec3(1, 1, 0); // Top-right
    uint patch_uuid = context.addPatch(v0, make_vec2(1, 1));
 
    // Ray hitting center of patch at (0.5, 0.5, 0)
    vec3 ray_origin = make_vec3(0.5f, 0.5f, -1.0f);
    vec3 ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult result = collision.castRay(ray_origin, ray_direction);
 
    DOCTEST_CHECK(result.hit == true);
    DOCTEST_CHECK(result.primitive_UUID == patch_uuid);
 
    // Mathematical validation: distance should be exactly 1.0
    DOCTEST_CHECK(std::abs(result.distance - 1.0f) < 1e-6f);
 
    // Intersection point should be exactly at (0.5, 0.5, 0)
    DOCTEST_CHECK(std::abs(result.intersection_point.x - 0.5f) < 1e-6f);
    DOCTEST_CHECK(std::abs(result.intersection_point.y - 0.5f) < 1e-6f);
    DOCTEST_CHECK(std::abs(result.intersection_point.z - 0.0f) < 1e-6f);
}
 
DOCTEST_TEST_CASE("CollisionDetection Mathematical Accuracy - Ray-Patch Edge Cases") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create a patch at origin
    uint patch_uuid = context.addPatch(make_vec3(0, 0, 0), make_vec2(2, 2));
 
    // Test 1: Ray hitting patch edge (should HIT with proper epsilon tolerance)
    vec3 edge_ray_origin = make_vec3(1, 0, -1); // Hit right edge at (1, 0, 0)
    vec3 edge_ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult edge_result = collision.castRay(edge_ray_origin, edge_ray_direction);
 
    DOCTEST_CHECK(edge_result.hit == true);
    DOCTEST_CHECK(std::abs(edge_result.intersection_point.x - 1.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(edge_result.intersection_point.y - 0.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(edge_result.intersection_point.z - 0.0f) < 1e-6f);
 
    // Test 2: Ray hitting patch corner (should HIT with proper epsilon tolerance)
    vec3 corner_ray_origin = make_vec3(0, 0, -1); // Hit corner at (0, 0, 0)
    vec3 corner_ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult corner_result = collision.castRay(corner_ray_origin, corner_ray_direction);
 
    DOCTEST_CHECK(corner_result.hit == true);
    DOCTEST_CHECK(std::abs(corner_result.intersection_point.x - 0.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(corner_result.intersection_point.y - 0.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(corner_result.intersection_point.z - 0.0f) < 1e-6f);
}
 
DOCTEST_TEST_CASE("CollisionDetection Complex Geometry - Multi-Patch Accuracy") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create complex scene with overlapping patch edges - similar to triangle test
    std::vector<uint> uuids;
 
    // Grid of patches with known intersection patterns
    for (int i = 0; i < 5; i++) {
        for (int j = 0; j < 5; j++) {
            float x = i * 0.8f;
            float y = j * 0.8f;
            uint uuid = context.addPatch(make_vec3(x, y, 0), make_vec2(0.5f, 0.5f));
            uuids.push_back(uuid);
        }
    }
 
    // Test systematic ray grid
    int correct_predictions = 0;
    int total_predictions = 0;
 
    for (int i = 0; i < 10; i++) {
        for (int j = 0; j < 10; j++) {
            float x = i * 0.4f;
            float y = j * 0.4f;
 
            vec3 ray_origin = make_vec3(x, y, -1);
            vec3 ray_direction = make_vec3(0, 0, 1);
 
            CollisionDetection::HitResult result = collision.castRay(ray_origin, ray_direction);
 
            // Manually determine if this point should hit any patch
            bool should_hit = false;
            for (int ti = 0; ti < 5; ti++) {
                for (int tj = 0; tj < 5; tj++) {
                    float px = ti * 0.8f;
                    float py = tj * 0.8f;
 
                    // Check if ray point is within patch bounds
                    const float EPSILON = 1e-6f;
                    if ((x >= px - 0.25f - EPSILON) && (x <= px + 0.25f + EPSILON) && (y >= py - 0.25f - EPSILON) && (y <= py + 0.25f + EPSILON)) {
                        should_hit = true;
                        break;
                    }
                }
                if (should_hit)
                    break;
            }
 
            if (result.hit == should_hit) {
                correct_predictions++;
            }
            total_predictions++;
        }
    }
 
    // Should have perfect accuracy in complex patch geometry
    float accuracy = (float) correct_predictions / (float) total_predictions;
    DOCTEST_CHECK(accuracy == 1.0f);
}
 
// -------- RAY-VOXEL MATHEMATICAL ACCURACY TESTS --------
 
DOCTEST_TEST_CASE("CollisionDetection Mathematical Accuracy - Ray-Voxel Intersection") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration(); // Use CPU for deterministic results
 
    // Test 1: Known analytical voxel intersection
    uint voxel_uuid = context.addVoxel(make_vec3(0.5f, 0.5f, 0.5f), make_vec3(1, 1, 1));
 
    // Ray hitting center of voxel front face at (0.5, 0.5, 0)
    vec3 ray_origin = make_vec3(0.5f, 0.5f, -1.0f);
    vec3 ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult result = collision.castRay(ray_origin, ray_direction);
 
    DOCTEST_CHECK(result.hit == true);
    DOCTEST_CHECK(result.primitive_UUID == voxel_uuid);
 
    // Mathematical validation: distance should be exactly 1.0 to reach front face
    DOCTEST_CHECK(std::abs(result.distance - 1.0f) < 1e-6f);
 
    // Intersection point should be exactly at (0.5, 0.5, 0) - front face of voxel
    DOCTEST_CHECK(std::abs(result.intersection_point.x - 0.5f) < 1e-6f);
    DOCTEST_CHECK(std::abs(result.intersection_point.y - 0.5f) < 1e-6f);
    DOCTEST_CHECK(std::abs(result.intersection_point.z - 0.0f) < 1e-6f);
}
 
DOCTEST_TEST_CASE("CollisionDetection Mathematical Accuracy - Ray-Voxel Edge Cases") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create a voxel at origin with size (2, 2, 2) - extends from (-1,-1,-1) to (1,1,1)
    uint voxel_uuid = context.addVoxel(make_vec3(0, 0, 0), make_vec3(2, 2, 2));
 
    // Test 1: Ray hitting voxel edge (should HIT with proper epsilon tolerance)
    vec3 edge_ray_origin = make_vec3(1, 0, -2); // Hit right edge at (1, 0, -1)
    vec3 edge_ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult edge_result = collision.castRay(edge_ray_origin, edge_ray_direction);
 
    DOCTEST_CHECK(edge_result.hit == true);
    DOCTEST_CHECK(edge_result.primitive_UUID == voxel_uuid);
    DOCTEST_CHECK(std::abs(edge_result.distance - 1.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(edge_result.intersection_point.x - 1.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(edge_result.intersection_point.y - 0.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(edge_result.intersection_point.z + 1.0f) < 1e-6f);
 
    // Test 2: Ray hitting voxel corner (should HIT)
    vec3 corner_ray_origin = make_vec3(-1, -1, -2); // Hit corner at (-1, -1, -1)
    vec3 corner_ray_direction = make_vec3(0, 0, 1);
 
    CollisionDetection::HitResult corner_result = collision.castRay(corner_ray_origin, corner_ray_direction);
 
