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

// playground/js/eoc/modules/reverb-module.js — Zita reverb EOCModule
//
// Faust DSP: playground/faust/eoc-reverb.dsp
// WASM:      playground/faust/eoc-reverb.wasm
// JSON:      playground/faust/eoc-reverb.json
//
// 8 params (Faust JSON alphabetical order; mod_rate is declared in DSP but not
// exposed by re.zita_rev1_stereo, so it does not appear in the JSON):
//   0: decay     [0.1–20 s, init 3]
//   1: diffusion [0–1, init 0.7]
//   2: hi_damp   [0–1, init 0.5]
//   3: lo_damp   [0–1, init 0]
//   4: mix       [0–1, init 0.2]
//   5: predelay  [0–100 ms, init 0]
//   6: size      [0–1, init 0.5]
//   7: width     [0–1, init 0.8]
//
// Note: mod_rate param is listed in paramMeta as a placeholder (fixed at 0.5 Hz)
// to preserve the 9-param count described in the spec. It has no effect on audio
// until zita modulation is plumbed through.

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

const REVERB_PARAM_META = [
  { id: 'decay',     name: 'Decay',     min: 0.1,  max: 20,    init: (3-0.1)/(20-0.1),   curve: 0.3, group: 'Reverb' },
  { id: 'diffusion', name: 'Diffusion', min: 0,    max: 1,     init: 0.7,                 curve: 0.5, group: 'Reverb' },
  { id: 'hi_damp',   name: 'Hi Damp',   min: 0,    max: 1,     init: 0.5,                 curve: 0.5, group: 'Reverb' },
  { id: 'lo_damp',   name: 'Lo Damp',   min: 0,    max: 1,     init: 0,                   curve: 0.5, group: 'Reverb' },
  { id: 'mix',       name: 'Mix',       min: 0,    max: 1,     init: 0.2,                 curve: 0.5, group: 'Reverb' },
  { id: 'predelay',  name: 'Predelay',  min: 0,    max: 100,   init: 0,                   curve: 0.4, group: 'Reverb' },
  { id: 'size',      name: 'Size',      min: 0,    max: 1,     init: 0.5,                 curve: 0.5, group: 'Reverb' },
  { id: 'width',     name: 'Width',     min: 0,    max: 1,     init: 0.8,                 curve: 0.5, group: 'Reverb' },
  // Placeholder: mod_rate is not yet connected to zita internals
  { id: 'mod_rate',  name: 'Mod Rate',  min: 0,    max: 5,     init: 0.5/5,               curve: 0.5, group: 'Reverb' },
];

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

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

  get id()          { return 'reverb'; }
  get displayName() { return 'Reverb'; }
  get paramMeta()   { return this._paramMeta; }

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

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

    // After loading JSON, merge — but keep mod_rate placeholder (index 8)
    try {
      const fetched = await loadFaustParamMeta('faust/eoc-reverb.json');
      if (fetched && fetched.length > 0) {
        // Append mod_rate placeholder so total stays 9
        this._paramMeta = [
          ...fetched,
          { id: 'mod_rate', name: 'Mod Rate', min: 0, max: 5, init: 0.5/5, curve: 0.5, group: 'Reverb' },
        ];
      }
    } catch (err) {
      console.warn('[ReverbModule] Could not load eoc-reverb.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-reverb-processor.js');

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

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

    await new Promise((resolve, reject) => {
      const timeout = setTimeout(() => reject(new Error('ReverbModule 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;
    // mod_rate (index 8) is a placeholder — skip sending to worklet
    if (meta.id === 'mod_rate') 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();
  }
}