OptionalparamsOptional per-pixel material data (loc 3): shadingModelId / specular / occlusion / custom0. Produced by the core mesh / block / terrain geometry passes; absent for custom geometry passes that don't write it (deferred lighting then falls back to the default 0.04 dielectric). See TODO/gltf-pbr-gbuffer-design.md.
G-Buffer handle set produced by deferred geometry features and consumed by AO, deferred lighting, and post-processing. Matches the per-pass shape used by GeometryPass / BlockGeometryPass / SkinnedGeometryPass.