    DOCTEST_CHECK(corner_result.hit == true);
    DOCTEST_CHECK(std::abs(corner_result.intersection_point.x + 1.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(corner_result.intersection_point.y + 1.0f) < 1e-6f);
    DOCTEST_CHECK(std::abs(corner_result.intersection_point.z + 1.0f) < 1e-6f);
}
 
DOCTEST_TEST_CASE("CollisionDetection Complex Geometry - Multi-Voxel Accuracy") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration();
 
    // Create complex scene with voxel grid - similar to patch test but in 3D
    std::vector<uint> uuids;
 
    // Grid of voxels with known intersection patterns (3x3x3 grid)
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            for (int k = 0; k < 3; k++) {
                float x = i * 1.5f; // Voxel centers spaced 1.5 units apart
                float y = j * 1.5f;
                float z = k * 1.5f;
                uint uuid = context.addVoxel(make_vec3(x, y, z), make_vec3(1, 1, 1)); // Size 1x1x1
                uuids.push_back(uuid);
            }
        }
    }
 
    // Test systematic ray grid in XY plane at z=-1
    int correct_predictions = 0;
    int total_predictions = 0;
 
    for (int i = 0; i < 10; i++) {
        for (int j = 0; j < 10; j++) {
            float x = i * 0.4f; // Ray grid with 0.4 spacing
            float y = j * 0.4f;
 
            vec3 ray_origin = make_vec3(x, y, -1);
            vec3 ray_direction = make_vec3(0, 0, 1);
 
            CollisionDetection::HitResult result = collision.castRay(ray_origin, ray_direction);
 
            // Manually determine if this point should hit any voxel at z=0 plane
            bool should_hit = false;
            for (int vi = 0; vi < 3; vi++) {
                for (int vj = 0; vj < 3; vj++) {
                    for (int vk = 0; vk < 3; vk++) {
                        float vx = vi * 1.5f; // voxel center x
                        float vy = vj * 1.5f; // voxel center y
                        float vz = vk * 1.5f; // voxel center z
 
                        // Voxel bounds: center ± size/2 = center ± 0.5
                        float voxel_x_min = vx - 0.5f;
                        float voxel_x_max = vx + 0.5f;
                        float voxel_y_min = vy - 0.5f;
                        float voxel_y_max = vy + 0.5f;
                        float voxel_z_min = vz - 0.5f;
                        float voxel_z_max = vz + 0.5f;
 
                        // Check if ray hits this voxel
                        const float EPSILON = 1e-6f;
                        if ((x >= voxel_x_min - EPSILON) && (x <= voxel_x_max + EPSILON) && (y >= voxel_y_min - EPSILON) && (y <= voxel_y_max + EPSILON)) {
                            // Check if ray z-range overlaps with voxel z-range
                            if (voxel_z_max >= -1.0f - EPSILON) {
                                should_hit = true;
                                break;
                            }
                        }
                    }
                    if (should_hit)
                        break;
                }
                if (should_hit)
                    break;
            }
 
            if (result.hit == should_hit) {
                correct_predictions++;
            }
            total_predictions++;
        }
    }
 
    // Should have perfect accuracy in complex voxel geometry
    float accuracy = (float) correct_predictions / (float) total_predictions;
    DOCTEST_CHECK(accuracy == 1.0f);
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Classification - Basic getVoxelRayHitCounts Functionality") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create a simple test geometry - single triangle in the middle of a voxel
    uint triangle_uuid = context.addTriangle(make_vec3(-0.5, -0.5, 0), make_vec3(0.5, -0.5, 0), make_vec3(0, 0.5, 0));
 
    // Set up voxel grid centered at origin
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(4, 4, 4);
    int3 grid_divisions(2, 2, 2); // 2x2x2 grid
 
    // Test rays with known behavior
    std::vector<vec3> ray_origins;
    std::vector<vec3> ray_directions;
 
    // Ray 1: hits triangle before entering voxel (0,0,0)
    ray_origins.push_back(make_vec3(0, 0, -3)); // Start outside grid
    ray_directions.push_back(make_vec3(0, 0, 1)); // Ray towards triangle at z=0
 
    // Ray 2: passes through voxel without hitting anything
    ray_origins.push_back(make_vec3(-1.5, -1.5, -3)); // Ray in corner voxel (0,0,0)
    ray_directions.push_back(make_vec3(0, 0, 1)); // Parallel to z-axis, misses triangle
 
    // Ray 3: hits triangle inside voxel
    ray_origins.push_back(make_vec3(0, 0, -0.5)); // Start inside voxel (1,1,0)
    ray_directions.push_back(make_vec3(0, 0, 1)); // Hit triangle at z=0
 
    // Calculate voxel ray path lengths with classification
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
    // Test voxel (1,1,0) - contains the triangle and center rays
    int hit_before, hit_after, hit_inside;
    collision.getVoxelRayHitCounts(make_int3(1, 1, 0), hit_before, hit_after, hit_inside);
 
    // Verify hit counts - expect rays 1 and 3 to intersect this voxel
    DOCTEST_CHECK(hit_before >= 0); // May have rays hitting before voxel
    DOCTEST_CHECK(hit_after >= 0); // May have rays reaching after voxel entry
    DOCTEST_CHECK(hit_inside >= 0); // May have rays hitting inside voxel
 
    // Test voxel (0,0,0) - corner voxel with ray 2
    collision.getVoxelRayHitCounts(make_int3(0, 0, 0), hit_before, hit_after, hit_inside);
 
    // For corner voxel, ray 2 should pass through without hitting geometry
    DOCTEST_CHECK(hit_before >= 0);
    DOCTEST_CHECK(hit_after >= 0);
    DOCTEST_CHECK(hit_inside >= 0);
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Classification - getVoxelRayPathLengths Individual Lengths") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Simple 1x1x1 voxel grid for precise control
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(2, 2, 2); // Voxel spans from (-1,-1,-1) to (1,1,1)
    int3 grid_divisions(1, 1, 1);
 
    // Create rays with known path lengths through the voxel
    std::vector<vec3> ray_origins;
    std::vector<vec3> ray_directions;
 
    // Ray 1: Straight through center, should have path length = 2.0
    ray_origins.push_back(make_vec3(0, 0, -2));
    ray_directions.push_back(make_vec3(0, 0, 1));
 
    // Ray 2: Diagonal corner-to-corner, path length = 2*sqrt(3) ≈ 3.464
    ray_origins.push_back(make_vec3(-2, -2, -2));
    ray_directions.push_back(normalize(make_vec3(1, 1, 1)));
 
    // Ray 3: Edge crossing, specific path length calculation
    ray_origins.push_back(make_vec3(0, -2, -2));
    ray_directions.push_back(normalize(make_vec3(0, 1, 1))); // Path length = 2*sqrt(2) ≈ 2.828
 
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
    // Get individual path lengths for the single voxel (0,0,0)
    std::vector<float> path_lengths = collision.getVoxelRayPathLengths(make_int3(0, 0, 0));
 
    // Should have path lengths for all rays that intersected the voxel
    DOCTEST_CHECK(path_lengths.size() >= 1); // At least one ray should intersect
 
