/* * 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 * 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 WaveTable_h #define WaveTable_h #include "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 WaveTable : public RefCounted<WaveTable> { public: static PassRefPtr<WaveTable> createSine(float sampleRate); static PassRefPtr<WaveTable> createSquare(float sampleRate); static PassRefPtr<WaveTable> createSawtooth(float sampleRate); static PassRefPtr<WaveTable> createTriangle(float sampleRate); // Creates an arbitrary wavetable given the frequency components (Fourier coefficients). static PassRefPtr<WaveTable> create(float sampleRate, Float32Array* real, Float32Array* imag); // Returns pointers to the lower and higher wavetable 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 wavetable is the next range containing fewer partials than the higher wavetable. // 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 waveTableSize() const { return m_waveTableSize; } float sampleRate() const { return m_sampleRate; } private: WaveTable(float sampleRate); void generateBasicWaveform(int); float m_sampleRate; unsigned m_waveTableSize; 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<OwnPtr<AudioFloatArray> > m_bandLimitedTables; }; } // namespace WebCore #endif // WaveTable_h