Threejs Bloom

Bloom

Bloom is a camera/display response to bright HDR signal. Establish scene exposure and emissive luminance before tuning blur.

Workflow

• Inspect pre-tone-map luminance.
• Choose which scene values should bloom.
• Choose a single-node or dual selective-render ownership model.
• Calibrate threshold, radius, smooth width, and strength in HDR.
• Restore all substituted materials transactionally for selective passes.
• Composite before exposure/tone mapping.
• Validate base, contribution, and final views.

Read references/hdr-bloom-system.md for the

HDR ordering, dual selective-bloom transaction, compact emissive hierarchy,

and the costs and limits of each ownership model.

Apply the material substitution/restoration ownership pattern in the

reference before adding selective bloom to a composed scene.

Failure conditions

• bloom creates the only visible form of an effect;
• all bright materials share one arbitrary emission multiplier;
• threshold is tuned after tone mapping;
• selective bloom requires mutating scene materials every frame without restoration guarantees;
• transparent particles disappear from extraction because pass ownership is unclear;
• bloom radius changes wildly with resolution;
• highlights become gray because energy is clamped too early.

Routing boundary

Use $threejs-exposure-color-grading for metering, adaptation, tone mapping,

and LUTs. Load $threejs-image-pipeline only when bloom must be composed with

several shared image-space systems.