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/*
* Copyright (C) 2012 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 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.
*/
#ifndef PeriodicWave_h
#define PeriodicWave_h
#include "AudioArray.h"
#include <memory>
#include <runtime/Float32Array.h>
#include <wtf/PassRefPtr.h>
#include <wtf/RefCounted.h>
#include <wtf/RefPtr.h>
#include <wtf/Vector.h>
namespace WebCore {
class PeriodicWave : public RefCounted<PeriodicWave> {
public:
static Ref<PeriodicWave> createSine(float sampleRate);
static Ref<PeriodicWave> createSquare(float sampleRate);
static Ref<PeriodicWave> createSawtooth(float sampleRate);
static Ref<PeriodicWave> createTriangle(float sampleRate);
// Creates an arbitrary wave given the frequency components (Fourier coefficients).
static RefPtr<PeriodicWave> create(float sampleRate, Float32Array* real, Float32Array* imag);
// Returns pointers to the lower and higher wave data for the pitch range containing
// the given fundamental frequency. These two tables are in adjacent "pitch" ranges
// where the higher table will have the maximum number of partials which won't alias when played back
// at this fundamental frequency. The lower wave is the next range containing fewer partials than the higher wave.
// Interpolation between these two tables can be made according to tableInterpolationFactor.
// Where values from 0 -> 1 interpolate between lower -> higher.
void waveDataForFundamentalFrequency(float, float* &lowerWaveData, float* &higherWaveData, float& tableInterpolationFactor);
// Returns the scalar multiplier to the oscillator frequency to calculate wave table phase increment.
float rateScale() const { return m_rateScale; }
unsigned periodicWaveSize() const { return m_periodicWaveSize; }
float sampleRate() const { return m_sampleRate; }
private:
explicit PeriodicWave(float sampleRate);
void generateBasicWaveform(int);
float m_sampleRate;
unsigned m_periodicWaveSize;
unsigned m_numberOfRanges;
float m_centsPerRange;
// The lowest frequency (in Hertz) where playback will include all of the partials.
// Playing back lower than this frequency will gradually lose more high-frequency information.
// This frequency is quite low (~10Hz @ 44.1KHz)
float m_lowestFundamentalFrequency;
float m_rateScale;
unsigned numberOfRanges() const { return m_numberOfRanges; }
// Maximum possible number of partials (before culling).
unsigned maxNumberOfPartials() const;
unsigned numberOfPartialsForRange(unsigned rangeIndex) const;
// Creates tables based on numberOfComponents Fourier coefficients.
void createBandLimitedTables(const float* real, const float* imag, unsigned numberOfComponents);
Vector<std::unique_ptr<AudioFloatArray>> m_bandLimitedTables;
};
} // namespace WebCore
#endif // PeriodicWave_h
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