helios::VulkanComputeBackend Class Reference

Vulkan compute shader ray tracing backend. More...

#include <VulkanComputeBackend.h>

Inheritance diagram for helios::VulkanComputeBackend:

Public Member Functions
	VulkanComputeBackend (VulkanDevice *external_device)
	Constructor for test mode with shared device.
void	initialize () override
	Initialize the ray tracing backend.
void	shutdown () override
	Shutdown the ray tracing backend.
void	updateGeometry (const RayTracingGeometry &geometry) override
	Update geometry data in the ray tracing backend.
void	buildAccelerationStructure () override
	Build or rebuild the acceleration structure.
void	updateMaterials (const RayTracingMaterial &materials) override
	Update material properties (reflectivity, transmissivity, specular)
void	updateSources (const std::vector< RayTracingSource > &sources) override
	Update radiation source definitions.
void	updateDiffuseRadiation (const std::vector< float > &flux, const std::vector< float > &extinction, const std::vector< helios::vec3 > &peak_dir, const std::vector< float > &dist_norm, const std::vector< float > &sky_energy) override
	Update diffuse (ambient) radiation parameters.
void	updateSkyModel (const std::vector< helios::vec4 > &sky_radiance_params, const std::vector< float > &camera_sky_radiance, const helios::vec3 &sun_direction, const std::vector< float > &solar_disk_radiance, float solar_disk_cos_angle) override
	Update sky radiance model parameters (for camera rendering)
void	launchDirectRays (const RayTracingLaunchParams &params) override
	Launch direct (unscattered) rays to radiation sources.
void	launchDiffuseRays (const RayTracingLaunchParams &params) override
	Launch diffuse (hemispherically-distributed) rays.
void	launchCameraRays (const RayTracingLaunchParams &params) override
	Launch camera rays for image rendering.
void	launchPixelLabelRays (const RayTracingLaunchParams &params) override
	Launch pixel labeling rays (for primitive identification in images)
void	getRadiationResults (RayTracingResults &results) override
	Get radiation simulation results.
void	getCameraResults (std::vector< float > &pixel_data, std::vector< uint > &pixel_labels, std::vector< float > &pixel_depths, uint camera_id, const helios::int2 &resolution) override
	Get camera rendering results.
void	zeroRadiationBuffers (size_t launch_band_count) override
	Zero all radiation result buffers (radiation_in, radiation_out, radiation_specular)
void	zeroScatterBuffers () override
	Zero scatter buffers (scatter_buff_top, scatter_buff_bottom)
void	zeroCameraPixelBuffers (const helios::int2 &resolution) override
	Zero camera pixel label and depth buffers.
void	copyScatterToRadiation () override
	Copy scatter buffer contents to radiation buffers.
void	uploadRadiationOut (const std::vector< float > &radiation_out_top, const std::vector< float > &radiation_out_bottom) override
	Upload radiation_out buffers directly (without launching rays)
void	uploadCameraScatterBuffers (const std::vector< float > &scatter_top_cam, const std::vector< float > &scatter_bottom_cam) override
	Upload camera scatter buffers.
void	zeroCameraScatterBuffers (size_t launch_band_count) override
	Zero camera scatter buffers (scatter_buff_top_cam, scatter_buff_bottom_cam)
void	uploadSourceFluxes (const std::vector< float > &fluxes) override
	Upload source flux values for launched bands.
void	uploadSourceFluxesCam (const std::vector< float > &fluxes_cam) override
	Upload camera-weighted source flux values for specular reflection.
void	queryGPUMemory () const override
	Query and report GPU memory usage.
std::string	getBackendName () const override
	Get the name of the backend implementation.

Static Public Member Functions
static bool	probe () noexcept
	Probe whether Vulkan compute is available.
Static Public Member Functions inherited from helios::RayTracingBackend
static std::unique_ptr< RayTracingBackend >	create (const std::string &backend_type)
	Create a ray tracing backend instance.

Detailed Description

Vulkan compute shader ray tracing backend.

Uses software BVH traversal in compute shaders (no VK_KHR_ray_tracing required). Supports AMD, Intel, and Apple Silicon GPUs via Vulkan or MoltenVK.

Performance target: 5-10x slower than OptiX (hardware RT).

Definition at line 47 of file VulkanComputeBackend.h.

Constructor & Destructor Documentation

VulkanComputeBackend() [1/2]

helios::VulkanComputeBackend::VulkanComputeBackend

(

)

Definition at line 34 of file VulkanComputeBackend.cpp.

