midimaps

packages/core/controls.mjs

@@ -1514,6 +1514,8 @@ export const { binshift } = registerControl('binshift');
 export const { hbrick } = registerControl('hbrick');
 export const { lbrick } = registerControl('lbrick');
 export const { midichan } = registerControl('midichan');
+export const { midimap } = registerControl('midimap');
+export const { midiport } = registerControl('midiport');
 export const { control } = registerControl('control');
 export const { ccn } = registerControl('ccn');
 export const { ccv } = registerControl('ccv');

packages/midi/midi.mjs

@@ -6,7 +6,7 @@ This program is free software: you can redistribute it and/or modify it under th
 
 import * as _WebMidi from 'webmidi';
 import { Pattern, getEventOffsetMs, isPattern, logger, ref } from '@strudel/core';
-import { noteToMidi } from '@strudel/core';
+import { noteToMidi, getControlName } from '@strudel/core';
 import { Note } from 'webmidi';
 // if you use WebMidi from outside of this package, make sure to import that instance:
 export const { WebMidi } = _WebMidi;
@@ -89,6 +89,113 @@ if (typeof window !== 'undefined') {
   });
 }
 
+// registry for midi mappings, converting control names to cc messages
+export const midicontrolMap = new Map();
+
+// takes midimap and converts each control key to the main control name
+function unifyMapping(mapping) {
+  return Object.fromEntries(
+    Object.entries(mapping).map(([key, mapping]) => {
+      if (typeof mapping === 'number') {
+        mapping = { ccn: mapping };
+      }
+      return [getControlName(key), mapping];
+    }),
+  );
+}
+
+function githubPath(base, subpath = '') {
+  if (!base.startsWith('github:')) {
+    throw new Error('expected "github:" at the start of pseudoUrl');
+  }
+  let [_, path] = base.split('github:');
+  path = path.endsWith('/') ? path.slice(0, -1) : path;
+  if (path.split('/').length === 2) {
+    // assume main as default branch if none set
+    path += '/main';
+  }
+  return `https://raw.githubusercontent.com/${path}/${subpath}`;
+}
+
+/**
+ * configures the default midimap, which is used when no "midimap" port is set
+ * @example
+ * defaultmidimap({ lpf: 74 })
+ * $: note("c a f e").midi();
+ * $: lpf(sine.slow(4).segment(16)).midi();
+ */
+export function defaultmidimap(mapping) {
+  midicontrolMap.set('default', unifyMapping(mapping));
+}
+
+let loadCache = {};
+
+/**
+ * Adds midimaps to the registry. Inside each midimap, control names (e.g. lpf) are mapped to cc numbers.
+ * @example
+ * midimaps({ mymap: { lpf: 74 } })
+ * $: note("c a f e")
+ * .lpf(sine.slow(4))
+ * .midimap('mymap')
+ * .midi()
+ * @example
+ * midimaps({ mymap: {
+ *   lpf: { ccn: 74, min: 0, max: 20000, exp: 0.5 }
+ * }})
+ * $: note("c a f e")
+ * .lpf(sine.slow(2).range(400,2000))
+ * .midimap('mymap')
+ * .midi()
+ */
+export async function midimaps(map) {
+  if (typeof map === 'string') {
+    if (map.startsWith('github:')) {
+      map = githubPath(map, 'midimap.json');
+    }
+    if (!loadCache[map]) {
+      loadCache[map] = fetch(map).then((res) => res.json());
+    }
+    map = await loadCache[map];
+  }
+  if (typeof map === 'object') {
+    Object.entries(map).forEach(([name, mapping]) => midicontrolMap.set(name, unifyMapping(mapping)));
+  }
+}
+
+// registry for midi sounds, converting sound names to controls
+export const midisoundMap = new Map();
+
+// normalizes the given value from the given range and exponent
+function normalize(value = 0, min = 0, max = 1, exp = 1) {
+  if (min === max) {
+    throw new Error('min and max cannot be the same value');
+  }
+  let normalized = (value - min) / (max - min);
+  normalized = Math.min(1, Math.max(0, normalized));
+  return Math.pow(normalized, exp);
+}
+function mapCC(mapping, value) {
+  return Object.keys(value)
+    .filter((key) => !!mapping[getControlName(key)])
+    .map((key) => {
+      const { ccn, min = 0, max = 1, exp = 1 } = mapping[key];
+      const ccv = normalize(value[key], min, max, exp);
+      return { ccn, ccv };
+    });
+}
+
+// sends a cc message to the given device on the given channel
+function sendCC(ccn, ccv, device, midichan, timeOffsetString) {
+  if (typeof ccv !== 'number' || ccv < 0 || ccv > 1) {
+    throw new Error('expected ccv to be a number between 0 and 1');
+  }
+  if (!['string', 'number'].includes(typeof ccn)) {
+    throw new Error('expected ccn to be a number or a string');
+  }
+  const scaled = Math.round(ccv * 127);
+  device.sendControlChange(ccn, scaled, midichan, { time: timeOffsetString });
+}
+
 Pattern.prototype.midi = function (output) {
   if (isPattern(output)) {
     throw new Error(
@@ -117,16 +224,39 @@ Pattern.prototype.midi = function (output) {
       console.log('not enabled');
       return;
     }
-    const device = getDevice(output, WebMidi.outputs);
     hap.ensureObjectValue();
     //magic number to get audio engine to line up, can probably be calculated somehow
     const latencyMs = 34;
     // passing a string with a +num into the webmidi api adds an offset to the current time https://webmidijs.org/api/classes/Output
     const timeOffsetString = `+${getEventOffsetMs(targetTime, currentTime) + latencyMs}`;
+
     // destructure value
-    let { note, nrpnn, nrpv, ccn, ccv, midichan = 1, midicmd, gain = 1, velocity = 0.9 } = hap.value;
+    let {
+      note,
+      ccn,
+      ccv,
+      midichan = 1,
+      midicmd,
+      gain = 1,
+      velocity = 0.9,
+      midimap = 'default',
+      midiport = output,
+    } = hap.value;
+
+    const device = getDevice(midiport, WebMidi.outputs);
+    if (!device) {
+      logger(
+        `[midi] midiport "${midiport}" not found! available: ${WebMidi.outputs.map((output) => `'${output.name}'`).join(', ')}`,
+      );
+      return;
+    }
 