    // Verify path lengths are reasonable (between 0 and voxel diagonal)
    float max_diagonal = 2.0f * sqrt(3.0f); // Maximum possible path through voxel
    for (float length: path_lengths) {
        DOCTEST_CHECK(length > 0.0f);
        DOCTEST_CHECK(length <= max_diagonal + 1e-6f); // Allow small numerical tolerance
    }
 
    // Check that we can identify the expected path lengths (within tolerance)
    bool found_center_ray = false;
    bool found_diagonal_ray = false;
 
    for (float length: path_lengths) {
        if (std::abs(length - 2.0f) < 0.1f) { // Center ray
            found_center_ray = true;
        }
        if (std::abs(length - 2.0f * sqrt(3.0f)) < 0.1f) { // Diagonal ray
            found_diagonal_ray = true;
        }
    }
 
    DOCTEST_CHECK(found_center_ray); // Should find the straight-through ray
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Classification - Beer's Law Scenario with Geometry") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create realistic Beer's law test scenario
    // Single patch in center voxel to create known occlusion pattern
    uint patch_uuid = context.addPatch(make_vec3(0, 0, 0), make_vec2(0.8, 0.8));
 
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(6, 6, 6);
    int3 grid_divisions(3, 3, 3); // 3x3x3 grid
 
    // Grid of parallel rays from below (simulating LiDAR from ground)
    std::vector<vec3> ray_origins;
    std::vector<vec3> ray_directions;
 
    int num_rays_per_axis = 10;
    for (int i = 0; i < num_rays_per_axis; i++) {
        for (int j = 0; j < num_rays_per_axis; j++) {
            float x = -2.5f + (5.0f * i) / (num_rays_per_axis - 1); // Spread across grid
            float y = -2.5f + (5.0f * j) / (num_rays_per_axis - 1);
 
            ray_origins.push_back(make_vec3(x, y, -4));
            ray_directions.push_back(make_vec3(0, 0, 1)); // All rays pointing up
        }
    }
 
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
    // Test center voxel (1,1,1) which contains the patch
    int hit_before, hit_after, hit_inside;
    collision.getVoxelRayHitCounts(make_int3(1, 1, 1), hit_before, hit_after, hit_inside);
 
    // With parallel upward rays and patch at z=0, expect:
    // - hit_before = 0 (no geometry below patch)
    // - hit_inside > 0 (some rays hit the patch inside voxel)
    // - hit_after depends on rays that pass through without hitting
 
    DOCTEST_CHECK(hit_before >= 0);
    DOCTEST_CHECK(hit_after >= 0);
    DOCTEST_CHECK(hit_inside >= 0);
    DOCTEST_CHECK((hit_before + hit_after + hit_inside) > 0); // Total hits should be positive
 
    // Verify path lengths exist for this voxel
    std::vector<float> path_lengths = collision.getVoxelRayPathLengths(make_int3(1, 1, 1));
    DOCTEST_CHECK(path_lengths.size() > 0); // Should have rays passing through center voxel
 
    // Test corner voxel that should have fewer intersections
    collision.getVoxelRayHitCounts(make_int3(0, 0, 0), hit_before, hit_after, hit_inside);
 
    // Corner voxel should have some ray intersections but likely no geometry hits
    // (depending on ray pattern)
    DOCTEST_CHECK(hit_before >= 0);
    DOCTEST_CHECK(hit_after >= 0);
    DOCTEST_CHECK(hit_inside >= 0);
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Classification - Edge Cases and Boundary Conditions") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create geometry at voxel boundaries to test edge cases
    uint triangle1 = context.addTriangle(make_vec3(-1, -1, -1), make_vec3(1, -1, -1), make_vec3(0, 1, -1)); // Bottom boundary
    uint triangle2 = context.addTriangle(make_vec3(-1, -1, 1), make_vec3(1, -1, 1), make_vec3(0, 1, 1)); // Top boundary
 
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(4, 4, 4);
    int3 grid_divisions(2, 2, 2);
 
    std::vector<vec3> ray_origins;
    std::vector<vec3> ray_directions;
 
    // Edge case 1: Ray starting inside voxel
    ray_origins.push_back(make_vec3(0, 0, -0.5)); // Inside voxel (1,1,0)
    ray_directions.push_back(make_vec3(0, 0, 1));
 
    // Edge case 2: Ray grazing voxel corner
    ray_origins.push_back(make_vec3(-1.99, -1.99, -3)); // Almost missing voxel (0,0,0)
    ray_directions.push_back(make_vec3(0, 0, 1));
 
    // Edge case 3: Ray parallel to voxel face (should miss or barely graze)
    ray_origins.push_back(make_vec3(-2, 0, 0)); // At voxel boundary
    ray_directions.push_back(make_vec3(1, 0, 0)); // Parallel to YZ face
 
    // Edge case 4: Ray exactly hitting voxel corner
    ray_origins.push_back(make_vec3(-2, -2, -2));
    ray_directions.push_back(normalize(make_vec3(1, 1, 1))); // Towards corner
 
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
    // Test that edge cases are handled without crashes or invalid data
    for (int i = 0; i < grid_divisions.x; i++) {
        for (int j = 0; j < grid_divisions.y; j++) {
            for (int k = 0; k < grid_divisions.z; k++) {
                int hit_before, hit_after, hit_inside;
                int3 voxel_idx = make_int3(i, j, k);
 
                // Should not throw exceptions for valid voxel indices
                collision.getVoxelRayHitCounts(voxel_idx, hit_before, hit_after, hit_inside);
 
                // Hit counts should be non-negative
                DOCTEST_CHECK(hit_before >= 0);
                DOCTEST_CHECK(hit_after >= 0);
                DOCTEST_CHECK(hit_inside >= 0);
 
                // Path lengths should be valid
                std::vector<float> path_lengths = collision.getVoxelRayPathLengths(voxel_idx);
                for (float length: path_lengths) {
                    DOCTEST_CHECK(length > 0.0f); // All path lengths should be positive
                    DOCTEST_CHECK(length < 100.0f); // Reasonable upper bound
                }
            }
        }
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Classification - Error Handling and Invalid Inputs") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test error handling for invalid voxel indices
    bool caught_negative_exception = false;
    bool caught_large_exception = false;
    std::string negative_error_msg;
    std::string large_error_msg;
 
    {
        capture_cerr capture;
 
        // Test invalid negative indices
        try {
            int hit_before, hit_after, hit_inside;
            collision.getVoxelRayHitCounts(make_int3(-1, 0, 0), hit_before, hit_after, hit_inside);
        } catch (const std::exception &e) {
            caught_negative_exception = true;
            negative_error_msg = e.what();
        }
 
        // Test invalid too-large indices
        try {
            std::vector<float> path_lengths = collision.getVoxelRayPathLengths(make_int3(100, 100, 100));
        } catch (const std::exception &e) {
            caught_large_exception = true;
            large_error_msg = e.what();
        }
    } // capture destroyed here
 
    // Assertions after capture is destroyed
    DOCTEST_CHECK(caught_negative_exception);
    DOCTEST_CHECK(negative_error_msg.find("Invalid voxel indices") != std::string::npos);
    DOCTEST_CHECK(caught_large_exception);
    DOCTEST_CHECK(large_error_msg.find("Invalid voxel indices") != std::string::npos);
 
    // Test accessing data before initialization
    int hit_before, hit_after, hit_inside;
    collision.getVoxelRayHitCounts(make_int3(0, 0, 0), hit_before, hit_after, hit_inside);
 
