O'Reilly Media, Inc. 4/5/2012 1 Shader 101 It seems an obvious question to ask at the beginning of an HLSL and shader book; what exactly is a shader? It's a small program or algorithm written explicitly to run on a computer Graphics Processing Unit (GPU). It provides a way for developers to extend the rendering capabilities of the GPU. Any program that works closely with graphics will benefit from using shaders. The video game industry spins off custom shaders by the