test_gainNode.html

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<html>

<head>

  <title>Test GainNode</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 gTest = {

  length: 2048,

  numberOfChannels: 1,

  createGraph(context) {

    var gain = new GainNode(context);

    ok(gain.gain, "The audioparam member must exist");

    is(gain.gain.value, 1.0, "Correct initial value");

    is(gain.gain.defaultValue, 1.0, "Correct default value");

    gain.gain.value = 0.5;

    is(gain.gain.value, 0.5, "Correct initial value");

    is(gain.gain.defaultValue, 1.0, "Correct default value");

    gain = new GainNode(context, { gain: 0.5 });

    ok(gain.gain, "The audioparam member must exist");

    is(gain.gain.value, 0.5, "Correct initial value");

    is(gain.gain.defaultValue, 1.0, "Correct default value");

    gain.gain.value = 0.5;

    is(gain.gain.value, 0.5, "Correct initial value");

    is(gain.gain.defaultValue, 1.0, "Correct default value");

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

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

      buffer.getChannelData(0)[i] = Math.sin(440 * 2 * Math.PI * i / context.sampleRate);

    var source = context.createBufferSource();

    source.buffer = buffer;

    gain = context.createGain();

    source.connect(gain);

    ok(gain.gain, "The audioparam member must exist");

    is(gain.gain.value, 1.0, "Correct initial value");

    is(gain.gain.defaultValue, 1.0, "Correct default value");

    gain.gain.value = 0.5;

    is(gain.gain.value, 0.5, "Correct initial value");

    is(gain.gain.defaultValue, 1.0, "Correct default value");

    is(gain.channelCount, 2, "gain node has 2 input channels by default");

    is(gain.channelCountMode, "max", "Correct channelCountMode for the gain node");

    is(gain.channelInterpretation, "speakers", "Correct channelCountInterpretation for the gain node");

    source.start(0);

    return gain;

},

  createExpectedBuffers(context) {

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

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

      expectedBuffer.getChannelData(0)[i] = Math.sin(440 * 2 * Math.PI * i / context.sampleRate) / 2;

    return expectedBuffer;

},

};

runTest();

</script>

</pre>

</body>

</html>