Module radiance 

Radiance Cascades 2D Global Illumination

Implements Alexander Sannikov’s Radiance Cascades algorithm using wgpu compute shaders. Provides real-time 2D GI with emissive surfaces, occluders, and light propagation.

Architecture:

1. Scene pass: CPU writes emissive/occluder data to a scene texture
2. Ray-march pass (per cascade): probes cast rays through the scene
3. Merge passes: upper cascades merge into lower (propagates far-field radiance)
4. Finalize pass: cascade 0 probes sum rays, produces light texture
5. Composition: sprite shader reads light texture to modulate output

Structs

DirectionalLight

A directional light (infinite distance, parallel rays).

EmissiveSurface

An emissive surface that radiates light.

Occluder

A rectangular occluder that blocks light.

RadiancePipeline

The radiance cascade compute pipeline.

RadianceState

Radiance state gathered from TypeScript each frame.

SpotLight

A spot light with position, direction, and spread.