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<!DOCTYPE html>
<html>
<head>
<title>
Test WaveShaper Copies Curve Data
</title>
<script src="/resources/testharness.js"></script>
<script src="/resources/testharnessreport.js"></script>
<script src="../../resources/audit-util.js"></script>
<script src="../../resources/audit.js"></script>
</head>
<body>
<script id="layout-test-code">
// Sample rate and number of frames are fairly arbitrary. We need to
// render, however, at least 384 frames. 1024 is a nice small value.
let sampleRate = 16000;
let renderFrames = 1024;
let audit = Audit.createTaskRunner();
audit.define(
{
label: 'test copying',
description: 'Modifying curve should not modify WaveShaper'
},
(task, should) => {
// Two-channel context; channel 0 contains the test data and channel
// 1 contains the expected result. Channel 1 has the normal
// WaveShaper output and channel 0 has the WaveShaper output with a
// modified curve.
let context = new OfflineAudioContext(2, renderFrames, sampleRate);
// Just use a default oscillator as the source. Doesn't really
// matter what we use.
let src = context.createOscillator();
src.type = 'sawtooth';
// Create the wave shapers: ws0 is the test shaper, and ws1 is the
// reference wave shaper.
let ws0 = context.createWaveShaper();
let ws1 = context.createWaveShaper();
// Wave shaper curves. Doesn't really matter what we use as long as
// it modifies the input in some way. Thus, keep it simple and just
// invert the input.
let desiredCurve = [1, 0, -1];
let curve0 = Float32Array.from(desiredCurve);
let curve1 = Float32Array.from(desiredCurve);
ws0.curve = curve0;
ws1.curve = curve1;
let merger = context.createChannelMerger(2);
// Connect the graph
src.connect(ws0);
src.connect(ws1);
ws0.connect(merger, 0, 0);
ws1.connect(merger, 0, 1);
merger.connect(context.destination);
// Let the context run for a bit and then modify the curve for ws0.
// Doesn't really matter what we modify the curve to as long as it's
// different.
context.suspend(256 / context.sampleRate)
.then(() => {
should(
() => {
curve0[0] = -0.5;
curve0[1] = 0.125;
curve0[2] = 0.75;
},
`Modifying curve array at time ${context.currentTime}`)
.notThrow();
})
.then(context.resume.bind(context));
src.start();
context.startRendering()
.then(function(renderedBuffer) {
let actual = renderedBuffer.getChannelData(0);
let expected = renderedBuffer.getChannelData(1);
// Modifying the wave shaper curve should not modify the
// output so the outputs from the two wave shaper nodes should
// be exactly identical.
should(actual, 'Output of WaveShaper with modified curve')
.beEqualToArray(expected);
})
.then(() => task.done());
});
audit.run();
</script>
</body>
</html>
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