    // Should return zeros when not initialized
    DOCTEST_CHECK(hit_before == 0);
    DOCTEST_CHECK(hit_after == 0);
    DOCTEST_CHECK(hit_inside == 0);
 
    std::vector<float> path_lengths = collision.getVoxelRayPathLengths(make_int3(0, 0, 0));
    DOCTEST_CHECK(path_lengths.empty()); // Should return empty vector when not initialized
}
 
DOCTEST_TEST_CASE("CollisionDetection Ray Classification - Beer's Law Integration Test") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Create realistic vegetation scenario for Beer's law testing
    // Multiple patches to create realistic occlusion pattern
    std::vector<uint> vegetation_uuids;
 
    // Create a sparse canopy layer
    for (int i = 0; i < 3; i++) {
        for (int j = 0; j < 3; j++) {
            if ((i + j) % 2 == 0) { // Checkerboard pattern for sparse coverage
                float x = -2.0f + i * 2.0f;
                float y = -2.0f + j * 2.0f;
                float z = 1.0f + i * 0.5f; // Varying height
 
                uint patch_uuid = context.addPatch(make_vec3(x, y, z), make_vec2(1.2, 1.2));
                vegetation_uuids.push_back(patch_uuid);
            }
        }
    }
 
    vec3 grid_center(0, 0, 0);
    vec3 grid_size(8, 8, 6);
    int3 grid_divisions(4, 4, 3); // 4x4x3 grid
 
    // LiDAR-style ray pattern from below
    std::vector<vec3> ray_origins;
    std::vector<vec3> ray_directions;
 
    int rays_per_axis = 20;
    for (int i = 0; i < rays_per_axis; i++) {
        for (int j = 0; j < rays_per_axis; j++) {
            float x = -3.5f + (7.0f * i) / (rays_per_axis - 1);
            float y = -3.5f + (7.0f * j) / (rays_per_axis - 1);
 
            ray_origins.push_back(make_vec3(x, y, -3));
            ray_directions.push_back(make_vec3(0, 0, 1));
        }
    }
 
    collision.calculateVoxelRayPathLengths(grid_center, grid_size, grid_divisions, ray_origins, ray_directions);
 
    // Analyze Beer's law statistics for each voxel
    bool found_realistic_data = false;
 
    for (int i = 0; i < grid_divisions.x; i++) {
        for (int j = 0; j < grid_divisions.y; j++) {
            for (int k = 0; k < grid_divisions.z; k++) {
                int hit_before, hit_after, hit_inside;
                collision.getVoxelRayHitCounts(make_int3(i, j, k), hit_before, hit_after, hit_inside);
 
                std::vector<float> path_lengths = collision.getVoxelRayPathLengths(make_int3(i, j, k));
 
                if (!path_lengths.empty() && (hit_before + hit_after + hit_inside) > 0) {
                    found_realistic_data = true;
 
                    // Beer's law validation: P_trans / P_denom should be between 0 and 1
                    int P_denom = path_lengths.size(); // Total rays through voxel
                    int P_trans = P_denom - hit_inside; // Rays not hitting inside voxel
 
                    DOCTEST_CHECK(P_trans >= 0);
                    DOCTEST_CHECK(P_trans <= P_denom);
 
                    if (P_denom > 0) {
                        float transmission_probability = static_cast<float>(P_trans) / static_cast<float>(P_denom);
                        DOCTEST_CHECK(transmission_probability >= 0.0f);
                        DOCTEST_CHECK(transmission_probability <= 1.0f);
 
                        // If we have hits inside, transmission should be less than 1
                        if (hit_inside > 0) {
                            DOCTEST_CHECK(transmission_probability < 1.0f);
                        }
                    }
 
                    // Average path length calculation (r_bar)
                    float total_path_length = 0.0f;
                    for (float length: path_lengths) {
                        total_path_length += length;
                    }
                    float r_bar = total_path_length / P_denom;
 
                    DOCTEST_CHECK(r_bar > 0.0f);
                    DOCTEST_CHECK(r_bar < 10.0f); // Reasonable for this voxel size
 
                    // For Beer's law: LAD = -ln(P_trans/P_denom) / (r_bar * G_theta)
                    // We can't test the full formula without G_theta, but we can verify components
                    if (P_trans < P_denom && P_trans > 0) {
                        float ln_arg = static_cast<float>(P_trans) / static_cast<float>(P_denom);
                        DOCTEST_CHECK(ln_arg > 0.0f); // ln argument must be positive
                        DOCTEST_CHECK(ln_arg <= 1.0f); // Probability can't exceed 1
                    }
                }
            }
        }
    }
 
    DOCTEST_CHECK(found_realistic_data); // Should have found some meaningful data
}
 
DOCTEST_TEST_CASE("CollisionDetection calculateVoxelPathLengths Enhanced Method") {
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
 
    // Test 1: Basic functionality with simple ray-voxel setup
    {
        vec3 scan_origin = make_vec3(0.0f, 0.0f, 0.0f);
 
        // Create rays pointing in positive X direction
        std::vector<vec3> ray_directions;
        ray_directions.push_back(normalize(make_vec3(1.0f, 0.0f, 0.0f))); // Straight along X
        ray_directions.push_back(normalize(make_vec3(1.0f, 0.1f, 0.0f))); // Slight Y offset
        ray_directions.push_back(normalize(make_vec3(1.0f, 0.0f, 0.1f))); // Slight Z offset
 
        // Create voxels that should intersect with rays
        std::vector<vec3> voxel_centers;
        std::vector<vec3> voxel_sizes;
 
        voxel_centers.push_back(make_vec3(2.0f, 0.0f, 0.0f)); // On ray path
        voxel_centers.push_back(make_vec3(5.0f, 0.0f, 0.0f)); // Further along ray path
        voxel_centers.push_back(make_vec3(2.0f, 3.0f, 0.0f)); // Off ray path
 
        voxel_sizes.push_back(make_vec3(1.0f, 1.0f, 1.0f));
        voxel_sizes.push_back(make_vec3(1.0f, 1.0f, 1.0f));
        voxel_sizes.push_back(make_vec3(1.0f, 1.0f, 1.0f));
 
        auto result = collision.calculateVoxelPathLengths(scan_origin, ray_directions, voxel_centers, voxel_sizes);
 
        // Verify result structure
        DOCTEST_CHECK(result.size() == 3); // One vector per voxel
 
        // First voxel should be hit by multiple rays
        DOCTEST_CHECK(result[0].size() > 0);
 
        // Second voxel should also be hit by multiple rays
        DOCTEST_CHECK(result[1].size() > 0);
 
        // Third voxel (off path) should have fewer or no hits
        // (This depends on the exact geometry, so we just check it's valid)
        DOCTEST_CHECK(result[2].size() >= 0);
 
        // Verify that path_length field is populated correctly
        for (size_t voxel_idx = 0; voxel_idx < 2; ++voxel_idx) {
            for (const auto &hit: result[voxel_idx]) {
                DOCTEST_CHECK(hit.path_length > 0.0f);
                DOCTEST_CHECK(hit.path_length <= 2.0f); // Should be at most the voxel diagonal
                DOCTEST_CHECK(hit.hit == false); // These are voxel traversals, not primitive hits
                DOCTEST_CHECK(hit.distance == -1.0f); // Not applicable for voxel traversals
                DOCTEST_CHECK(hit.primitive_UUID == 0); // No primitive
            }
        }
    }
 
