LLVMpipe Gallium3D Driver Now Exposes OpenGL 4.0

The LLVMpipe Gallium3D driver that provides a software/CPU-based OpenGL implementation for running on systems as a fallback path when no GPU / hardware OpenGL driver is available, a vendor-neutral path for debug purposes, and similar use-cases, now has OpenGL 4.0 support.

For years LLVMpipe had been stuck at OpenGL 3.3 with not much effort on exposing OpenGL 4.x. Overnight, however, a merge request that had been open for four months finally landed. That MR adds ARB_gpu_shader5 with the necessary bits needed to push LLVMpipe into OpenGL 4.0 compliance.

For those now building LLVMpipe on Mesa 20.2, OpenGL 4.0 is now exposed. Just don't expect much in the way of great performance.

Blocking LLVMpipe from OpenGL 4.1 is ARB_get_program_binary and ARB_shader_precision while after that it will be able to jump straight to OpenGL 4.2 due to having those prerequisites addressed. For OpenGL 4.3 it needs ARB_robust_buffer_access_behavior support and after that it will be able to jump straight to OpenGL 4.4. For OpenGL 4.5/4.6 is where next a lot of work is left to tackle.

David Airlie of Red Hat continues to lead much of the work on LLVMpipe while also in recent months hacking on Vallium as a Vulkan software implementation.