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      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 "core/platform/audio/AudioBus.h"
     29 #include "modules/webaudio/AudioParam.h"
     30 #include "modules/webaudio/AudioScheduledSourceNode.h"
     31 #include "wtf/OwnArrayPtr.h"
     32 #include "wtf/PassRefPtr.h"
     33 #include "wtf/RefPtr.h"
     34 #include "wtf/Threading.h"
     35 
     36 namespace WebCore {
     37 
     38 class AudioContext;
     39 class PeriodicWave;
     40 
     41 // OscillatorNode is an audio generator of periodic waveforms.
     42 
     43 class OscillatorNode : public AudioScheduledSourceNode {
     44 public:
     45     // The waveform type.
     46     // These must be defined as in the .idl file.
     47     enum {
     48         SINE = 0,
     49         SQUARE = 1,
     50         SAWTOOTH = 2,
     51         TRIANGLE = 3,
     52         CUSTOM = 4
     53     };
     54 
     55     static PassRefPtr<OscillatorNode> create(AudioContext*, float sampleRate);
     56 
     57     virtual ~OscillatorNode();
     58 
     59     // AudioNode
     60     virtual void process(size_t framesToProcess);
     61     virtual void reset();
     62 
     63     String type() const;
     64 
     65     bool setType(unsigned); // Returns true on success.
     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 private:
     74     OscillatorNode(AudioContext*, float sampleRate);
     75 
     76     // Returns true if there are sample-accurate timeline parameter changes.
     77     bool calculateSampleAccuratePhaseIncrements(size_t framesToProcess);
     78 
     79     virtual bool propagatesSilence() const OVERRIDE;
     80 
     81     // One of the waveform types defined in the enum.
     82     unsigned short m_type;
     83 
     84     // Frequency value in Hertz.
     85     RefPtr<AudioParam> m_frequency;
     86 
     87     // Detune value (deviating from the frequency) in Cents.
     88     RefPtr<AudioParam> m_detune;
     89 
     90     bool m_firstRender;
     91 
     92     // m_virtualReadIndex is a sample-frame index into our buffer representing the current playback position.
     93     // Since it's floating-point, it has sub-sample accuracy.
     94     double m_virtualReadIndex;
     95 
     96     // This synchronizes process().
     97     mutable Mutex m_processLock;
     98 
     99     // Stores sample-accurate values calculated according to frequency and detune.
    100     AudioFloatArray m_phaseIncrements;
    101     AudioFloatArray m_detuneValues;
    102 
    103     RefPtr<PeriodicWave> m_periodicWave;
    104 
    105     // Cache the wave tables for different waveform types, except CUSTOM.
    106     static PeriodicWave* s_periodicWaveSine;
    107     static PeriodicWave* s_periodicWaveSquare;
    108     static PeriodicWave* s_periodicWaveSawtooth;
    109     static PeriodicWave* s_periodicWaveTriangle;
    110 };
    111 
    112 } // namespace WebCore
    113 
    114 #endif // OscillatorNode_h
    115