8dfd8392f3
6 Commits
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189328587d |
Epic 2.4: a slow axis, and an honest account of what it fixes
Eleven scenes changed as much in half a second as in two minutes. The cause
was that everything moving in them was cyclic: ArcDriver's drift is a 20-70
second LFO, and an LFO returns, so ten cycles of it over five minutes is not
five minutes of anything. The eye adapts in about two seconds and then there
is nothing left to find — violently animated, and reads as static.
ArcDriver._slowAxisFor adds the missing timescale: a param that travels ONE
WAY across the whole track, keyed on the module so a scene returning in the
last section arrives further along rather than resetting. Rate params are
excluded for the reason schema.js already gives.
Two things were learned by getting them wrong first, and both are recorded
where the next person will hit them.
The first version chose the param at random from everything eligible and
measured as doing NOTHING — identical structural change with the axis applied
and with it disabled. Which param you move decides everything: sweeping Moiré
Grid's `width` moves its time-averaged structure by 0.110 and its `offset` by
0.002, and a random draw finds the second kind almost every time. So the axis
is now DECLARED, `slowAxis: true`, validated by the schema (and rejected on
rate params, where walking one would jump the animation phase).
The second is that single-frame distance cannot measure this at all. A
churning scene's consecutive frames are already ~0.6 apart, so every pair of
its frames scores the same whether the structure moved or not — the metric is
saturated by the churn it exists to see through, and the first gate passed
while the mechanism was provably inert. The gate now compares TEN-SECOND
time-averaged frames. The window was measured rather than guessed: at one
second Moiré Grid's frozen control still reads 0.024, at ten it reads 0.0095
while the signal holds at 0.037.
Per EPIC-2.md §4, the metric is verified by breaking what it should catch:
a second check runs the identical measurement with the axis disabled and
requires it to read ~1.0. It reads exactly 1.00x on all three scenes.
The honest scope, measured across ten candidates and written into EPIC-2.md
§3.4: the axis works on Moiré Grid (3.93x), Gate Corridor (2.88x) and Truchet
Fold (1.40x). Curl Flow, Signal Decay and Circuit Bloom have NO parameter that
changes their structure and still need shader work — parameter automation
cannot substitute for structure a scene does not have. Four more already
develop on their own and were never the problem. The flag is set only where it
is proven, so it means something.
69/70 on phases 3,4,7-11 slow; the one failure is the known load-dependent
Horizon Lines flake recorded in
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14d1204e82 |
Make grain a treatment, tempo a governor, and params commit harder
Grain was in every video. It was added twice unconditionally — every scene called sigGrain, and the grade added its own on top — so the only thing that varied between two tracks was how much of it there was. That makes grain the renderer's fingerprint rather than a decision about one video. It is now described rather than dialled (look/grain.js): a mode (off / constant / swell / sections / transient), a cell size in pixels, a refresh rate in frames, a mask (uniform, shadows, highlights, edges, bands) and a chroma amount. Roughly 45% of tracks get none at all. The non-constant modes carry a per-frame envelope computed in Show._postAt from frame and features only, so preview and export still agree. Scene-side grain is gated the same way, and a module can decline it outright with `texture: 0` — crisp line work should stay crisp. The post tab grew a real grain block so any of it can be forced per track. Slow songs got fast scenes. `motion` bias was mostly section energy with tempo as a small correction, so a 70bpm track's drop asked for nearly as much speed as a 150bpm one. Motion is now tempo-dominated, and every `rate: true` param is additionally scaled by a per-track rateScale — measured, 84bpm now samples its rate params at 0.276 of range against 148bpm's 0.571. Parameter sampling also commits harder: extremity starts at 0.45 rather than 0.25 and shapes the draw more aggressively. This was first pushed to 0.82 and backed off to 0.72, because the gates caught the overshoot — seeds began collapsing onto the same range ends and a sparse scene sampled at its low end rendered effectively black. Fallout worth recording: turning the default grade grain off exposed two scenes that were never really animating. Dust Chamber and Eclipse Field passed the Phase 7 movement gate only because per-pixel noise was moving underneath them; both now breathe on their own fixed clock, and Dust Chamber needed a brightness floor as well. Four scenes (Classic Wave, Silk Ribbon, Kaleido Tunnel, Slow Orb) express the style trait ONLY through grain and so cannot opt out yet; they hold a reduced share at 0.35 pending real edge and softness response. Phase 3's look-space check now measures its closest pair relative to image brightness, the same correction Phase 10 already documents for sparse scenes: the absolute number was being propped up by grain rather than by look-space width. Five new Phase 10 checks cover grain distribution, treatment variety, envelope range, the texture opt-out, and tempo. 