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
35namespace blink {
36
37const int HRTFDatabase::MinElevation = -45;
38const int HRTFDatabase::MaxElevation = 90;
39const unsigned HRTFDatabase::RawElevationAngleSpacing = 15;
40const unsigned HRTFDatabase::NumberOfRawElevations = 10; // -45 -> +90 (each 15 degrees)
41const unsigned HRTFDatabase::InterpolationFactor = 1;
42const unsigned HRTFDatabase::NumberOfTotalElevations = NumberOfRawElevations * InterpolationFactor;
43
44PassOwnPtr<HRTFDatabase> HRTFDatabase::create(float sampleRate)
45{
46    OwnPtr<HRTFDatabase> hrtfDatabase = adoptPtr(new HRTFDatabase(sampleRate));
47    return hrtfDatabase.release();
48}
49
50HRTFDatabase::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
82void 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
108unsigned 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)
121