VulkanHub

VK_NV_ray_tracing

Other Extension Metadata

Last Modified Date

2018-11-20

Interactions and External Dependencies
Contributors
  • Eric Werness, NVIDIA
  • Ashwin Lele, NVIDIA
  • Robert Stepinski, NVIDIA
  • Nuno Subtil, NVIDIA
  • Christoph Kubisch, NVIDIA
  • Martin Stich, NVIDIA
  • Daniel Koch, NVIDIA
  • Jeff Bolz, NVIDIA
  • Joshua Barczak, Intel
  • Tobias Hector, AMD
  • Henrik Rydgard, NVIDIA
  • Pascal Gautron, NVIDIA

Description

Rasterization has been the dominant method to produce interactive graphics, but increasing performance of graphics hardware has made ray tracing a viable option for interactive rendering. Being able to integrate ray tracing with traditional rasterization makes it easier for applications to incrementally add ray traced effects to existing applications or to do hybrid approaches with rasterization for primary visibility and ray tracing for secondary queries.

To enable ray tracing, this extension adds a few different categories of new functionality:

  • Acceleration structure objects and build commands
  • A new pipeline type with new shader domains
  • An indirection table to link shader groups with acceleration structure items

This extension adds support for the following SPIR-V extension in Vulkan:

  • SPV_NV_ray_tracing

New Object Types

New Commands

New Structures

If VK_KHR_get_memory_requirements2 or Vulkan Version 1.1 is supported:

