2022-05-17 21:38:47 +02:00

93 lines
3.8 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 { Tone } from '@strudel.cycles/tone';
const { Pattern, getFrequency, patternify2 } = strudel;
// let audioContext;
/* if (!audioContext) {
audioContext = new AudioContext();
}
return audioContext; */
const lookahead = 0.2;
const adsr = (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.withAudioNode = function (createAudioNode) {
return this._withHap((hap) => {
return hap.setContext({
...hap.context,
createAudioNode: (t, e) => createAudioNode(t, e, hap.context.createAudioNode?.(t, hap)),
});
});
};
Pattern.prototype._wave = function (type) {
return this.withAudioNode((t, e) => {
const osc = getAudioContext().createOscillator();
osc.type = type;
const f = getFrequency(e);
osc.frequency.value = f; // expects frequency..
const begin = t ?? e.whole.begin.valueOf() + lookahead;
const end = begin + e.duration.valueOf();
osc.start(begin);
osc.stop(end); // release?
return osc;
});
};
Pattern.prototype.adsr = function (a = 0.01, d = 0.05, s = 1, r = 0.01) {
return this.withAudioNode((t, e, node) => {
const velocity = e.context?.velocity || 1;
const begin = t ?? e.whole.begin.valueOf() + lookahead;
const end = begin + e.duration.valueOf() + lookahead;
const envelope = adsr(a, d, s, r, velocity, begin, end);
node?.connect(envelope);
return envelope;
});
};
Pattern.prototype._filter = function (type = 'lowpass', frequency = 1000) {
return this.withAudioNode((t, e, node) => {
const filter = getAudioContext().createBiquadFilter();
filter.type = type;
filter.frequency.value = frequency;
node?.connect(filter);
return filter;
});
};
Pattern.prototype.filter = function (type, frequency) {
return patternify2(Pattern.prototype._filter)(reify(type), reify(frequency), this);
};
Pattern.prototype.out = function () {
const master = getAudioContext().createGain();
master.gain.value = 0.1;
master.connect(getAudioContext().destination);
return this.withAudioNode((t, e, node) => {
if (!node) {
console.warn('out: no source! call .osc() first');
}
node?.connect(master);
})._withHap((hap) => {
const onTrigger = (time, e) => e.context?.createAudioNode?.(time, e);
return hap.setContext({ ...hap.context, onTrigger });
});
};
Pattern.prototype.define('wave', (type, pat) => pat.wave(type), { patternified: true });