Hand tracking at 30fps was writing 126 params per frame to the C15 ring
buffer (capacity 512), flooding it and starving arpeggiator noteOn/noteOff
messages — causing stuck/dropped notes.
Three-part fix:
- Arpeggiator now runs in a dedicated Web Worker with direct
SharedArrayBuffer access, bypassing the main thread entirely for
note timing. Worker setInterval isn't subject to main thread jank.
- RingBufferWriter uses CAS (Atomics.compareExchange) for multi-producer
safety — both main thread (params) and worker (notes) write safely.
- routeOutputs throttles synth parameter sends: dead-zone filter
(0.2% change threshold) + rate cap (~20fps), reducing ring buffer
pressure from ~3800 msg/s to ~50-100 msg/s of actual changes.
Hand tracking via webcam as alternative to joystick input:
- Right hand tracks 14 derived features (palm XY, finger curls, spread,
roll, pitch, pinch) through a separate 14-input MLP
- Left hand gesture recognition (1 finger = thumbs up, 2 = thumbs down)
with 400ms debounce hold
- Split-zone PIP display (no camera feed, skeleton only) with dashed
divider and cross-zone dimming
- Dual IML architecture: independent imlJoy (2 inputs) and imlHand
(14 inputs) with pointer swap, preserving training data per mode
- Dev panel (?devmode=true): draggable/collapsible floating panel with
sliders for MediaPipe confidence thresholds, smoothing, gesture hold
time, world landmarks toggle, and live feature bar monitor
- Visual presets always route to joystick IML (prevents dimension mismatch)
- Race condition guard on input mode switching
Compile nisps-core C++ MLP to WASM (36KB) and use it as the ML engine
in the playground, replacing the JavaScript port for inference, training,
and weight manipulation.
- Add extern "C" WASM bindings with spread-aware drawWeights/moveWeights
- WasmIML class is a drop-in replacement for the JS IML
- Inference runs on main thread via WASM (fast, synchronous)
- Training runs in a Web Worker with its own WASM instance (non-blocking)
- Interactive training (thumbs-up, train button) no longer freezes UI/audio
- Preset loading and state restore still use sync training
4 tiers of progressive complexity (Beginner 15 params → Expert 126),
13 presets total with per-param min/max/curve overrides that bias
distributions without clamping extremes. Preset dropdown in UI,
persisted to localStorage, supports ?preset= URL param.
SVF count was 7 (actual 9), Gap Filter section was missing (6 params),
FB Mix count was 10 (actual 9) — causing cascading mislabeling of all
synth sections from SVF onwards. Also sync volume/tempo changes from
bottom sheet back to quick-play controls.
- Glass-style modal explains NISPS, how learning works, and what to expect
- Documents all controls: touch, keyboard, and gamepad bindings
- Shows automatically on first visit (localStorage flag)
- Dismissible via close button, "Got it", overlay click, or Escape
- Reopenable via ? button at bottom right
- Map A=Train, B=Clear Examples, X=Randomize, LB=Thumbs Down, RB=Thumbs Up
- Add periodic gamepad polling fallback for environments where
gamepadconnected event doesn't fire reliably (Steam Deck, some Linux browsers)
- Show "Press any gamepad button to connect" hint on page load
When synth controls (volume, tempo, etc.) have focus after dragging,
keyboard shortcuts 1/2 for thumbs down/up were intercepted by the
range input. Now all four UIs skip shortcut handling when an input,
select, or textarea element has focus.
Relocated the output mode toggle from a floating top-right position into
the bottom floating bar where it's more discoverable. Removed the
duplicate toggle from the expanded sheet. Compact pill-toggle-sm style
fits the toolbar layout.
Merge Examples/RL tabs into single unified toolbar across all four UIs.
Users can now freely mix supervised learning (Add Example + Train) with
RL feedback (thumbs up/down) without switching modes. Param bar dragging
is always enabled.
Add Web MIDI input module (js/synth/midi-input.js) for external MIDI
controllers — routes note on/off to C15 synth, CC 1/2 to joystick.
Add gamepad module (js/ui/gamepad.js) with auto-detection, deadzone,
and axis normalization across all UIs.
