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54 lines
1.9 KiB
HTML
54 lines
1.9 KiB
HTML
<!DOCTYPE html>
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<title>Test setTargetAtTime after an event in the same processing block</title>
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<script src="/resources/testharness.js"></script>
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<script src="/resources/testharnessreport.js"></script>
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<script>
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promise_test(function() {
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const bufferSize = 179;
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const valueStartOffset = 42;
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const targetStartOffset = 53;
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const sampleRate = 48000;
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const scheduledValue = -0.5;
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var context = new OfflineAudioContext(1, bufferSize, sampleRate);
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var gain = context.createGain();
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gain.gain.setValueAtTime(scheduledValue, valueStartOffset/sampleRate);
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gain.gain.setTargetAtTime(scheduledValue, targetStartOffset/sampleRate,
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128/sampleRate);
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gain.connect(context.destination);
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// Apply unit DC signal to gain node.
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var source = context.createBufferSource();
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source.buffer =
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function() {
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var buffer = context.createBuffer(1, 1, context.sampleRate);
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buffer.getChannelData(0)[0] = 1.0;
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return buffer;
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}();
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source.loop = true;
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source.start();
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source.connect(gain);
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return context.startRendering().
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then(function(buffer) {
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assert_equals(buffer.length, bufferSize, "output buffer length");
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var output = buffer.getChannelData(0);
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var i = 0;
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for (; i < valueStartOffset; ++i) {
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// "Its default value is 1."
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assert_equals(output[i], 1.0, "default gain at sample " + i);
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}
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for (; i < buffer.length; ++i) {
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// "If the next event (having time T1) after this SetValue event is
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// not of type LinearRampToValue or ExponentialRampToValue, then, for
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// T0≤t<T1: v(t)=V".
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// "Start exponentially approaching the target value at the given time
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// with a rate having the given time constant."
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// The target is the same value, and so the SetValue value continues.
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assert_equals(output[i], scheduledValue,
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"scheduled value at sample " + i);
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}
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});
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});
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</script>
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