93/93 pass. Two transport bugs, both stale state surfacing in the UI: - Loading a track replaces audio.src, which stops playback silently, so state.playing stayed true and the play button stayed on pause — the first click after a track change only flipped the flag back. Added stopPlayback(). - The controls row wrapped mid-song because two readouts that change length while playing were sized by their content: the clock crossing ten minutes and the section label whenever a scene name is long or a crossfade appears. The clock is now fixed-width with tabular figures and the section label is the row's only flexible item, laying out at zero width and ellipsising into whatever space is left. The two spacers competed with it for that space and are gone; its own text-align does their job. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
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2806ef1386 |
Phase 10: variety, twelve scenes, and tooling to write the next one
Watching several finished tracks side by side turned up the problem neither Phase 8 (too few cuts) nor Phase 9 (no through-line) addressed: the same scene cast in two different videos looked like the same footage twice. Section bias is nearly identical between two tracks' drops, so both sampled their parameters around the same centre, and the library's own averageness did the rest. Three answers, none of them a new scene: Temperament — a per-track hand on every parameter dial: intensity, pace, detail, and an extremity that decides how far toward the ends of a range the track is willing to sample. Bias comes from the section and is shared between tracks; temperament comes from the track and is not. Overlays — sometimes a second full scene composited over the shot, from a different family, in a blend that preserves what is underneath and never above 0.6 opacity. Not always: a stack that always doubled up would read as permanently cluttered rather than as occasionally layered. A wider palette — hue now derives from SPECTRAL TILT, the log ratio of treble to body. The centroid is a number most masters sit in the middle of, and the plain body/(body+treble) fraction is worse: low frequencies carry most of the energy in all music, so it read 0.98-1.00 for everything and four different battery tracks came out within 0.02 of each other. The ratio is multiplicative, so its logarithm is what spreads — the same four measure -9.3, -5.0, -4.1, -3.8. Also both ways round the wheel (violet, magenta and pink were unreachable by construction), four new schemes, and seeded chroma profile and lightness curve. Closest battery pair went from 0.005 to 0.113. Twelve scenes take the library to 36, six per family: Aurora Veil, Vortex Drift, Tide Rings, Ink Bleed, Dust Chamber, Salt Flat, Cargo Belt, Gate Corridor, Circuit Bloom, Truchet Fold, Signal Decay, Storm Rift. Weighted toward the 'space' and 'shape' traits, which were thinnest and so the signatures most likely to run a track out of cast — the Phase 9 casting rule means the pool a track draws from is smaller than the library. Also fixes a real one in shots.js: heavy LRU weighting was not enough to make a section reach its whole roster, and a five-shot section still came out 0,2,0,2,0 about a fifth of the time. An unseen companion now wins outright; which one is still free, so only the coverage is guaranteed. Block Mosh declared the camera trait, assigned sigCamera(p) to a p it then never read, and passed the lint's evidence grep. The Phase 9 render gate measured its response to the camera at exactly zero. --- tooling --- Adding a scene was mostly boilerplate and round-trips, which is expensive in both senses. The irreducible cost is the shader body; everything around it is now mechanical: npm run new:scene -- "Name" --family=... --traits=... writes the module, registers it, and leaves a skeleton that already passes every gate, with name-derived constants so two skeletons are not twins. The lint grew the rules that previously needed a GPU to catch: the dead camera above, prev() with no base image, and large loops with no early break (with a `// lint: fixed-cost` opt-out for a genuinely fixed-cost sampling loop). checks.html?scene=Name runs the per-scene acceptance battery for one scene — ten lines and a verdict instead of rendering the whole library to find out whether one shader is alive. The same procedure is a repo skill under .claude/skills/build-visualizer/. --- checks changed, with the measurements --- P5 determinism compared two WebGL CONTEXTS, which is not what it is for. Measured: one context is bit-exact over 40 frames with feedback at 0.6; two contexts disagree by up to 2/255 whether feedback is on or off. It now asserts generation is byte-identical (hard) and rendering within 2/255, since feedback compounds single-level variance. P10's cross-track comparison measures distance RELATIVE to how much image there is. Most scenes are mostly dark, so two genuinely different renders — 25 bars against 53 — scored under 0.02 absolute purely because the black background agrees with itself. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |
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ca5a68eb84 |
Phases 8 and 9: shots, and a production design per track
Both phases come out of the manual gate — watching whole tracks — and both
fix something no automated check was looking for.
