Merge pull request 'Feature: reconnectable MIDI inputs that keep track of last known CC state' (#1852) from unframework/strudel:nm/midi-input-state into main

Reviewed-on: https://codeberg.org/uzu/strudel/pulls/1852

packages/midi/input.mjs

@@ -0,0 +1,193 @@
+/*
+input.mjs - MIDI input wrapper
+Copyright (C) 2022 Strudel contributors - see <https://codeberg.org/uzu/strudel/src/branch/main/packages/midi/midi.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 { WebMidi } from 'webmidi';
+import { logger, ref } from '@strudel/core';
+import { getDevice } from './util.mjs';
+
+/**
+ * MIDI input device wrapper that manages connection and reconnection, tracks
+ * persisted CC states, etc. These instances are long-lived and are maintained as singletons
+ * (keyed globally by input string/number).
+ */
+export class MidiInput {
+  /**
+   *
+   * @param {string | number} input MIDI device name or index defaulting to 0
+   */
+  constructor(input) {
+    this.input = input;
+    this.stateKey = typeof input === 'string' ? input : undefined; // Saved state is not tracked for numeric index inputs
+
+    this._refs = {};
+    this._refsByChan = {};
+
+    this._loadAllStates();
+
+    this.initialDevice = this._startDeviceListener();
+  }
+
+  /**
+   * Implementation for the cc() factory function tied to this specific input.
+   * @param {number} cc MIDI CC number
+   * @param {number | undefined} chan MIDI channel (1-16) or undefined for all channels
+   */
+  createCC(cc, chan) {
+    const lookupMap = chan === undefined ? this._refs : this._refsByChan[chan];
+    if (!(cc in lookupMap)) {
+      const initialState = this._loadState(chan);
+      lookupMap[cc] = initialState[cc] || 0;
+    }
+
+    return ref(() => lookupMap[cc]);
+  }
+
+  _startDeviceListener() {
+    const initialDevice = getDevice(this.input, WebMidi.inputs);
+
+    // Background connection loop
+    (async () => {
+      const midiListener = this._onMidiMessage.bind(this);
+      let device = initialDevice;
+
+      while (true) {
+        if (!device) {
+          device = await this._waitForDevice();
+        }
+
+        // Wait a bit for device to be ready to receive last state
+        await new Promise((resolve) => setTimeout(resolve, 2000));
+
+        try {
+          // Still continue if sending did not work
+          this._sendAllStates(device);
+        } catch (err) {
+          console.error('midiin: failed to send last state on connect:', device.name, err);
+        }
+
+        // Listen for incoming MIDI messages and for disconnection
+        device.addListener('midimessage', midiListener);
+
+        await this._waitForDeviceDisconnect(device);
+
+        device.removeListener('midimessage', midiListener);
+        device = null; // Clear var to trigger wait for connection
+      }
+    })();
+
+    return initialDevice;
+  }
+
+  // Returns a promise that resolves when the specified device is connected
+  _waitForDevice() {
+    return new Promise((resolve) => {
+      const connListener = () => {
+        const device = getDevice(this.input, WebMidi.inputs);
+        if (device) {
+          logger(`[midi] device reconnected: ${device.name}`);
+
+          WebMidi.removeListener('connected', connListener);
+          resolve(device);
+        }
+      };
+
+      WebMidi.addListener('connected', connListener);
+    });
+  }
+
+  // Returns a promise that resolves when the specified device is disconnected
+  _waitForDeviceDisconnect(device) {
+    return new Promise((resolve) => {
+      const disconnListener = (e) => {
+        if (e.port.name === device.name) {
+          logger(`[midi] device disconnected: ${device.name}`);
+
+          WebMidi.removeListener('disconnected', disconnListener);
+          resolve();
+        }
+      };
+
+      WebMidi.addListener('disconnected', disconnListener);
+    });
+  }
+
+  _onMidiMessage(e) {
+    const ccNum = e.dataBytes[0];
+    const v = e.dataBytes[1];
+    const chan = e.message.channel;
+    const scaled = v / 127;
+
+    this._refs[ccNum] = scaled;
+    this._refsByChan[chan] ??= {};
+    this._refsByChan[chan][ccNum] = scaled;
+
+    this._saveState(undefined, ccNum, scaled);
+    this._saveState(chan, ccNum, scaled);
+  }
+
+  _loadAllStates() {
+    Object.assign(this._refs, this._loadState(undefined));
+
+    for (let chan = 1; chan <= 16; chan++) {
+      this._refsByChan[chan] ??= {};
+      Object.assign(this._refsByChan[chan], this._loadState(chan));
+    }
+  }
+
+  _loadState(chan) {
+    if (!this.stateKey) {
+      return {};
+    }
+
+    const initialDataRaw = localStorage.getItem(
+      `strudel-midin-${this.stateKey}-chan${chan !== undefined ? chan : 'all'}`,
+    );
+    if (!initialDataRaw) {
+      return {};
+    }
+
+    try {
+      return JSON.parse(initialDataRaw);
+    } catch (err) {
+      console.warn(
+        `Failed to parse MIDI state from localStorage for input "${this.stateKey}" and channel "${chan}"`,
+        initialDataRaw,
+        err,
+      );
+      return {};
+    }
+  }
+
+  _saveState(chan, cc, value) {
+    if (!this.stateKey) {
+      return;
+    }
+
+    const state = this._loadState(chan);
+    state[cc] = value;
+    localStorage.setItem(
+      `strudel-midin-${this.stateKey}-chan${chan !== undefined ? chan : 'all'}`,
+      JSON.stringify(state),
+    );
+  }
+
+  // Send CC values back to device to restore encoders and motorized sliders
+  _sendAllStates(device) {
+    const output = WebMidi.outputs.find((o) => o.name === device.name);
+    if (!output) {
+      return;
+    }
+
+    for (const [chan, refs] of Object.entries(this._refsByChan)) {
+      const channel = Number(chan);
+      for (const [cc, value] of Object.entries(refs)) {
+        const ccn = Number(cc);
+        const scaled = Math.round(value * 127);
+        output.sendControlChange(ccn, scaled, channel);
+      }
+    }
+  }
+}

