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 "HRTFDatabase.h"
34
35 #include "HRTFElevation.h"
36
37 using namespace std;
38
39 namespace WebCore {
40
41 const int HRTFDatabase::MinElevation = -45;
42 const int HRTFDatabase::MaxElevation = 90;
43 const unsigned HRTFDatabase::RawElevationAngleSpacing = 15;
44 const unsigned HRTFDatabase::NumberOfRawElevations = 10; // -45 -> +90 (each 15 degrees)
45 const unsigned HRTFDatabase::InterpolationFactor = 1;
46 const unsigned HRTFDatabase::NumberOfTotalElevations = NumberOfRawElevations * InterpolationFactor;
47
create(double sampleRate)48 PassOwnPtr<HRTFDatabase> HRTFDatabase::create(double sampleRate)
49 {
50 OwnPtr<HRTFDatabase> hrtfDatabase = adoptPtr(new HRTFDatabase(sampleRate));
51 return hrtfDatabase.release();
52 }
53
HRTFDatabase(double sampleRate)54 HRTFDatabase::HRTFDatabase(double sampleRate)
55 : m_elevations(NumberOfTotalElevations)
56 , m_sampleRate(sampleRate)
57 {
58 unsigned elevationIndex = 0;
59 for (int elevation = MinElevation; elevation <= MaxElevation; elevation += RawElevationAngleSpacing) {
60 OwnPtr<HRTFElevation> hrtfElevation = HRTFElevation::createForSubject("Composite", elevation, sampleRate);
61 ASSERT(hrtfElevation.get());
62 if (!hrtfElevation.get())
63 return;
64
65 m_elevations[elevationIndex] = hrtfElevation.release();
66 elevationIndex += InterpolationFactor;
67 }
68
69 // Now, go back and interpolate elevations.
70 if (InterpolationFactor > 1) {
71 for (unsigned i = 0; i < NumberOfTotalElevations; i += InterpolationFactor) {
72 unsigned j = (i + InterpolationFactor);
73 if (j >= NumberOfTotalElevations)
74 j = i; // for last elevation interpolate with itself
75
76 // Create the interpolated convolution kernels and delays.
77 for (unsigned jj = 1; jj < InterpolationFactor; ++jj) {
78 double x = static_cast<double>(jj) / static_cast<double>(InterpolationFactor);
79 m_elevations[i + jj] = HRTFElevation::createByInterpolatingSlices(m_elevations[i].get(), m_elevations[j].get(), x, sampleRate);
80 ASSERT(m_elevations[i + jj].get());
81 }
82 }
83 }
84 }
85
getKernelsFromAzimuthElevation(double azimuthBlend,unsigned azimuthIndex,double elevationAngle,HRTFKernel * & kernelL,HRTFKernel * & kernelR,double & frameDelayL,double & frameDelayR)86 void HRTFDatabase::getKernelsFromAzimuthElevation(double azimuthBlend, unsigned azimuthIndex, double elevationAngle, HRTFKernel* &kernelL, HRTFKernel* &kernelR,
87 double& frameDelayL, double& frameDelayR)
88 {
89 unsigned elevationIndex = indexFromElevationAngle(elevationAngle);
90 ASSERT(elevationIndex < m_elevations.size() && m_elevations.size() > 0);
91
92 if (!m_elevations.size()) {
93 kernelL = 0;
94 kernelR = 0;
95 return;
96 }
97
98 if (elevationIndex > m_elevations.size() - 1)
99 elevationIndex = m_elevations.size() - 1;
100
101 HRTFElevation* hrtfElevation = m_elevations[elevationIndex].get();
102 ASSERT(hrtfElevation);
103 if (!hrtfElevation) {
104 kernelL = 0;
105 kernelR = 0;
106 return;
107 }
108
109 hrtfElevation->getKernelsFromAzimuth(azimuthBlend, azimuthIndex, kernelL, kernelR, frameDelayL, frameDelayR);
110 }
111
indexFromElevationAngle(double elevationAngle)112 unsigned HRTFDatabase::indexFromElevationAngle(double elevationAngle)
113 {
114 // Clamp to allowed range.
115 elevationAngle = max(static_cast<double>(MinElevation), elevationAngle);
116 elevationAngle = min(static_cast<double>(MaxElevation), elevationAngle);
117
118 unsigned elevationIndex = static_cast<int>(InterpolationFactor * (elevationAngle - MinElevation) / RawElevationAngleSpacing);
119 return elevationIndex;
120 }
121
122 } // namespace WebCore
123
124 #endif // ENABLE(WEB_AUDIO)
125