More Raymarching Resources
Raymarching and related techniques are an active area of research.
Jamie Wong’s Raymarching and Signed Distance Functions
Very clear explanations with interactive demos describing what raymarching is and how to build up a shader that does it.
The demogroup Mercury’s glsl library of SDF primitives and “space-folding operators.” Super readable code!
These and his Shadertoy examples are some of the best places online to go to learn.
The earliest paper and description (the particular kind used here at least) of raymarching I’ve seen.
Contains some optimizations and clever tweaks to the classic raymarching algorithm for producing nicer looking images, faster.
Numerical Methods for Ray Tracing Implicitly Defined Surfaces (local copy) by Morgan McGuire
Useful summary of primitives and operations, as well as implementation details of some of the optimizations in “Enhanced Sphere Tracing.”