Experimental Ray-Tracing For Open-Source Radeon Vulkan Driver Nears Upstream Mesa

It looks like within the coming days that the Vulkan ray-tracing support for Mesa's "RADV" Radeon Vulkan driver will be upstreamed for Mesa 21.3.

Over the past number of months RADV developer Bas Nieuwenhuizen has been working on Vulkan ray-tracing support for RADV, this unofficial open-source Vulkan driver for Radeon GPUs. This has been without any hardware documentation from AMD and not having any other open-source AMD driver to use as a reference point since AMD has not yet published any Vulkan ray-tracing support for their official AMDVLK driver.

Last month he got RADV ray-tracing with RDNA2 GPUs to a point that Quake II RTX can now be rendered correctly albeit not the most performant implementation.

It's now looking like that initial ray-tracing driver support will be upstreamed soon into Mesa 21.3-devel, which in turn will be released in Q4. Over the weekend Bas opened a MR for adding this experimental ray-tracing support to mainline. He notes that the performance is still lacking, but the code should be of good enough quality for mainlining.

So unless any issues come up soon, it's looking like this early RADV ray-tracing support will be merged to Mesa Git. This is around 2.6k lines of new RADV driver code crafted over the past half-year for enabling the ray-tracing support. This mainlining milestone would also place it ahead of AMDVLK in seeing ray-tracing support. To date AMD has only supported ray-tracing on Linux when making use of their closed-source Vulkan driver within the "Radeon Software for Linux" package that makes use of their proprietary shader compiler back-end.

Going on separately has been experimental work to allow ray-tracing for pre-RDNA2 GPUs but that work by developer Joshua Ashton is not part of this initial pull request.