Microsoft's Direct3D 12 Code For Mesa Now Supports OpenGL Tessellation Functionality

Microsoft's D3D12 Gallium3D code for Mesa 22.0 can now handle tessellations to expose GL_ARB_tessellation_shader in exposing OpenGL over Direct3D 12.

Microsoft continues investing in their D3D12 Mesa driver for allowing OpenGL to be implemented over Direct3D 12 for benefiting Windows Subsystem for Linux (WSL2) usage and cases where there may be no host OpenGL driver on Windows available but there is Direct3D 12.

A set of 39 patches were merged overnight getting the D3D12 tessellation support in to order so that the important GL_ARB_tessellation_shader extension can be enabled. Around two thousand lines of this D3D12 Mesa driver code had to be reworked for getting tessellation support up.

GL_ARB_tessellation_shader is one of the key extensions introduced in OpenGL 4.0. With this extension out of the way, the D3D12 code just needs to get FP64 support and ARB_transform_feedback2/ARB_transform_feedback3 support in to order before it can expose OpenGL 4.0 rather than being limited to GL 3.3.