memlnaut-nisps/playground/js/eoc/modules/compressor-module.js

// playground/js/eoc/modules/compressor-module.js — Stereo compressor EOCModule
//
// Faust DSP: playground/faust/eoc-compressor.dsp
// WASM:      playground/faust/eoc-compressor.wasm
// JSON:      playground/faust/eoc-compressor.json
//
// 7 params (Faust JSON alphabetical order):
//   0: attack   [0.1–200 ms, init 10]
//   1: knee     [0–24 dB, init 6]
//   2: makeup   [0–24 dB, init 0]
//   3: mix      [0–1, init 1]  (dry/wet for parallel compression)
//   4: ratio    [1–20, init 4]
//   5: release  [10–2000 ms, init 100]
//   6: threshold [-60–0 dBFS, init -24]

import { EOCModule } from '../eoc-module.js';
import { loadFaustParamMeta } from '../../synth/faust-param-meta.js';

const COMP_PARAM_META = [
  { id: 'attack',    name: 'Attack',    min: 0.1,  max: 200,   init: (10-0.1)/(200-0.1),      curve: 0.3, group: 'Compressor' },
  { id: 'knee',      name: 'Knee',      min: 0,    max: 24,    init: 6/24,                    curve: 0.5, group: 'Compressor' },
  { id: 'makeup',    name: 'Makeup',    min: 0,    max: 24,    init: 0,                       curve: 0.5, group: 'Compressor' },
  { id: 'mix',       name: 'Mix',       min: 0,    max: 1,     init: 1,                       curve: 0.5, group: 'Compressor' },
  { id: 'ratio',     name: 'Ratio',     min: 1,    max: 20,    init: (4-1)/(20-1),            curve: 0.4, group: 'Compressor' },
  { id: 'release',   name: 'Release',   min: 10,   max: 2000,  init: (100-10)/(2000-10),      curve: 0.3, group: 'Compressor' },
  { id: 'threshold', name: 'Threshold', min: -60,  max: 0,     init: (-24-(-60))/(0-(-60)),   curve: 0.5, group: 'Compressor' },
];

export class CompressorModule extends EOCModule {
  constructor() {
    super();
    this._workletNode = null;
    this._effectGain  = null;
    this._paramMeta   = COMP_PARAM_META;
  }

  // ---------------------------------------------------------------------------
  // EOCModule identity
  // ---------------------------------------------------------------------------

  get id()          { return 'compressor'; }
  get displayName() { return 'Compressor'; }
  get paramMeta()   { return this._paramMeta; }

  // ---------------------------------------------------------------------------
  // Lifecycle
  // ---------------------------------------------------------------------------

  async init(audioCtx) {
    await super.init(audioCtx);

    try {
      const fetched = await loadFaustParamMeta('faust/eoc-compressor.json');
      if (fetched && fetched.length > 0) this._paramMeta = fetched;
    } catch (err) {
      console.warn('[CompressorModule] Could not load eoc-compressor.json, using static paramMeta:', err.message);
    }

    try {
      await audioCtx.audioWorklet.addModule('faust/faust-worklet-processor.js');
    } catch (_) { /* already registered */ }
    await audioCtx.audioWorklet.addModule('faust/eoc-compressor-processor.js');

    this._workletNode = new AudioWorkletNode(audioCtx, 'eoc-compressor-processor', {
      numberOfInputs:    1,
      numberOfOutputs:   1,
      outputChannelCount: [2],
    });

    const wasmResp  = await fetch('faust/eoc-compressor.wasm');
    const wasmBytes = await wasmResp.arrayBuffer();

    await new Promise((resolve, reject) => {
      const timeout = setTimeout(() => reject(new Error('CompressorModule worklet init timeout')), 10000);
      this._workletNode.port.onmessage = (e) => {
        if (e.data.type === 'ready')  { clearTimeout(timeout); resolve(); }
        if (e.data.type === 'error')  { clearTimeout(timeout); reject(new Error(e.data.message)); }
      };
      this._workletNode.port.postMessage(
        { type: 'init', wasmBytes, sampleRate: audioCtx.sampleRate },
        [wasmBytes],
      );
    });

    this._effectGain = audioCtx.createGain();
    this._effectGain.gain.value = 1;

    this._bypassIn.connect(this._workletNode);
    this._workletNode.connect(this._effectGain);
    this._effectGain.connect(this._bypassOut);

    this._finishInit();
  }

  // ---------------------------------------------------------------------------
  // Real-time control
  // ---------------------------------------------------------------------------

  setParam(index, normalizedValue) {
    super.setParam(index, normalizedValue);
    if (!this._workletNode) return;
    const meta = this._paramMeta[index];
    if (!meta) return;
    const raw = meta.min + normalizedValue * (meta.max - meta.min);
    this._workletNode.port.postMessage({ type: 'setParam', index, value: raw });
  }

  // ---------------------------------------------------------------------------
  // Bypass
  // ---------------------------------------------------------------------------

  _onBypassChange(enabled) {
    if (!this._effectGain) return;
    const t = this._audioCtx.currentTime;
    this._effectGain.gain.setTargetAtTime(enabled ? 1 : 0, t, 0.005);
  }

  // ---------------------------------------------------------------------------
  // Dispose
  // ---------------------------------------------------------------------------

  dispose() {
    this._workletNode?.disconnect();
    this._effectGain?.disconnect();
    this._workletNode = null;
    this._effectGain  = null;
    super.dispose();
  }
}