third_party/WebKit/LayoutTests/webaudio/audioparam-linearRampToValueAtTime.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 linearRampToValueAtTime() functionality.");
  16
  17 // Play a long DC signal out through an AudioGainNode, and call setValueAtTime() and
  18 // linearRampToValueAtTime() at regular intervals to set the starting and ending values for a
  19 // linear ramp. Each time interval has a ramp with a different starting and ending value so
  20 // that there is a discontinuity at each time interval boundary.  The discontinuity is for
  21 // testing timing.  Also, we alternate between an increasing and decreasing ramp for each
  22 // interval.
  23
  24 // Number of tests to run.
  25 var numberOfTests = 100;
  26
  27 // Max allowed difference between the rendered data and the expected result.
  28 var maxAllowedError = 7.51e-7;
  29
  30 // Set the gain node value to the specified value at the specified time.
  31 function setValue(value, time)
  32 {
  33     gainNode.gain.setValueAtTime(value, time);
  34 }
  35
  36 // Generate a linear ramp ending at time |endTime| with an ending value of |value|.
  37 function generateRamp(value, startTime, endTime)
  38 {
  39     // |startTime| is ignored because the linear ramp uses the value from the setValueAtTime() call above.
  40     gainNode.gain.linearRampToValueAtTime(value, endTime)
  41 }
  42
  43 function runTest()
  44 {
  45     createAudioGraphAndTest(numberOfTests,
  46                             1,
  47                             setValue,
  48                             generateRamp,
  49                             "linearRampToValueAtTime()",
  50                             maxAllowedError,
  51                             createLinearRampArray);
  52 }
  53
  54 runTest();
  55 successfullyParsed = true;
  56
  57 </script>
  58
  59 </body>
  60 </html>