Adjust frequency, hold note, better synth
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parent
8fde361246
commit
eea0e3f879
35
index.css
35
index.css
@ -1,17 +1,19 @@
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.whiteKey {
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color: white;
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background-color: white;
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border: solid 1px;
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border-color: grey;
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height: 67pt;
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/*
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max-height: 60pt;
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max-width: 20pt;
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*/
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position: relative;
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left: 7.5pt;
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width: 20pt;
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display: inline-block;
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height: 67pt;
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width: 20pt;
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}
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.blackKeyOuter {
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position: relative;
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left: -7.5pt;
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z-index: 1;
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}
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.blackKey {
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@ -19,12 +21,19 @@
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background-color: black;
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position: absolute;
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z-index: 1;
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display: inline-block;
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height: 40pt;
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width: 15pt;
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/*
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max-height: 40pt;
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max-width: 15pt;
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*/
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display: inline-block;
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}
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.playing {
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background-color: lime;
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}
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.held {
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background-color: gold;
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}
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#keyboard {
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white-space: nowrap;
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}
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61
index.html
61
index.html
@ -11,8 +11,65 @@
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</head>
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<body>
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<main class="container">
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<div id="keyboard">
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</div>
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<article>
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<div id="keyboard" class="overflow-auto"></div>
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<label>
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Volume
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<input type="range" min="0.0" max="2.0" value="1.0" step="0.01" id="range">
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</label>
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</article>
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<section id="options">
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<form>
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<article>
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<h3 id="current-note">-</h3>
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<label>
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<input type="checkbox" role="switch" id="hold">
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Hold
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</label>
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</article>
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<article>
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<label>
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<small>Frequency</small>
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<input type="number" id="current-frequency" step="0.01">
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</label>
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</article>
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<article>
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<fieldset>
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<legend><small>Tuning</small></legend>
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<label>
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<input type="radio" name="tuning">
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Equal temperament
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</label>
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<label>
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<input type="radio" name="tuning">
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Perfect 5th
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</label>
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<label>
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<input type="radio" name="tuning">
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Perfect 4th
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</label>
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<label>
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<input type="radio" name="tuning">
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Perfect major 3rd
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</label>
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<label>
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<input type="radio" name="tuning">
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Perfect minor 3rd
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</label>
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<div id="tune-from" style="display: none">
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<label>
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From:
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<select name="tuning-from">
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<option selected disabled value></option>
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<option>C2</option>
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</select>
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</label>
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</div>
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<button>Tune</button>
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</fieldset>
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</article>
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</form>
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</section>
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</main>
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</body>
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</html>
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173
index.js
173
index.js
@ -1,80 +1,142 @@
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const kNumKeys = 49;
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const kMaxKeys = 88;
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const kFirstKey = 'C2';
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const kNotes = ['C', 'C#', 'D', 'Eb', 'E', 'F', 'F#', 'G', 'G#', 'A', 'Bb', 'B'];
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const kA0Frequency = 27.5;
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const kSemiToneMultiplier = Math.pow(2, 1/12);
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const audioCtx = new AudioContext();
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const frequencies = [];
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const holds = [];
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function playNote(frequency, duration) {
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let currentGain = 1.0;
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let globalVolume = 1.0;
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/*
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* TODO:
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* - smooth frequency adjustments
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* - auto octave update
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* - implement perfect 5/4/3M/3m
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* - keyboard playing (qwerty)
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*/
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function playNote(frequency, duration=86400) {
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let currentGain = globalVolume;
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const bassBoost = f => {
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const t = f / 20000;
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const a = 4.0;
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const b = 0.2;
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const t = Math.pow(f / 20000, 1/10);
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const a = 1.0;
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const b = 0.05;
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return b * t + a * (1 - t);
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};
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const oscillators = [];
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while (frequency < 20000) {
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const oscillator = new OscillatorNode(audioCtx);
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const oscillator = new OscillatorNode(audioCtx, {frequency});
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const gain = new GainNode(audioCtx);
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oscillator.type = 'sine';
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oscillator.frequency.value = frequency; // value in hertz
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oscillator.connect(gain);
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const g = bassBoost(frequency) * currentGain;
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gain.gain.setValueAtTime(0, audioCtx.currentTime);
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gain.gain.exponentialRampToValueAtTime(bassBoost(frequency) * currentGain, audioCtx.currentTime + 0.010);
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gain.gain.linearRampToValueAtTime(1e-10, audioCtx.currentTime + 0.500);
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gain.connect(audioCtx.destination);
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gain.gain.linearRampToValueAtTime(g, audioCtx.currentTime + 0.010);
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gain.gain.linearRampToValueAtTime(0, audioCtx.currentTime + duration);
