1 files changed, 124 insertions, 0 deletions
diff --git a/WebCore/platform/audio/HRTFDatabase.cpp b/WebCore/platform/audio/HRTFDatabase.cpp
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+++ b/WebCore/platform/audio/HRTFDatabase.cpp
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+/*
+ * Copyright (C) 2010 Google Inc. All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions
+ * are met:
+ *
+ * 1.  Redistributions of source code must retain the above copyright
+ *     notice, this list of conditions and the following disclaimer.
+ * 2.  Redistributions in binary form must reproduce the above copyright
+ *     notice, this list of conditions and the following disclaimer in the
+ *     documentation and/or other materials provided with the distribution.
+ * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
+ *     its contributors may be used to endorse or promote products derived
+ *     from this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
+ * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
+ * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
+ * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "config.h"
+
+#if ENABLE(WEB_AUDIO)
+
+#include "HRTFDatabase.h"
+
+#include "HRTFElevation.h"
+
+using namespace std;
+
+namespace WebCore {
+
+const int HRTFDatabase::MinElevation = -45;
+const int HRTFDatabase::MaxElevation = 90;
+const unsigned HRTFDatabase::RawElevationAngleSpacing = 15;
+const unsigned HRTFDatabase::NumberOfRawElevations = 10; // -45 -> +90 (each 15 degrees)
+const unsigned HRTFDatabase::InterpolationFactor = 1;
+const unsigned HRTFDatabase::NumberOfTotalElevations = NumberOfRawElevations * InterpolationFactor;
+
+PassOwnPtr<HRTFDatabase> HRTFDatabase::create(double sampleRate)
+{
+    OwnPtr<HRTFDatabase> hrtfDatabase = adoptPtr(new HRTFDatabase(sampleRate));
+    return hrtfDatabase.release();
+}
+
+HRTFDatabase::HRTFDatabase(double sampleRate)
+    : m_elevations(NumberOfTotalElevations)
+    , m_sampleRate(sampleRate)
+{
+    unsigned elevationIndex = 0;
+    for (int elevation = MinElevation; elevation <= MaxElevation; elevation += RawElevationAngleSpacing) {
+        OwnPtr<HRTFElevation> hrtfElevation = HRTFElevation::createForSubject("Composite", elevation, sampleRate);
+        ASSERT(hrtfElevation.get());
+        if (!hrtfElevation.get())
+            return;
+        
+        m_elevations[elevationIndex] = hrtfElevation.release();
+        elevationIndex += InterpolationFactor;
+    }
+
+    // Now, go back and interpolate elevations.
+    if (InterpolationFactor > 1) {
+        for (unsigned i = 0; i < NumberOfTotalElevations; i += InterpolationFactor) {
+            unsigned j = (i + InterpolationFactor);
+            if (j >= NumberOfTotalElevations)
+                j = i; // for last elevation interpolate with itself
+
+            // Create the interpolated convolution kernels and delays.
+            for (unsigned jj = 1; jj < InterpolationFactor; ++jj) {
+                double x = static_cast<double>(jj) / static_cast<double>(InterpolationFactor);
+                m_elevations[i + jj] = HRTFElevation::createByInterpolatingSlices(m_elevations[i].get(), m_elevations[j].get(), x, sampleRate);
+                ASSERT(m_elevations[i + jj].get());
+            }
+        }
+    }
+}
+
+void HRTFDatabase::getKernelsFromAzimuthElevation(double azimuthBlend, unsigned azimuthIndex, double elevationAngle, HRTFKernel* &kernelL, HRTFKernel* &kernelR,
+                                                  double& frameDelayL, double& frameDelayR)
+{
+    unsigned elevationIndex = indexFromElevationAngle(elevationAngle);
+    ASSERT(elevationIndex < m_elevations.size() && m_elevations.size() > 0);
+    
+    if (!m_elevations.size()) {
+        kernelL = 0;
+        kernelR = 0;
+        return;
+    }
+    
+    if (elevationIndex > m_elevations.size() - 1)
+        elevationIndex = m_elevations.size() - 1;    
+    
+    HRTFElevation* hrtfElevation = m_elevations[elevationIndex].get();
+    ASSERT(hrtfElevation);
+    if (!hrtfElevation) {
+        kernelL = 0;
+        kernelR = 0;
+        return;
+    }
+    
+    hrtfElevation->getKernelsFromAzimuth(azimuthBlend, azimuthIndex, kernelL, kernelR, frameDelayL, frameDelayR);
+}                                                     
+
+unsigned HRTFDatabase::indexFromElevationAngle(double elevationAngle)
+{
+    // Clamp to allowed range.
+    elevationAngle = max(static_cast<double>(MinElevation), elevationAngle);
+    elevationAngle = min(static_cast<double>(MaxElevation), elevationAngle);
+
+    unsigned elevationIndex = static_cast<int>(InterpolationFactor * (elevationAngle - MinElevation) / RawElevationAngleSpacing);    
+    return elevationIndex;
+}
+
+} // namespace WebCore
+
+#endif // ENABLE(WEB_AUDIO)