From a glance it looks fairly standard for a fixed-function GPU of the day. These GPUs were primitive by modern standards; they didn't even have hardware T&L, meaning everything essentially had to be converted from 3D to 2D on the CPU†. The weirdest part is per-polygon mipmapping, which is not normal. (I didn't even know anyone even did this; it's clearly going to look terrible in many common cases, such as large textured floors. That being said, I can understand why they'd do this if they were in a rush; calculating screen space derivatives in both X and Y, as required for per-pixel mipmapping, is really annoying with a scanline algorithm, which they were probably using as Pineda rasterization hadn't caught on yet.)

†I know that normalized device coordinates are still 3D, so "converting 3D to 2D" is technically wrong, but it conveys the right intuition.

I strongly recommend https://fgiesen.wordpress.com/2011/07/09/a-trip-through-the-... if you're curious about GPU architectures. Though in the 14 (!) years since, a lot has changed still.

In the modern era the 'compute shaders' part of that has become more dominant and lots of fixed function parts of the graphics pipeline have moved to software.

I'd love to see a more modern take on this if someone has run across it.