Shadertoy

If you're writing GLSL fragment shaders for Shadertoy or WebGL, this gives you the patterns and reference you need without digging through documentation. It covers the Shadertoy-specific setup (mainImage, iResolution, iTime), common techniques like ray marching and distance fields, and the critical GLSL ES gotchas that cause compilation errors. The included code snippets for things like cosine color palettes, hash functions, and rotation matrices are copy-paste ready. What's useful here is the opinionated structure: it assumes you know what a shader is and jumps straight to the patterns you'll actually reuse. The multi-pass rendering section is solid if you need buffer feedback effects.