BSP's were first used in Quake, not Doom. Doom was not 3D, just 2.5D. Full BSP's as used in common VR's applications those times were not needed then.
The Doom precomputed z-buffer hack is described in this article, but I wouldn't call it genius. The Quake BSP was much better, but neither genius as a lot of people used it before to their advantage. It was a common technique, just not in games. Even we used it in our VR application years before Quake.
The Doom precomputed z-buffer hack is described in this article, but I wouldn't call it genius. The Quake BSP was much better, but neither genius as a lot of people used it before to their advantage. It was a common technique, just not in games. Even we used it in our VR application years before Quake.