VK_KHR_ray_tracing_position_fetch

Other Extension Metadata

Last Modified Date

2023-02-17

Interactions and External Dependencies

• This extension provides API support for GLSL_EXT_ray_tracing_position_fetch
• Interacts with VK_KHR_ray_tracing_pipeline
• Interacts with VK_KHR_ray_query

Contributors

• Eric Werness, NVIDIA
• Stu Smith, AMD
• Yuriy O’Donnell, Epic Games
• Ralph Potter, Samsung
• Joshua Barczak, Intel
• Lionel Landwerlin, Intel
• Andrew Garrard, Imagination Technologies
• Alex Bourd, Qualcomm
• Yunpeng Zhu, Huawei Technologies
• Marius Bjorge, Arm
• Daniel Koch, NVIDIA

Description

VK_KHR_ray_tracing_position_fetch adds the ability to fetch the vertex positions in the shader from a hit triangle as stored in the acceleration structure.

An application adds VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_DATA_ACCESS_KHR to the acceleration structure at build time. Then, if the hit is a triangle geometry, the shader (any-hit or closest hit for ray pipelines or using ray query) can fetch the three, three-component vertex positions in object space, of the triangle which was hit.

New Structures

• Extending VkPhysicalDeviceFeatures2, VkDeviceCreateInfo:
  • VkPhysicalDeviceRayTracingPositionFetchFeaturesKHR

New Enum Constants

• VK_KHR_RAY_TRACING_POSITION_FETCH_EXTENSION_NAME
• VK_KHR_RAY_TRACING_POSITION_FETCH_SPEC_VERSION
• Extending VkBuildAccelerationStructureFlagBitsKHR:
  • VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_DATA_ACCESS_KHR
• Extending VkStructureType:
  • VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_POSITION_FETCH_FEATURES_KHR

New Built-In Variables

• HitTriangleVertexPositionsKHR

New SPIR-V Capabilities

• RayTracingPositionFetchKHR
• RayQueryPositionFetchKHR

Issues

None Yet!

Version History

• Revision 1, 2023-02-17 (Eric Werness)
  • internal revisions