waveshaper-copy-curve.html

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This test has a WPT meta file that expects 1 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-waveshapernode-interface/waveshaper-copy-curve.html - WPT Dashboard Interop Dashboard

<!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>