VulkanComputeBackend() [2/2]

helios::VulkanComputeBackend::VulkanComputeBackend ( VulkanDevice *  external_device )

explicit

Constructor for test mode with shared device.

Parameters

external_device

Non-owning pointer to shared VulkanDevice (must be pre-initialized)

INTERNAL TEST-ONLY CONSTRUCTOR Used by test suite to share single VulkanDevice across all test cases. Precondition: external_device must outlive this backend (satisfied by static singleton).

Definition at line 38 of file VulkanComputeBackend.cpp.

~VulkanComputeBackend()

helios::VulkanComputeBackend::~VulkanComputeBackend ( )

override

Definition at line 45 of file VulkanComputeBackend.cpp.

Member Function Documentation

buildAccelerationStructure()

void helios::VulkanComputeBackend::buildAccelerationStructure ( )

overridevirtual

Build or rebuild the acceleration structure.

Constructs the BVH or other acceleration structure for efficient ray traversal. Should be called after updateGeometry() or when geometry changes.

Implements helios::RayTracingBackend.

Definition at line 564 of file VulkanComputeBackend.cpp.

copyScatterToRadiation()

void helios::VulkanComputeBackend::copyScatterToRadiation ( )

overridevirtual

Copy scatter buffer contents to radiation buffers.

Used for multi-bounce radiation: scattering iteration results are accumulated into the main radiation buffers.

Implements helios::RayTracingBackend.

Definition at line 1933 of file VulkanComputeBackend.cpp.

getBackendName()

std::string helios::VulkanComputeBackend::getBackendName ( ) const

inlineoverridevirtual

Get the name of the backend implementation.

Returns

Backend name (e.g., "OptiX 6.5", "OptiX 7.7", "Vulkan")

Implements helios::RayTracingBackend.

Definition at line 116 of file VulkanComputeBackend.h.

getCameraResults()

void helios::VulkanComputeBackend::getCameraResults ( std::vector< float > &  pixel_data, std::vector< uint > &  pixel_labels, std::vector< float > &  pixel_depths, uint  camera_id, const helios::int2 &  resolution  )

overridevirtual

Get camera rendering results.

Parameters

[out]	pixel_data	Flattened pixel values [band][pixel_y][pixel_x]
[out]	pixel_labels	Primitive UUID for each pixel (0 if sky/miss)
[out]	pixel_depths	Depth value for each pixel
[in]	camera_id	Camera identifier
[in]	resolution	Camera resolution (width, height)

Implements helios::RayTracingBackend.

Definition at line 1760 of file VulkanComputeBackend.cpp.

getRadiationResults()

void helios::VulkanComputeBackend::getRadiationResults ( RayTracingResults &  results )

overridevirtual

Get radiation simulation results.

Parameters

[out]

results

Structure containing radiation_in, radiation_out, scatter buffers, etc.

Retrieves absorbed and emitted radiation for all primitives and bands.

Implements helios::RayTracingBackend.

Definition at line 1646 of file VulkanComputeBackend.cpp.

initialize()

void helios::VulkanComputeBackend::initialize ( )

overridevirtual

Initialize the ray tracing backend.

Creates the ray tracing context, allocates buffers, compiles/loads programs, and sets up the acceleration structure.

Implements helios::RayTracingBackend.

Definition at line 52 of file VulkanComputeBackend.cpp.

launchCameraRays()

void helios::VulkanComputeBackend::launchCameraRays ( const RayTracingLaunchParams &  params )

overridevirtual

Launch camera rays for image rendering.

Parameters

[in]

params

Launch parameters including camera position, direction, FOV, etc.

Implements helios::RayTracingBackend.

Definition at line 1332 of file VulkanComputeBackend.cpp.

launchDiffuseRays()

void helios::VulkanComputeBackend::launchDiffuseRays ( const RayTracingLaunchParams &  params )

overridevirtual

Launch diffuse (hemispherically-distributed) rays.

Parameters

[in]

params

Launch parameters including diffuse distribution parameters

Implements helios::RayTracingBackend.

Definition at line 972 of file VulkanComputeBackend.cpp.

launchDirectRays()

void helios::VulkanComputeBackend::launchDirectRays ( const RayTracingLaunchParams &  params )

overridevirtual

Launch direct (unscattered) rays to radiation sources.

