| name | threejs-exposure-color-grading |
| description | Build a measured exposure and grading path in Three.js. Use for a 64x36 encoded luminance meter, asynchronous readback, weighted log-average exposure, asymmetric adaptation, single tone-map ownership, and a generated 32-cube post-tone-map LUT. |
Exposure and Color Grading
Treat exposure, tone mapping, grading, and output conversion as distinct stages. Tune them from measured HDR signal, not by stacking compensating color operations.
Order
HDR scene
→ luminance meter
→ adapted exposure
→ tone map
→ creative grade / 3D LUT
→ final output conversion
Read references/scene-referred-color-pipeline.md
for the exact 64x36 meter, encoded readback, adaptation constants, 32-cube LUT,
and signal-ownership ambiguities.
Failure conditions
- tone mapping occurs in both materials and post;
- exposure is used to repair physically inconsistent light ratios;
- meter weighting and scene framing are not inspected;
- adaptation speed is the same toward light and dark;
- LUT input/output spaces are undocumented;
- sRGB encoding happens twice;
- a display-domain LUT is moved before tone mapping without being rebuilt.
Routing boundary
Use $threejs-bloom for HDR glow contribution and
$threejs-image-pipeline when this color path must share ownership with AO,
atmosphere, or effect-local render targets.