Fix synth parameter sync: routeOutputs() now called after trainModel()
in onThumbsUp and loadState to prevent stale params on first joystick
move. Add separate Clear Examples button (dataset only, keeps weights).
- Fix RL buttons stuck high on desktop: media query was overriding
bottom to 196px, now matches mobile 92px
- Add floating Visual/Synth toggle at top-right of immersive view,
synced with the existing sheet toggle
Add ?spread=0-1 URL param that controls weight initialization scaling,
RL noise scaling per layer, noise cap, and weight decay to prevent
sigmoid output saturation. At spread=0 (original behavior) weights are
uniform [-1,1] and outputs polarise near 0/1. At spread=1 weights use
Xavier scaling (1/sqrt(fan_in)), noise is proportionally reduced, and
10% weight decay per thumbs-down prevents unbounded magnitude drift.
Also fix randomise to re-inject current joystick position and re-run
inference before routing outputs, eliminating the jump on first
joystick move after randomise.
Defaults: tame=1, spread=0.6 across all app variants.
When switching from synth back to visual mode, the FlowFieldVisualizer
canvas had stale dimensions from being hidden. Add requestAnimationFrame
resize call after toggling canvas visibility so the visualizer picks up
correct dimensions and renders properly.
Three redesigns of the playground UI, each exploring a different
interaction philosophy for the NISPS interactive ML engine:
A) Immersive — fullscreen canvas with floating glassmorphism overlays
B) Workbench — dashboard with 2D mapping heatmap as centerpiece
C) Journey — phased UI that dissolves (Explore → Teach → Perform)
All share the same 126-output MLP ([32,48,64] hidden layers), C15
synth bridge, and flow field visualizer. Each adds:
- SynthVisualizer (126 grouped vertical bars) replacing particles in synth mode
- RL as default learning mode with keyboard shortcuts (1/2)
- Follow mode for trackpad exploration
- ?tame= URL param for safe-range constraining
- localStorage persistence (random on first boot)
- Live iframe previews on designs.html homepage
See devlog/2026-03-21-ui-redesign-explorations.md and meml-2c3 for
remaining refinements identified during browser testing.
- Insert DynamicsCompressorNode as always-on brick-wall limiter after
master gain (threshold -6dB, ratio 20:1, 2ms attack)
- Add devmode tame parameter (0-1) controlling range constraining:
- ?tame=0.7 URL param (default) or window.setTameLevel(n)
- 0 = no mitigation, 1 = strongest constraining
- Constrain 20 volume/buildup-sensitive params with safeMin/safeMax:
- Envelope release/decay2 times capped to prevent infinite ringing
- Envelope gains kept in moderate range
- All 5 drive stages (ShpA/B, FB, Out, Cabinet) capped
- Output mixer levels given floor and ceiling
- Echo feedback and reverb size limited to prevent wash buildup
- Fix Comb Filter group count (8, not 9) in comments and color generator
Control all sonically meaningful C15 parameters through NISPS ML outputs.
Excludes hardware routing, macros, scale/tuning, key tracking, velocity,
envelope mod depths, discrete switches, and dangerous volume/pitch params.
- Expand param-map.js with 126 curated params grouped by synthesis section
- Widen MLP architecture from [3,10,10,14,20] to [3,32,48,64,126]
- Add ParamDisplay.rebuild() for mode-dependent bar count (20 visual, 126 synth)
- Add scrollable compact layout for synth mode param bars
- Pad visual presets and old saves to 126 outputs for backward compatibility
Adds a secondary Synth mode (toggled via collapsible left side panel)
where the NISPS ML engine's 20 outputs control curated C15 synthesizer
parameters (oscillator PM, shapers, filters, reverb, echo, flanger,
output mixer) through a WASM AudioWorklet bridge.
Includes a chord progression arpeggiator with controls for tempo (BPM),
octave range, octave offset, and 4 selectable progressions. The C15
engine runs in an AudioWorklet with lock-free SharedArrayBuffer ring
buffer communication.
New files: c15/ (WASM assets), js/synth/ (bridge, arpeggiator, param map),
serve-coop.py (COOP/COEP headers for SharedArrayBuffer support).