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oscillator.connect(gain).connect(audioCtx.destination);
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oscillator.start();
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setTimeout(() => {oscillator.stop();}, duration);
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oscillators.push(oscillator);
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// break; // only one frequency for now
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frequency *= 2;
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currentGain *= 0.3;
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}
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const stop = () => {
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for (let oscillator of oscillators) {
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oscillator.stop();
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}
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};
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setTimeout(stop, duration*1000);
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return stop;
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}
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function noteFrequency(key) {
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function keyIndex(key) {
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let [note, octave, ] = key.split(/(\d)/);
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octave = parseInt(octave);
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const interval = kNotes.indexOf(note) - kNotes.indexOf('A') + octave * 12;
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return kNotes.indexOf(note) - kNotes.indexOf('A') + octave * 12;
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}
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let freq = kA0Frequency * Math.pow(kSemiToneMultiplier, interval);
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function noteFrequency(key) {
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return frequencies[keyIndex(key)];
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}
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return freq;
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function setFrequency(key, frequency) {
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frequencies[keyIndex(key)] = frequency;
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}
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function tuneEqual() {
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const startFrequency = kA0Frequency;
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let frequency = startFrequency;
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for (let i = 0; i < kMaxKeys; i++) {
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frequencies[i] = frequency;
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frequency *= kSemiToneMultiplier;
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}
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}
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function updateOptions(key) {
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const noteSpan = document.getElementById("current-note");
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const frequencySpan = document.getElementById("current-frequency");
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noteSpan.innerHTML = key;
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frequencySpan.value = noteFrequency(key).toFixed(2);
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const index = keyIndex(key);
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const hold = document.getElementById("hold");
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if (holds[index] !== undefined) {
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hold.checked = true;
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} else {
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hold.checked = false;
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}
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}
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function onKeyClick(event) {
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const note = event.srcElement.id;
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const freq = noteFrequency(note);
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playNote(freq, 500);
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const keySpan = event.srcElement;
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const key = keySpan.id;
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playNote(noteFrequency(key), 0.5);
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updateOptions(key);
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keySpan.classList.add('playing');
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setTimeout(() => { keySpan.classList.remove('playing'); }, 500)
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}
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function makeKey(note) {
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const key = document.createElement('span');
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if (note.includes('#') || note.includes('b')) {
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key.classList.add('blackKey');
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} else {
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key.classList.add('whiteKey');
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}
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key.id = note;
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key.addEventListener('click', onKeyClick);
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if (note.includes('#') || note.includes('b')) {
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key.classList.add('blackKey');
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const container = document.createElement('span');
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container.classList.add('blackKeyOuter');
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container.appendChild(key);
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return container;
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}
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key.classList.add('whiteKey');
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return key;
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}
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function setupKeyboard() {
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function setupKeyboard(firstKey=kFirstKey, numKeys=kNumKeys) {
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const keyboard = document.getElementById('keyboard');
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keyboard.innerHTML = '';
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let curIndex = kNotes.indexOf(kFirstKey.charAt(0));
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let octave = parseInt(kFirstKey.charAt(1));
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let curIndex = kNotes.indexOf(firstKey.charAt(0));
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let octave = parseInt(firstKey.charAt(1));
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for (let i = 0; i < kNumKeys; i++) {
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for (let i = 0; i < numKeys; i++) {
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const note = kNotes[curIndex] + octave;
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const key = makeKey(note)
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keyboard.appendChild(key);
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@ -87,6 +149,57 @@ function setupKeyboard() {
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}
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}
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function addHold(key) {
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holds[keyIndex(key)] = playNote(noteFrequency(key));
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document.getElementById(key).classList.add('held');
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}
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function removeHold(key) {
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const index = keyIndex(key);
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if (holds[index] !== undefined) {
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holds[index]();
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}
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delete holds[index];
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document.getElementById(key).classList.remove('held');
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}
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function refreshHolds() {
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for (let i = 0; i < holds.length; i++) {
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if (holds[i] !== undefined) {
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holds[i]();
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holds[i] = playNote(frequencies[i]);
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}
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}
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}
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function setupListeners() {
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const freq = document.getElementById("current-frequency");
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freq.onchange = e => {
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const key = document.getElementById("current-note").innerHTML;
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setFrequency(key, parseFloat(freq.value));
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refreshHolds();
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};
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freq.oninput = freq.onchange;
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const hold = document.getElementById("hold");
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hold.onchange = e => {
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const key = document.getElementById("current-note").innerHTML;
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if (hold.checked) {
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addHold(key);
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} else {
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removeHold(key);
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}
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}
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const range = document.getElementById("range");
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range.onchange = e => {
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const val = parseFloat(range.value);
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globalVolume = val;
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refreshHolds();
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}
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}
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window.addEventListener('load', e => {
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setupKeyboard();
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setupKeyboard('C2', 49);
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tuneEqual();
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setupListeners();
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});
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