chip.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
 
#ifndef AUDIO_CHIP_H
#define AUDIO_CHIP_H
 
#include "common/func.h"
#include "common/ptr.h"
 
#include "audio/audiostream.h"
 
namespace Audio {
class SoundHandle;
 
class Chip {
public:
    virtual ~Chip() {}
 
    typedef Common::Functor0<void> TimerCallback;
 
    void start(TimerCallback *callback, int timerFrequency);
 
    void stop();
 
    virtual void setCallbackFrequency(int timerFrequency) = 0;
 
protected:
    virtual void startCallbacks(int timerFrequency) = 0;
 
    virtual void stopCallbacks() = 0;
 
    Common::ScopedPtr<TimerCallback> _callback;
};
 
class RealChip : virtual public Chip {
public:
    RealChip();
    virtual ~RealChip();
 
    // Chip API
    void setCallbackFrequency(int timerFrequency) override;
 
protected:
    // Chip API
    void startCallbacks(int timerFrequency) override;
    void stopCallbacks() override;
    virtual void onTimer();
 
private:
    static void timerProc(void *refCon);
 
    uint _baseFreq;
    uint _remainingTicks;
 
    enum {
        kMaxFreq = 100
    };
};
 
class EmulatedChip : virtual public Chip, protected Audio::AudioStream {
protected:
    static const int FIXP_SHIFT = 16;
 
public:
    EmulatedChip();
    virtual ~EmulatedChip();
 
    // Chip API
    void setCallbackFrequency(int timerFrequency) override;
 
    // AudioStream API
    int readBuffer(int16 *buffer, const int numSamples) override;
    int getRate() const override;
    bool endOfData() const override { return false; }
 
protected:
    // Chip API
    void startCallbacks(int timerFrequency) override final;
    void stopCallbacks() override final;
 
    virtual void generateSamples(int16 *buffer, int numSamples) = 0;
 
private:
    int _baseFreq;
 
    int _nextTick;
    int _samplesPerTick;
 
    Audio::SoundHandle *_handle;
};
 
} // End of namespace Audio
 
#endif