Technical details behind the difficulty of VR support.

Hello,

So, BeamNG is probably the one game I own (save for Star Citizen if/when that ever becomes a proper fully-developed title) that would persuade me to drop the ~$650 (or whatever it is now) to get an HTC Vive if support for it were implemented. While I noticed that a dev had spoken about the difficulties of VR support due to the need of overhauling much of the game's engine code, they didn't provide any technical details.

As an amateur programmer, I am curious about what the technical details are behind the difficulty of implementing VR support. I know that it's more involved than just having two slightly offset renderings of the game (my cousin wrote VR code once, and explained to me that four-dimensional math is involved...), but I don't currently understand why the rendering engine itself (if not other things) would need rewritten.

My current understanding is that you need to (A) implement the API calls to move the cameras around in-sync with the VR headset, and (B) there is some math that needs done on the image post-render to change the rectangular image that would display on a monitor with something more suitable to the human eye.

 

All I know is that having 2nd camera is challenge, which currently is not possible. That was related to split screen where I did read about it, I think.