<!DOCTYPE html>
<html>
  <head>
    <title>Test Panner Azimuth Calculation</title>
    <script src="/resources/testharness.js"></script>
    <script src="/resources/testharnessreport.js"></script>
    <script src="../../resources/audit.js"></script>
  </head>

  <body>
    <script>
      const audit = Audit.createTaskRunner();

      // Fairly arbitrary sample rate
      const sampleRate = 16000;

      audit.define('Azimuth calculation', (task, should) => {
        // Two channels for the context so we can see each channel of the
        // panner node.
        let context = new OfflineAudioContext(2, sampleRate, sampleRate);

        let src = new ConstantSourceNode(context);
        let panner = new PannerNode(context);

        src.connect(panner).connect(context.destination);

        // The source is still pointed directly at the listener, but is now
        // directly above.  The audio should be the same in both the left and
        // right channels.
        panner.positionY.value = 1;

        src.start();

        context.startRendering()
            .then(audioBuffer => {
              // The left and right channels should contain the same signal.
              let c0 = audioBuffer.getChannelData(0);
              let c1 = audioBuffer.getChannelData(1);

              let expected = Math.fround(Math.SQRT1_2);

              should(c0, 'Left channel').beConstantValueOf(expected);
              should(c1, 'Righteft channel').beConstantValueOf(expected);
            })
            .then(() => task.done());
      });

      audit.run();
    </script>
  </body>
</html>