Parameters

[in]

params

Launch parameters (dimensions, seed, band config, etc.)

Implements helios::RayTracingBackend.

Definition at line 743 of file VulkanComputeBackend.cpp.

launchPixelLabelRays()

void helios::VulkanComputeBackend::launchPixelLabelRays ( const RayTracingLaunchParams &  params )

overridevirtual

Launch pixel labeling rays (for primitive identification in images)

Parameters

[in]

params

Launch parameters with camera configuration

Implements helios::RayTracingBackend.

Definition at line 1499 of file VulkanComputeBackend.cpp.

probe()

bool helios::VulkanComputeBackend::probe ( )

staticnoexcept

Probe whether Vulkan compute is available.

Creates a temporary VulkanDevice (which includes compute capability probing), then destroys it. All resources are cleaned up before returning.

Returns

true if a suitable Vulkan compute device exists and can execute shaders

Definition at line 23 of file VulkanComputeBackend.cpp.

queryGPUMemory()

void helios::VulkanComputeBackend::queryGPUMemory ( ) const

overridevirtual

Query and report GPU memory usage.

Implements helios::RayTracingBackend.

Definition at line 2151 of file VulkanComputeBackend.cpp.

shutdown()

void helios::VulkanComputeBackend::shutdown ( )

overridevirtual

Shutdown the ray tracing backend.

Destroys the context, frees all buffers and resources.

Implements helios::RayTracingBackend.

Definition at line 87 of file VulkanComputeBackend.cpp.

updateDiffuseRadiation()

void helios::VulkanComputeBackend::updateDiffuseRadiation ( const std::vector< float > &  flux, const std::vector< float > &  extinction, const std::vector< helios::vec3 > &  peak_dir, const std::vector< float > &  dist_norm, const std::vector< float > &  sky_energy  )

overridevirtual

Update diffuse (ambient) radiation parameters.

Parameters

[in]	flux	Diffuse flux per band
[in]	extinction	Extinction coefficient per band
[in]	peak_dir	Peak direction for diffuse distribution per band
[in]	dist_norm	Distribution normalization factor per band
[in]	sky_energy	Energy absorbed by sky per band

Implements helios::RayTracingBackend.

Definition at line 690 of file VulkanComputeBackend.cpp.

updateGeometry()

void helios::VulkanComputeBackend::updateGeometry ( const RayTracingGeometry &  geometry )

overridevirtual

Update geometry data in the ray tracing backend.

Parameters

[in]

geometry

Geometry data for all primitive types

This uploads vertex data, transform matrices, UUIDs, texture masks, and all other geometry-related data to the GPU.

Implements helios::RayTracingBackend.

Definition at line 189 of file VulkanComputeBackend.cpp.

updateMaterials()

void helios::VulkanComputeBackend::updateMaterials ( const RayTracingMaterial &  materials )

overridevirtual

Update material properties (reflectivity, transmissivity, specular)

Parameters

[in]

materials

Material data for all primitives, sources, and bands

Implements helios::RayTracingBackend.

Definition at line 568 of file VulkanComputeBackend.cpp.

updateSkyModel()

void helios::VulkanComputeBackend::updateSkyModel ( const std::vector< helios::vec4 > &  sky_radiance_params, const std::vector< float > &  camera_sky_radiance, const helios::vec3 &  sun_direction, const std::vector< float > &  solar_disk_radiance, float  solar_disk_cos_angle  )

overridevirtual

Update sky radiance model parameters (for camera rendering)

Parameters

[in]	sky_radiance_params	Prague sky model parameters per band (vec4)
[in]	camera_sky_radiance	Sky radiance for cameras per band
[in]	sun_direction	Direction to the sun
[in]	solar_disk_radiance	Solar disk radiance per band
[in]	solar_disk_cos_angle	Cosine of solar disk angular radius

Implements helios::RayTracingBackend.

Definition at line 697 of file VulkanComputeBackend.cpp.

updateSources()

void helios::VulkanComputeBackend::updateSources ( const std::vector< RayTracingSource > &  sources )

overridevirtual

Update radiation source definitions.

Parameters

[in]

sources

Vector of radiation sources (collimated, sphere, sun, rectangle, disk)

Implements helios::RayTracingBackend.

Definition at line 636 of file VulkanComputeBackend.cpp.

uploadCameraScatterBuffers()

void helios::VulkanComputeBackend::uploadCameraScatterBuffers ( const std::vector< float > &  scatter_top_cam, const std::vector< float > &  scatter_bottom_cam  )

overridevirtual

Upload camera scatter buffers.

