But I said to myself, before I figure this out, I'm just going to write a little texture mapper. So, I went through
Michael Abrash's articles on texture mapping and looked at some stuff that Billy Zelsnack has shared early on. The texture mapping was actually pretty simple, so I said, "I guess I can figure this out".
The one real piece of wizardry in the early Unreal Editor – before I implemented lighting and things like that – was the real-time BSP tree creation. The idea is that you can reposition brushes in 3-D space, and then all the BSP work is updated completely in real-time.
This had some mind-boggling implications, and I created this torus-building tool just to show off how cool it was. I got together with James – who, remember, had been building his BSPs by hand – and I said "check this out." I created two toruses that were interlocked, and subtracted them from the world, and he said "Whoa, no way? That's awesome!" It was a real example of programmer geekery.
[...]
Carmack had written this really advanced editor on the
NeXT. I'd read all about it and I had seen screenshots of it, but I never actually used it. At the time, I thought to myself "Holy shit, Carmack wrote a real-time BSP editor!" What I didn't realize was that it wasn't actually real-time, there was this re-build process and all this other offline stuff. I didn't know that, and so I thought I had to create a completely real-time thing, and so I did. [laughs]
