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 | |
37 | namespace WebCore { |
38 | |
39 | class PeriodicWave final : public RefCounted<PeriodicWave> { |
40 | public: |
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 | |
63 | private: |
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 | |