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Add MIDI output support (with some limitations) #7

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Add MIDI output support (with some limitations) #7

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178 changes: 178 additions & 0 deletions autokalimba.js
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Original file line number Diff line number Diff line change
Expand Up @@ -18,7 +18,9 @@ cps.connect(mix);
mix.connect(ctx.destination);
mix.gain.value = 1.0;
const pointers = new Map();
const A440MIDINote = 69;
let currentBass = 220.0;
let currentBassMIDINote = A440MIDINote - 12;
// let frozenBass = 220.0;
let sampleBuffers = [];
let strumSetting = 0.04;
Expand All @@ -32,6 +34,8 @@ let lastVoicing = undefined;
let lastBassTime = Date.now();
let forceFifthInBass = false;

let midiOpenDevice = null;

function subSemitones() {
// If the last voicing contains b5 or #5, drop a tritone; otherwise, drop a fourth.
return lastVoicing && lastVoicing.some((v) => v % 12 === 6 || v % 12 === 8)
Expand Down Expand Up @@ -150,13 +154,39 @@ function chordFreq(semitones) {
return k;
}

function chordMIDINote(semitones) {
if (bend) {
if (semitones === 3 || semitones === 4) semitones = 2;
if (semitones === 15 || semitones === 16) semitones = 14;
}

const chordOctave = +$("#midi-chord-octave").value;
const bassOctave = +$("#midi-bass-octave").value;

let k = currentBassMIDINote + (chordOctave - bassOctave) * 12 + semitones;

const chordRangeStart = +$("#midi-chord-range-start").value;
const chordRangeSize = +$("#midi-chord-range-size").value;

if (k < A440MIDINote + (chordOctave - 4) * 12 + chordRangeStart) k += 12;
if (k > A440MIDINote + (chordOctave - 4) * 12 + chordRangeStart + chordRangeSize) k -= 12;
return k;
}

function bassFreq(semitones) {
const st = semitones + getTuningSemitones();
const base = Number($("#base").value);
const wrapped = ((st + 1200 - base) % 12) + base;
return 110 * 2 ** (wrapped / 12);
}

function bassMIDINote(semitones) {
const st = semitones;
const base = Number($("#base").value);
const wrapped = ((st + 1200 - base) % 12) + base;
return A440MIDINote + ($("#midi-bass-octave").value - 4) * 12 + wrapped;
}

function noteNameToSemitone(note) {
return (
"A BC D EF G ".indexOf(note.charAt(0)) + /♯|#/.test(note) - /♭|b/.test(note)
Expand Down Expand Up @@ -230,6 +260,11 @@ function recomputeKeyLabels() {
});
}

function midiPlayNote(channel, note, velocity) {
// Mask potentially out-of-range values just in case.
midiOpenDevice.send([0x90 | (channel & 0xF), note & 0x7F, velocity & 0x7F]);
}

window.addEventListener("DOMContentLoaded", (event) => {
if (/harp/.test(window.location.href)) $(".refresh-link").remove();
recomputeKeyLabels();
Expand Down Expand Up @@ -323,6 +358,15 @@ window.addEventListener("DOMContentLoaded", (event) => {
e.target.style.background = "#f80";
}

const midiNotes = [];
if (midiOpenDevice !== null) {
currentBassMIDINote = bassMIDINote(semitones);
const channel = +$("#midi-bass-channel").value;
const time = performance.now();
midiPlayNote(channel, currentBassMIDINote, 100);
midiNotes.push([channel, currentBassMIDINote]);
}

pointers.set(e.pointerId, {
centerX: centerX,
centerY: centerY,
Expand All @@ -332,6 +376,7 @@ window.addEventListener("DOMContentLoaded", (event) => {
rootSemitone: noteNameToSemitone(note),
isSub,
oscs: [makeOsc(freq, 0.5 * bassGain, 0, true)],
midiNotes,
});

// Correct chord voicing to this new bass note
Expand All @@ -357,6 +402,15 @@ window.addEventListener("DOMContentLoaded", (event) => {
osc.gainNode.gain.setTargetAtTime(0, ctx.currentTime + 0.05, 0.01);
osc.stop(ctx.currentTime + 0.2);
}

const midiNotes = [];
if (midiOpenDevice !== null) {
const time = performance.now();
for (let [channel, note] of p.midiNotes) {
midiPlayNote(channel, note, 0 /* Note Off */);
}
}

p.target.style.background = "";
pointers.delete(pointerId);
}
Expand Down Expand Up @@ -385,6 +439,16 @@ window.addEventListener("DOMContentLoaded", (event) => {
lastFreqs = freqs;
}

const midiNotes = [];
if (midiOpenDevice !== null) {
const channel = +$("#midi-chord-channel").value;
for (let voice of voicing) {
const midiNote = chordMIDINote(voice);
midiPlayNote(channel, midiNote, 100);
midiNotes.push([channel, midiNote]);
}
}

pointers.set(e.pointerId, {
centerX: rect.left + rect.width / 2,
centerY: rect.top + rect.height / 2,
Expand All @@ -408,6 +472,7 @@ window.addEventListener("DOMContentLoaded", (event) => {
: 0;
return makeOsc(freq, 0.2 * chordGain, delay, false);
}),
midiNotes,
});

