/*
* 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 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
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#ifndef PeriodicWave_h
#define PeriodicWave_h
#include "bindings/v8/ScriptWrappable.h"
#include "platform/audio/AudioArray.h"
#include "wtf/Float32Array.h"
#include "wtf/OwnPtr.h"
#include "wtf/PassRefPtr.h"
#include "wtf/RefCounted.h"
#include "wtf/RefPtr.h"
#include "wtf/Vector.h"
namespace WebCore {
class PeriodicWave : public ScriptWrappable, public RefCounted<PeriodicWave> {
public:
static PassRefPtr<PeriodicWave> createSine(float sampleRate);
static PassRefPtr<PeriodicWave> createSquare(float sampleRate);
static PassRefPtr<PeriodicWave> createSawtooth(float sampleRate);
static PassRefPtr<PeriodicWave> createTriangle(float sampleRate);
// Creates an arbitrary periodic wave given the frequency components (Fourier coefficients).
static PassRefPtr<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 buffer phase increment.
float rateScale() const { return m_rateScale; }
unsigned periodicWaveSize() const { return m_periodicWaveSize; }
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;
// 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<OwnPtr<AudioFloatArray> > m_bandLimitedTables;
};
} // namespace WebCore
#endif // PeriodicWave_h