Microsoft Begins Landing Changes For Cross-Platform Support With Their Mesa D3D12 Code

Last month the Microsoft-backed Direct3D 12 Gallium3D driver was merged into Mesa 21.0. This is the driver for allowing graphics/compute APIs like OpenGL and OpenCL to run on top of Direct3D with Windows 10. That work to the Gallium D3D12 code has been continuing with the start of the cross-platform code now being merged.

Before getting too excited, while this is about cross-platform support for this Gallium Direct3D 12 code, the use-case is about getting OpenGL working within Windows Subsystem for Linux (WSL). This effort is not focused outside of the WSL context or doing any crazy things to improve Linux gaming.

This merge request was honored on Tuesday as the initial preparations for cross-platform support of the D3D12 code. The initial work was on allowing this D3D12 and NIR to DXI code to work in compiler toolchains outside of Microsoft MSVC and non-Windows SDKs. Given it will be built within Linux distributions on Windows Subsystem for Linux 2, various clean-ups and build changes were necessary.

The actual wiring up of allowing OpenGL to work within Windows Subsystem for Linux 2 instances (by means of translating to Direct3D 12) is still being tackled. This code is already proving useful to Windows itself for allowing OpenGL (and ultimately OpenCL) to run on Windows itself off D3D12 drivers, which is particularly useful right now for Windows on Arm where GL/CL drivers may not be available.