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<!DOCTYPE HTML>
<html>
<head>
<title>Test the OscillatorNode when the frequency is negative</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">
SimpleTest.waitForExplicitFinish();
addLoadEvent(function() {
var types = ["sine",
"square",
"sawtooth",
"triangle"];
var finished = 0;
function finish() {
if (++finished == types.length) {
SimpleTest.finish();
}
}
types.forEach(function(t) {
var context = new OfflineAudioContext(1, 256, 44100);
var osc = context.createOscillator();
osc.frequency.value = -440;
osc.type = t;
osc.connect(context.destination);
osc.start();
context.startRendering().then(function(buffer) {
var samples = buffer.getChannelData(0);
// This samples the wave form in the middle of the first period, the value
// should be negative.
ok(samples[Math.floor(44100 / 440 / 4)] < 0., "Phase should be inverted when using a " + t + " waveform");
finish();
});
});
});
</script>
</pre>
</body>
</html>
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