    // Test 2: Performance test with larger numbers of rays and voxels
    {
        vec3 scan_origin = make_vec3(0.0f, 0.0f, 0.0f);
 
        // Create 1000 rays in various directions
        std::vector<vec3> ray_directions;
        for (int i = 0; i < 1000; ++i) {
            float theta = i * 0.01f; // Small angle variations
            ray_directions.push_back(normalize(make_vec3(1.0f, sin(theta), cos(theta))));
        }
 
        // Create 100 voxels in a grid pattern
        std::vector<vec3> voxel_centers;
        std::vector<vec3> voxel_sizes;
        for (int x = 0; x < 10; ++x) {
            for (int y = 0; y < 10; ++y) {
                voxel_centers.push_back(make_vec3(x + 1.0f, y - 5.0f, 0.0f));
                voxel_sizes.push_back(make_vec3(0.5f, 0.5f, 0.5f));
            }
        }
 
        // Time the calculation
        auto start_time = std::chrono::high_resolution_clock::now();
        auto result = collision.calculateVoxelPathLengths(scan_origin, ray_directions, voxel_centers, voxel_sizes);
        auto end_time = std::chrono::high_resolution_clock::now();
 
        auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(end_time - start_time);
 
        // Verify performance requirement (should be much faster than 2 seconds for this smaller test)
        DOCTEST_CHECK(duration.count() < 500); // 500ms for 1K rays x 100 voxels
 
        // Verify result structure
        DOCTEST_CHECK(result.size() == 100); // One vector per voxel
 
        // Count total intersections and verify path lengths
        size_t total_intersections = 0;
        for (size_t i = 0; i < 100; ++i) {
            total_intersections += result[i].size();
            for (const auto &hit: result[i]) {
                DOCTEST_CHECK(hit.path_length > 0.0f);
                DOCTEST_CHECK(hit.path_length <= 1.0f); // Max voxel diagonal for 0.5x0.5x0.5 voxel
            }
        }
 
        // Should have found some intersections
        DOCTEST_CHECK(total_intersections > 0);
    }
 
    // Test 3: Edge cases and error handling
    {
        vec3 scan_origin = make_vec3(0.0f, 0.0f, 0.0f);
 
        // Test empty rays
        std::vector<vec3> empty_rays;
        std::vector<vec3> voxel_centers = {make_vec3(1.0f, 0.0f, 0.0f)};
        std::vector<vec3> voxel_sizes = {make_vec3(1.0f, 1.0f, 1.0f)};
 
        auto result = collision.calculateVoxelPathLengths(scan_origin, empty_rays, voxel_centers, voxel_sizes);
        DOCTEST_CHECK(result.empty());
 
        // Test empty voxels
        std::vector<vec3> ray_directions = {normalize(make_vec3(1.0f, 0.0f, 0.0f))};
        std::vector<vec3> empty_voxels;
        std::vector<vec3> empty_sizes;
 
        result = collision.calculateVoxelPathLengths(scan_origin, ray_directions, empty_voxels, empty_sizes);
        DOCTEST_CHECK(result.empty());
 
        // Test mismatched voxel center/size arrays
        std::vector<vec3> mismatched_sizes = {make_vec3(1.0f, 1.0f, 1.0f), make_vec3(2.0f, 2.0f, 2.0f)};
 
        bool threw_exception = false;
        {
            capture_cerr capture;
            try {
                collision.calculateVoxelPathLengths(scan_origin, ray_directions, voxel_centers, mismatched_sizes);
            } catch (const std::exception &) {
                threw_exception = true;
            }
        } // capture destroyed here
 
        DOCTEST_CHECK(threw_exception);
    }
 
    // Test 4: Geometric accuracy - ray exactly through voxel center
    {
        vec3 scan_origin = make_vec3(0.0f, 0.0f, 0.0f);
        vec3 ray_direction = normalize(make_vec3(1.0f, 0.0f, 0.0f));
        vec3 voxel_center = make_vec3(5.0f, 0.0f, 0.0f);
        vec3 voxel_size = make_vec3(2.0f, 2.0f, 2.0f);
 
        auto result = collision.calculateVoxelPathLengths(scan_origin, {ray_direction}, {voxel_center}, {voxel_size});
 
        DOCTEST_CHECK(result.size() == 1); // One voxel
        DOCTEST_CHECK(result[0].size() == 1); // One ray hit
 
        // Path length through center of cube should be exactly the voxel width (2.0)
        float path_length = result[0][0].path_length;
        DOCTEST_CHECK(std::abs(path_length - 2.0f) < 1e-4f);
    }
 
    // Test 5: Multiple rays through same voxel at different angles
    {
        vec3 scan_origin = make_vec3(-1.0f, 0.0f, 0.0f);
        std::vector<vec3> ray_directions;
 
        // Rays at different angles through the same voxel
        ray_directions.push_back(normalize(make_vec3(1.0f, 0.0f, 0.0f))); // Straight through
        ray_directions.push_back(normalize(make_vec3(1.0f, 0.2f, 0.0f))); // Diagonal
        ray_directions.push_back(normalize(make_vec3(1.0f, 0.0f, 0.2f))); // Different diagonal
 
        vec3 voxel_center = make_vec3(1.0f, 0.0f, 0.0f);
        vec3 voxel_size = make_vec3(1.0f, 1.0f, 1.0f);
 
        auto result = collision.calculateVoxelPathLengths(scan_origin, ray_directions, {voxel_center}, {voxel_size});
 
        // All rays should intersect
        DOCTEST_CHECK(result.size() == 1); // One voxel
        DOCTEST_CHECK(result[0].size() == 3); // Three ray hits
 
        // Path lengths should be different for different angles
        std::vector<float> path_lengths;
        for (const auto &hit: result[0]) {
            path_lengths.push_back(hit.path_length);
        }
 
        // Verify all path lengths are reasonable
        for (float path: path_lengths) {
            DOCTEST_CHECK(path > 0.5f); // At least half the voxel width
            DOCTEST_CHECK(path < 2.0f); // At most the full diagonal
        }
 
        // The straight ray should generally be the shortest, but due to OpenMP ordering
        // we can't guarantee which hit comes first, so just verify they're not all the same
        DOCTEST_CHECK(!(path_lengths[0] == path_lengths[1] && path_lengths[1] == path_lengths[2]));
    }
 
    // Test 6: Usage pattern test - verify the exact API the LiDAR plugin will use
    {
        vec3 scan_origin = make_vec3(0.0f, 0.0f, 0.0f);
        std::vector<vec3> ray_directions = {normalize(make_vec3(1.0f, 0.0f, 0.0f)), normalize(make_vec3(1.0f, 0.1f, 0.0f)), normalize(make_vec3(1.0f, 0.0f, 0.1f))};
 
        std::vector<vec3> voxel_centers = {make_vec3(2.0f, 0.0f, 0.0f), make_vec3(5.0f, 0.0f, 0.0f)};
 
        std::vector<vec3> voxel_sizes = {make_vec3(1.0f, 1.0f, 1.0f), make_vec3(1.0f, 1.0f, 1.0f)};
 
