test_audioParamLinearRamp.html

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<!DOCTYPE HTML>

<html>

<head>

  <title>Test AudioParam.linearRampToValue</title>

  <script src="/tests/SimpleTest/SimpleTest.js"></script>

  <script type="text/javascript" src="webaudio.js"></script>

  <link rel="stylesheet" type="text/css" href="/tests/SimpleTest/test.css" />

</head>

<body>

<pre id="test">

<script class="testbody" type="text/javascript">

var V0 = 0.1;

var V1 = 0.9;

var T0 = 0;

var gTest = {

  length: 2048,

  numberOfChannels: 1,

  createGraph(context) {

    var sourceBuffer = context.createBuffer(1, 2048, context.sampleRate);

    for (var i = 0; i < 2048; ++i) {

      sourceBuffer.getChannelData(0)[i] = 1;

    var source = context.createBufferSource();

    source.buffer = sourceBuffer;

    var gain = context.createGain();

    gain.gain.setValueAtTime(V0, 0);

    gain.gain.linearRampToValueAtTime(V1, 2048/context.sampleRate);

    source.connect(gain);

    source.start(0);

    return gain;

},

  createExpectedBuffers(context) {

    var T1 = 2048 / context.sampleRate;

    var expectedBuffer = context.createBuffer(1, 2048, context.sampleRate);

    for (var i = 0; i < 2048; ++i) {

      var t = i / context.sampleRate;

      expectedBuffer.getChannelData(0)[i] = V0 + (V1 - V0) * ((t - T0) / (T1 - T0));

    return expectedBuffer;

},

};

runTest();

</script>

</pre>

</body>

</html>