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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 "third_party/blink/renderer/platform/audio/hrtf_database.h"
#include <memory>
#include <utility>
#include "base/memory/ptr_util.h"
#include "third_party/blink/public/resources/grit/blink_resources.h"
#include "third_party/blink/renderer/platform/wtf/math_extras.h"
namespace blink {
namespace {
// Minimum and maximum elevation angles (inclusive) for a HRTFDatabase.
constexpr int kMinElevation = -45;
constexpr int kMaxElevation = 90;
constexpr unsigned kRawElevationAngleSpacing = 15;
// = 10, -45 -> +90 (each 15 degrees)
constexpr unsigned kNumberOfRawElevations =
1 + ((kMaxElevation - kMinElevation) / kRawElevationAngleSpacing);
// Interpolates by this factor to get the total number of elevations from
// every elevation loaded from resource.
constexpr unsigned kInterpolationFactor = 1;
// Total number of elevations after interpolation.
constexpr unsigned kNumberOfTotalElevations =
kNumberOfRawElevations * kInterpolationFactor;
// Returns the index for the correct HRTFElevation given the elevation angle.
unsigned IndexFromElevationAngle(double elevation_angle) {
// Clamp to allowed range.
elevation_angle =
ClampTo<double, double>(elevation_angle, kMinElevation, kMaxElevation);
unsigned elevation_index = static_cast<int>(
kInterpolationFactor * (elevation_angle - kMinElevation) /
kRawElevationAngleSpacing);
return elevation_index;
}
} // namespace
HRTFDatabase::HRTFDatabase(float sample_rate)
: elevations_(kNumberOfTotalElevations) {
unsigned elevation_index = 0;
for (int elevation = kMinElevation; elevation <= kMaxElevation;
elevation += kRawElevationAngleSpacing) {
std::unique_ptr<HRTFElevation> hrtf_elevation =
HRTFElevation::CreateForSubject(IDR_AUDIO_SPATIALIZATION_COMPOSITE,
elevation, sample_rate);
DCHECK(hrtf_elevation.get());
elevations_[elevation_index] = std::move(hrtf_elevation);
elevation_index += kInterpolationFactor;
}
// Now, go back and interpolate elevations.
if (kInterpolationFactor > 1) {
for (unsigned i = 0; i < kNumberOfTotalElevations;
i += kInterpolationFactor) {
unsigned j = (i + kInterpolationFactor);
if (j >= kNumberOfTotalElevations) {
j = i; // for last elevation interpolate with itself
}
// Create the interpolated convolution kernels and delays.
for (unsigned jj = 1; jj < kInterpolationFactor; ++jj) {
float x =
static_cast<float>(jj) / static_cast<float>(kInterpolationFactor);
elevations_[i + jj] = HRTFElevation::CreateByInterpolatingSlices(
elevations_[i].get(), elevations_[j].get(), x);
DCHECK(elevations_[i + jj].get());
}
}
}
}
unsigned HRTFDatabase::NumberOfAzimuths() {
return HRTFElevation::NumberOfAzimuths();
}
unsigned HRTFDatabase::NumberOfRawElevations() {
return kNumberOfRawElevations;
}
void HRTFDatabase::GetKernelsFromAzimuthElevation(double azimuth_blend,
unsigned azimuth_index,
double elevation_angle,
HRTFKernel*& kernel_l,
HRTFKernel*& kernel_r,
double& frame_delay_l,
double& frame_delay_r) const {
unsigned elevation_index = IndexFromElevationAngle(elevation_angle);
SECURITY_DCHECK(elevation_index < elevations_.size());
SECURITY_DCHECK(elevations_.size() > 0);
if (elevation_index > elevations_.size() - 1) {
elevation_index = elevations_.size() - 1;
}
HRTFElevation* hrtf_elevation = elevations_[elevation_index].get();
DCHECK(hrtf_elevation);
hrtf_elevation->GetKernelsFromAzimuth(azimuth_blend, azimuth_index, kernel_l,
kernel_r, frame_delay_l, frame_delay_r);
}
} // namespace blink
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