2000s-visualization-expert

✅ Use for:

• Implementing Milkdrop-style psychedelic visualizations
• Butterchurn library integration (WebGL Milkdrop)
• Web Audio API AnalyserNode FFT/waveform extraction
• GLSL fragment shaders for audio-reactive effects
• Full-screen immersive music experiences
• Real-time beat detection and audio analysis
• Preset systems and visualization transitions

❌ NOT for:

• Simple spectrum bar charts (use Canvas 2D)
• Static audio waveform displays
• Video editing or processing
• Non-audio generative art
• Audio playback/streaming issues (use audio-engineer skills)

| Era | Key Software | Innovation |

|-----|--------------|------------|

| 1998-2000 | Geiss | Simple plasma effects, DirectX |

| 2001-2007 | Milkdrop 1 & 2 | Per-pixel equations, preset system |

| 2007-2015 | Decline | Streaming services rise |

| 2018-Present | Butterchurn | WebGL renaissance |

Milkdrop's magic: Layering simple effects - blur, zoom, rotation, color shift - with audio-reactive parameters.

→ See references/butterchurn-guide.md for full history and integration.

Butterchurn (WebGL Milkdrop)

• 1.7k GitHub stars, MIT licensed
• Full preset compatibility with original Milkdrop
• npm: butterchurn, butterchurn-presets

```typescript

import butterchurn from 'butterchurn';

const visualizer = butterchurn.createVisualizer(audioContext, canvas, {

width: window.innerWidth,

height: window.innerHeight,

pixelRatio: window.devicePixelRatio || 1,

});

visualizer.connectAudio(audioNode);

visualizer.loadPreset(preset, 2.0); // 2s blend

```

Web Audio API FFT

```typescript

const analyser = audioContext.createAnalyser();

analyser.fftSize = 2048;

analyser.smoothingTimeConstant = 0.8;

const frequencyData = new Uint8Array(analyser.frequencyBinCount);

analyser.getByteFrequencyData(frequencyData);

```

Critical: FFT bins are linear but hearing is logarithmic! Use logarithmic mapping.

→ See references/web-audio-fft.md for frequency band extraction.

GLSL Shaders

Pass audio data as 1D texture, use uniforms for bass/mid/treble:

```glsl

uniform float u_bass;

float glow = smoothstep(0.5 - u_bass * 0.3, 0.0, dist);

```

→ See references/glsl-shaders.md for complete patterns.

1. Ignoring AudioContext State

What it looks like: Visualization silently fails

Why it's wrong: AudioContext starts suspended, needs user interaction

Fix: Resume on click: await audioContext.resume()

2. Linear Frequency Display

What it looks like: Bass dominates, treble invisible

Why it's wrong: FFT bins are linear; first 100 bins might be 0-2kHz

Fix: Use logarithmic bin mapping (code in references)

3. No Smoothing

What it looks like: Jittery, seizure-inducing visuals

Why it's wrong: Raw FFT data is noisy frame-to-frame

Fix: analyserNode.smoothingTimeConstant = 0.7

4. requestAnimationFrame Without Cleanup

What it looks like: Memory leaks, multiple render loops

Fix: Store animation ID, call cancelAnimationFrame on unmount

5. Hardcoded Canvas Size

What it looks like: Blurry on retina, wrong aspect ratio

Fix: Multiply by devicePixelRatio, handle resize events

6. Blocking Main Thread

What it looks like: Choppy audio, dropped frames

Why it's wrong: Heavy shader compilation on UI thread

Fix: Compile shaders during loading, not during playback

Psychedelic/Trippy:

• Flexi, martin + geiss - dedicated to the sherwin maxawow
• Rovastar - Fractopia

Smooth/Chill:

• Flexi - predator-prey-spirals
• Geiss - Cosmic Strings 2

High Energy:

• Flexi + Martin - disconnected
• shifter - tumbling cubes

• [ ] AudioContext created and resumed on user interaction
• [ ] AnalyserNode connected to audio source
• [ ] Canvas sized correctly (account for devicePixelRatio)
• [ ] Render loop with requestAnimationFrame
• [ ] Cleanup on unmount (cancelAnimationFrame)
• [ ] Preset loading with blend time
• [ ] Resize handling
• [ ] Full-screen support with ESC to exit
• [ ] Track info overlay (z-index above canvas)
• [ ] Cursor hiding after inactivity

1. Lower texture ratio for older GPUs: textureRatio: 0.5
2. Reduce fftSize if not needed: 512 or 1024 vs 2048
3. Use will-change: transform on canvas
4. Avoid DOM updates during render loop
5. Profile with Chrome DevTools GPU timeline

→ references/butterchurn-guide.md - Complete Butterchurn integration

→ references/web-audio-fft.md - FFT extraction and frequency analysis

→ references/glsl-shaders.md - Audio-reactive shader patterns

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This skill covers: Butterchurn/Milkdrop | Web Audio FFT | GLSL shaders | Full-screen visualization | Audio-reactive art