        // This is exactly how the LiDAR plugin will use it
        auto result = collision.calculateVoxelPathLengths(scan_origin, ray_directions, voxel_centers, voxel_sizes);
 
        // LiDAR plugin usage pattern:
        for (size_t c = 0; c < voxel_centers.size(); ++c) {
            std::vector<float> dr_agg;
            uint hit_after_agg = 0;
 
            // Extract path lengths and ray count for this voxel
            for (const auto &hit: result[c]) {
                dr_agg.push_back(hit.path_length); // Direct assignment as specified
                hit_after_agg++; // Count rays
            }
 
            // Verify the data is usable
            DOCTEST_CHECK(hit_after_agg == result[c].size());
            for (float path_length: dr_agg) {
                DOCTEST_CHECK(path_length > 0.0f);
                DOCTEST_CHECK(path_length <= 2.0f);
            }
        }
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - Patch with no slices") {
    Context context;
 
    // Create patch using center and size instead of vertices
    vec3 patch_center = make_vec3(0.5, 0, 0.5);
    vec2 patch_size = make_vec2(1, 1);
 
    uint prim_UUID = context.addPatch(patch_center, patch_size);
 
    vec3 grid_center = make_vec3(0, 1, 0);
    vec3 grid_size = make_vec3(10, 10, 10);
 
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    std::vector<uint> voxel_UUIDs = collisiondetection.slicePrimitivesUsingGrid(std::vector<uint>{prim_UUID}, grid_center, grid_size, make_int3(2, 2, 2));
 
    DOCTEST_CHECK(voxel_UUIDs.size() >= 1);
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - Patch with one slice") {
    Context context;
 
    // Create patch using center and size instead of vertices
    vec3 patch_center = make_vec3(0.5, 0, 0);
    vec2 patch_size = make_vec2(2, 2);
 
    uint prim_UUID = context.addPatch(patch_center, patch_size);
 
    vec3 grid_center = make_vec3(0, 0, 0);
    vec3 grid_size = make_vec3(1, 10, 10);
 
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    std::vector<uint> voxel_UUIDs = collisiondetection.slicePrimitivesUsingGrid(std::vector<uint>{prim_UUID}, grid_center, grid_size, make_int3(2, 1, 1));
 
    DOCTEST_CHECK(voxel_UUIDs.size() >= 1);
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - Patch with 2 slices") {
    Context context;
 
    // Create patch using center and size instead of vertices
    vec3 patch_center = make_vec3(1, 0, 0);
    vec2 patch_size = make_vec2(3, 1);
 
    uint prim_UUID = context.addPatch(patch_center, patch_size);
 
    vec3 grid_center = make_vec3(0, 0, 0);
    vec3 grid_size = make_vec3(2, 10, 1);
 
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    std::vector<uint> voxel_UUIDs = collisiondetection.slicePrimitivesUsingGrid(std::vector<uint>{prim_UUID}, grid_center, grid_size, make_int3(3, 1, 1));
 
    DOCTEST_CHECK(voxel_UUIDs.size() >= 1);
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - Patch with 3 slices and no vertices inside voxel") {
    Context context;
 
    // Create patch using center and size instead of vertices
    vec3 patch_center = make_vec3(2, 0, 0);
    vec2 patch_size = make_vec2(3, 2);
 
    uint prim_UUID = context.addPatch(patch_center, patch_size);
 
    vec3 grid_center = make_vec3(0, 0, 0);
    vec3 grid_size = make_vec3(4, 10, 10);
 
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    std::vector<uint> voxel_UUIDs = collisiondetection.slicePrimitivesUsingGrid(std::vector<uint>{prim_UUID}, grid_center, grid_size, make_int3(4, 1, 1));
 
    DOCTEST_CHECK(voxel_UUIDs.size() >= 1);
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - Areas after slicing (non-textured)") {
    Context context;
 
    // Create patch using center and size instead of vertices
    vec3 patch_center = make_vec3(0, 0, 0);
    vec2 patch_size = make_vec2(2, 2);
 
    uint prim_UUID = context.addPatch(patch_center, patch_size);
 
    float area_patch = context.getPrimitiveArea(prim_UUID);
 
    vec3 grid_center = make_vec3(0, 0, 0);
    vec3 grid_size = make_vec3(2, 10, 2);
 
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    std::vector<uint> voxel_UUIDs = collisiondetection.slicePrimitivesUsingGrid(std::vector<uint>{prim_UUID}, grid_center, grid_size, make_int3(2, 1, 2));
 
    float area_tot = 0;
    for (uint UUID: voxel_UUIDs) {
        area_tot += context.getPrimitiveArea(UUID);
    }
 
    DOCTEST_CHECK(fabs(area_tot - area_patch) / area_patch < 0.05f);
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - Textured areas after slicing") {
    Context context;
 
    // Create textured patch using center, size, and texture file
    vec3 patch_center = make_vec3(0, 0, 0);
    vec2 patch_size = make_vec2(2, 2);
 
    uint prim_UUID = context.addPatch(patch_center, patch_size, make_SphericalCoord(0, 0), "lib/images/disk_texture.png");
 
    float area_patch = context.getPrimitiveArea(prim_UUID);
 
    vec3 grid_center = make_vec3(0, 0, 0);
    vec3 grid_size = make_vec3(2, 10, 2);
 
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    std::vector<uint> voxel_UUIDs = collisiondetection.slicePrimitivesUsingGrid(std::vector<uint>{prim_UUID}, grid_center, grid_size, make_int3(2, 1, 2));
 
    float area_tot = 0;
    for (uint UUID: voxel_UUIDs) {
        area_tot += context.getPrimitiveArea(UUID);
    }
 
    DOCTEST_CHECK(fabs(area_tot - area_patch) / area_patch < 0.05f);
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - Cropping non-textured primitives") {
    Context context;
 
    // Create two triangles to form a quad (replacement for addPolygon)
    uint tri1_UUID = context.addTriangle(make_vec3(-1, 0, 1), make_vec3(1, 0, 1), make_vec3(1, 0, -1));
    uint tri2_UUID = context.addTriangle(make_vec3(1, 0, -1), make_vec3(-1, 0, -1), make_vec3(-1, 0, 1));
    uint prim_UUID = tri1_UUID; // Use first triangle for the test
 
    vec3 grid_center = make_vec3(0, 0, 0);
    vec3 grid_size = make_vec3(1, 10, 1);
 
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    // Test slicing the primitive within the voxel bounds
    std::vector<uint> voxel_UUIDs = collisiondetection.slicePrimitivesUsingGrid(std::vector<uint>{prim_UUID}, grid_center, grid_size, make_int3(1, 1, 1));
 
    DOCTEST_CHECK(voxel_UUIDs.size() >= 1);
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - Cropping textured primitives") {
    Context context;
 
    // Create textured patch using center, size, and texture file
    vec3 patch_center = make_vec3(0, 0, 0);
    vec2 patch_size = make_vec2(2, 2);
 
    uint prim_UUID = context.addPatch(patch_center, patch_size, make_SphericalCoord(0, 0), "lib/images/disk_texture.png");
 
    vec3 grid_center = make_vec3(0, 0, 0);
    vec3 grid_size = make_vec3(1, 10, 1);
 
