This is dated back to 2006, when I was in a demoscene group.
All 3d algorithms and texture mapping are done using mathematics and a software renderer. Everything is written from scratch. Good and fun times.
I also load a model from Blender (raw trianges). Generally there are some cool effects, bitmap loading etc. I am only using Allergo for putpixel, so it is pretty easy to port it to another graphics library.
This runs on Windows, using VS 6.0 and the allegro library but someday I'll port it back to Linux and MacOSX.
TODO: Create a video and post it on YouTube :D
Enjoy and I hope you can understand the basic of how these cool demos were done back then.
JR - @jonromero