OpenGL 4.5 Compat Being Worked On For RadeonSI, Helping Out No Man's Sky & Others

What does Valve's Linux GPU driver developer Timothy Arceri do now that he took the RadeonSI Gallium3D driver up to OpenGL 4.4 in its compatibility profile mode? Work on OpenGL 4.5 compatibility profile support, of course.

While the recent effort from taking the OpenGL compatibility profile mode in RadeonSI from OpenGL 3.1 to OpenGL 4.4 means a great deal of more games/applications are now working with this open-source Radeon GCN OpenGL driver, Arceri is working on OpenGL 4.5 support for this context that allows deprecated OpenGL features to still be mixed in with newer versions of OpenGL.

Hitting the OpenGL 4.5 compatibility profile support isn't going to be a trivial task as there are some big enablers left like getting OpenGL Direct State Access (DSA) working in this mode. Arceri already commented that seeing that support is unlikely before the Mesa 18.2 branching in late July.

But for a temporary measure at least, he sent out a patch loosely enabling it when forcing the OpenGL 4.5 compatibility mode. With the patch and setting the MESA_GL_VERSION_OVERRIDE=4.5COMPAT environment variable is good enough to make some software happy.

One game helped out by this override is using the game No Man's Sky under Wine, but others are also apparently helped based on the aforelinked mailing list post.

Mesa 18.2 is expected to be branching around 20 July while the official release of this quarterly feature update will likely be around mid-August.