XNA Integration (0.43)

Finally got around to updating my old 0.2x based XNA integration. Its built on 0.43 now. It uses SDK distortion rendering. I haven't been able to get XNA to work with direct mode, but it works fine in extended mode. Its built specifically for the game Eterium, so its not as well documented, or designed for general use as it could be. It shows the tricks you need to "dig out" the native DirectX9 pointers from the managed classes that the Oculus SDK needs. Also has a fix for the SDK not saving/restoring the vertex declaration in DistortionRenderer::GraphicsState::Save that breaks XNA spritebatches. Just does that around the SDK EndFrame call. It does use ovrHmd_GetTrackingState for head tracking. Was easiest for me retrofitting an already shipped existing game. Read the readme for more info.

https://github.com/duhone/EteriumRift