VkAccelerationStructureBuildRangeInfoKHR(3)

Name

VkAccelerationStructureBuildRangeInfoKHR - Structure specifying build offsets and counts for acceleration structure builds

C Specification

VkAccelerationStructureBuildRangeInfoKHR is defined as:

// Provided by VK_KHR_acceleration_structure
typedef struct VkAccelerationStructureBuildRangeInfoKHR {
    uint32_t    primitiveCount;
    uint32_t    primitiveOffset;
    uint32_t    firstVertex;
    uint32_t    transformOffset;
} VkAccelerationStructureBuildRangeInfoKHR;

Members

primitiveCount defines the number of primitives for a corresponding acceleration structure geometry.
primitiveOffset defines an offset in bytes into the memory where primitive data is defined.
firstVertex is the index of the first vertex to build from for triangle geometry.
transformOffset defines an offset in bytes into the memory where a transform matrix is defined.

Description

The primitive count and primitive offset are interpreted differently depending on the VkGeometryTypeKHR used:

For geometries of type VK_GEOMETRY_TYPE_TRIANGLES_KHR, primitiveCount is the number of triangles to be built, where each triangle is treated as 3 vertices.
- If the geometry uses indices, primitiveCount × 3 indices are consumed from VkAccelerationStructureGeometryTrianglesDataKHR::indexData, starting at an offset of primitiveOffset. The value of firstVertex is added to the index values before fetching vertices.
- If the geometry does not use indices, primitiveCount × 3 vertices are consumed from VkAccelerationStructureGeometryTrianglesDataKHR::vertexData, starting at an offset of primitiveOffset + VkAccelerationStructureGeometryTrianglesDataKHR::vertexStride × firstVertex.
- If VkAccelerationStructureGeometryTrianglesDataKHR::transformData is not NULL, a single VkTransformMatrixKHR structure is consumed from VkAccelerationStructureGeometryTrianglesDataKHR::transformData, at an offset of transformOffset. This matrix describes a transformation from the space in which the vertices for all triangles in this geometry are described to the space in which the acceleration structure is defined.
For geometries of type VK_GEOMETRY_TYPE_AABBS_KHR, primitiveCount is the number of axis-aligned bounding boxes. primitiveCount VkAabbPositionsKHR structures are consumed from VkAccelerationStructureGeometryAabbsDataKHR::data, starting at an offset of primitiveOffset.
For geometries of type VK_GEOMETRY_TYPE_SPHERES_NV, primitiveCount is the number of spheres to be built, where each sphere is treated as 1 vertex.
- If the geometry uses indices, primitiveCount indices are consumed from VkAccelerationStructureGeometrySpheresDataNV::indexData, starting at an offset of primitiveOffset. The value of firstVertex is added to the index values before fetching vertices and radii.
- If the geometry does not use indices, primitiveCount vertices and radii are consumed from VkAccelerationStructureGeometrySpheresDataNV::vertexData, starting at an offset of primitiveOffset + VkAccelerationStructureGeometrySpheresDataNV::vertexStride × firstVertex and VkAccelerationStructureGeometrySpheresDataNV::radiusData, starting at an offset of primitiveOffset + VkAccelerationStructureGeometrySpheresDataNV::radiusStride × firstVertex respectively.
For geometries of type VK_GEOMETRY_TYPE_LINEAR_SWEPT_SPHERES_NV, primitiveCount is the number of LSS primitives to be built, where each LSS primitive is treated as 2 vertices.
- If the geometry uses indices, primitiveCount × 2 indices are consumed from VkAccelerationStructureGeometryLinearSweptSpheresDataNV::indexData, starting at an offset of primitiveOffset. The value of firstVertex is added to the index values before fetching vertices and radii.
- If the geometry does not use indices, primitiveCount × 2 vertices and radii are consumed from VkAccelerationStructureGeometryLinearSweptSpheresDataNV::vertexData, starting at an offset of primitiveOffset + VkAccelerationStructureGeometryLinearSweptSpheresDataNV::vertexStride × firstVertex and VkAccelerationStructureGeometryLinearSweptSpheresDataNV::radiusData, starting at an offset of primitiveOffset + VkAccelerationStructureGeometryLinearSweptSpheresDataNV::radiusStride × firstVertex respectively.
For geometries of type VK_GEOMETRY_TYPE_INSTANCES_KHR, primitiveCount is the number of acceleration structures. primitiveCount VkAccelerationStructureInstanceKHR or VkAccelerationStructureMotionInstanceNV structures are consumed from VkAccelerationStructureGeometryInstancesDataKHR::data, starting at an offset of primitiveOffset.

