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/*
* Copyright (C) 2012, Google Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
* DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE FOR ANY
* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
* LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
* ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#ifndef Oscillator_h
#define Oscillator_h
#include "AudioBus.h"
#include "AudioParam.h"
#include "AudioScheduledSourceNode.h"
#include <wtf/OwnArrayPtr.h>
#include <wtf/PassRefPtr.h>
#include <wtf/RefPtr.h>
#include <wtf/Threading.h>
namespace WebCore {
class AudioContext;
class WaveTable;
// Oscillator is an audio generator of periodic waveforms.
class Oscillator : public AudioScheduledSourceNode {
public:
// The waveform type.
// These must be defined as in the .idl file.
enum {
SINE = 0,
SQUARE = 1,
SAWTOOTH = 2,
TRIANGLE = 3,
CUSTOM = 4
};
static PassRefPtr<Oscillator> create(AudioContext*, float sampleRate);
virtual ~Oscillator();
// AudioNode
virtual void process(size_t framesToProcess);
virtual void reset();
unsigned short type() const { return m_type; }
void setType(unsigned short);
AudioParam* frequency() { return m_frequency.get(); }
AudioParam* detune() { return m_detune.get(); }
void setWaveTable(WaveTable*);
private:
Oscillator(AudioContext*, float sampleRate);
// Returns true if there are sample-accurate timeline parameter changes.
bool calculateSampleAccuratePhaseIncrements(size_t framesToProcess);
virtual bool propagatesSilence() const OVERRIDE;
// One of the waveform types defined in the enum.
unsigned short m_type;
// Frequency value in Hertz.
RefPtr<AudioParam> m_frequency;
// Detune value (deviating from the frequency) in Cents.
RefPtr<AudioParam> m_detune;
bool m_firstRender;
// m_virtualReadIndex is a sample-frame index into our buffer representing the current playback position.
// Since it's floating-point, it has sub-sample accuracy.
double m_virtualReadIndex;
// This synchronizes process().
mutable Mutex m_processLock;
// Stores sample-accurate values calculated according to frequency and detune.
AudioFloatArray m_phaseIncrements;
AudioFloatArray m_detuneValues;
RefPtr<WaveTable> m_waveTable;
// Cache the wave tables for different waveform types, except CUSTOM.
static WaveTable* s_waveTableSine;
static WaveTable* s_waveTableSquare;
static WaveTable* s_waveTableSawtooth;
static WaveTable* s_waveTableTriangle;
};
} // namespace WebCore
#endif // Oscillator_h
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