Multi-layer stacks with blend modes, feedback, post chain, and a 3D
particle layer proving the compositor is genuinely hybrid. Looks now
generate accent layers from a different family, composited additively at
low opacity, weighted by section energy so intros stay sparse.
Adds flash-rate safety (engine/flash.js), which was not in the original
plan and should have been. This generates beat-reactive video for
publication, and rapid light-dark cycling is the photosensitive-epilepsy
trigger; WCAG 2.3.1 caps it at three flashes per second. Classic Wave
measured 7-8/s at every output resolution from 96x54 to 1920x1080, so it
was a real hazard rather than a sampling artefact.
Root cause was general, not one bad shader: `u_time * u_speed` where speed
is reactively modulated. Phase is elapsed*rate, so changing the rate at
time T jumps phase by T*delta — sixty seconds in, a 0.05 wobble throws the
phase three whole units between consecutive frames, and it worsens as the
track runs. Fixed by introducing rate params:
- schema flag `rate: true` documents and marks them
- Layer.resolveParams skips reactivity on them
- ArcDriver skips drift on them
- validateModule rejects a reactive entry on one
- lint-scenes greps shaders for `u_time * u_X` and fails if X is unmarked,
so no future scene can reintroduce it
Every rate param across the six scenes is now marked. Two checks were
needed to find this: a per-look flash check, and a per-SCENE sweep at
aggressive params, since the look generator only samples part of the space
and a scene can hide an unsafe region for a long time.
Gate 10/10. Worst flash rate now 1/s. Feedback stable over 10,000 frames
(luminance 0.17-0.59, no saturation or decay). 0.17ms/frame at 1280x720.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
All five party-stage shaders now ported. Each declares its params
declaratively; uniform binding, UI controls, seeded sampling and arc
automation all derive from that one block, so a new scene costs a shader
and a schema and nothing else.
Port changes: LED-grid masks stripped, hardcoded colours replaced with
palette lookups, magic numbers lifted into params. Psychedelic Drift's
internal 15-second scene timer removed — keeping the visuals moving is the
arc driver's job, and it knows where the song's real transitions are.
ParamPanel generates controls from the schema alone and knows about no
specific scene; a hand-written control would be a bug.
Gate 8/8: schemas valid, uniforms accounted for in both directions, all
scenes compile and render, 128 range-sweep frames with no black, blown or
flat results, every param exposed in the UI, edits clamped, presets
round-trip and survive schema drift.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
