retrospective-setValueAtTime.html | Explore in Territory

<!DOCTYPE html>
<html>
  <head>
    <title>Test setValueAtTime with startTime in the past</title>
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <script src="/webaudio/resources/audit-util.js"></script>
    <script src="/webaudio/resources/audit.js"></script>
    <script src="retrospective-test.js"></script>
  </head>
  <body>
    <script>
      let audit = Audit.createTaskRunner();

      audit.define(
          {
            label: 'test',
            description: 'Test setValueAtTime with startTime in the past'
          },
          (task, should) => {
            let {context, source, test, reference} = setupRetrospectiveGraph();

            // Suspend the context at this frame so we can synchronously set up
            // automations.
            const suspendFrame = 128;

            // Use a ramp of slope 1 per frame to measure time.
            // The end value is the extent of exact precision in single
            // precision float.
            const rampEnd = context.length - suspendFrame;
            const rampEndSeconds = context.length / context.sampleRate;

            context.suspend(suspendFrame / context.sampleRate)
                .then(() => {
                  // Call setValueAtTime with a time in the past
                  test.gain.setValueAtTime(0.0, 0.5 * context.currentTime);
                  test.gain.linearRampToValueAtTime(rampEnd, rampEndSeconds);

                  reference.gain.setValueAtTime(0.0, context.currentTime);
                  reference.gain.linearRampToValueAtTime(
                      rampEnd, rampEndSeconds);
                })
                .then(() => context.resume());

            source.start();

            context.startRendering()
                .then(resultBuffer => {
                  let testValue = resultBuffer.getChannelData(0);
                  let referenceValue = resultBuffer.getChannelData(1);

                  // Until the suspendFrame, both should be exactly equal to 1.
                  should(
                      testValue.slice(0, suspendFrame),
                      `Test[0:${suspendFrame - 1}]`)
                      .beConstantValueOf(1);
                  should(
                      referenceValue.slice(0, suspendFrame),
                      `Reference[0:${suspendFrame - 1}]`)
                      .beConstantValueOf(1);

                  // After the suspendFrame, both should be equal (and not
                  // constant)
                  should(
                      testValue.slice(suspendFrame), `Test[${suspendFrame}:]`)
                      .beEqualToArray(referenceValue.slice(suspendFrame));
                })
                .then(() => task.done());
          });

      audit.run();
    </script>
  </body>
</html>
chromium/third_party/blink/web_tests/external/wpt/webaudio/the-audio-api/the-audioparam-interface/retrospective-setValueAtTime.html