     velocity = gain * velocity;
+    // if midimap is set, send a cc messages from defined controls
+    if (midicontrolMap.has(midimap)) {
+      const ccs = mapCC(midicontrolMap.get(midimap), hap.value);
+      ccs.forEach(({ ccn, ccv }) => sendCC(ccn, ccv, device, midichan, timeOffsetString));
+    }
 
     // note off messages will often a few ms arrive late, try to prevent glitching by subtracting from the duration length
     const duration = (hap.duration.valueOf() / cps) * 1000 - 10;
@@ -138,14 +268,7 @@ Pattern.prototype.midi = function (output) {
       });
     }
     if (ccv !== undefined && ccn !== undefined) {
-      if (typeof ccv !== 'number' || ccv < 0 || ccv > 1) {
-        throw new Error('expected ccv to be a number between 0 and 1');
-      }
-      if (!['string', 'number'].includes(typeof ccn)) {
-        throw new Error('expected ccn to be a number or a string');
-      }
-      const scaled = Math.round(ccv * 127);
-      device.sendControlChange(ccn, scaled, midichan, { time: timeOffsetString });
+      sendCC(ccn, ccv, device, midichan, timeOffsetString);
     }
     if (hap.whole.begin + 0 === 0) {
       // we need to start here because we have the timing info

test/examples.test.mjs

@@ -18,6 +18,8 @@ const skippedExamples = [
   'accelerationZ',
   'accelerationY',
   'accelerationX',
+  'defaultmidimap',
+  'midimaps',
 ];
 
 describe('runs examples', () => {

website/src/pages/learn/input-output.mdx

@@ -46,6 +46,16 @@ But you can also control cc messages separately like this:
 $: ccv(sine.segment(16).slow(4)).ccn(74).midi()`}
 />
 
+Instead of setting `ccn` and `ccv` directly, you can also create mappings with `midimaps`:
+
+## midimaps
+
+<JsDoc client:idle name="midimaps" h={0} />
+
+## defaultmidimap
+
+<JsDoc client:idle name="defaultmidimap" h={0} />
+
 # OSC/SuperDirt/StrudelDirt
 
 In TidalCycles, sound is usually generated using [SuperDirt](https://github.com/musikinformatik/SuperDirt/), which runs inside SuperCollider. Strudel also supports using SuperDirt, although it requires installing some additional software.