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basic samples tab

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This commit is contained in:
Felix Roos 2022-11-12 20:17:01 +01:00
parent a27f399a9e
commit 5fc8f10602
4 changed files with 107 additions and 79 deletions
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53
packages/webaudio/sampler.mjs
View file

@ -19,6 +19,57 @@ function humanFileSize(bytes, si) {
return bytes.toFixed(1) + ' ' + units[u];
}
export const getSampleBufferSource = async (s, n, note, speed) => {
let transpose = 0;
let midi = typeof note === 'string' ? toMidi(note) : note || 36;
transpose = midi - 36; // C3 is middle C
const ac = getAudioContext();
// is sample from loaded samples(..)
const samples = getLoadedSamples();
if (!samples) {
throw new Error('no samples loaded');
}
const bank = samples?.[s];
if (!bank) {
throw new Error(
`sample not found: "${s}"`,
// , try one of ${Object.keys(samples)
// .map((s) => `"${s}"`)
// .join(', ')}.
);
}
if (typeof bank !== 'object') {
throw new Error('wrong format for sample bank:', s);
}
let sampleUrl;
if (Array.isArray(bank)) {
sampleUrl = bank[n % bank.length];
} else {
const midiDiff = (noteA) => toMidi(noteA) - midi;
// object format will expect keys as notes
const closest = Object.keys(bank)
.filter((k) => !k.startsWith('_'))
.reduce(
(closest, key, j) => (!closest || Math.abs(midiDiff(key)) < Math.abs(midiDiff(closest)) ? key : closest),
null,
);
transpose = -midiDiff(closest); // semitones to repitch
sampleUrl = bank[closest][n % bank[closest].length];
}
let buffer = await loadBuffer(sampleUrl, ac, s, n);
if (speed < 0) {
// should this be cached?
buffer = reverseBuffer(buffer);
}
const bufferSource = ac.createBufferSource();
bufferSource.buffer = buffer;
const playbackRate = 1.0 * Math.pow(2, transpose / 12);
// bufferSource.playbackRate.value = Math.pow(2, transpose / 12);
bufferSource.playbackRate.value = playbackRate;
return bufferSource;
};
export const loadBuffer = (url, ac, s, n = 0) => {
const label = s ? `sound "${s}:${n}"` : 'sample';
if (!loadCache[url]) {
@ -27,7 +78,7 @@ export const loadBuffer = (url, ac, s, n = 0) => {
loadCache[url] = fetch(url)
.then((res) => res.arrayBuffer())
.then(async (res) => {
const took = (Date.now() - timestamp);
const took = Date.now() - timestamp;
const size = humanFileSize(res.byteLength);
// const downSpeed = humanFileSize(res.byteLength / took);
logger(`[sampler] load ${label}... done! loaded ${size} in ${took}ms`, 'loaded-sample', { url });

53
packages/webaudio/webaudio.mjs
View file

@ -9,7 +9,7 @@ import * as strudel from '@strudel.cycles/core';
import { fromMidi, logger, toMidi } from '@strudel.cycles/core';
import './feedbackdelay.mjs';
import './reverb.mjs';
import { loadBuffer, reverseBuffer } from './sampler.mjs';
import { getSampleBufferSource } from './sampler.mjs';
const { Pattern } = strudel;
import './vowel.mjs';
import workletsUrl from './worklets.mjs?url';
@ -98,57 +98,6 @@ const getSoundfontKey = (s) => {
return;
};
const getSampleBufferSource = async (s, n, note, speed) => {
let transpose = 0;
let midi = typeof note === 'string' ? toMidi(note) : note || 36;
transpose = midi - 36; // C3 is middle C
const ac = getAudioContext();
// is sample from loaded samples(..)
const samples = getLoadedSamples();
if (!samples) {
throw new Error('no samples loaded');
}
const bank = samples?.[s];
if (!bank) {
throw new Error(
`sample not found: "${s}"`,
// , try one of ${Object.keys(samples)
// .map((s) => `"${s}"`)
// .join(', ')}.
);
}
if (typeof bank !== 'object') {
throw new Error('wrong format for sample bank:', s);
}
let sampleUrl;
if (Array.isArray(bank)) {
sampleUrl = bank[n % bank.length];
} else {
const midiDiff = (noteA) => toMidi(noteA) - midi;
// object format will expect keys as notes
const closest = Object.keys(bank)
.filter((k) => !k.startsWith('_'))
.reduce(
(closest, key, j) => (!closest || Math.abs(midiDiff(key)) < Math.abs(midiDiff(closest)) ? key : closest),
null,
);
transpose = -midiDiff(closest); // semitones to repitch
sampleUrl = bank[closest][n % bank[closest].length];
}
let buffer = await loadBuffer(sampleUrl, ac, s, n);
if (speed < 0) {
// should this be cached?
buffer = reverseBuffer(buffer);
}
const bufferSource = ac.createBufferSource();
bufferSource.buffer = buffer;
const playbackRate = 1.0 * Math.pow(2, transpose / 12);
// bufferSource.playbackRate.value = Math.pow(2, transpose / 12);
bufferSource.playbackRate.value = playbackRate;
return bufferSource;
};
const splitSN = (s, n) => {
if (!s.includes(':')) {
return [s, n];