1 /* 2 * Copyright (C) 2012 Google Inc. All rights reserved. 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of Apple Computer, Inc. ("Apple") nor the names of 14 * its contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 17 * THIS SOFTWARE IS PROVIDED BY APPLE AND ITS CONTRIBUTORS "AS IS" AND ANY 18 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED 19 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE 20 * DISCLAIMED. IN NO EVENT SHALL APPLE OR ITS CONTRIBUTORS BE LIABLE FOR ANY 21 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES 22 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 23 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND 24 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 25 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 26 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #ifndef PeriodicWave_h 30 #define PeriodicWave_h 31 32 #include "bindings/v8/ScriptWrappable.h" 33 #include "platform/audio/AudioArray.h" 34 #include "wtf/Float32Array.h" 35 #include "wtf/OwnPtr.h" 36 #include "wtf/PassRefPtr.h" 37 #include "wtf/RefCounted.h" 38 #include "wtf/RefPtr.h" 39 #include "wtf/Vector.h" 40 41 namespace WebCore { 42 43 class PeriodicWave : public ScriptWrappable, public RefCounted<PeriodicWave> { 44 public: 45 static PassRefPtr<PeriodicWave> createSine(float sampleRate); 46 static PassRefPtr<PeriodicWave> createSquare(float sampleRate); 47 static PassRefPtr<PeriodicWave> createSawtooth(float sampleRate); 48 static PassRefPtr<PeriodicWave> createTriangle(float sampleRate); 49 50 // Creates an arbitrary periodic wave given the frequency components (Fourier coefficients). 51 static PassRefPtr<PeriodicWave> create(float sampleRate, Float32Array* real, Float32Array* imag); 52 53 // Returns pointers to the lower and higher wave data for the pitch range containing 54 // the given fundamental frequency. These two tables are in adjacent "pitch" ranges 55 // where the higher table will have the maximum number of partials which won't alias when played back 56 // at this fundamental frequency. The lower wave is the next range containing fewer partials than the higher wave. 57 // Interpolation between these two tables can be made according to tableInterpolationFactor. 58 // Where values from 0 -> 1 interpolate between lower -> higher. 59 void waveDataForFundamentalFrequency(float, float* &lowerWaveData, float* &higherWaveData, float& tableInterpolationFactor); 60 61 // Returns the scalar multiplier to the oscillator frequency to calculate wave buffer phase increment. rateScale()62 float rateScale() const { return m_rateScale; } 63 periodicWaveSize()64 unsigned periodicWaveSize() const { return m_periodicWaveSize; } sampleRate()65 float sampleRate() const { return m_sampleRate; } 66 67 private: 68 explicit PeriodicWave(float sampleRate); 69 70 void generateBasicWaveform(int); 71 72 float m_sampleRate; 73 unsigned m_periodicWaveSize; 74 unsigned m_numberOfRanges; 75 float m_centsPerRange; 76 77 // The lowest frequency (in Hertz) where playback will include all of the partials. 78 // Playing back lower than this frequency will gradually lose more high-frequency information. 79 // This frequency is quite low (~10Hz @ 44.1KHz) 80 float m_lowestFundamentalFrequency; 81 82 float m_rateScale; 83 numberOfRanges()84 unsigned numberOfRanges() const { return m_numberOfRanges; } 85 86 // Maximum possible number of partials (before culling). 87 unsigned maxNumberOfPartials() const; 88 89 unsigned numberOfPartialsForRange(unsigned rangeIndex) const; 90 91 // Creates tables based on numberOfComponents Fourier coefficients. 92 void createBandLimitedTables(const float* real, const float* imag, unsigned numberOfComponents); 93 Vector<OwnPtr<AudioFloatArray> > m_bandLimitedTables; 94 }; 95 96 } // namespace WebCore 97 98 #endif // PeriodicWave_h 99