// Correct bass sub to this new chord voicing
Expand Down Expand Up @@ -597,4 +662,117 @@ window.addEventListener("DOMContentLoaded", (event) => {
window.localStorage.setItem(key, String(e.target.value));
});
});

// Web MIDI setup.
// This part of the MIDI code was originally written for
// https://github.com/hikari-no-yume/SoundPalette, so if there's a problem
// with it, please file a bug there too.
const midiEnableButton = $("#midi-enable");
midiEnableButton.disabled = true;
const midiDevicesDropdown = $("#midi-devices");
midiDevicesDropdown.disabled = true;
const midiDevices = [];
const midiDeviceConnectButton = $("#midi-device-connect");
midiDeviceConnectButton.disabled = true;
const midiOptionsZone = $("#midi-options");
midiOptionsZone.disabled = true;
if (!navigator.requestMIDIAccess) {
$("#midi-setup").innerText = "Your browser does not support Web MIDI.";
} else {
midiEnableButton.disabled = false;
midiEnableButton.addEventListener("click", () => {
midiEnableButton.innerText = "(Requesting permission)";
midiEnableButton.disabled = true;
navigator.requestMIDIAccess({
software: true,
}).then((midiAccess) => {
midiEnableButton.innerText = "(MIDI enabled)";
midiDevicesDropdown.innerHTML = "";
let option = document.createElement("option");
option.value = "";
option.innerText = "(please select a device)";
midiDevicesDropdown.appendChild(option);
midiDevicesDropdown.required = true;
for (let device of midiAccess.outputs.values()) {
option = document.createElement("option");
option.value = midiDevices.length;
option.innerText = device.name + " (output)";
midiDevicesDropdown.appendChild(option);
midiDevices.push(device);
}
midiDevicesDropdown.onchange = () => {
midiDeviceConnectButton.disabled = (midiDevicesDropdown.value === "");
};
midiDevicesDropdown.disabled = false;
midiDevicesDropdown.focus();
}).catch((error) => {
midiEnableButton.innerText = "(Can't enable MIDI)";
console.log(error);
});
});
midiDeviceConnectButton.addEventListener("click", () => {
midiDeviceConnectButton.disabled = true;
midiDevicesDropdown.disabled = true;
midiOptionsZone.disabled = true;
if (midiOpenDevice) {
midiDeviceConnectButton.innerText = "(disconnecting)";
midiOpenDevice.close().then(() => {
midiDeviceConnectButton.disabled = false;
midiDeviceConnectButton.innerText = "Connect";
midiDevicesDropdown.disabled = false;
}).catch((e) => {
alert("Couldn't close MIDI device?! " + e);
});
midiOpenDevice = null;
} else {
midiDeviceConnectButton.innerText = "(connecting)";
let newDevice = midiDevices[midiDevicesDropdown.value];
newDevice.open().then(() => {
midiOpenDevice = newDevice;
midiDeviceConnectButton.disabled = false;
midiDeviceConnectButton.innerText = "Disconnect";
midiOptionsZone.disabled = false;
}).catch((e) => {
alert("Could not connect to MIDI device: " + e);
midiDeviceConnectButton.disabled = false;
midiDeviceConnectButton.innerText = "Connect";
midiDevicesDropdown.disabled = false;
});
}
});
}

// MIDI options
$("#midi-bass-channel").oninput = $("#midi-bass-channel").onchange = (e) => {
$("#midi-bass-channel-value").innerText = (+e.target.value) + 1;
};
$("#midi-chord-channel").oninput = $("#midi-chord-channel").onchange = (e) => {
$("#midi-chord-channel-value").innerText = (+e.target.value) + 1;
};
$("#midi-bass-octave").value = 2; // reset so it matches currentBassMIDINote
$("#midi-bass-octave-value").innerText = 2;
$("#midi-bass-octave").oninput = $("#midi-bass-octave").onchange = (e) => {
$("#midi-bass-octave-value").innerText = +e.target.value;
};
$("#midi-chord-octave").value = 4;
$("#midi-chord-octave-value").innerText = 4;
$("#midi-chord-octave").oninput = $("#midi-chord-octave").onchange = (e) => {
$("#midi-chord-octave-value").innerText = +e.target.value;
};
$("#midi-chord-range-start").oninput = $("#midi-chord-range-start").onchange = (e) => {
$("#midi-chord-range-start-value").innerText = ["C", "C#", "D", "Eb", "E", "F", "F#", "G", "Ab", "A", "Bb", "B"][+e.target.value + 9];
};
$("#midi-chord-range-size").oninput = $("#midi-chord-range-size").onchange = (e) => {
$("#midi-chord-range-size-value").innerText = +e.target.value;
};
$("#midi-pc-send-bass").addEventListener("click", () => {
let channel = $("#midi-bass-channel").value;
let programNumber = $("#midi-pc").value;
midiOpenDevice.send([0xC0 | (channel & 0xF), programNumber & 0x7F]);
});
$("#midi-pc-send-chord").addEventListener("click", () => {
let channel = $("#midi-chord-channel").value;
let programNumber = $("#midi-pc").value;
midiOpenDevice.send([0xC0 | (channel & 0xF), programNumber & 0x7F]);
});
});
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