>>272953931
At the easiest it's just a mod that changes the camera and character position as you move your head, at worst even just doing that breaks a bunch of shit because things were originally written with a single screen, world position and viewpoint in mind. Croteam talked about the process of porting their games to VR without the kind of VR support you already get on an engine like UE4. It sounded like a lot of the UI and some graphical effects needed to be redone just for VR because the original implementation couldn't be adapted, things like getting particle effects to render differently for each eye.