This brings back some fond memories. I still have a copy of the book "Tips and Tricks of the Game Programming Gurus", though it's not in very decent condition. It has this ray traced image on the front cover (with a crazy monster) that is very characteristic of the early 90s. Though, I could never help but notice what appeared to be an error on the staircase banister where it looked like the normals were facing the wrong way. So it looked hollow. Or maybe the (object's) matrix was wrong. Anyway. The book really had me hyped up to create some virtual worlds. Like DOOM.

I learned a lot from the book but some of the topics where a little too advanced for me at the time, as I was still learning C and grappling with x86 assembly language.

However, I rediscovered the book several years ago and implemented something similar to the ray caster (which had really impressed me at the time) in DOSBox. I tried to optimize the algorithm and add a few enhancements. It was lots of fun! A genuine (early 90s) retro experience! I think I even had to fire up Turbo Debugger to solve a few problems.