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xen fixes

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This commit is contained in:
Felix Roos 2022-03-04 00:09:53 +01:00
parent 29802b0f4d
commit 43f861e219
1 changed files with 22 additions and 11 deletions
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33
repl/src/xen.mjs
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@ -2,10 +2,10 @@ import { Pattern } from '../../strudel.mjs';
import { mod } from '../../util.mjs'; import { mod } from '../../util.mjs';
function edo(name) { function edo(name) {
if (!/^[1-9]+edo$/.test(name)) { if (!/^[1-9]+[0-9]*edo$/.test(name)) {
throw new Error('not an edo scale: "' + name + '"'); throw new Error('not an edo scale: "' + name + '"');
} }
const [_, divisions] = name.match(/^([1-9]+)edo$/); const [_, divisions] = name.match(/^([1-9]+[0-9]*)edo$/);
return Array.from({ length: divisions }, (_, i) => Math.pow(2, i / divisions)); return Array.from({ length: divisions }, (_, i) => Math.pow(2, i / divisions));
} }
@ -13,16 +13,23 @@ const presets = {
'12ji': [1 / 1, 16 / 15, 9 / 8, 6 / 5, 5 / 4, 4 / 3, 45 / 32, 3 / 2, 8 / 5, 5 / 3, 16 / 9, 15 / 8], '12ji': [1 / 1, 16 / 15, 9 / 8, 6 / 5, 5 / 4, 4 / 3, 45 / 32, 3 / 2, 8 / 5, 5 / 3, 16 / 9, 15 / 8],
}; };
function withBase(freq, scale) {
return scale.map((r) => r * freq);
}
const defaultBase = 220;
function getXenScale(scale, indices) { function getXenScale(scale, indices) {
if (typeof scale === 'string') { if (typeof scale === 'string') {
if (/^[1-9]+edo$/.test(scale)) { if (/^[1-9]+[0-9]*edo$/.test(scale)) {
return edo(scale); scale = edo(scale);
} else if (presets[scale]) {
scale = presets[scale];
} else {
throw new Error('unknown scale name: "' + scale + '"');
} }
if (presets[scale]) {
return presets[scale];
}
throw new Error('unknown scale name: "' + scale + '"');
} }
scale = withBase(defaultBase, scale);
if (!indices) { if (!indices) {
return scale; return scale;
} }
@ -32,15 +39,19 @@ function getXenScale(scale, indices) {
function xenOffset(xenScale, offset, index = 0) { function xenOffset(xenScale, offset, index = 0) {
const i = mod(index + offset, xenScale.length); const i = mod(index + offset, xenScale.length);
const oct = Math.floor(offset / xenScale.length); const oct = Math.floor(offset / xenScale.length);
return xenScale[i] * 440 * Math.pow(2, oct); return xenScale[i] * Math.pow(2, oct);
} }
Pattern.prototype._xen = function (scaleNameOrRatios) { // scaleNameOrRatios: string || number[], steps?: number
Pattern.prototype._xen = function (scaleNameOrRatios, steps) {
return this._asNumber()._withEvent((event) => { return this._asNumber()._withEvent((event) => {
const frequency = xenOffset(getXenScale(scaleNameOrRatios), event.value); const scale = getXenScale(scaleNameOrRatios);
steps = steps || scale.length;
const frequency = xenOffset(scale, event.value);
return event.withValue(() => frequency).setContext({ ...event.context, type: 'frequency' }); return event.withValue(() => frequency).setContext({ ...event.context, type: 'frequency' });
}); });
}; };
Pattern.prototype.tuning = function (steps) { Pattern.prototype.tuning = function (steps) {
return this._asNumber()._withEvent((event) => { return this._asNumber()._withEvent((event) => {
const frequency = xenOffset(steps, event.value); const frequency = xenOffset(steps, event.value);