third_party/WebKit/Source/platform/audio/HRTFDatabase.cpp

   1 /*
   2  * Copyright (C) 2010 Google Inc. All rights reserved.
   3  *
   4  * Redistribution and use in source and binary forms, with or without
   5  * modification, are permitted provided that the following conditions
   6  * are met:
   7  *
   8  * 1.  Redistributions of source code must retain the above copyright
   9  *     notice, this list of conditions and the following disclaimer.
  10  * 2.  Redistributions in binary form must reproduce the above copyright
  11  *     notice, this list of conditions and the following disclaimer in the
  12  *     documentation and/or other materials provided with the distribution.
  13  * 3.  Neither the name of Apple Computer, Inc. ("Apple") nor the names of
  14  *     its contributors may be used to endorse or promote products derived
  15  *     from this software without specific prior written permission.
  16  *
  17  * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY
  18  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
  19  * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  20  * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY
  21  * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
  22  * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  23  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
  24  * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  25  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  26  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  27  */
  28
  29 #include "config.h"
  30
  31 #if ENABLE(WEB_AUDIO)
  32
  33 #include "platform/audio/HRTFDatabase.h"
  34
  35 namespace blink {
  36
  37 const int HRTFDatabase::MinElevation = -45;
  38 const int HRTFDatabase::MaxElevation = 90;
  39 const unsigned HRTFDatabase::RawElevationAngleSpacing = 15;
  40 const unsigned HRTFDatabase::NumberOfRawElevations = 10; // -45 -> +90 (each 15 degrees)
  41 const unsigned HRTFDatabase::InterpolationFactor = 1;
  42 const unsigned HRTFDatabase::NumberOfTotalElevations = NumberOfRawElevations * InterpolationFactor;
  43
  44 PassOwnPtr<HRTFDatabase> HRTFDatabase::create(float sampleRate)
  45 {
  46     OwnPtr<HRTFDatabase> hrtfDatabase = adoptPtr(new HRTFDatabase(sampleRate));
  47     return hrtfDatabase.release();
  48 }
  49
  50 HRTFDatabase::HRTFDatabase(float sampleRate)
  51     : m_elevations(NumberOfTotalElevations)
  52     , m_sampleRate(sampleRate)
  53 {
  54     unsigned elevationIndex = 0;
  55     for (int elevation = MinElevation; elevation <= MaxElevation; elevation += RawElevationAngleSpacing) {
  56         OwnPtr<HRTFElevation> hrtfElevation = HRTFElevation::createForSubject("Composite", elevation, sampleRate);
  57         ASSERT(hrtfElevation.get());
  58         if (!hrtfElevation.get())
  59             return;
  60
  61         m_elevations[elevationIndex] = hrtfElevation.release();
  62         elevationIndex += InterpolationFactor;
  63     }
  64
  65     // Now, go back and interpolate elevations.
  66     if (InterpolationFactor > 1) {
  67         for (unsigned i = 0; i < NumberOfTotalElevations; i += InterpolationFactor) {
  68             unsigned j = (i + InterpolationFactor);
  69             if (j >= NumberOfTotalElevations)
  70                 j = i; // for last elevation interpolate with itself
  71
  72             // Create the interpolated convolution kernels and delays.
  73             for (unsigned jj = 1; jj < InterpolationFactor; ++jj) {
  74                 float x = static_cast<float>(jj) / static_cast<float>(InterpolationFactor);
  75                 m_elevations[i + jj] = HRTFElevation::createByInterpolatingSlices(m_elevations[i].get(), m_elevations[j].get(), x, sampleRate);
  76                 ASSERT(m_elevations[i + jj].get());
  77             }
  78         }
  79     }
  80 }
  81
  82 void HRTFDatabase::getKernelsFromAzimuthElevation(double azimuthBlend, unsigned azimuthIndex, double elevationAngle, HRTFKernel* &kernelL, HRTFKernel* &kernelR,
  83                                                   double& frameDelayL, double& frameDelayR)
  84 {
  85     unsigned elevationIndex = indexFromElevationAngle(elevationAngle);
  86     ASSERT_WITH_SECURITY_IMPLICATION(elevationIndex < m_elevations.size() && m_elevations.size() > 0);
  87
  88     if (!m_elevations.size()) {
  89         kernelL = 0;
  90         kernelR = 0;
  91         return;
  92     }
  93
  94     if (elevationIndex > m_elevations.size() - 1)
  95         elevationIndex = m_elevations.size() - 1;
  96
  97     HRTFElevation* hrtfElevation = m_elevations[elevationIndex].get();
  98     ASSERT(hrtfElevation);
  99     if (!hrtfElevation) {
 100         kernelL = 0;
 101         kernelR = 0;
 102         return;
 103     }
 104
 105     hrtfElevation->getKernelsFromAzimuth(azimuthBlend, azimuthIndex, kernelL, kernelR, frameDelayL, frameDelayR);
 106 }
 107
 108 unsigned HRTFDatabase::indexFromElevationAngle(double elevationAngle)
 109 {
 110     // Clamp to allowed range.
 111     elevationAngle = std::max(static_cast<double>(MinElevation), elevationAngle);
 112     elevationAngle = std::min(static_cast<double>(MaxElevation), elevationAngle);
 113
 114     unsigned elevationIndex = static_cast<int>(InterpolationFactor * (elevationAngle - MinElevation) / RawElevationAngleSpacing);
 115     return elevationIndex;
 116 }
 117
 118 } // namespace blink
 119
 120 #endif // ENABLE(WEB_AUDIO)