The core loop:
In ps2/video.c , you find macros that spit out VU assembly code. Criterion invented a system where the CPU would double-buffer display lists while the VU processed the next frame. The source code comments are filled with warnings like: "Do not allocate more than 2kb of VU memory here or the texture pipeline stalls." It is a textbook on how to squeeze blood from a stone. renderware source code
Grand Theft Auto III , Vice City , and San Andreas . Criterion Games: The entire Burnout series. The core loop: In ps2/video