Change the default panning mode from HRTF to equal-power

LayoutTests/webaudio/resources/panner-model-testing.js

 var sampleRate = 44100.0;
 
 var numberOfChannels = 1;
 
 // Time step when each panner node starts.
 var timeStep = 0.001;
 
 // Length of the impulse signal.
 var pulseLengthFrames = Math.round(timeStep * sampleRate);
 
 // How many panner nodes to create for the test
 var nodesToCreate = 100;
 
 // Be sure we render long enough for all of our nodes.
 var renderLengthSeconds = timeStep * (nodesToCreate + 1);
 
 // These are global mostly for debugging.
 var context;
 var impulse;
 var bufferSource;
 var panner;
 var position;
 var time;
-      
+
 var renderedBuffer;
 var renderedLeft;
 var renderedRight;
 
 function createGraph(context, nodeCount) {
     bufferSource = new Array(nodeCount);
     panner = new Array(nodeCount);
     position = new Array(nodeCount);
     time = new Array(nodeCount);
     // Angle between panner locations.  (nodeCount - 1 because we want
     // to include both 0 and 180 deg.
     var angleStep = Math.PI / (nodeCount - 1);
 
     if (numberOfChannels == 2) {
         impulse = createStereoImpulseBuffer(context, pulseLengthFrames);
     }
     else
         impulse = createImpulseBuffer(context, pulseLengthFrames);
 
     for (var k = 0; k < nodeCount; ++k) {
         bufferSource[k] = context.createBufferSource();
         bufferSource[k].buffer = impulse;
 
         panner[k] = context.createPanner();
+        // Equalpower is default now. May not be necessary.
+        // https://code.google.com/p/chromium/issues/detail?id=424356
         panner[k].panningModel = "equalpower";

[Raymond Toy, 2014/10/17 17:39:30]

I would just remove the comment and the assignment.  If somebody in the future
changes the default panning model, this will be caught here and in the other
layout test where you check that the default model is "equalpower"

[hongchan, 2014/10/17 18:13:41]

Done.

         panner[k].distanceModel = "linear";
 
         var angle = angleStep * k;
         position[k] = {angle : angle, x : Math.cos(angle), z : Math.sin(angle)};
         panner[k].setPosition(position[k].x, 0, position[k].z);
 
         bufferSource[k].connect(panner[k]);
         panner[k].connect(context.destination);
 
         // Start the source
@@ skipping 25 matching lines @@
     if (numberOfChannels == 1) {
         var panPosition = (azimuth + 90) / 180;
 
         var gainL = Math.cos(0.5 * Math.PI * panPosition);
         var gainR = Math.sin(0.5 * Math.PI * panPosition);
 
         return { left : gainL, right : gainR };
     } else {
         if (azimuth <= 0) {
             var panPosition = (azimuth + 90) / 90;
-    
+

[Raymond Toy, 2014/10/17 17:39:30]

Removing more blank lines?

[hongchan, 2014/10/17 18:13:41]

Yes.

             var gainL = 1 + Math.cos(0.5 * Math.PI * panPosition);
             var gainR = Math.sin(0.5 * Math.PI * panPosition);
-    
+
             return { left : gainL, right : gainR };
         } else {
             var panPosition = azimuth / 90;
-    
+
             var gainL = Math.cos(0.5 * Math.PI * panPosition);
             var gainR = 1 + Math.sin(0.5 * Math.PI * panPosition);
-    
+
             return { left : gainL, right : gainR };
         }
     }
 }
 
 function checkResult(event) {
     renderedBuffer = event.renderedBuffer;
     renderedLeft = renderedBuffer.getChannelData(0);
     renderedRight = renderedBuffer.getChannelData(1);
 
     // The max error we allow between the rendered impulse and the
     // expected value.  This value is experimentally determined.  Set
     // to 0 to make the test fail to see what the actual error is.
     var maxAllowedError = 1.3e-6;
-  
+
     var success = true;
 
     // Number of impulses found in the rendered result.
     var impulseCount = 0;
 
     // Max (relative) error and the index of the maxima for the left
     // and right channels.
     var maxErrorL = 0;
     var maxErrorIndexL = 0;
     var maxErrorR = 0;
@@ skipping 53 matching lines @@
     } else {
         testPassed("All impulses at expected offsets.");
     }
 
     if (maxErrorL <= maxAllowedError) {
         testPassed("Left channel gain values are correct.");
     } else {
         testFailed("Left channel gain values are incorrect.  Max error = " + maxErrorL + " at time " + time[maxErrorIndexL] + " (threshold = " + maxAllowedError + ")");
         success = false;
     }
-    
+
     if (maxErrorR <= maxAllowedError) {
         testPassed("Right channel gain values are correct.");
     } else {
         testFailed("Right channel gain values are incorrect.  Max error = " + maxErrorR + " at time " + time[maxErrorIndexR] + " (threshold = " + maxAllowedError + ")");
         success = false;
     }
 
     if (success) {
         testPassed("EqualPower panner test passed");
     } else {
         testFailed("EqualPower panner test failed");
     }
 
     finishJSTest();
 }