SubpatchUUIDCalculator Class Reference

Subpatch UUID calculator for tiled/subdivided geometry. More...

#include <BufferIndexing.h>

Public Member Functions
	SubpatchUUIDCalculator (uint base_UUID, helios::int2 subdivisions)
	Construct subpatch UUID calculator.
HELIOS_HOST_DEVICE uint	getUUID (int col, int row) const
	Get UUID for subpatch at (col, row) position.
HELIOS_HOST_DEVICE int	getSubpatchCount () const
	Get total number of subpatches.
helios::int2	getSubdivisions () const
	Get subdivisions (useful for loop bounds)

Detailed Description

Subpatch UUID calculator for tiled/subdivided geometry.

Encapsulates the subdivision offset calculation pattern. Prevents wrong dimension order (i vs j, x vs y, row vs col).

This helper makes it impossible to:

• Get subdivision offset formula wrong
• Swap row/column indices
• Use wrong dimension (NX vs NY)

Usage in CUDA ray generation:

uint base_UUID = primitiveID[objID];
SubpatchUUIDCalculator calc(base_UUID, object_subdivisions[objID]);
 
// Clear semantic names prevent index swapping
for (int row = 0; row < calc.getSubdivisions().y; row++) {
    for (int col = 0; col < calc.getSubdivisions().x; col++) {
        uint subpatch_UUID = calc.getUUID(col, row);
        // ... launch ray for this subpatch
    }
}

Historical bugs prevented (commit 53ca9687d):

• Swapped indices: UUID = base + ii * NY + jj (should be jj * NX + ii)
• Wrong subdivision counts from parent inheritance

Definition at line 457 of file BufferIndexing.h.

Constructor & Destructor Documentation

SubpatchUUIDCalculator()

SubpatchUUIDCalculator::SubpatchUUIDCalculator ( uint  base_UUID, helios::int2  subdivisions  )

inline

Construct subpatch UUID calculator.

Parameters

base_UUID	UUID of first subpatch (at position 0,0)
subdivisions	Subdivision counts in x and y directions

Definition at line 476 of file BufferIndexing.h.

Member Function Documentation

getSubdivisions()

helios::int2 SubpatchUUIDCalculator::getSubdivisions ( ) const

inline

Get subdivisions (useful for loop bounds)

Returns

Subdivision counts as int2

Definition at line 510 of file BufferIndexing.h.

getSubpatchCount()

HELIOS_HOST_DEVICE int SubpatchUUIDCalculator::getSubpatchCount ( ) const

inline

Get total number of subpatches.

Returns

subdivisions.x * subdivisions.y

Definition at line 497 of file BufferIndexing.h.

getUUID()

HELIOS_HOST_DEVICE uint SubpatchUUIDCalculator::getUUID ( int  col, int  row  ) const

inline

Get UUID for subpatch at (col, row) position.

Parameters

col	Column index (x-direction, 0 to subdivisions.x-1)
row	Row index (y-direction, 0 to subdivisions.y-1)

Returns

UUID = base_UUID + row * subdivisions.x + col

Parameter names make dimension order explicit - can't accidentally swap.

Definition at line 489 of file BufferIndexing.h.

---

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

• plugins/radiation/include/BufferIndexing.h