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    // Test slicing the textured primitive within the voxel bounds
    std::vector<uint> voxel_UUIDs = collisiondetection.slicePrimitivesUsingGrid(std::vector<uint>{prim_UUID}, grid_center, grid_size, make_int3(1, 1, 1));
 
    DOCTEST_CHECK(voxel_UUIDs.size() >= 1);
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - Basic functionality test") {
    Context context;
 
    // Create patch using center and size instead of vertices
    vec3 patch_center = make_vec3(0, 0, 0);
    vec2 patch_size = make_vec2(2, 2);
 
    uint prim_UUID = context.addPatch(patch_center, patch_size);
 
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    // Test slicing the primitive within a grid
    vec3 grid_center = make_vec3(0, 0, 0);
    vec3 grid_size = make_vec3(3, 3, 3);
    std::vector<uint> sliced_UUIDs = collisiondetection.slicePrimitivesUsingGrid(std::vector<uint>{prim_UUID}, grid_center, grid_size, make_int3(2, 1, 2));
 
    // Check that slicing worked and produced some output
    DOCTEST_CHECK(sliced_UUIDs.size() >= 1);
}
 
// ============================================================================
// VOXEL-PRIMITIVE INTERSECTION TESTS (calculatePrimitiveVoxelIntersection)
// ============================================================================
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - calculatePrimitiveVoxelIntersection Basic") {
    Context context;
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    // Create a voxel at origin
    vec3 voxel_center = make_vec3(0, 0, 0);
    vec3 voxel_size = make_vec3(2, 2, 2);
    uint voxel_uuid = context.addVoxel(voxel_center, voxel_size);
 
    // Create a patch inside the voxel
    vec3 patch_center = make_vec3(0.5, 0.5, 0.5);
    vec2 patch_size = make_vec2(0.5, 0.5);
    uint patch_uuid = context.addPatch(patch_center, patch_size);
 
    // Create a patch outside the voxel
    vec3 outside_center = make_vec3(5, 5, 5);
    uint outside_uuid = context.addPatch(outside_center, patch_size);
 
    // Calculate intersection
    collisiondetection.calculatePrimitiveVoxelIntersection();
 
    // Voxel should have "inside_UUIDs" data containing the inside patch
    DOCTEST_CHECK(context.doesPrimitiveDataExist(voxel_uuid, "inside_UUIDs"));
 
    std::vector<uint> inside_prims;
    context.getPrimitiveData(voxel_uuid, "inside_UUIDs", inside_prims);
 
    DOCTEST_CHECK(inside_prims.size() == 1);
    DOCTEST_CHECK(inside_prims[0] == patch_uuid);
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - calculatePrimitiveVoxelIntersection Axis-Aligned") {
    Context context;
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    // Create voxel at origin
    uint voxel_uuid = context.addVoxel(make_vec3(0, 0, 0), make_vec3(2, 2, 2));
 
    // Create patch with centroid on X-axis (tests divide-by-zero fix for y,z components)
    uint patch_x = context.addPatch(make_vec3(0.5, 0, 0), make_vec2(0.2, 0.2));
 
    // Create patch with centroid on Y-axis (tests divide-by-zero fix for x,z components)
    uint patch_y = context.addPatch(make_vec3(0, 0.5, 0), make_vec2(0.2, 0.2));
 
    // Create patch with centroid on Z-axis (tests divide-by-zero fix for x,y components)
    uint patch_z = context.addPatch(make_vec3(0, 0, 0.5), make_vec2(0.2, 0.2));
 
    // This should NOT crash with divide-by-zero
    collisiondetection.calculatePrimitiveVoxelIntersection();
 
    // All three patches should be detected inside the voxel
    DOCTEST_CHECK(context.doesPrimitiveDataExist(voxel_uuid, "inside_UUIDs"));
 
    std::vector<uint> inside_prims;
    context.getPrimitiveData(voxel_uuid, "inside_UUIDs", inside_prims);
 
    DOCTEST_CHECK(inside_prims.size() == 3);
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - calculatePrimitiveVoxelIntersection Multiple Voxels") {
    Context context;
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    // Create 3 voxels in a row
    uint voxel1 = context.addVoxel(make_vec3(-2, 0, 0), make_vec3(1, 1, 1));
    uint voxel2 = context.addVoxel(make_vec3(0, 0, 0), make_vec3(1, 1, 1));
    uint voxel3 = context.addVoxel(make_vec3(2, 0, 0), make_vec3(1, 1, 1));
 
    // Create primitives in different voxels
    uint patch1 = context.addPatch(make_vec3(-2, 0, 0), make_vec2(0.2, 0.2));
    uint patch2 = context.addPatch(make_vec3(0, 0, 0), make_vec2(0.2, 0.2));
    uint patch3a = context.addPatch(make_vec3(2, 0, 0), make_vec2(0.2, 0.2));
    uint patch3b = context.addPatch(make_vec3(2, 0.2, 0.2), make_vec2(0.1, 0.1));
 
    collisiondetection.calculatePrimitiveVoxelIntersection();
 
    // Check voxel 1 contains patch1
    std::vector<uint> inside1;
    context.getPrimitiveData(voxel1, "inside_UUIDs", inside1);
    DOCTEST_CHECK(inside1.size() == 1);
    DOCTEST_CHECK(inside1[0] == patch1);
 
    // Check voxel 2 contains patch2
    std::vector<uint> inside2;
    context.getPrimitiveData(voxel2, "inside_UUIDs", inside2);
    DOCTEST_CHECK(inside2.size() == 1);
    DOCTEST_CHECK(inside2[0] == patch2);
 
    // Check voxel 3 contains both patch3a and patch3b
    std::vector<uint> inside3;
    context.getPrimitiveData(voxel3, "inside_UUIDs", inside3);
    DOCTEST_CHECK(inside3.size() == 2);
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - calculatePrimitiveVoxelIntersection Empty Inputs") {
    Context context;
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    // Test with no voxels (should handle gracefully)
    uint patch_uuid = context.addPatch(make_vec3(0, 0, 0), make_vec2(1, 1));
    collisiondetection.calculatePrimitiveVoxelIntersection();
    // Should complete without error
 
    // Test with no primitives (should handle gracefully)
    Context context2;
    CollisionDetection collisiondetection2(&context2);
    collisiondetection2.disableMessages();
    uint voxel_uuid = context2.addVoxel(make_vec3(0, 0, 0), make_vec3(1, 1, 1));
    collisiondetection2.calculatePrimitiveVoxelIntersection();
    // Should complete without error
    DOCTEST_CHECK(!context2.doesPrimitiveDataExist(voxel_uuid, "inside_UUIDs"));
}
 
DOCTEST_TEST_CASE("CollisionDetection VoxelIntersection Integration - calculatePrimitiveVoxelIntersection Specific UUIDs") {
    Context context;
    CollisionDetection collisiondetection(&context);
    collisiondetection.disableMessages();
 
    // Create voxel and primitives
    uint voxel_uuid = context.addVoxel(make_vec3(0, 0, 0), make_vec3(2, 2, 2));
    uint patch1 = context.addPatch(make_vec3(0.5, 0.5, 0.5), make_vec2(0.2, 0.2));
    uint patch2 = context.addPatch(make_vec3(-0.5, -0.5, -0.5), make_vec2(0.2, 0.2));
    uint patch3 = context.addPatch(make_vec3(5, 5, 5), make_vec2(0.2, 0.2)); // Outside
 
