VK_KHR_ray_tracing_maintenance1

Other Extension Metadata

Last Modified Date

2022-02-21

Interactions and External Dependencies

• This extension provides API support for GLSL_EXT_ray_cull_mask
• Interacts with VK_KHR_ray_tracing_pipeline
• Interacts with VK_KHR_synchronization2

Contributors

• Stu Smith, AMD
• Tobias Hector, AMD
• Marius Bjorge, Arm
• Tom Olson, Arm
• Yuriy O’Donnell, Epic Games
• Yunpeng Zhu, Huawei
• Andrew Garrard, Imagination
• Dae Kim, Imagination
• Joshua Barczak, Intel
• Lionel Landwerlin, Intel
• Daniel Koch, NVIDIA
• Eric Werness, NVIDIA
• Spencer Fricke, Samsung

Description

VK_KHR_ray_tracing_maintenance1 adds a collection of minor ray tracing features, none of which would warrant an entire extension of their own.

The new features are as follows:

• Adds support for the SPV_KHR_ray_cull_mask SPIR-V extension in Vulkan. This extension provides access to built-in CullMaskKHR shader variable which contains the value of the OpTrace* Cull Mask parameter. This new shader variable is accessible in the intersection, any-hit, closest hit and miss shader stages.
• Adds support for a new pipeline stage and access mask built on top of VK_KHR_synchronization2:
  • VK_PIPELINE_STAGE_2_ACCELERATION_STRUCTURE_COPY_BIT_KHR to specify execution of acceleration structure copy commands
  • VK_ACCESS_2_SHADER_BINDING_TABLE_READ_BIT_KHR to specify read access to a shader binding table in any shader pipeline stage
• Adds two new acceleration structure query parameters:
  • VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SIZE_KHR to query the acceleration structure size on the device timeline
  • VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_BOTTOM_LEVEL_POINTERS_KHR to query the number of bottom level acceleration structure pointers for serialization
• Adds an optional new indirect ray tracing dispatch command, vkCmdTraceRaysIndirect2KHR, which sources the shader binding table parameters as well as the dispatch dimensions from the device. The rayTracingPipelineTraceRaysIndirect2 feature indicates whether this functionality is supported.

New Commands

If VK_KHR_ray_tracing_pipeline is supported:

• vkCmdTraceRaysIndirect2KHR

New Structures

• Extending VkPhysicalDeviceFeatures2, VkDeviceCreateInfo:
  • VkPhysicalDeviceRayTracingMaintenance1FeaturesKHR

If VK_KHR_ray_tracing_pipeline is supported:

• VkTraceRaysIndirectCommand2KHR

New Enum Constants

• VK_KHR_RAY_TRACING_MAINTENANCE_1_EXTENSION_NAME
• VK_KHR_RAY_TRACING_MAINTENANCE_1_SPEC_VERSION
• Extending VkQueryType:
  • VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SERIALIZATION_BOTTOM_LEVEL_POINTERS_KHR
  • VK_QUERY_TYPE_ACCELERATION_STRUCTURE_SIZE_KHR
• Extending VkStructureType:
  • VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_MAINTENANCE_1_FEATURES_KHR

If VK_KHR_synchronization2 or Vulkan Version 1.3 and VK_KHR_ray_tracing_pipeline is supported:

• Extending VkAccessFlagBits2:
  • VK_ACCESS_2_SHADER_BINDING_TABLE_READ_BIT_KHR

If VK_KHR_synchronization2 or Vulkan Version 1.3 is supported:

• Extending VkPipelineStageFlagBits2:
  • VK_PIPELINE_STAGE_2_ACCELERATION_STRUCTURE_COPY_BIT_KHR

New Built-In Variables

• CullMaskKHR

New SPIR-V Capabilities

• RayCullMaskKHR

Issues

None Yet!

Version History

• Revision 1, 2022-02-21 (Members of the Vulkan Ray Tracing TSG)
  • internal revisions