The reason why OpenGL was not ever officially supported by Microsoft was because of Direct3D. Direct3D is Microsoft's driver model whichis intended to make OpenGL unnecessary. However many games and applications use OpenGL even today. With Windows Vista, Microsoft made it clear that OpenGL support would only work as a layer sitting on top of Direct3D. There was going to be translation involved and thus, a performance hit.
This week the Khronos group, which is responsible for developing and maintaining OpenGL, has released a report indicating that OpenGL support will now be natively supported in
- Hardware overlays are not supported
- Hardware OpenGL overlays are an obsolete feature on
- ATI and NVIDIA strongly recommend using compositing desktop/FBOs for same functionality
News source: DailyTech