New Enums

New Bitmasks

New Enum Constants

  • VK_NV_RAY_TRACING_EXTENSION_NAME
  • VK_NV_RAY_TRACING_SPEC_VERSION
  • VK_SHADER_UNUSED_NV
  • Extending VkAccelerationStructureTypeKHR:
    • VK_ACCELERATION_STRUCTURE_TYPE_BOTTOM_LEVEL_NV
    • VK_ACCELERATION_STRUCTURE_TYPE_TOP_LEVEL_NV
  • Extending VkAccessFlagBits:
    • VK_ACCESS_ACCELERATION_STRUCTURE_READ_BIT_NV
    • VK_ACCESS_ACCELERATION_STRUCTURE_WRITE_BIT_NV
  • Extending VkBufferUsageFlagBits:
    • VK_BUFFER_USAGE_RAY_TRACING_BIT_NV
  • Extending VkBuildAccelerationStructureFlagBitsKHR:
    • VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_COMPACTION_BIT_NV
    • VK_BUILD_ACCELERATION_STRUCTURE_ALLOW_UPDATE_BIT_NV
    • VK_BUILD_ACCELERATION_STRUCTURE_LOW_MEMORY_BIT_NV
    • VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_BUILD_BIT_NV
    • VK_BUILD_ACCELERATION_STRUCTURE_PREFER_FAST_TRACE_BIT_NV
  • Extending VkCopyAccelerationStructureModeKHR:
    • VK_COPY_ACCELERATION_STRUCTURE_MODE_CLONE_NV
    • VK_COPY_ACCELERATION_STRUCTURE_MODE_COMPACT_NV
  • Extending VkDescriptorType:
    • VK_DESCRIPTOR_TYPE_ACCELERATION_STRUCTURE_NV
  • Extending VkGeometryFlagBitsKHR:
    • VK_GEOMETRY_NO_DUPLICATE_ANY_HIT_INVOCATION_BIT_NV
    • VK_GEOMETRY_OPAQUE_BIT_NV
  • Extending VkGeometryInstanceFlagBitsKHR:
    • VK_GEOMETRY_INSTANCE_FORCE_NO_OPAQUE_BIT_NV
    • VK_GEOMETRY_INSTANCE_FORCE_OPAQUE_BIT_NV
    • VK_GEOMETRY_INSTANCE_TRIANGLE_CULL_DISABLE_BIT_NV
    • VK_GEOMETRY_INSTANCE_TRIANGLE_FRONT_COUNTERCLOCKWISE_BIT_NV
  • Extending VkGeometryTypeKHR:
    • VK_GEOMETRY_TYPE_AABBS_NV
    • VK_GEOMETRY_TYPE_TRIANGLES_NV
  • Extending VkIndexType:
    • VK_INDEX_TYPE_NONE_NV
  • Extending VkObjectType:
    • VK_OBJECT_TYPE_ACCELERATION_STRUCTURE_NV
  • Extending VkPipelineBindPoint:
    • VK_PIPELINE_BIND_POINT_RAY_TRACING_NV
  • Extending VkPipelineCreateFlagBits:
    • VK_PIPELINE_CREATE_DEFER_COMPILE_BIT_NV
  • Extending VkPipelineStageFlagBits:
    • VK_PIPELINE_STAGE_ACCELERATION_STRUCTURE_BUILD_BIT_NV
    • VK_PIPELINE_STAGE_RAY_TRACING_SHADER_BIT_NV
  • Extending VkQueryType:
    • VK_QUERY_TYPE_ACCELERATION_STRUCTURE_COMPACTED_SIZE_NV
  • Extending VkRayTracingShaderGroupTypeKHR:
    • VK_RAY_TRACING_SHADER_GROUP_TYPE_GENERAL_NV
    • VK_RAY_TRACING_SHADER_GROUP_TYPE_PROCEDURAL_HIT_GROUP_NV
    • VK_RAY_TRACING_SHADER_GROUP_TYPE_TRIANGLES_HIT_GROUP_NV
  • Extending VkShaderStageFlagBits:
    • VK_SHADER_STAGE_ANY_HIT_BIT_NV
    • VK_SHADER_STAGE_CALLABLE_BIT_NV
    • VK_SHADER_STAGE_CLOSEST_HIT_BIT_NV
    • VK_SHADER_STAGE_INTERSECTION_BIT_NV
    • VK_SHADER_STAGE_MISS_BIT_NV
    • VK_SHADER_STAGE_RAYGEN_BIT_NV
  • Extending VkStructureType:
    • VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_CREATE_INFO_NV
    • VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_INFO_NV
    • VK_STRUCTURE_TYPE_ACCELERATION_STRUCTURE_MEMORY_REQUIREMENTS_INFO_NV
    • VK_STRUCTURE_TYPE_BIND_ACCELERATION_STRUCTURE_MEMORY_INFO_NV
    • VK_STRUCTURE_TYPE_GEOMETRY_AABB_NV
    • VK_STRUCTURE_TYPE_GEOMETRY_NV
    • VK_STRUCTURE_TYPE_GEOMETRY_TRIANGLES_NV
    • VK_STRUCTURE_TYPE_PHYSICAL_DEVICE_RAY_TRACING_PROPERTIES_NV
    • VK_STRUCTURE_TYPE_RAY_TRACING_PIPELINE_CREATE_INFO_NV
    • VK_STRUCTURE_TYPE_RAY_TRACING_SHADER_GROUP_CREATE_INFO_NV
    • VK_STRUCTURE_TYPE_WRITE_DESCRIPTOR_SET_ACCELERATION_STRUCTURE_NV

If VK_EXT_debug_report is supported:

New or Modified Built-In Variables

New SPIR-V Capabilities

Issues

1) Are there issues?

RESOLVED: Yes.

Sample Code

Example ray generation GLSL shader

#version 450 core
#extension GL_NV_ray_tracing : require
layout(set = 0, binding = 0, rgba8) uniform image2D image;
layout(set = 0, binding = 1) uniform accelerationStructureNV as;
layout(location = 0) rayPayloadNV float payload;

void main()
{
   vec4 col = vec4(0, 0, 0, 1);

   vec3 origin = vec3(float(gl_LaunchIDNV.x)/float(gl_LaunchSizeNV.x), float(gl_LaunchIDNV.y)/float(gl_LaunchSizeNV.y), 1.0);
   vec3 dir = vec3(0.0, 0.0, -1.0);

   traceNV(as, 0, 0xff, 0, 1, 0, origin, 0.0, dir, 1000.0, 0);

   col.y = payload;

   imageStore(image, ivec2(gl_LaunchIDNV.xy), col);
}

Version History

  • Revision 1, 2018-09-11 (Robert Stepinski, Nuno Subtil, Eric Werness)
    • Internal revisions
  • Revision 2, 2018-10-19 (Eric Werness)
    • rename to VK_NV_ray_tracing, add support for callables.
    • too many updates to list
  • Revision 3, 2018-11-20 (Daniel Koch)
    • update to use InstanceId instead of InstanceIndex as implemented.