Khronos Releases Final Ray Tracing Specification for Vulkan

Khronos has released the final versions of the set of Vulkan, GLSL and SPIR-V extension specifications that seamlessly integrate ray tracing into the existing Vulkan framework. This is a significant milestone as it is the industry’s first open, cross-vendor, cross-platform standard for ray tracing acceleration - and can be deployed either using existing GPU compute or dedicated ray tracing cores.

Vulkan Ray Tracing will be familiar to anyone who has used DirectX Raytracing (DXR) in DirectX 12, but also introduces advanced functionality such as the ability to load balance ray tracing setup operations onto the host CPU. Although ray tracing will be first deployed on desktop systems, these Vulkan extensions have been designed to enable and encourage ray tracing to also be deployed on mobile. These extensions were initially released as provisional versions in March 2020. Since that time (see Figure 1), we have received and incorporated feedback from hardware vendors and software developers, both inside Khronos and from the wider industry, but the overall shape of the API and the functionality provided are fundamentally unchanged. 

Over the coming days and weeks, additional ecosystem components such as shader toolchains and validation layers will be updated with support for ray tracing functionality to ensure developers can easily use these extensions in their applications. Progress on these ecosystem updates can be tracked in GitHub. This will culminate with the release of the Vulkan SDK (1.2.162.0 or later) with Khronos Vulkan Ray Tracing support in mid-December.

This post will highlight the most important differences between the provisional and final versions of the Vulkan Ray Tracing extensions and explain some of the reasoning behind the changes.