Valid Usage

VUID-VkAccelerationStructureBuildRangeInfoKHR-vertexData-10418
The number of vertices consumed from VkAccelerationStructureGeometryTrianglesDataKHR::vertexData must be less than or equal to VkAccelerationStructureGeometryTrianglesDataKHR::maxVertex + 1
VUID-VkAccelerationStructureBuildRangeInfoKHR-primitiveOffset-03656
For geometries of type VK_GEOMETRY_TYPE_TRIANGLES_KHR, if the geometry uses indices, the offset primitiveOffset from VkAccelerationStructureGeometryTrianglesDataKHR::indexData must be a multiple of the element size of VkAccelerationStructureGeometryTrianglesDataKHR::indexType
VUID-VkAccelerationStructureBuildRangeInfoKHR-primitiveOffset-03657
For geometries of type VK_GEOMETRY_TYPE_TRIANGLES_KHR, if the geometry does not use indices, the offset primitiveOffset from VkAccelerationStructureGeometryTrianglesDataKHR::vertexData must be a multiple of:
- the size of the format specified in VkAccelerationStructureGeometryTrianglesDataKHR::vertexFormat, if that format is a packed format
- the component size of the VkAccelerationStructureGeometryTrianglesDataKHR::vertexFormat, if that format is not a packed format
VUID-VkAccelerationStructureBuildRangeInfoKHR-maxVertex-10774
For geometries of type VK_GEOMETRY_TYPE_TRIANGLES_KHR, if the geometry uses indices, then VkAccelerationStructureGeometryTrianglesDataKHR::maxVertex must be greater than or equal to firstVertex plus the maximum index value found in the VkAccelerationStructureGeometryTrianglesDataKHR::indexData in the range [primitiveOffset, primitiveOffset
primitiveCount x 3]
VUID-VkAccelerationStructureBuildRangeInfoKHR-None-10775
For geometries of type VK_GEOMETRY_TYPE_TRIANGLES_KHR, if the geometry does not use indices, then VkAccelerationStructureGeometryTrianglesDataKHR::maxVertex must be greater than or equal to firstVertex + primitiveCount x 3 - 1
VUID-VkAccelerationStructureBuildRangeInfoKHR-transformOffset-03658
For geometries of type VK_GEOMETRY_TYPE_TRIANGLES_KHR, the offset transformOffset from VkAccelerationStructureGeometryTrianglesDataKHR::transformData must be a multiple of 16
VUID-VkAccelerationStructureBuildRangeInfoKHR-primitiveOffset-03659
For geometries of type VK_GEOMETRY_TYPE_AABBS_KHR, the offset primitiveOffset from VkAccelerationStructureGeometryAabbsDataKHR::data must be a multiple of 8
VUID-VkAccelerationStructureBuildRangeInfoKHR-primitiveOffset-03660
For geometries of type VK_GEOMETRY_TYPE_INSTANCES_KHR, the offset primitiveOffset from VkAccelerationStructureGeometryInstancesDataKHR::data must be a multiple of 16

Document Notes

For more information, see the Vulkan Specification.

This page is extracted from the Vulkan Specification. Fixes and changes should be made to the Specification, not directly.