WaveTable name has changed to PeriodicWave

Source/modules/webaudio/WaveTable.cpp

-/*
- * 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.
- */
-
-#include "config.h"
-
-#if ENABLE(WEB_AUDIO)
-
-#include "modules/webaudio/WaveTable.h"
-
-#include "core/platform/audio/FFTFrame.h"
-#include "core/platform/audio/VectorMath.h"
-#include "modules/webaudio/OscillatorNode.h"
-#include <algorithm>
-#include "wtf/OwnPtr.h"
-
-const unsigned WaveTableSize = 4096; // This must be a power of two.
-const unsigned NumberOfRanges = 36; // There should be 3 * log2(WaveTableSize) 1/3 octave ranges.
-const float CentsPerRange = 1200 / 3; // 1/3 Octave.
-
-namespace WebCore {
-    
-using namespace VectorMath;
-
-PassRefPtr<WaveTable> WaveTable::create(float sampleRate, Float32Array* real, Float32Array* imag)
-{
-    bool isGood = real && imag && real->length() == imag->length();
-    ASSERT(isGood);
-    if (isGood) {
-        RefPtr<WaveTable> waveTable = adoptRef(new WaveTable(sampleRate));
-        size_t numberOfComponents = real->length();
-        waveTable->createBandLimitedTables(real->data(), imag->data(), numberOfComponents);
-        return waveTable;
-    }
-    return 0;
-}
-
-PassRefPtr<WaveTable> WaveTable::createSine(float sampleRate)
-{
-    RefPtr<WaveTable> waveTable = adoptRef(new WaveTable(sampleRate));
-    waveTable->generateBasicWaveform(OscillatorNode::SINE);
-    return waveTable;
-}
-
-PassRefPtr<WaveTable> WaveTable::createSquare(float sampleRate)
-{
-    RefPtr<WaveTable> waveTable = adoptRef(new WaveTable(sampleRate));
-    waveTable->generateBasicWaveform(OscillatorNode::SQUARE);
-    return waveTable;
-}
-
-PassRefPtr<WaveTable> WaveTable::createSawtooth(float sampleRate)
-{
-    RefPtr<WaveTable> waveTable = adoptRef(new WaveTable(sampleRate));
-    waveTable->generateBasicWaveform(OscillatorNode::SAWTOOTH);
-    return waveTable;
-}
-
-PassRefPtr<WaveTable> WaveTable::createTriangle(float sampleRate)
-{
-    RefPtr<WaveTable> waveTable = adoptRef(new WaveTable(sampleRate));
-    waveTable->generateBasicWaveform(OscillatorNode::TRIANGLE);
-    return waveTable;
-}
-
-WaveTable::WaveTable(float sampleRate)
-    : m_sampleRate(sampleRate)
-    , m_waveTableSize(WaveTableSize)
-    , m_numberOfRanges(NumberOfRanges)
-    , m_centsPerRange(CentsPerRange)
-{
-    ScriptWrappable::init(this);
-    float nyquist = 0.5 * m_sampleRate;
-    m_lowestFundamentalFrequency = nyquist / maxNumberOfPartials();
-    m_rateScale = m_waveTableSize / m_sampleRate;
-}
-
-void WaveTable::waveDataForFundamentalFrequency(float fundamentalFrequency, float* &lowerWaveData, float* &higherWaveData, float& tableInterpolationFactor)
-{
-    // Negative frequencies are allowed, in which case we alias to the positive frequency.
-    fundamentalFrequency = fabsf(fundamentalFrequency);
-
-    // Calculate the pitch range.
-    float ratio = fundamentalFrequency > 0 ? fundamentalFrequency / m_lowestFundamentalFrequency : 0.5;
-    float centsAboveLowestFrequency = log2f(ratio) * 1200;
-
-    // Add one to round-up to the next range just in time to truncate partials before aliasing occurs.
-    float pitchRange = 1 + centsAboveLowestFrequency / m_centsPerRange;
-
-    pitchRange = std::max(pitchRange, 0.0f);
-    pitchRange = std::min(pitchRange, static_cast<float>(m_numberOfRanges - 1));
-
-    // The words "lower" and "higher" refer to the table data having the lower and higher numbers of partials.
-    // It's a little confusing since the range index gets larger the more partials we cull out.
-    // So the lower table data will have a larger range index.
-    unsigned rangeIndex1 = static_cast<unsigned>(pitchRange);
-    unsigned rangeIndex2 = rangeIndex1 < m_numberOfRanges - 1 ? rangeIndex1 + 1 : rangeIndex1;
-
-    lowerWaveData = m_bandLimitedTables[rangeIndex2]->data();
-    higherWaveData = m_bandLimitedTables[rangeIndex1]->data();
-    
-    // Ranges from 0 -> 1 to interpolate between lower -> higher.
-    tableInterpolationFactor = pitchRange - rangeIndex1;
-}
-
-unsigned WaveTable::maxNumberOfPartials() const
-{
-    return m_waveTableSize / 2;
-}
-
-unsigned WaveTable::numberOfPartialsForRange(unsigned rangeIndex) const
-{
-    // Number of cents below nyquist where we cull partials.
-    float centsToCull = rangeIndex * m_centsPerRange;
-
-    // A value from 0 -> 1 representing what fraction of the partials to keep.
-    float cullingScale = pow(2, -centsToCull / 1200);
-
-    // The very top range will have all the partials culled.
