UUIDLookupHelper Class Reference

Safe UUID→Position lookup with automatic bounds checking. More...

#include <BufferIndexing.h>

Public Member Functions
HELIOS_HOST_DEVICE	UUIDLookupHelper (const uint *prim_positions, size_t prim_count)
	Construct UUID lookup helper.
HELIOS_HOST_DEVICE bool	toPosition (uint UUID, uint &position) const
	Convert UUID to position with automatic bounds checking.

Detailed Description

Safe UUID→Position lookup with automatic bounds checking.

Encapsulates the UUID→position conversion pattern used throughout CUDA code. Prevents forgetting bounds check or using UUID as direct array index.

This helper makes it impossible to:

• Use UUID directly as array index (sparse UUIDs cause out-of-bounds)
• Forget bounds checking (built into toPosition())
• Access deleted/invalid primitives (returns false for UINT_MAX)

Usage in CUDA ray hit programs:

UUIDLookupHelper lookup(primitive_positions, Nprimitives);
uint position;
if (!lookup.toPosition(hit_UUID, position)) {
    return;  // Invalid UUID - primitive was deleted or never existed
}
// Safe to use position for all buffer access
bool two_sided = twosided_flag[position];
int2 subdivs = object_subdivisions[position];

Historical bugs prevented (commit 0ec2dc25a):

• 20+ instances of direct UUID indexing: twosided_flag[UUID], objectID[UUID]

Definition at line 292 of file BufferIndexing.h.

Constructor & Destructor Documentation

UUIDLookupHelper()

HELIOS_HOST_DEVICE UUIDLookupHelper::UUIDLookupHelper ( const uint *  prim_positions, size_t  prim_count  )

inline

Construct UUID lookup helper.

Parameters

prim_positions	Pointer to primitive_positions buffer (sparse array indexed by UUID)
prim_count	Total number of primitives (for bounds validation)

Definition at line 304 of file BufferIndexing.h.

Member Function Documentation

toPosition()

HELIOS_HOST_DEVICE bool UUIDLookupHelper::toPosition ( uint  UUID, uint &  position  ) const

inline

Convert UUID to position with automatic bounds checking.

Parameters

	UUID	Primitive UUID to look up
[out]	position	Output position (only written if UUID is valid)

Returns

true if UUID is valid and position was written, false if UUID not found

Returns false if:

• primitive_positions[UUID] == UINT_MAX (deleted/never created)
• primitive_positions[UUID] >= primitive_count (corrupted data)

Position parameter is unchanged if function returns false.

Definition at line 320 of file BufferIndexing.h.

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

• plugins/radiation/include/BufferIndexing.h