2022-06-18 00:56:58 +02:00

108 lines
3.9 KiB
JavaScript

/*
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 { Pattern, getFrequency, patternify2 } from '@strudel.cycles/core';
import * as strudel from '@strudel.cycles/core';
import { fromMidi } from '@strudel.cycles/core';
const { Pattern } = strudel;
// export const getAudioContext = () => Tone.getContext().rawContext;
let audioContext;
export const getAudioContext = () => {
if (!audioContext) {
audioContext = new AudioContext();
}
return audioContext;
};
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
return gainNode;
};
Pattern.prototype.out = function () {
return this.onTrigger((t, hap, ct) => {
const ac = getAudioContext();
// calculate correct time (tone.js workaround)
t = ac.currentTime + t - ct;
// destructure value
let {
freq,
s,
n,
gain = 1,
cutoff,
resonance = 1,
hcutoff,
hresonance = 1,
bandf,
bandq = 1,
pan,
attack = 0.001,
decay = 0,
sustain = 1,
release = 0.001,
} = hap.value;
if (!n && !freq) {
console.warn('unplayable value:', hap.value);
return;
}
// get frequency
if (!freq && typeof n === 'number') {
freq = fromMidi(n); // + 48);
}
if (!freq && typeof n === 'string') {
freq = fromMidi(toMidi(n));
}
// the chain will hold all audio nodes that connect to each other
const chain = [];
// make oscillator
const o = ac.createOscillator();
o.type = s || 'triangle';
o.frequency.value = Number(freq);
o.start(t);
o.stop(t + hap.duration + release);
chain.push(o);
// envelope
const adsr = getADSR(attack, decay, sustain, release, 1, t, t + hap.duration);
chain.push(adsr);
// 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));
// TODO vowel
// TODO delay / delaytime / delayfeedback
// panning
if (pan !== undefined) {
const panner = ac.createStereoPanner();
panner.pan.value = 2 * pan - 1;
chain.push(panner);
}
// master out
const master = ac.createGain();
master.gain.value = 0.1 * gain;
chain.push(master);
chain.push(ac.destination);
// connect chain elements together
chain.slice(1).reduce((last, current) => last.connect(current), chain[0]);
});
};