Unity Game Optimization - Third Edition

Shader optimization

Fragment shaders are the primary consumers of Fill Rate and memory bandwidth. The costs depend on their complexity—how much texture sampling takes place, how many mathematical functions are used, and many more factors. The GPU's parallel nature (sharing small pieces of the overall job between hundreds of threads) means that any bottleneck in a thread will limit how many fragments can be pushed through that thread during a frame.

The classic analogy is a vehicle assembly line. A complete vehicle requires multiple stages of manufacture to complete. The critical path to completion might involve stamping, welding, painting, assembly, and inspection, where each step is completed by a single team. For any given vehicle, no stage ...