feedBack/plugins/keys_highway_3d/README.md

Keys Highway 3D

RS+-style falling-note 3D piano highway for Slopsmith, fed by the Sloppak Notation Format (sloppak-spec §5.3) — part of the piano/keys first-class epic (slopsmith#828, plugin workstream slopsmith#824).

• Consumes the notation_info / notation_measures highway-WS stream over a private per-instance socket and flattens measure → staff → voice → beat → note into {midi, t, durSec, hand} (durations derived from written dur/dot/tu at the running tempo; ties extend; overlap-clamped).
• 3D perspective highway to a vanishing point with a real white/black-key keyboard; per-key pitch-class colours (Synthesia convention — C red, D yellow, E blue, …) with hand (rh/lh) as a secondary brightness cue.
• Full RS+ visual treatment: key letter glyphs printed on the active-range key tops (cached CanvasTextures), bevelled gem-style note blocks (ExtrudeGeometry, geometry/material caches keyed by size and pitch-class×hand), floating bar numbers scrolling with the notes, active-range lane dimming so the playable span pops, and a glowing pulsing hit-line (layered additive gradient planes — no postprocessing).
• Performance discipline: no per-frame allocations or DOM queries in draw(). Chart-scoped resources — note geometries/materials, bar-number and glow textures — are cached and disposed on chart teardown; the key-letter glyph CanvasTextures live in a shared module-level cache that survives teardown and is reused across instances.
• Auto-selected for arrangements with notation via matchesArrangement(songInfo.has_notation); capability-native visualization provider declaration.
• Web MIDI input scoring: module-level MIDI singleton (one access per tab, focused-instance routing) with device auto-connect by saved id+name, loopback blocklist, channel filter, transpose and CC64 sustain (keys3d_ localStorage prefix; window.keysH3d* settings API). Hit detection matches played MIDI against the flattened chart notes within ±0.10 s with per-note dedupe and a missed-note sweep (only while a device is connected — never retroactive across a mid-song connect).
• Live hit feedback on the MIDI path (not the chart): key depress (~4° back-edge pivot, ~120 ms spring; the key letter rides along), wrong-note red key flash, and a vertical flame flare on hits (pooled additive sprites, white-hot base fading into the pitch-class colour, ~400 ms).
• End-of-run stats: POSTs /api/stats {filename, arrangement, score, accuracy} exactly once per run with the same formula as the guitar notedetect path (accuracy = hits / max(1, hits+misses), score = round(hits·100·accuracy)), then notifies the progression core when present.
• Capability wiring (all guarded for servers without the hosts): registers as a note-detection midi provider (keys-midi, verify.target), opens a per-song binding scoped to the chart's keys range, reports hit/miss observability events, and exposes Web MIDI inputs to the audio-input domain with pseudonymized labels (midi-input-1, …) via source.enumerate/describe/open/close.
• Headless test hook: window.__keysHwTest = { injectNoteOn(midi, when), getScore() }.

Tests

node --test tests/*.test.js

Ported helpers (keep in sync with highway_3d)

Visual-parity code copied from plugins/highway_3d/screen.js — same function names, signatures, and constants on purpose, marked with PORTED FROM highway_3d comments at each site. If the guitar highway tunes one of these, mirror the change here (and in drum_highway_3d):

• _bloomEnsure() / _bloomDispose() — EffectComposer + UnrealBloomPass (0.65/0.5/0.82) on a multisampled HalfFloat target, ACES↔None tone- mapping switch in draw(); addons dynamic-imported from /static/vendor/three/addons/ (no CDN fallback — direct render is the graceful degrade)
• _sparkBurst() / _sparkUpdate() — pooled additive Points hit sparks (pool 96 here — the flame sprites carry most of the hit feedback)
• _timingHex() / _classifyTiming() — early/late/on-time feedback colors (green/cyan/amber) + the 40%-window classifier
• _ssActive() — host splitscreen probe (minus the guitar's focus-API checks, which it needs for input routing and we don't)
• BG_THEMES / _bgThemeColors() — the scene theme table (same ids/values as the guitar's, except default which is this plugin's original palette); one pick drives background gradient + floor + lane rails
• _makeStudioEnv() — procedural PMREM studio environment (shared with drum_highway_3d; RoomEnvironment isn't vendored)
• _applyCinematic() — ambient/key rebalance (values tuned per plugin)

License

AGPL-3.0.