strudel/packages/webaudio/webaudio.mjs

/*
webaudio.mjs - <short description TODO>
Copyright (C) 2022 Strudel contributors - see <https://github.com/tidalcycles/strudel/blob/main/packages/webaudio/webaudio.mjs>
This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General Public License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later version. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Affero General Public License for more details. You should have received a copy of the GNU Affero General Public License along with this program.  If not, see <https://www.gnu.org/licenses/>.
*/

import * as strudel from '@strudel.cycles/core';
import { fromMidi, logger, toMidi } from '@strudel.cycles/core';
import './feedbackdelay.mjs';
import './reverb.mjs';
import { getSampleBufferSource } from './sampler.mjs';
const { Pattern } = strudel;
import './vowel.mjs';
import workletsUrl from './worklets.mjs?url';

// export const getAudioContext = () => Tone.getContext().rawContext;

let audioContext;
export const getAudioContext = () => {
  if (!audioContext) {
    audioContext = new AudioContext();
  }
  return audioContext;
};

let destination;
const getDestination = () => {
  const ctx = getAudioContext();
  if (!destination) {
    destination = ctx.createGain();
    destination.connect(ctx.destination);
  }
  return destination;
};

export const panic = () => {
  getDestination().gain.linearRampToValueAtTime(0, getAudioContext().currentTime + 0.01);
  destination = null;
};

const getFilter = (type, frequency, Q) => {
  const filter = getAudioContext().createBiquadFilter();
  filter.type = type;
  filter.frequency.value = frequency;
  filter.Q.value = Q;
  return filter;
};

const getADSR = (attack, decay, sustain, release, velocity, begin, end) => {
  const gainNode = getAudioContext().createGain();
  gainNode.gain.setValueAtTime(0, begin);
  gainNode.gain.linearRampToValueAtTime(velocity, begin + attack); // attack
  gainNode.gain.linearRampToValueAtTime(sustain * velocity, begin + attack + decay); // sustain start
  gainNode.gain.setValueAtTime(sustain * velocity, end); // sustain end
  gainNode.gain.linearRampToValueAtTime(0, end + release); // release
  // for some reason, using exponential ramping creates little cracklings
  /* let t = begin;
  gainNode.gain.setValueAtTime(0, t);
  gainNode.gain.exponentialRampToValueAtTime(velocity, (t += attack));
  const sustainGain = Math.max(sustain * velocity, 0.001);
  gainNode.gain.exponentialRampToValueAtTime(sustainGain, (t += decay));
  if (end - begin < attack + decay) {
    gainNode.gain.cancelAndHoldAtTime(end);
  } else {
    gainNode.gain.setValueAtTime(sustainGain, end);
  }
  gainNode.gain.exponentialRampToValueAtTime(0.001, end + release); // release */
  return gainNode;
};

const getOscillator = ({ s, freq, t, duration, release }) => {
  // make oscillator
  const o = getAudioContext().createOscillator();
  o.type = s || 'triangle';
  o.frequency.value = Number(freq);
  o.start(t);
  o.stop(t + duration + release);
  return o;
};

const getSoundfontKey = (s) => {
  if (!globalThis.soundfontList) {
    // soundfont package not loaded
    return false;
  }
  if (globalThis.soundfontList?.instruments?.includes(s)) {
    return s;
  }
  // check if s is one of the soundfonts, which are loaded into globalThis, to avoid coupling both packages
  const nameIndex = globalThis.soundfontList?.instrumentNames?.indexOf(s);
  // convert number nameIndex (0-128) to 3 digit string (001-128)
  const name = nameIndex < 10 ? `00${nameIndex}` : nameIndex < 100 ? `0${nameIndex}` : nameIndex;
  if (nameIndex !== -1) {
    // TODO: indices of instrumentNames do not seem to match instruments
    return globalThis.soundfontList.instruments.find((instrument) => instrument.startsWith(name));
  }
  return;
};

const splitSN = (s, n) => {
  if (!s.includes(':')) {
    return [s, n];
  }
  let [s2, n2] = s.split(':');
  if (isNaN(Number(n2))) {
    return [s, n];
  }
  return [s2, n2];
};

let workletsLoading;
function loadWorklets() {
  if (workletsLoading) {
    return workletsLoading;
  }
  workletsLoading = getAudioContext().audioWorklet.addModule(workletsUrl);
  return workletsLoading;
}

function getWorklet(ac, processor, params) {
  const node = new AudioWorkletNode(ac, processor);
  Object.entries(params).forEach(([key, value]) => {
    node.parameters.get(key).value = value;
  });
  return node;
}

