I agree that Mantle seems like a perfect fit for VR, and one of the best things that could happen to get some Mantle traction would be that Unreal Engine 4 supported it.
DirectX12 could be nice and dandy for Windows when it’s out, but what about Linux? If VR is to become mainstream one of the key factors could be Valve’s Steam Machines, that people could just plug and play.
Since UE4 is Open Source, what i really don’t understand is why can’t AMD add Mantle support themselves? Creating and maintaining a UE4 Mantle branch?
After all i believe the developers of Thief added Mantle support to their custom UE3 game by themselves, i guess it wouldn’t be so hard for AMD to do… (or would it?).