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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 "platform/audio/HRTFDatabase.h"
#include "wtf/MathExtras.h"
#include "wtf/PtrUtil.h"
#include <memory>
namespace blink {
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;
std::unique_ptr<HRTFDatabase> HRTFDatabase::create(float sampleRate) {
return WTF::wrapUnique(new HRTFDatabase(sampleRate));
}
HRTFDatabase::HRTFDatabase(float sampleRate)
: m_elevations(NumberOfTotalElevations), m_sampleRate(sampleRate) {
unsigned elevationIndex = 0;
for (int elevation = MinElevation; elevation <= MaxElevation;
elevation += RawElevationAngleSpacing) {
std::unique_ptr<HRTFElevation> hrtfElevation =
HRTFElevation::createForSubject("Composite", elevation, sampleRate);
ASSERT(hrtfElevation.get());
if (!hrtfElevation.get())
return;
m_elevations[elevationIndex] = std::move(hrtfElevation);
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) {
float x =
static_cast<float>(jj) / static_cast<float>(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);
SECURITY_DCHECK(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 =
clampTo<double, double>(elevationAngle, MinElevation, MaxElevation);
unsigned elevationIndex =
static_cast<int>(InterpolationFactor * (elevationAngle - MinElevation) /
RawElevationAngleSpacing);
return elevationIndex;
}
} // namespace blink
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