VkPartitionedAccelerationStructureUpdateInstanceDataNV(3)

Name

VkPartitionedAccelerationStructureUpdateInstanceDataNV - Structure describing instance data to update in PTLAS

C Specification

The VkPartitionedAccelerationStructureUpdateInstanceDataNV structure is defined as:

// Provided by VK_NV_partitioned_acceleration_structure
typedef struct VkPartitionedAccelerationStructureUpdateInstanceDataNV {
    uint32_t           instanceIndex;
    uint32_t           instanceContributionToHitGroupIndex;
    VkDeviceAddress    accelerationStructure;
} VkPartitionedAccelerationStructureUpdateInstanceDataNV;

Members

instanceIndex is the index of the instance being updated.
instanceContributionToHitGroupIndex is a 24-bit per instance value added in the indexing into the shader binding table to fetch the hit group to use.
accelerationStructure is the device address of the bottom level acceleration structure or a clustered bottom level acceleration structure whose instance is being updated. The instance is disabled if the device address is 0.

Description

If the instance was originally disabled by specifying a 0 in VkPartitionedAccelerationStructureWriteInstanceDataNV::accelerationStructure, it can not be updated to a new acceleration structure as the instance may have been permanently disabled by the implementation.

To avoid a refit, the new acceleration structure must be within the bounding box specified by VkPartitionedAccelerationStructureWriteInstanceDataNV::explicitAABB when the instance was first created.

Valid Usage

VUID-VkPartitionedAccelerationStructureUpdateInstanceDataNV-instanceContributionToHitGroupIndex-10571
The most significant 8 bits of instanceContributionToHitGroupIndex must be 0
VUID-VkPartitionedAccelerationStructureUpdateInstanceDataNV-None-10572
The instance must have either been created with flag VK_PARTITIONED_ACCELERATION_STRUCTURE_INSTANCE_FLAG_ENABLE_EXPLICIT_BOUNDING_BOX_NV or did not have an acceleration structure assigned with VkPartitionedAccelerationStructureWriteInstanceDataNV
VUID-VkPartitionedAccelerationStructureUpdateInstanceDataNV-instanceIndex-10573
instanceIndex must be less than VkBuildPartitionedAccelerationStructureInfoNV::input.instanceCount

Valid Usage (Implicit)

VUID-VkPartitionedAccelerationStructureUpdateInstanceDataNV-accelerationStructure-parameter
accelerationStructure must be a valid VkDeviceAddress value

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.