probe_bake

Bakes irradiance-volume probes on the GPU — one thread per probe. Each thread casts N uniform-sphere rays and path-traces each one through up to bounces surface interactions: every path vertex contributes its emissive plus its albedo (carried on the triangle records by compute.buildBvh) times the shadowed direct light there, and a segment that escapes contributes the sky. The resulting incoming radiance is projected into 9 SH L2 coefficients (Monte Carlo weighted) and written as 9 RGBA vec4s into output. Mirrors lightmap_bake's traversal + light model.

Bindings (see bindings.yaml): output (read_write), probe_positions, bvh_nodes, triangles, lights, params — all array<vec4<f32>>.

Usage: dispatch by identity with compute.dispatch("@builtin::systems.globalIllumination.probe_bake", ...) (buffers in bindings order) — it resolves to the shader's stable guid and auto-compiles on first use (no setup).