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 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#pragma once
30
31#include "AudioArray.h"
32#include <JavaScriptCore/Float32Array.h>
33#include <memory>
34#include <wtf/RefCounted.h>
35#include <wtf/Vector.h>
36
37namespace WebCore {
38
39class PeriodicWave final : public RefCounted<PeriodicWave> {
40public:
41 static Ref<PeriodicWave> createSine(float sampleRate);
42 static Ref<PeriodicWave> createSquare(float sampleRate);
43 static Ref<PeriodicWave> createSawtooth(float sampleRate);
44 static Ref<PeriodicWave> createTriangle(float sampleRate);
45
46 // Creates an arbitrary wave given the frequency components (Fourier coefficients).
47 static Ref<PeriodicWave> create(float sampleRate, Float32Array& real, Float32Array& imag);
48
49 // Returns pointers to the lower and higher wave data for the pitch range containing
50 // the given fundamental frequency. These two tables are in adjacent "pitch" ranges
51 // where the higher table will have the maximum number of partials which won't alias when played back
52 // at this fundamental frequency. The lower wave is the next range containing fewer partials than the higher wave.
53 // Interpolation between these two tables can be made according to tableInterpolationFactor.
54 // Where values from 0 -> 1 interpolate between lower -> higher.
55 void waveDataForFundamentalFrequency(float, float* &lowerWaveData, float* &higherWaveData, float& tableInterpolationFactor);
56
57 // Returns the scalar multiplier to the oscillator frequency to calculate wave table phase increment.
58 float rateScale() const { return m_rateScale; }
59
60 unsigned periodicWaveSize() const { return m_periodicWaveSize; }
61 float sampleRate() const { return m_sampleRate; }
62
63private:
64 enum class Type {
65 Sine,
66 Square,
67 Sawtooth,
68 Triangle,
69 };
70
71 explicit PeriodicWave(float sampleRate);
72
73 void generateBasicWaveform(Type);
74
75 float m_sampleRate;
76 unsigned m_periodicWaveSize;
77 unsigned m_numberOfRanges;
78 float m_centsPerRange;
79
80 // The lowest frequency (in Hertz) where playback will include all of the partials.
81 // Playing back lower than this frequency will gradually lose more high-frequency information.
82 // This frequency is quite low (~10Hz @ 44.1KHz)
83 float m_lowestFundamentalFrequency;
84
85 float m_rateScale;
86
87 unsigned numberOfRanges() const { return m_numberOfRanges; }
88
89 // Maximum possible number of partials (before culling).
90 unsigned maxNumberOfPartials() const;
91
92 unsigned numberOfPartialsForRange(unsigned rangeIndex) const;
93
94 // Creates tables based on numberOfComponents Fourier coefficients.
95 void createBandLimitedTables(const float* real, const float* imag, unsigned numberOfComponents);
96 Vector<std::unique_ptr<AudioFloatArray>> m_bandLimitedTables;
97};
98
99} // namespace WebCore
100