Phase 8: shots. A section is a STAGE of the song and can run ninety
seconds; one scene held that long reads as a still image with a wobble on
it. Each section kind now gets a roster of three or four stage visuals
instead of one scene, and each section is cut into shots that rotate
between them on phrase lines, never holding past 22s. The roster stays per
kind, so a track's drops still cut between the same images and the video
keeps its identity; the anchor opens each section and the rotation returns
to it, and when a companion is due it is the least recently shown one.
The arc driver stopped working in sections and started working in cues, one
per shot, so a shot cut and a section change take the same code path and
differ only in transition length. The default transition is a slow
dissolve — two bars calm, one loud; a straight cut is reserved for
sections above the energy threshold, because on calm material a cut reads
as a glitch rather than as an edit.
Phase 9: production design. With cuts every fifteen seconds the next
problem was that the images being cut between shared nothing but the
palette. What a music video actually shares across shots is a location, a
cast, a camera operator and an art direction, so each track now generates a
personality in four traits (shape, camera, space, style) off the look seed.
The traits reach shaders as uniforms plus four helpers in the contract, and
each scene expresses them its own way: Classic Wave's rings take the
signature polygon, Metaballs merge as one, Floating Geometry no longer
picks between a box and a circle because the production already decided.
The part that makes it a design rather than a filter: scenes DECLARE which
traits they honour, a track is built on one or two, and a scene that does
not honour all of them is not cast in that track. The library shrinks per
track on purpose.
Two gates keep the declaration honest — lint greps each shader for evidence
of every trait it claims, and a render check measures that each declared
trait actually moves the image (41 scene/trait pairs, weakest response 64
of 255). A layer with no personality renders bit-identically to before,
which is what keeps every earlier sweep and regression valid.
Checks changed rather than added:
- P4 scene-change and drift checks now measure per shot, not per section;
the crossfade check reads its length off the cue.
- P5 flash sweep runs per shot, so the visuals that only appear
mid-section are measured too.
- P6 preview/export parity primes first (as both real paths do) and
compares at the one-LSB tolerance Phase 7 already uses. Measured over
four consecutive shows: 3 frames at delta 1, then bit-exact — GPU
variance on first render, not a divergence.
- P2's contract-uniform list is derived from the contract instead of
retyped, so the signature uniforms cannot fall out of sync.
Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
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59180948d0 |
Phase 5: compositing depth ("C" complete)
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> |
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7e31c19d6e |
Phase 0: determinism spine
Engine core: Timeline (fixed dt, audio-mastered in realtime), seeded Rng, Renderer, Layer/ShaderLayer/SceneLayer, Compositor with blend modes, feedback and post chain. Shader scenes are compiled against a fixed uniform contract and define only `vec4 scene(vec2 uv, vec2 p)`, so adding a scene costs a shader plus a params block. Deep Nebula ported from party-stage as the first one. Gate passes, 7/7 in checks.html: - 300 frames rendered twice are bit-identical - a fresh Engine reproduces the same frames - simulated dropped frames change nothing (proves dt is fixed) - seek matches sequential playback - 320x180 vs 1280x720 agree within 0.010 (limit 0.06) - seeded rng reproducible, forked streams independent - compositor reset clears feedback history Static gates: no wall-clock or unseeded randomness in deterministic directories; scene schemas and shader sources agree in both directions. Co-Authored-By: Claude Opus 5 <noreply@anthropic.com> |