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gain.html
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gain.html
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<html>
<head>
<title>NEJS 2016 - Gain</title>
<style>
body {
align-items: center;
display: flex;
flex-direction: column;
font-size: 30px;
height: 100%;
justify-content: center;
}
.controls {
display: flex;
font-size: 20px;
}
.control {
text-align: center;
}
input[type="range"] {
font-size: 30px;
}
</style>
</head>
<body>
<p><strong>Gain level</strong></p>
<div class="controls">
<div class="control">
<p><strong>Sine</strong></p>
<input
data-sine-gain-slider
type="range"
value="0"
min="0"
max=".8"
step=".01" />
</div>
<div class="control">
<p><strong>Triangle</strong></p>
<input
data-triangle-gain-slider
type="range"
value="0"
min="0"
max=".8"
step=".01" />
</div>
<div class="control">
<p><strong>Square</strong></p>
<input
data-square-gain-slider
type="range"
value="0"
min="0"
max=".8"
step=".01" />
</div>
</div>
<script>
// create web audio context
const audioCtx = new (window.AudioContext || window.webkitAudioContext)();
// DOM nodes
const ui = {
sineGainSlider: document.querySelector('[data-sine-gain-slider]'),
triangleGainSlider: document.querySelector('[data-triangle-gain-slider]'),
squareGainSlider: document.querySelector('[data-square-gain-slider]'),
};
// create gain nodes
const gains = {
sine: audioCtx.createGain(),
triangle: audioCtx.createGain(),
square: audioCtx.createGain(),
};
// create oscillator nodes
const oscillators = {
sine: audioCtx.createOscillator(),
triangle: audioCtx.createOscillator(),
square: audioCtx.createOscillator(),
};
// set oscillator values
oscillators.sine.type = 'sine';
oscillators.sine.frequency.value = 440;
oscillators.triangle.type = 'triangle';
oscillators.triangle.frequency.value = 660;
oscillators.square.type = 'square';
oscillators.square.frequency.value = 110;
// set gain values
gains.sine.gain.value = 0;
gains.triangle.gain.value = 0;
gains.square.gain.value = 0;
// connect oscillators to gains
// connect gains to output
oscillators.sine.connect(gains.sine);
oscillators.triangle.connect(gains.triangle);
oscillators.square.connect(gains.square);
gains.sine.connect(audioCtx.destination);
gains.triangle.connect(audioCtx.destination);
gains.square.connect(audioCtx.destination);
// start oscillators
oscillators.sine.start();
oscillators.triangle.start();
oscillators.square.start();
// update sine gain with slider
ui.sineGainSlider.addEventListener('input', e => {
gains.sine.gain.value = e.currentTarget.value;
});
// update triangle gain with slider
ui.triangleGainSlider.addEventListener('input', e => {
gains.triangle.gain.value = e.currentTarget.value;
});
// update square gain with slider
ui.squareGainSlider.addEventListener('input', e => {
gains.square.gain.value = e.currentTarget.value;
});
console.log(audioCtx);
console.log(gains);
</script>
</body>
</html>