Currently, how vr development works is that the biggesst engines out there - ue4, unity, cryengine, etc - employ build options for various headsets that utilizes proprietary apis. Example - i make a vr game, then i tell unity to export a gear vr binary. It uses the gear vr api to turn my code into something gear vr can use. Then i tell it to export an oculus rift binary - same thing only using the rift api. Then a morpheus binary, and so forth. I cant run a rift executable on gear vr or vice versa. And if you are not using an engine with vr support - as we are doing with hl2vr - you have to link against individual apis and dlls per port.No more. Valve is developing a universal api - write once, build one binary, and it works on every headset.This will be discussed more at GDC.