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 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.

VK_KHR_ray_tracing_position_fetch

Name String

VK_KHR_ray_tracing_position_fetch

Extension Type

Device extension

Registered Extension Number

482

Revision

1

Extension and Version Dependencies

VK_KHR_acceleration_structure

Contact

• Eric Werness

Extension Proposal

VK_KHR_ray_tracing_position_fetch

Other Extension Metadata

Last Modified Date

2023-02-17

Interactions and External Dependencies

• This extension requires SPV_KHR_ray_tracing_position_fetch
• 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