In an interview with Bit Tech, id Software co-founder John Carmack spoke about the future of OpenGL. He told the site that Direct3D is now better than OpenGL and that it's really just inertia that keeps id Software on OpenGL. Carmack acknowledges that Microsoft had the courage to continue make significant incompatible changes to improve their API, which gives DirectX 11 better multi-threading and state than OpenGL.
Future games from id Software will not make the switch to DirectX though, Carmack says they wouldn't be getting any huge benefits by adopting DirectX and that it would be too much work because all of id Software's tool code would have to be reprogrammed.
Speaking to bit-tech for a forthcoming Custom PC feature about the future of OpenGL in PC gaming, Carmack said 'I actually think that Direct3D is a rather better API today.' He also added that 'Microsoft had the courage to continue making significant incompatible changes to improve the API, while OpenGL has been held back by compatibility concerns. Direct3D handles multi-threading better, and newer versions manage state better.'
While newer versions of OpenGL have kept up-to-date with some of the features found in DirectX, including DirectX 10's geometry shader, they usually have to be implemented via extensions, rather than the main API. Not only that, but Microsoft has now assumed the role of primary innovator in 3D PC gaming graphics, when it historically played a game of catch-up.