    // Test with specific UUIDs only
    std::vector<uint> test_uuids = {voxel_uuid, patch1, patch3};
    collisiondetection.calculatePrimitiveVoxelIntersection(test_uuids);
 
    // Should only find patch1, not patch2 (wasn't in test UUIDs)
    std::vector<uint> inside_prims;
    context.getPrimitiveData(voxel_uuid, "inside_UUIDs", inside_prims);
 
    DOCTEST_CHECK(inside_prims.size() == 1);
    DOCTEST_CHECK(inside_prims[0] == patch1);
}
 
DOCTEST_TEST_CASE("CollisionDetection GPU/CPU Ray Casting Parity") {
    // Test that GPU and CPU ray-casting produce similar results for large ray batches
    // This test exposes the bug where GPU returns far fewer hits than CPU when
    // BVH is transferred to GPU memory
 
    Context context;
    CollisionDetection cd(&context);
    cd.disableMessages();
 
    // Create a simple 2m x 2m wall of triangles at x=0
    // This ensures rays shooting in +x direction will hit
    int grid_size = 50;
    float wall_size = 2.0f;
    float spacing = wall_size / grid_size;
 
    for (int iy = 0; iy < grid_size; iy++) {
        for (int iz = 0; iz < grid_size; iz++) {
            float y = -wall_size/2.0f + iy * spacing;
            float z = -wall_size/2.0f + iz * spacing;
 
            // Create two triangles per grid cell to form a quad
            vec3 v0(0, y, z);
            vec3 v1(0, y + spacing, z);
            vec3 v2(0, y + spacing, z + spacing);
            vec3 v3(0, y, z + spacing);
 
            context.addTriangle(v0, v1, v2);
            context.addTriangle(v0, v2, v3);
        }
    }
 
    uint triangle_count = context.getPrimitiveCount();
    std::cout << "Test geometry: " << triangle_count << " triangles" << std::endl;
 
    // Build BVH (this will call transferBVHToGPU when HELIOS_CUDA_AVAILABLE is defined)
    cd.buildBVH();
 
    // Create rays shooting at the wall from x=-2
    std::vector<CollisionDetection::RayQuery> ray_queries;
    int rays_per_dim = 1050; // 1,102,500 total rays (exceeds 1M GPU threshold to test GPU path)
 
    for (int iy = 0; iy < rays_per_dim; iy++) {
        for (int iz = 0; iz < rays_per_dim; iz++) {
            float y = -wall_size/2.0f + (iy + 0.5f) * wall_size / rays_per_dim;
            float z = -wall_size/2.0f + (iz + 0.5f) * wall_size / rays_per_dim;
            vec3 origin(-2.0f, y, z);
            vec3 direction(1.0f, 0.0f, 0.0f);
            ray_queries.emplace_back(origin, direction, 10.0f);
        }
    }
 
    std::cout << "Casting " << ray_queries.size() << " rays through wall (testing GPU path)..." << std::endl;
 
    // Test with GPU disabled first (to get baseline)
    cd.disableGPUAcceleration();
    std::vector<CollisionDetection::HitResult> cpu_results = cd.castRays(ray_queries);
 
    size_t cpu_hits = 0;
    for (const auto& result : cpu_results) {
        if (result.hit) cpu_hits++;
    }
 
    // Test with GPU enabled
    cd.enableGPUAcceleration();
    std::vector<CollisionDetection::HitResult> gpu_results = cd.castRays(ray_queries);
 
    size_t gpu_hits = 0;
    for (const auto& result : gpu_results) {
        if (result.hit) gpu_hits++;
    }
 
    std::cout << "CPU hits: " << cpu_hits << " (" << (100.0*cpu_hits/ray_queries.size()) << "%)" << std::endl;
    std::cout << "GPU hits: " << gpu_hits << " (" << (100.0*gpu_hits/ray_queries.size()) << "%)" << std::endl;
 
    // CPU should find most rays hit the wall (>90%)
    float cpu_hit_rate = static_cast<float>(cpu_hits) / ray_queries.size();
    DOCTEST_CHECK(cpu_hit_rate > 0.90f);
 
    // GPU and CPU should produce similar hit counts (within 5%)
    // This will FAIL if GPU ray-casting has bugs
    if (cpu_hits > 0) {
        float hit_ratio = static_cast<float>(gpu_hits) / static_cast<float>(cpu_hits);
        DOCTEST_CHECK(hit_ratio > 0.95f);
        DOCTEST_CHECK(hit_ratio < 1.05f);
    }
}
 
DOCTEST_TEST_CASE("CollisionDetection Flat Single-Plane Mesh Ray Casting") {
    // Regression guard: a perfectly flat (coplanar) mesh produces BVH nodes whose AABB has
    // zero thickness along one axis. Verify that scanning such a mesh still produces hits,
    // i.e. that the ray-AABB slab test handles degenerate (zero-extent) bounding boxes.
    Context context;
    CollisionDetection collision(&context);
    collision.disableMessages();
    collision.disableGPUAcceleration(); // deterministic CPU path
 
    // Build a flat sheet of many coplanar triangles in the z=0 plane (10x10 grid of quads
    // split into triangles). Many primitives force a multi-level BVH whose internal nodes
    // all have aabb_min.z == aabb_max.z == 0.
    std::vector<uint> sheet_UUIDs;
    const int N = 10;
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            float x = static_cast<float>(i);
            float y = static_cast<float>(j);
            sheet_UUIDs.push_back(context.addTriangle(make_vec3(x, y, 0), make_vec3(x + 1, y, 0), make_vec3(x + 1, y + 1, 0)));
            sheet_UUIDs.push_back(context.addTriangle(make_vec3(x, y, 0), make_vec3(x + 1, y + 1, 0), make_vec3(x, y + 1, 0)));
        }
    }
 
    collision.buildBVH();
 
    // Cast a grid of top-down rays (direction perpendicular to the flat plane). Every ray that
    // lands inside the sheet footprint must hit. If the BVH culled against a zero-thickness AABB
    // incorrectly, these would all miss.
    int hit_count = 0;
    int total = 0;
    for (int i = 0; i < N; i++) {
        for (int j = 0; j < N; j++) {
            vec3 origin = make_vec3(static_cast<float>(i) + 0.5f, static_cast<float>(j) + 0.5f, 5.0f);
            CollisionDetection::HitResult result = collision.castRay(origin, make_vec3(0, 0, -1), 10.0f);
            total++;
            if (result.hit) {
                hit_count++;
                DOCTEST_CHECK(std::abs(result.intersection_point.z) < 1e-4f); // hit lands on the plane
            }
        }
    }
    DOCTEST_CHECK(hit_count == total); // every interior top-down ray hits the flat sheet
 
    // Verify a shallow oblique ray (originating off the plane) still hits the flat sheet. This
    // approaches the zero-thickness z-slab at a grazing angle but is not coplanar with it, which
    // is the realistic LiDAR grazing-incidence case.
    vec3 oblique_dir = normalize(make_vec3(0.0f, 1.0f, -0.05f));
    CollisionDetection::HitResult oblique = collision.castRay(make_vec3(5.5f, -1.0f, 0.05f), oblique_dir, 20.0f);
    DOCTEST_CHECK(oblique.hit == true);
}