michael@0: var sampleRate = 48000.0;
michael@0: 
michael@0: var numberOfChannels = 1;
michael@0: 
michael@0: // Time step when each panner node starts.
michael@0: var timeStep = 0.001;
michael@0: 
michael@0: // Length of the impulse signal.
michael@0: var pulseLengthFrames = Math.round(timeStep * sampleRate);
michael@0: 
michael@0: // How many panner nodes to create for the test
michael@0: var nodesToCreate = 100;
michael@0: 
michael@0: // Be sure we render long enough for all of our nodes.
michael@0: var renderLengthSeconds = timeStep * (nodesToCreate + 1);
michael@0: 
michael@0: // These are global mostly for debugging.
michael@0: var context;
michael@0: var impulse;
michael@0: var bufferSource;
michael@0: var panner;
michael@0: var position;
michael@0: var time;
michael@0:       
michael@0: var renderedBuffer;
michael@0: var renderedLeft;
michael@0: var renderedRight;
michael@0: 
michael@0: function createGraph(context, nodeCount) {
michael@0:     bufferSource = new Array(nodeCount);
michael@0:     panner = new Array(nodeCount);
michael@0:     position = new Array(nodeCount);
michael@0:     time = new Array(nodeCount);
michael@0:     // Angle between panner locations.  (nodeCount - 1 because we want
michael@0:     // to include both 0 and 180 deg.
michael@0:     var angleStep = Math.PI / (nodeCount - 1);
michael@0: 
michael@0:     if (numberOfChannels == 2) {
michael@0:         impulse = createStereoImpulseBuffer(context, pulseLengthFrames);
michael@0:     }
michael@0:     else
michael@0:         impulse = createImpulseBuffer(context, pulseLengthFrames);
michael@0: 
michael@0:     for (var k = 0; k < nodeCount; ++k) {
michael@0:         bufferSource[k] = context.createBufferSource();
michael@0:         bufferSource[k].buffer = impulse;
michael@0: 
michael@0:         panner[k] = context.createPanner();
michael@0:         panner[k].panningModel = "equalpower";
michael@0:         panner[k].distanceModel = "linear";
michael@0: 
michael@0:         var angle = angleStep * k;
michael@0:         position[k] = {angle : angle, x : Math.cos(angle), z : Math.sin(angle)};
michael@0:         panner[k].setPosition(position[k].x, 0, position[k].z);
michael@0: 
michael@0:         bufferSource[k].connect(panner[k]);
michael@0:         panner[k].connect(context.destination);
michael@0: 
michael@0:         // Start the source
michael@0:         time[k] = k * timeStep;
michael@0:         bufferSource[k].start(time[k]);
michael@0:     }
michael@0: }
michael@0: 
michael@0: function createTestAndRun(context, nodeCount, numberOfSourceChannels) {
michael@0:     numberOfChannels = numberOfSourceChannels;
michael@0: 
michael@0:     createGraph(context, nodeCount);
michael@0: 
michael@0:     context.oncomplete = checkResult;
michael@0:     context.startRendering();
michael@0: }
michael@0: 
michael@0: // Map our position angle to the azimuth angle (in degrees).
michael@0: //
michael@0: // An angle of 0 corresponds to an azimuth of 90 deg; pi, to -90 deg.
michael@0: function angleToAzimuth(angle) {
michael@0:     return 90 - angle * 180 / Math.PI;
michael@0: }
michael@0: 
michael@0: // The gain caused by the EQUALPOWER panning model
michael@0: function equalPowerGain(angle) {
michael@0:     var azimuth = angleToAzimuth(angle);
michael@0: 
michael@0:     if (numberOfChannels == 1) {
michael@0:         var panPosition = (azimuth + 90) / 180;
michael@0: 
michael@0:         var gainL = Math.cos(0.5 * Math.PI * panPosition);
michael@0:         var gainR = Math.sin(0.5 * Math.PI * panPosition);
michael@0: 
michael@0:         return { left : gainL, right : gainR };
michael@0:     } else {
michael@0:         if (azimuth <= 0) {
michael@0:             var panPosition = (azimuth + 90) / 90;
michael@0:     
michael@0:             var gainL = 1 + Math.cos(0.5 * Math.PI * panPosition);
michael@0:             var gainR = Math.sin(0.5 * Math.PI * panPosition);
michael@0:     
michael@0:             return { left : gainL, right : gainR };
michael@0:         } else {
michael@0:             var panPosition = azimuth / 90;
michael@0:     
michael@0:             var gainL = Math.cos(0.5 * Math.PI * panPosition);
michael@0:             var gainR = 1 + Math.sin(0.5 * Math.PI * panPosition);
michael@0:     
michael@0:             return { left : gainL, right : gainR };
michael@0:         }
michael@0:     }
michael@0: }
michael@0: 
michael@0: function checkResult(event) {
michael@0:     renderedBuffer = event.renderedBuffer;
michael@0:     renderedLeft = renderedBuffer.getChannelData(0);
michael@0:     renderedRight = renderedBuffer.getChannelData(1);
michael@0: 
michael@0:     // The max error we allow between the rendered impulse and the
michael@0:     // expected value.  This value is experimentally determined.  Set
michael@0:     // to 0 to make the test fail to see what the actual error is.
