third_party/WebKit/LayoutTests/webaudio/audioparam-setValueCurveAtTime.html

   1 <!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
   2 <html>
   3 <head>
   4 <script src="resources/compatibility.js"></script>
   5 <script src="resources/audio-testing.js"></script>
   6 <script src="resources/audioparam-testing.js"></script>
   7 <script src="../resources/js-test.js"></script>
   8 </head>
   9
  10 <body>
  11 <div id="description"></div>
  12 <div id="console"></div>
  13
  14 <script>
  15 description("Test AudioParam setValueCurveAtTime() functionality.");
  16
  17 // Play a long DC signal out through an AudioGainNode and for each time interval call
  18 // setValueCurveAtTime() to set the values for the duration of the interval.  Each curve is a sine
  19 // wave, and we assume that the time interval is not an exact multiple of the period. This causes a
  20 // discontinuity between time intervals which is used to test timing.
  21
  22 // Number of tests to run.
  23 var numberOfTests = 20;
  24
  25 // Max allowed difference between the rendered data and the expected result.  Because of the linear
  26 // interpolation, the rendered curve isn't exactly the same as the reference.  This value is
  27 // experimentally determined.
  28 var maxAllowedError = 4.657e-10;
  29
  30 // The amplitude of the sine wave.
  31 var sineAmplitude = 1;
  32
  33 // Frequency of the sine wave.
  34 var freqHz = 440;
  35
  36 // Curve to use for setValueCurveAtTime().
  37 var curve;
  38
  39 // Sets the curve data for the entire time interval.
  40 function automation(value, startTime, endTime)
  41 {
  42     gainNode.gain.setValueCurveAtTime(curve, startTime, endTime - startTime);
  43 }
  44
  45 // Create a sine wave of the specified duration.
  46 function createReferenceSineArray(startTime, endTime, startValue, endValue, sampleRate)
  47 {
  48     // Ignore |startValue| and |endValue| for the sine wave.
  49     return createSineWaveArray(endTime - startTime, freqHz, sineAmplitude, sampleRate);
  50 }
  51
  52 function runTest()
  53 {
  54     // The curve of values to use.
  55     curve = createSineWaveArray(timeInterval, freqHz, sineAmplitude, sampleRate);
  56
  57     createAudioGraphAndTest(numberOfTests,
  58                             sineAmplitude,
  59                             function(k) {
  60                                 // Don't need to set the value.
  61                             },
  62                             automation,
  63                             "setValueCurveAtTime()",
  64                             maxAllowedError,
  65                             createReferenceSineArray,
  66                             2 * Math.PI * sineAmplitude * freqHz / sampleRate);
  67 }
  68
  69 runTest();
  70 successfullyParsed = true;
  71
  72 </script>
  73
  74 </body>
  75 </html>