FWIW...
http://www.neogaf.com/forum/showthread.php?t=715118
http://www.neogaf.com/forum/showthread.php?t=715118
We do have to build and continue to maintain our OpenGL and DirectX rendering path but we really try to avoid limiting ourselves to what we can do in those APIs. So I think going forward, the main things to drive the design we have in Frostbite and the type of optimisations we will do, will be what we can do with Mantle, and also what we can do with PS4. PS4 also has its own graphics API that’s really quite programmable and really a lot of good control and performance from it, so we can share concepts, methods and various types of hardware level optimisations between those and see where we end up with that, which is quite exciting.