michael@0:     var maxAllowedError = 1.3e-6;
michael@0:   
michael@0:     var success = true;
michael@0: 
michael@0:     // Number of impulses found in the rendered result.
michael@0:     var impulseCount = 0;
michael@0: 
michael@0:     // Max (relative) error and the index of the maxima for the left
michael@0:     // and right channels.
michael@0:     var maxErrorL = 0;
michael@0:     var maxErrorIndexL = 0;
michael@0:     var maxErrorR = 0;
michael@0:     var maxErrorIndexR = 0;
michael@0: 
michael@0:     // Number of impulses that don't match our expected locations.
michael@0:     var timeCount = 0;
michael@0: 
michael@0:     // Locations of where the impulses aren't at the expected locations.
michael@0:     var timeErrors = new Array();
michael@0: 
michael@0:     for (var k = 0; k < renderedLeft.length; ++k) {
michael@0:         // We assume that the left and right channels start at the same instant.
michael@0:         if (renderedLeft[k] != 0 || renderedRight[k] != 0) {
michael@0:             // The expected gain for the left and right channels.
michael@0:             var pannerGain = equalPowerGain(position[impulseCount].angle);
michael@0:             var expectedL = pannerGain.left;
michael@0:             var expectedR = pannerGain.right;
michael@0: 
michael@0:             // Absolute error in the gain.
michael@0:             var errorL = Math.abs(renderedLeft[k] - expectedL);
michael@0:             var errorR = Math.abs(renderedRight[k] - expectedR);
michael@0: 
michael@0:             if (Math.abs(errorL) > maxErrorL) {
michael@0:                 maxErrorL = Math.abs(errorL);
michael@0:                 maxErrorIndexL = impulseCount;
michael@0:             }
michael@0:             if (Math.abs(errorR) > maxErrorR) {
michael@0:                 maxErrorR = Math.abs(errorR);
michael@0:                 maxErrorIndexR = impulseCount;
michael@0:             }
michael@0: 
michael@0:             // Keep track of the impulses that didn't show up where we
michael@0:             // expected them to be.
michael@0:             var expectedOffset = timeToSampleFrame(time[impulseCount], sampleRate);
michael@0:             if (k != expectedOffset) {
michael@0:                 timeErrors[timeCount] = { actual : k, expected : expectedOffset};
michael@0:                 ++timeCount;
michael@0:             }
michael@0:             ++impulseCount;
michael@0:         }
michael@0:     }
michael@0: 
michael@0:     if (impulseCount == nodesToCreate) {
michael@0:         testPassed("Number of impulses matches the number of panner nodes.");
michael@0:     } else {
michael@0:         testFailed("Number of impulses is incorrect.  (Found " + impulseCount + " but expected " + nodesToCreate + ")");
michael@0:         success = false;
michael@0:     }
michael@0: 
michael@0:     if (timeErrors.length > 0) {
michael@0:         success = false;
michael@0:         testFailed(timeErrors.length + " timing errors found in " + nodesToCreate + " panner nodes.");
michael@0:         for (var k = 0; k < timeErrors.length; ++k) {
michael@0:             testFailed("Impulse at sample " + timeErrors[k].actual + " but expected " + timeErrors[k].expected);
michael@0:         }
michael@0:     } else {
michael@0:         testPassed("All impulses at expected offsets.");
michael@0:     }
michael@0: 
michael@0:     if (maxErrorL <= maxAllowedError) {
michael@0:         testPassed("Left channel gain values are correct.");
michael@0:     } else {
michael@0:         testFailed("Left channel gain values are incorrect.  Max error = " + maxErrorL + " at time " + time[maxErrorIndexL] + " (threshold = " + maxAllowedError + ")");
michael@0:         success = false;
michael@0:     }
michael@0: 
michael@0:     if (maxErrorR <= maxAllowedError) {
michael@0:         testPassed("Right channel gain values are correct.");
michael@0:     } else {
michael@0:         testFailed("Right channel gain values are incorrect.  Max error = " + maxErrorR + " at time " + time[maxErrorIndexR] + " (threshold = " + maxAllowedError + ")");
michael@0:         success = false;
michael@0:     }
michael@0: 
michael@0:     if (success) {
michael@0:         testPassed("EqualPower panner test passed");
michael@0:     } else {
michael@0:         testFailed("EqualPower panner test failed");
michael@0:     }
michael@0: 
michael@0:     finishJSTest();
michael@0: }