1 files changed, 210 insertions, 0 deletions
diff --git a/dom/media/webaudio/test/blink/panner-model-testing.js b/dom/media/webaudio/test/blink/panner-model-testing.js
new file mode 100644
index 0000000000..45460e2768
--- /dev/null
+++ b/dom/media/webaudio/test/blink/panner-model-testing.js
@@ -0,0 +1,210 @@
+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].positionX.value = position[k].x;
+        panner[k].positionZ.value = 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();
+}