R600g & RadeonSI Scratch Off Another OpenGL 4.3 Extension

Tonight was busy for Mesa Git landings with more OpenGL 4.x activity hitting mainline Mesa.

Thanks to work spearheaded by Edward O'Callaghan, ARB_framebuffer_no_attachments -- an OpenGL 4.3 extension -- is now flipped on on for both AMD's RadeonSI and R600g Gallium3D drivers. Up to now, the Intel Mesa driver was the only driver exposing this OpenGL 4.3 extension. With O'Callaghan making the Mesa state tracker changes for ARB_framebuffer_no_attachments, hopefully the Nouveau support for it in Mesa Git isn't too far behind.

As can be seen via MesaMatrix.net, the RadeonSI Gallium3D driver is getting very close to OpenGL 4.2 and 4.3 support, which we will hopefully see in time for the next Mesa release in about three months. Nouveau NVC0 should be in similar standing and the Intel driver will also get there if we finally see them land their FP64 support to officially enter a GL4 world. Closing in on new GL4 support levels paired with the Vulkan code about to be mainlined should make for a very exciting next release.