A small Rust ray tracer helped fix a game’s clouds

Thomas ten Cate wrote a small Rust ray tracer to generate cloud-lighting lookup tables for his Godot game. Accounting for light scattering multiple times made cloud undersides brighter; adjusting their normals also brought in indirect sky color. The walkthrough shows successive visual changes and their tradeoffs. Its comparisons include other parameter changes, and the author explicitly leaves an atmospheric-rendering discrepancy unresolved.

Frozen Fractal · Oct 12, 2026

Why it matters

A focused offline model can improve a real-time renderer without adding all its complexity to every frame.

More context

Read the cloud-scattering and indirect-light sections for the mechanism, then the tone-mapping discussion for how later display choices affect earlier lighting decisions.

Keep in mind

These are project-specific visual experiments, not a controlled renderer benchmark or a complete physical simulation.

Original read