Ray-tracing a rotating black hole in the browser

Null geodesics, a WebGPU compute shader, and why the first frame is allowed to look terrible.

A draft. Integrating null geodesics through the Kerr metric in a compute shader, and the progressive-refinement scheme that lets the first frame be rough without anyone minding.

Written by Martin Dahl. If you want to argue about any of it, say hello.