third_party/WebKit/LayoutTests/webaudio/audioparam-exponentialRampToValueAtTime.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 exponentialRampToValueAtTime() functionality.");
  16
  17       // Play a long DC signal out through an AudioGainNode, and call setValueAtTime() and
  18       // exponentialRampToValueAtTime() at regular intervals to set the starting and ending values
  19       // for an exponential ramp.  Each time interval has a ramp with a different starting and
  20       // ending value so that there is a discontinuity at each time interval boundary.  The
  21       // discontinuity is for testing timing.  Also, we alternate between an increasing and
  22       // decreasing ramp for each 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 = 6.75e-4;
  29
  30       // The AudioGainNode starts with this value instead of the default value.
  31       var initialValue = 100;
  32
  33       // Set the gain node value to the specified value at the specified time.
  34       function setValue(value, time)
  35       {
  36           gainNode.gain.setValueAtTime(value, time);
  37       }
  38
  39       // Generate an exponential ramp ending at time |endTime| with an ending value of |value|.
  40       function generateRamp(value, startTime, endTime)
  41       {
  42           // |startTime| is ignored because the exponential ramp
  43           // uses the value from the setValueAtTime() call above.
  44           gainNode.gain.exponentialRampToValueAtTime(value, endTime)
  45       }
  46
  47       function runTest()
  48       {
  49           createAudioGraphAndTest(numberOfTests,
  50                                   initialValue,
  51                                   setValue,
  52                                   generateRamp,
  53                                   "exponentialRampToValueAtTime()",
  54                                   maxAllowedError,
  55                                   createExponentialRampArray);
  56
  57       }
  58
  59       runTest();
  60       successfullyParsed = true;
  61
  62     </script>
  63
  64   </body>
  65 </html>