Lavapipe Lands Vulkan Descriptors Support, Can Run Some VKD3D-Proton Games

Lavapipe as the software-based Vulkan implementation within Mesa has now landed support for Vulkan descriptor extensions and in turn this CPU-based Vulkan implementation can begin running some Direct3D 12 games with VKD3D-Proton. Keep in mind, however, the performance is severely limited.

Konstantin Seurer has landed the Lavapipe descriptors support in Mesa 23.2 that now allows for the VK_EXT_descriptor_buffer, EXT_descriptor_indexing, and VK_EXT_mutable_descriptor_type extensions to be exposed.

"Make llvmpipe jit resources explicit in lavapipe. This allows creating buffers for descriptor sets and binding them to UBO slots. The resource lowering and llvmpipe backend compiler is updated to lead jit resources from those UBOs. Texture sampling and image operations are implemented by pre compiling sample and image functions based on the used textures, samplers, sample keys and image operations. The shader then calls those functions by loading a function pointer from the descriptor."

Zink hacker Mike Blumenkrantz at Valve commented that this work is "enough to run a credible amount of VKD3D-Proton, in fact." Granted, don't expect much in the way of performance but nevertheless LLVMpipe/Lavapipe prove useful for debugging/profiling and other purposes.

Mesa 23.2 is shaping up to be another exciting release with countless OpenGL and Vulkan driver improvements. The stable release of Mesa 23.2 will likely be out in August or otherwise September if hitting delays.