Parameters

[in]	scatter_top_cam	Scattered radiation for cameras (top surface) indexed by [primitive * Nbands_launch + band]
[in]	scatter_bottom_cam	Scattered radiation for cameras (bottom surface)

Used to upload emission energy that cameras should see before scatter iterations.

Implements helios::RayTracingBackend.

Definition at line 2040 of file VulkanComputeBackend.cpp.

uploadRadiationOut()

void helios::VulkanComputeBackend::uploadRadiationOut ( const std::vector< float > &  radiation_out_top, const std::vector< float > &  radiation_out_bottom  )

overridevirtual

Upload radiation_out buffers directly (without launching rays)

Parameters

[in]	radiation_out_top	Top-face outgoing radiation [Nprims * Nbands]
[in]	radiation_out_bottom	Bottom-face outgoing radiation [Nprims * Nbands]

Used to set outgoing radiation for scattering iterations.

Implements helios::RayTracingBackend.

Definition at line 1992 of file VulkanComputeBackend.cpp.

uploadSourceFluxes()

void helios::VulkanComputeBackend::uploadSourceFluxes ( const std::vector< float > &  fluxes )

overridevirtual

Upload source flux values for launched bands.

Parameters

[in]

fluxes

Source flux values indexed by [source * Nbands_launch + band]

Used to set per-band source fluxes before direct ray launch.

Implements helios::RayTracingBackend.

Definition at line 2104 of file VulkanComputeBackend.cpp.

uploadSourceFluxesCam()

void helios::VulkanComputeBackend::uploadSourceFluxesCam ( const std::vector< float > &  fluxes_cam )

overridevirtual

Upload camera-weighted source flux values for specular reflection.

Parameters

[in]

fluxes_cam

Camera spectral response weights indexed by [source * Nbands_launch + band]

Uploads per-camera spectral response weights used for specular reflection in camera rendering. The weights represent ∫(source_spectrum × camera_response) / ∫(source_spectrum) for each source/band combination. Called before each camera render with the current camera's weights.

Implements helios::RayTracingBackend.

Definition at line 2130 of file VulkanComputeBackend.cpp.

zeroCameraPixelBuffers()

void helios::VulkanComputeBackend::zeroCameraPixelBuffers ( const helios::int2 &  resolution )

overridevirtual

Zero camera pixel label and depth buffers.

Parameters

[in]

resolution

Full camera resolution (width, height)

Must be called before launching pixel label rays for multiple tiles. Each tile launch accumulates results without zeroing, so this must be called once before the tile loop to initialize the buffers.

Implements helios::RayTracingBackend.

Definition at line 1900 of file VulkanComputeBackend.cpp.

zeroCameraScatterBuffers()

void helios::VulkanComputeBackend::zeroCameraScatterBuffers ( size_t  launch_band_count )

overridevirtual

Zero camera scatter buffers (scatter_buff_top_cam, scatter_buff_bottom_cam)

Parameters

[in]

launch_band_count

Number of bands being launched in current iteration

Buffers are sized by launch_band_count to prevent double-counting when accumulating camera scatter across multiple ray launches.

Implements helios::RayTracingBackend.

Definition at line 2072 of file VulkanComputeBackend.cpp.

zeroRadiationBuffers()

void helios::VulkanComputeBackend::zeroRadiationBuffers ( size_t  launch_band_count )

overridevirtual

Zero all radiation result buffers (radiation_in, radiation_out, radiation_specular)

Parameters

[in]

launch_band_count

Number of bands being launched in current iteration

Camera scatter buffers are sized by launch_band_count (not global band count) to match per-launch accumulation semantics. All other buffers use the global band count.

Implements helios::RayTracingBackend.

Definition at line 1817 of file VulkanComputeBackend.cpp.

zeroScatterBuffers()

void helios::VulkanComputeBackend::zeroScatterBuffers ( )

overridevirtual

Zero scatter buffers (scatter_buff_top, scatter_buff_bottom)

Implements helios::RayTracingBackend.

Definition at line 1868 of file VulkanComputeBackend.cpp.

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The documentation for this class was generated from the following files:

• plugins/radiation/src/backends/VulkanComputeBackend.h
• plugins/radiation/src/backends/VulkanComputeBackend.cpp