packages/midi/midi.mjs

@@ -23,6 +23,8 @@ import { noteToMidi, getControlName } from '@strudel/core';
 import { Note } from 'webmidi';
 import { getAudioContext } from '@strudel/webaudio';
 import { scheduleAtTime } from '../superdough/helpers.mjs';
+import { getMidiDeviceNamesString, getDevice } from './util.mjs';
+import { MidiInput } from './input.mjs';
 
 // if you use WebMidi from outside of this package, make sure to import that instance:
 export const { WebMidi } = _WebMidi;
@@ -31,10 +33,6 @@ function supportsMidi() {
   return typeof navigator.requestMIDIAccess === 'function';
 }
 
-function getMidiDeviceNamesString(devices) {
-  return devices.map((o) => `'${o.name}'`).join(' | ');
-}
-
 export function enableWebMidi(options = {}) {
   const { onReady, onConnected, onDisconnected, onEnabled } = options;
   if (WebMidi.enabled) {
@@ -72,29 +70,6 @@ export function enableWebMidi(options = {}) {
   });
 }
 
-function getDevice(indexOrName, devices) {
-  if (!devices.length) {
-    throw new Error(`🔌 No MIDI devices found. Connect a device or enable IAC Driver.`);
-  }
-  if (typeof indexOrName === 'number') {
-    return devices[indexOrName];
-  }
-  const byName = (name) => devices.find((output) => output.name.includes(name));
-  if (typeof indexOrName === 'string') {
-    return byName(indexOrName);
-  }
-  // attempt to default to first IAC device if none is specified
-  const IACOutput = byName('IAC');
-  const device = IACOutput ?? devices[0];
-  if (!device) {
-    throw new Error(
-      `🔌 MIDI device '${device ? device : ''}' not found. Use one of ${getMidiDeviceNamesString(devices)}`,
-    );
-  }
-
-  return IACOutput ?? devices[0];
-}
-
 // send start/stop messages to outputs when repl starts/stops
 if (typeof window !== 'undefined') {
   window.addEventListener('message', (e) => {
@@ -495,9 +470,9 @@ Pattern.prototype.midi = function (midiport, options = {}) {
 };
 