// this function should be called on first user interaction (to avoid console warning)
export async function initAudio() {
  if (typeof window !== 'undefined') {
    try {
      await getAudioContext().resume();
      await loadWorklets();
    } catch (err) {
      console.warn('could not load AudioWorklet effects coarse, crush and shape', err);
    }
  }
}

export async function initAudioOnFirstClick() {
  return new Promise((resolve) => {
    document.addEventListener('click', async function listener() {
      await initAudio();
      resolve();
      document.removeEventListener('click', listener);
    });
  });
}

function gainNode(value) {
  const node = getAudioContext().createGain();
  node.gain.value = value;
  return node;
}
const cutGroups = [];

let delays = {};
function getDelay(orbit, delaytime, delayfeedback, t) {
  if (!delays[orbit]) {
    const ac = getAudioContext();
    const dly = ac.createFeedbackDelay(1, delaytime, delayfeedback);
    dly.start?.(t); // for some reason, this throws when audion extension is installed..
    dly.connect(getDestination());
    delays[orbit] = dly;
  }
  delays[orbit].delayTime.value !== delaytime && delays[orbit].delayTime.setValueAtTime(delaytime, t);
  delays[orbit].feedback.value !== delayfeedback && delays[orbit].feedback.setValueAtTime(delayfeedback, t);
  return delays[orbit];
}

let reverbs = {};
function getReverb(orbit, duration = 2) {
  if (!reverbs[orbit]) {
    const ac = getAudioContext();
    const reverb = ac.createReverb(duration);
    reverb.connect(getDestination());
    reverbs[orbit] = reverb;
  }
  if (reverbs[orbit].duration !== duration) {
    reverbs[orbit] = reverbs[orbit].setDuration(duration);
    reverbs[orbit].duration = duration;
  }
  return reverbs[orbit];
}

function effectSend(input, effect, wet) {
  const send = gainNode(wet);
  input.connect(send);
  send.connect(effect);
  return send;
}

// export const webaudioOutput = async (t, hap, ct, cps) => {
export const webaudioOutput = async (hap, deadline, hapDuration, cps) => {
  const ac = getAudioContext();
  hap.ensureObjectValue();

  // calculate absolute time
  let t = ac.currentTime + deadline;
  // destructure value
  let {
    freq,
    s,
    bank,
    sf,
    clip = 0, // if 1, samples will be cut off when the hap ends
    n = 0,
    note,
    gain = 0.8,
    // low pass
    cutoff,
    resonance = 1,
    // high pass
    hcutoff,
    hresonance = 1,
    // band pass
    bandf,
    bandq = 1,
    //
    coarse,
    crush,
    shape,
    pan,
    speed = 1, // sample playback speed
    begin = 0,
    end = 1,
    vowel,
    delay = 0,
    delayfeedback = 0.5,
    delaytime = 0.25,
    unit,
    nudge = 0, // TODO: is this in seconds?
    cut,
    loop,
    orbit = 1,
    room,
    size = 2,
  } = hap.value;
  const { velocity = 1 } = hap.context;
  gain *= velocity; // legacy fix for velocity
  // the chain will hold all audio nodes that connect to each other
  const chain = [];
  if (bank && s) {
    s = `${bank}_${s}`;
  }
  if (typeof s === 'string') {
    [s, n] = splitSN(s, n);
  }
  if (typeof note === 'string') {
    [note, n] = splitSN(note, n);
  }
  if (!s || ['sine', 'square', 'triangle', 'sawtooth'].includes(s)) {
    // destructure adsr here, because the default should be different for synths and samples
    const { attack = 0.001, decay = 0.05, sustain = 0.6, release = 0.01 } = hap.value;
    // with synths, n and note are the same thing
    n = note || n || 36;
    if (typeof n === 'string') {
      n = toMidi(n); // e.g. c3 => 48
    }
    // get frequency
    if (!freq && typeof n === 'number') {
      freq = fromMidi(n); // + 48);
    }
    // make oscillator
    const o = getOscillator({ t, s, freq, duration: hapDuration, release });
    chain.push(o);
    // level down oscillators as they are really loud compared to samples i've tested
    chain.push(gainNode(0.3));
    // TODO: make adsr work with samples without pops
    // envelope
    const adsr = getADSR(attack, decay, sustain, release, 1, t, t + hapDuration);
    chain.push(adsr);
  } else {
    // destructure adsr here, because the default should be different for synths and samples
    const { attack = 0.001, decay = 0.001, sustain = 1, release = 0.001 } = hap.value;
    // load sample
    if (speed === 0) {
      // no playback
      return;
    }
    if (!s) {
      console.warn('no sample specified');
      return;
    }
    const soundfont = getSoundfontKey(s);
    let bufferSource;

