GenMusic

Seed-deterministic generative music engine for the web. Feed it a seed and an intensity signal — it composes and plays music in real time.

Architecture

Pattern → Player separation. Patterns are seed-generated note sequences. Players interpret them into sound. The engine just routes.

seed ──→ patterns (shared)
              │
engine ──→ arpeggio player ──→ audio
       ──→ melody player   ──→ audio
       ──→ solo player     ──→ audio

Same seed = same composition. Always.

Features

• Deterministic: seeded PRNG controls all randomness
• Single control signal: just feed setIntensity(0-1) continuously
• Player system: modular musical interpreters (arpeggio, melody, solo, rhythm, bass)
• Phrase engine: configurable styles with form structures (AABA), contours, verse alternation
• Time signatures: 4/4, 3/4, 6/8
• Production moods: intimate, warm, distant, bright (effect chain presets)
• Zero dependencies: vanilla TypeScript, WebAudio API
• Auto-rebirth: when intensity drops to 0 and rises, generates a new key and patterns

Quick Start

import { GenMusic } from './src/engine.js';

button.onclick = () => {
  const engine = new GenMusic({ seed: 42 });
  engine.start();

  // Feed intensity from your simulation
  function loop() {
    engine.setIntensity(mySimulation.getActivity());
    requestAnimationFrame(loop);
  }
  loop();
};

Build

npx tsc
npx esbuild src/index.ts --bundle --format=iife --global-name=GenMusicLib --outfile=dist/genmusic.bundle.js --minify

Playground

Open playground/index.html — interactive test UI with seed controls, intensity slider, and real-time visualization.

Docs

• Architecture — module structure, data flow, Player interface
• Composition — what the seed controls, phrase engine, melody design
• Players — each player type and its behavior
• Intensity — the single control signal
• Production — moods, voices, tempo
• Integration — how to connect to your project
• Playground — test UI documentation

Used In

• Petri — Gray-Scott reaction-diffusion dish that composes its own music