Simulates lights in 2D scenes, with soft shadows. It's a very unpolished implementation in Rust/Bevy.
It's based on the radiance cascades paper, but with a much improved storage layout:
- It uses pre-averaging, so that results of tracing of individual rays don't need to be stored, and cascades store only merged average of a cone needed for the next cascade.
- It uses direction-first storage to be able to merge probes using hardware filtering (the hw part is not implemented yet).
See src/cascades.rs and assets/radiance_cascades.wgsl.
This implementation is different than most other examples:
- It uses a "gear fix" workaround to reduce halos at the seams between cascades (instead of "bilinear fix").
- It uses a 2x scaling factor for the lenghts of cascades and the number of rays (most use much more expensive 4x scaling).
- It doesn't use SDFs (it naively marches density map).
- it doesn't use mipmaps (yet).
- There's no bounce light implemented yet.