    if (soundfont) {
      // is soundfont
      bufferSource = await globalThis.getFontBufferSource(soundfont, note || n, ac, freq);
    } else {
      // is sample from loaded samples(..)
      bufferSource = await getSampleBufferSource(s, n, note, speed, freq);
    }
    // asny stuff above took too long?
    if (ac.currentTime > t) {
      logger(`[sampler] still loading sound "${s}:${n}"`, 'highlight');
      // console.warn('sample still loading:', s, n);
      return;
    }
    if (!bufferSource) {
      console.warn('no buffer source');
      return;
    }
    bufferSource.playbackRate.value = Math.abs(speed) * bufferSource.playbackRate.value;
    if (unit === 'c') {
      // are there other units?
      bufferSource.playbackRate.value = bufferSource.playbackRate.value * bufferSource.buffer.duration * cps;
    }
    let duration = soundfont || clip ? hapDuration : bufferSource.buffer.duration / bufferSource.playbackRate.value;
    // "The computation of the offset into the sound is performed using the sound buffer's natural sample rate,
    // rather than the current playback rate, so even if the sound is playing at twice its normal speed,
    // the midway point through a 10-second audio buffer is still 5."
    const offset = begin * duration * bufferSource.playbackRate.value;
    duration = (end - begin) * duration;
    if (loop) {
      bufferSource.loop = true;
      bufferSource.loopStart = offset;
      bufferSource.loopEnd = offset + duration;
      duration = loop * duration;
    }
    t += nudge;

    bufferSource.start(t, offset);
    if (cut !== undefined) {
      cutGroups[cut]?.stop(t); // fade out?
      cutGroups[cut] = bufferSource;
    }
    chain.push(bufferSource);
    bufferSource.stop(t + duration + release);
    const adsr = getADSR(attack, decay, sustain, release, 1, t, t + duration);
    chain.push(adsr);
  }

  // gain stage
  chain.push(gainNode(gain));

  // filters
  cutoff !== undefined && chain.push(getFilter('lowpass', cutoff, resonance));
  hcutoff !== undefined && chain.push(getFilter('highpass', hcutoff, hresonance));
  bandf !== undefined && chain.push(getFilter('bandpass', bandf, bandq));
  vowel !== undefined && chain.push(ac.createVowelFilter(vowel));

  // effects
  coarse !== undefined && chain.push(getWorklet(ac, 'coarse-processor', { coarse }));
  crush !== undefined && chain.push(getWorklet(ac, 'crush-processor', { crush }));
  shape !== undefined && chain.push(getWorklet(ac, 'shape-processor', { shape }));

  // panning
  if (pan !== undefined) {
    const panner = ac.createStereoPanner();
    panner.pan.value = 2 * pan - 1;
    chain.push(panner);
  }

  // last gain
  const post = gainNode(1);
  chain.push(post);
  post.connect(getDestination());

  // delay
  let delaySend;
  if (delay > 0 && delaytime > 0 && delayfeedback > 0) {
    const delyNode = getDelay(orbit, delaytime, delayfeedback, t);
    delaySend = effectSend(post, delyNode, delay);
  }
  // reverb
  let reverbSend;
  if (room > 0 && size > 0) {
    const reverbNode = getReverb(orbit, size);
    reverbSend = effectSend(post, reverbNode, room);
  }

  // connect chain elements together
  chain.slice(1).reduce((last, current) => last.connect(current), chain[0]);

  // disconnect all nodes when source node has ended:
  chain[0].onended = () => chain.concat([delaySend, reverbSend]).forEach((n) => n?.disconnect());
};

export const webaudioOutputTrigger = (t, hap, ct, cps) => webaudioOutput(hap, t - ct, hap.duration / cps, cps);

Pattern.prototype.webaudio = function () {
  // TODO: refactor (t, hap, ct, cps) to (hap, deadline, duration) ?
  return this.onTrigger(webaudioOutputTrigger);
};