The Tor Browser: content/media/webaudio/test/blink/panner-model-testing.js@6474c204b198 (annotated)

content/media/webaudio/test/blink/panner-model-testing.js@6474c204b198 (annotated)

content/media/webaudio/test/blink/panner-model-testing.js

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 var sampleRate = 48000.0;
 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();
         panner[k].panningModel = "equalpower";
         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
         time[k] = k * timeStep;
         bufferSource[k].start(time[k]);
     }
 }
 function createTestAndRun(context, nodeCount, numberOfSourceChannels) {
     numberOfChannels = numberOfSourceChannels;
     createGraph(context, nodeCount);
     context.oncomplete = checkResult;
     context.startRendering();
 }
 // Map our position angle to the azimuth angle (in degrees).
 //
 // An angle of 0 corresponds to an azimuth of 90 deg; pi, to -90 deg.
 function angleToAzimuth(angle) {
     return 90 - angle * 180 / Math.PI;
 }
 // The gain caused by the EQUALPOWER panning model
 function equalPowerGain(angle) {
     var azimuth = angleToAzimuth(angle);
     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;
             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;
     var maxErrorIndexR = 0;
     // Number of impulses that don't match our expected locations.
     var timeCount = 0;
     // Locations of where the impulses aren't at the expected locations.
     var timeErrors = new Array();
     for (var k = 0; k < renderedLeft.length; ++k) {
         // We assume that the left and right channels start at the same instant.
         if (renderedLeft[k] != 0 || renderedRight[k] != 0) {
             // The expected gain for the left and right channels.
             var pannerGain = equalPowerGain(position[impulseCount].angle);
             var expectedL = pannerGain.left;
             var expectedR = pannerGain.right;
             // Absolute error in the gain.
             var errorL = Math.abs(renderedLeft[k] - expectedL);
             var errorR = Math.abs(renderedRight[k] - expectedR);
             if (Math.abs(errorL) > maxErrorL) {
                 maxErrorL = Math.abs(errorL);
                 maxErrorIndexL = impulseCount;
             }
             if (Math.abs(errorR) > maxErrorR) {
                 maxErrorR = Math.abs(errorR);
                 maxErrorIndexR = impulseCount;
             }
             // Keep track of the impulses that didn't show up where we
             // expected them to be.
             var expectedOffset = timeToSampleFrame(time[impulseCount], sampleRate);
             if (k != expectedOffset) {
                 timeErrors[timeCount] = { actual : k, expected : expectedOffset};
                 ++timeCount;
             }
             ++impulseCount;
         }
     }
     if (impulseCount == nodesToCreate) {
         testPassed("Number of impulses matches the number of panner nodes.");
     } else {
         testFailed("Number of impulses is incorrect.  (Found " + impulseCount + " but expected " + nodesToCreate + ")");
         success = false;
     }
     if (timeErrors.length > 0) {
         success = false;
         testFailed(timeErrors.length + " timing errors found in " + nodesToCreate + " panner nodes.");
         for (var k = 0; k < timeErrors.length; ++k) {
             testFailed("Impulse at sample " + timeErrors[k].actual + " but expected " + timeErrors[k].expected);
         }
     } 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();
 }