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94 lines
3.3 KiB
JavaScript
94 lines
3.3 KiB
JavaScript
import { getAudioContext } from './superdough.mjs';
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import * as zzfx from 'zzfx';
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export function gainNode(value) {
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const node = getAudioContext().createGain();
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node.gain.value = value;
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return node;
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}
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export const getZZFX = ({ wave, freq, t, params}) => {
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params.frequency = freq;
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params.shape = {
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'zsine': 0,
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'ztri': 1,
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'zsaw': 2,
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'ztan': 3,
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'znoise': 4,
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}[wave];
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const samples = zzfx.buildSamples(...params);
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const context = getAudioContext();
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const buffer = context.createBuffer(
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samples.length,
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samples[0].length,
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context.sampleRate
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);
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const source = context.createBufferSource();
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return {
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node: source,
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stop: (time) => source.stop(time), buffer}
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}
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export const getOscillator = ({ s, freq, t }) => {
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// make oscillator
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const o = getAudioContext().createOscillator();
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o.type = s || 'triangle';
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o.frequency.value = Number(freq);
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o.start(t);
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//o.stop(t + duration + release);
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const stop = (time) => o.stop(time);
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return { node: o, stop };
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};
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// alternative to getADSR returning the gain node and a stop handle to trigger the release anytime in the future
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export const getEnvelope = (attack, decay, sustain, release, velocity, begin) => {
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const gainNode = getAudioContext().createGain();
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gainNode.gain.setValueAtTime(0, begin);
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gainNode.gain.linearRampToValueAtTime(velocity, begin + attack); // attack
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gainNode.gain.linearRampToValueAtTime(sustain * velocity, begin + attack + decay); // sustain start
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// sustain end
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return {
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node: gainNode,
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stop: (t) => {
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//if (typeof gainNode.gain.cancelAndHoldAtTime === 'function') {
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// gainNode.gain.cancelAndHoldAtTime(t); // this seems to release instantly....
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// see https://discord.com/channels/779427371270275082/937365093082079272/1086053607360712735
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//} else {
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// firefox: this will glitch when the sustain has not been reached yet at the time of release
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gainNode.gain.setValueAtTime(sustain * velocity, t);
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//}
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gainNode.gain.linearRampToValueAtTime(0, t + release);
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},
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};
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};
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export const getADSR = (attack, decay, sustain, release, velocity, begin, end) => {
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const gainNode = getAudioContext().createGain();
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gainNode.gain.setValueAtTime(0, begin);
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gainNode.gain.linearRampToValueAtTime(velocity, begin + attack); // attack
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gainNode.gain.linearRampToValueAtTime(sustain * velocity, begin + attack + decay); // sustain start
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gainNode.gain.setValueAtTime(sustain * velocity, end); // sustain end
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gainNode.gain.linearRampToValueAtTime(0, end + release); // release
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// for some reason, using exponential ramping creates little cracklings
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/* let t = begin;
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gainNode.gain.setValueAtTime(0, t);
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gainNode.gain.exponentialRampToValueAtTime(velocity, (t += attack));
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const sustainGain = Math.max(sustain * velocity, 0.001);
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gainNode.gain.exponentialRampToValueAtTime(sustainGain, (t += decay));
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if (end - begin < attack + decay) {
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gainNode.gain.cancelAndHoldAtTime(end);
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} else {
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gainNode.gain.setValueAtTime(sustainGain, end);
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}
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gainNode.gain.exponentialRampToValueAtTime(0.001, end + release); // release */
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return gainNode;
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};
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export const getFilter = (type, frequency, Q) => {
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const filter = getAudioContext().createBiquadFilter();
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filter.type = type;
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filter.frequency.value = frequency;
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filter.Q.value = Q;
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return filter;
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};
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