-    unsigned numberOfPartials = cullingScale * maxNumberOfPartials();
-
-    return numberOfPartials;
-}
-
-// Convert into time-domain wave tables.
-// One table is created for each range for non-aliasing playback at different playback rates.
-// Thus, higher ranges have more high-frequency partials culled out.
-void WaveTable::createBandLimitedTables(const float* realData, const float* imagData, unsigned numberOfComponents)
-{
-    float normalizationScale = 1;
-
-    unsigned fftSize = m_waveTableSize;
-    unsigned halfSize = fftSize / 2;
-    unsigned i;
-    
-    numberOfComponents = std::min(numberOfComponents, halfSize);
-
-    m_bandLimitedTables.reserveCapacity(m_numberOfRanges);
-
-    for (unsigned rangeIndex = 0; rangeIndex < m_numberOfRanges; ++rangeIndex) {
-        // This FFTFrame is used to cull partials (represented by frequency bins).
-        FFTFrame frame(fftSize);
-        float* realP = frame.realData();
-        float* imagP = frame.imagData();
-
-        // Copy from loaded frequency data and scale.
-        float scale = fftSize;
-        vsmul(realData, 1, &scale, realP, 1, numberOfComponents);
-        vsmul(imagData, 1, &scale, imagP, 1, numberOfComponents);
-
-        // If fewer components were provided than 1/2 FFT size, then clear the remaining bins.
-        for (i = numberOfComponents; i < halfSize; ++i) {
-            realP[i] = 0;
-            imagP[i] = 0;
-        }
-        
-        // Generate complex conjugate because of the way the inverse FFT is defined.
-        float minusOne = -1;
-        vsmul(imagP, 1, &minusOne, imagP, 1, halfSize);
-
-        // Find the starting bin where we should start culling.
-        // We need to clear out the highest frequencies to band-limit the waveform.
-        unsigned numberOfPartials = numberOfPartialsForRange(rangeIndex);
-
-        // Cull the aliasing partials for this pitch range.
-        for (i = numberOfPartials + 1; i < halfSize; ++i) {
-            realP[i] = 0;
-            imagP[i] = 0;
-        }
-        // Clear packed-nyquist if necessary.
-        if (numberOfPartials < halfSize)
-            imagP[0] = 0;
-
-        // Clear any DC-offset.
-        realP[0] = 0;
-
-        // Create the band-limited table.
-        OwnPtr<AudioFloatArray> table = adoptPtr(new AudioFloatArray(m_waveTableSize));
-        m_bandLimitedTables.append(table.release());
-
-        // Apply an inverse FFT to generate the time-domain table data.
-        float* data = m_bandLimitedTables[rangeIndex]->data();
-        frame.doInverseFFT(data);
-
-        // For the first range (which has the highest power), calculate its peak value then compute normalization scale.
-        if (!rangeIndex) {
-            float maxValue;
-            vmaxmgv(data, 1, &maxValue, m_waveTableSize);
-
-            if (maxValue)
-                normalizationScale = 1.0f / maxValue;
-        }
-
-        // Apply normalization scale.
-        vsmul(data, 1, &normalizationScale, data, 1, m_waveTableSize);          
-    }
-}
-
-void WaveTable::generateBasicWaveform(int shape)
-{
-    unsigned fftSize = waveTableSize();
-    unsigned halfSize = fftSize / 2;
-
-    AudioFloatArray real(halfSize);
-    AudioFloatArray imag(halfSize);
-    float* realP = real.data();
-    float* imagP = imag.data();
-
-    // Clear DC and Nyquist.
-    realP[0] = 0;
-    imagP[0] = 0;
-
-    for (unsigned n = 1; n < halfSize; ++n) {
-        float omega = 2 * piFloat * n;
-        float invOmega = 1 / omega;
-
-        // Fourier coefficients according to standard definition.
-        float a; // Coefficient for cos().
-        float b; // Coefficient for sin().
-
-        // Calculate Fourier coefficients depending on the shape.
-        // Note that the overall scaling (magnitude) of the waveforms is normalized in createBandLimitedTables().
-        switch (shape) {
-        case OscillatorNode::SINE:
-            // Standard sine wave function.
-            a = 0;
-            b = (n == 1) ? 1 : 0;
-            break;
-        case OscillatorNode::SQUARE:
-            // Square-shaped waveform with the first half its maximum value and the second half its minimum value.
-            a = 0;
-            b = invOmega * ((n & 1) ? 2 : 0);
-            break;
-        case OscillatorNode::SAWTOOTH:
-            // Sawtooth-shaped waveform with the first half ramping from zero to maximum and the second half from minimum to zero.
-            a = 0;
-            b = -invOmega * cos(0.5 * omega);
-            break;
-        case OscillatorNode::TRIANGLE:
-            // Triangle-shaped waveform going from its maximum value to its minimum value then back to the maximum value.
-            a = (4 - 4 * cos(0.5 * omega)) / (n * n * piFloat * piFloat);
-            b = 0;
-            break;
-        default:
-            ASSERT_NOT_REACHED();
-            a = 0;
-            b = 0;
-            break;
-        }
-
-        realP[n] = a;
-        imagP[n] = b;
-    }
-
-    createBandLimitedTables(realP, imagP, halfSize);
-}
-
-} // namespace WebCore
-
-#endif // ENABLE(WEB_AUDIO)