VkBuildAccelerationStructureFlagBitsKHR

Bits which can be set in VkAccelerationStructureBuildGeometryInfoKHR::flags or VkAccelerationStructureInfoNV::flags specifying additional parameters for acceleration structure builds, are:

typedef enum VkBuildAccelerationStructureFlagBitsKHR {
    VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_KHR = 0x00000001,
    VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR = 0x00000002,
    VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR = 0x00000004,
    VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_KHR = 0x00000008,
    VK_BUILD_ACCELERATION_STRUCTURE_LOW_MEMORY_BIT_KHR = 0x00000010,
} VkBuildAccelerationStructureFlagBitsKHR;

or the equivalent

#define VkBuildAccelerationStructureFlagBitsNV VkBuildAccelerationStructureFlagBitsKHR

• VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_KHR specifies that the specified acceleration structure can be updated with a mode of VK_BUILD_ACCELERATION_STRUCTURE_MODE_UPDATE_KHR in VkAccelerationStructureBuildGeometryInfoKHR or an update of VK_TRUE in vkCmdBuildAccelerationStructureNV . For sphere and LSS primitives, only positions and radii may be updated, the provided index buffers and flags must remain unchanged from the initial build.
• VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_KHR specifies that the specified acceleration structure can act as the source for a copy acceleration structure command with mode of VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_KHR to produce a compacted acceleration structure.
• VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_KHR specifies that the given acceleration structure build should prioritize trace performance over build time.
• VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_KHR specifies that the given acceleration structure build should prioritize build time over trace performance.
• VK_BUILD_ACCELERATION_STRUCTURE_LOW_MEMORY_BIT_KHR specifies that this acceleration structure should minimize the size of the scratch memory and the final result acceleration structure, potentially at the expense of build time or trace performance.
• VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_OPACITY_MICROMAP_UPDATE_EXT specifies that the opacity micromaps associated with the specified acceleration structure may change with an acceleration structure update.
• VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_OPACITY_MICROMAP_DATA_UPDATE_EXT specifies that the data of the opacity micromaps associated with the specified acceleration structure may change with an acceleration structure update.
• VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_DISABLE_OPACITY_MICROMAPS_EXT specifies that the specified acceleration structure may be referenced in an instance with VK_GEOMETRY_INSTANCE_DISABLE_OPACITY_MICROMAPS_EXT set.
• VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_DATA_ACCESS_KHR specifies that the specified acceleration structure can be used when fetching the vertex and radius positions of a hit LSS or sphere primitive, or vertex positions of a hit triangle.
• VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_DISPLACEMENT_MICROMAP_UPDATE_NV specifies that the displacement micromaps associated with the specified acceleration structure may change with an acceleration structure update.