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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 "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 
     36 namespace blink {
     37 
     38 class AudioContext;
     39 class PeriodicWave;
     40 
     41 // OscillatorNode is an audio generator of periodic waveforms.
     42 
     43 class OscillatorNode FINAL : public AudioScheduledSourceNode {
     44     DEFINE_WRAPPERTYPEINFO();
     45 public:
     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 
     75 private:
     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