 /**
- * Initialize a midi device
+ * Initialize a midi input device
  */
-async function _initialize(input) {
+async function _initializeInput(input) {
   if (isPattern(input)) {
     throw new Error(
       `[midi] Midi input cannot be a pattern. Make sure to pass device name with single quotes. Example: midin('${
@@ -505,24 +480,31 @@ async function _initialize(input) {
       }')`,
     );
   }
+
   const initial = await enableWebMidi(); // only returns on first init
-  const device = getDevice(input, WebMidi.inputs);
+
-  if (!device) {
+  const instance = midiInputs[input] || new MidiInput(input);
-    throw new Error(
+  midiInputs[input] = instance;
-      `[midi] Midi device "${input}" not found.. connected devices: ${getMidiDeviceNamesString(WebMidi.inputs)}`,
+
-    );
-  }
   if (initial) {
+    const device = instance.initialDevice;
+
     const otherInputs = WebMidi.inputs.filter((o) => o.name !== device.name);
     logger(
-      `[midi] Midi enabled! Using "${device.name}". ${
+      device
-        otherInputs?.length ? `Also available: ${getMidiDeviceNamesString(otherInputs)}` : ''
+        ? `[midi] Midi enabled! Using "${device.name}". ${
-      }`,
+            otherInputs?.length ? `Also available: ${getMidiDeviceNamesString(otherInputs)}` : ''
+          }`
+        : `[midi] Midi enabled! Waiting for device "${input}"... Currently connected devices: ${getMidiDeviceNamesString(WebMidi.inputs)}`,
     );
   }
-  return device;
+
+  return instance;
 }
 
+// MIDI input wrappers, by specified input string/index
+const midiInputs = {};
+
 /**
  * MIDI input: Opens a MIDI input port to receive MIDI control change messages.
  *
@@ -543,31 +525,10 @@ async function _initialize(input) {
  * note("c a f e").s("saw")
  *   .when(cc(0).gt(0), x => x.postgain(0))
  */
-let listeners = {};
-const refs = {};
-const refsByChan = {};
 export async function midin(input) {
-  const device = await _initialize(input);
+  const instance = await _initializeInput(input);
-  refs[input] ??= {};
-  refsByChan[input] ??= {};
-  const cc = (cc, chan) => {
-    if (chan !== undefined) {
-      return ref(() => refsByChan[input][cc]?.[chan] || 0);
-    }
-    return ref(() => refs[input][cc] || 0);
-  };
 
-  listeners[input] && device.removeListener('midimessage', listeners[input]);
+  return instance.createCC.bind(instance);
-  listeners[input] = (e) => {
-    const [ccNum, v] = e.dataBytes;
-    const chan = e.message.channel;
-    const scaled = v / 127;
-    refsByChan[input][ccNum] ??= {};
-    refsByChan[input][ccNum][chan] = scaled;
-    refs[input][ccNum] = scaled;
-  };
-  device.addListener('midimessage', listeners[input]);
-  return cc;
 }
 
 /**
@@ -622,7 +583,16 @@ function _triggerKeyboard(input, cps, now, latencyCycles) {
   return true;
 }
 export async function midikeys(input) {
-  const device = await _initialize(input);
+  const instance = await _initializeInput(input);
+
+  // TODO: support unpluggable device usage
+  const device = instance.initialDevice;
+  if (!device) {
+    throw new Error(
+      `[midi] Midi device "${input}" not found.. connected devices: ${getMidiDeviceNamesString(WebMidi.inputs)}`,
+    );
+  }
+
   if (!kHaps[input]) {
     kHaps[input] = [];
   }

packages/midi/util.mjs

@@ -0,0 +1,44 @@
+/*
+util.mjs - MIDI utility functions
+Copyright (C) 2022 Strudel contributors - see <https://codeberg.org/uzu/strudel/src/branch/main/packages/midi/midi.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 { Input, Output } from 'webmidi';
+
+/**
+ * Get a string listing device names for error messages.
+ * @param {Input[] | Output[]} devices
+ * @returns {string}
+ */
+export function getMidiDeviceNamesString(devices) {
+  return devices.map((o) => `'${o.name}'`).join(' | ');
+}
+
+/**
+ * Look up a device by index or name. Otherwise return a default device, or fail if none are connected.
+ *
+ * @param {string | number} indexOrName
+ * @param {Input[] | Output[]} devices
+ * @returns {Input | Output | undefined}
+ */
+export function getDevice(indexOrName, devices) {
+  if (typeof indexOrName === 'number') {
+    return devices[indexOrName];
+  }
+  const byName = (name) => devices.find((output) => output.name.includes(name));
+  if (typeof indexOrName === 'string') {
+    return byName(indexOrName);
+  }
+  // attempt to default to first IAC device if none is specified
+  const IACOutput = byName('IAC');
+  const device = IACOutput ?? devices[0];
+  if (!device) {
+    if (!devices.length) {
+      throw new Error(`🔌 No MIDI devices found. Connect a device or enable IAC Driver.`);
+    }
+    throw new Error(`🔌 Default MIDI device not found. Use one of ${getMidiDeviceNamesString(devices)}`);
+  }
+
+  return device;
+}