Ambient Contact Shading

AO is visibility of indirect illumination. It may attenuate indirect diffuse and environment/specular response. Do not multiply direct light, emission, UI, or an already tone-mapped frame by AO. The final image changes through indirect lighting; test direct/emissive invariance in separate scene-linear terms at fixed exposure, not by requiring unchanged final RGB.

$threejs-choose-skills is an optional multi-system coordinator. Use $threejs-image-pipeline when AO shares depth, normals, velocity, history, or final-output ownership.

1. Choose the ambient-visibility branch

Use the first branch whose gate passes: