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

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);
}

VK_NV_ray_tracing

Name String

VK_NV_ray_tracing

Extension Type

Device extension

Registered Extension Number

166

Revision

3

Extension and Version Dependencies

VK_KHR_get_physical_device_properties2 and VK_KHR_get_memory_requirements2

Contact

• Eric Werness ewerness-nv

Other Extension Metadata

Last Modified Date

2018-11-20

Interactions and External Dependencies

• This extension requires SPV_NV_ray_tracing
• This extension provides API support for GL_NV_ray_tracing

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