Flipped projection matrix on iOS

[ahegedusniantic]

Thanks for all the hard work from everyone. I have been experimenting with using this renderer on iOS. I ran into an issue where everything was drawn upside down. I used to be able to fix this by flipping the projection matrix, but since the new commits related to VR, rendering now uses the built-in projection matrix (UNITY_MATRIX_P and UNITY_MATRIX_VP) so my fix is no longer applicable. Any insight how to fix this issue would be very welcome. Thanks!

[aras-p]

@ahegedusniantic hmm curious. I wonder why it is not flipped on macOS then. Since both of these would be going through Metal graphics APIs and should generally behave extremely similarly.

[ahegedusniantic]

I ended up injecting a matrix to multiply UNITY_MATRIX_P every time it is used. Of course this just treats the symptom, it would be good to get to the root of this problem.