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 * 1.  Redistributions of source code must retain the above copyright
8 *    notice, this list of conditions and the following disclaimer.
9 * 2.  Redistributions in binary form must reproduce the above copyright
10 *    notice, this list of conditions and the following disclaimer in the
11 *    documentation and/or other materials provided with the distribution.
12 *
13 * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
14 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
15 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
16 * DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
17 * DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
18 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
19 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
20 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
21 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
22 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
23 */
24
25#ifndef OscillatorNode_h
26#define OscillatorNode_h
27
28#include "platform/audio/AudioBus.h"
29#include "modules/webaudio/AudioParam.h"
30#include "modules/webaudio/AudioScheduledSourceNode.h"
31#include "wtf/OwnPtr.h"
32#include "wtf/PassRefPtr.h"
33#include "wtf/RefPtr.h"
34#include "wtf/Threading.h"
35
36namespace blink {
37
38class AudioContext;
39class PeriodicWave;
40
41// OscillatorNode is an audio generator of periodic waveforms.
42
43class OscillatorNode FINAL : public AudioScheduledSourceNode {
44    DEFINE_WRAPPERTYPEINFO();
45public:
46    // The waveform type.
47    // These must be defined as in the .idl file.
48    enum {
49        SINE = 0,
50        SQUARE = 1,
51        SAWTOOTH = 2,
52        TRIANGLE = 3,
53        CUSTOM = 4
54    };
55
56    static OscillatorNode* create(AudioContext*, float sampleRate);
57
58    virtual ~OscillatorNode();
59
60    // AudioNode
61    virtual void dispose() OVERRIDE;
62    virtual void process(size_t framesToProcess) OVERRIDE;
63
64    String type() const;
65
66    void setType(const String&);
67
68    AudioParam* frequency() { return m_frequency.get(); }
69    AudioParam* detune() { return m_detune.get(); }
70
71    void setPeriodicWave(PeriodicWave*);
72
73    virtual void trace(Visitor*) OVERRIDE;
74
75private:
76    OscillatorNode(AudioContext*, float sampleRate);
77
78    bool setType(unsigned); // Returns true on success.
79
80    // Returns true if there are sample-accurate timeline parameter changes.
81    bool calculateSampleAccuratePhaseIncrements(size_t framesToProcess);
82
83    virtual bool propagatesSilence() const OVERRIDE;
84
85    // One of the waveform types defined in the enum.
86    unsigned short m_type;
87
88    // Frequency value in Hertz.
89    Member<AudioParam> m_frequency;
90
91    // Detune value (deviating from the frequency) in Cents.
92    Member<AudioParam> m_detune;
93
94    bool m_firstRender;
95
96    // m_virtualReadIndex is a sample-frame index into our buffer representing the current playback position.
97    // Since it's floating-point, it has sub-sample accuracy.
98    double m_virtualReadIndex;
99
100    // This synchronizes process().
101    mutable Mutex m_processLock;
102
103    // Stores sample-accurate values calculated according to frequency and detune.
104    AudioFloatArray m_phaseIncrements;
105    AudioFloatArray m_detuneValues;
106
107    Member<PeriodicWave> m_periodicWave;
108};
109
110} // namespace blink
111
112#endif // OscillatorNode_h
113