fmopl.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_FMOPL_H
#define AUDIO_FMOPL_H

#include "audio/audiostream.h"

#include "common/func.h"
#include "common/ptr.h"
#include "common/scummsys.h"

namespace Audio {
class SoundHandle;
}

namespace Common {
class String;
}

namespace OPL {

class OPL;

class Config {
public:
    enum OplFlags {
        kFlagOpl2       = (1 << 0),
        kFlagDualOpl2   = (1 << 1),
        kFlagOpl3       = (1 << 2)
    };

    enum OplType {
        kOpl2,
        kDualOpl2,
        kOpl3
    };

    typedef int8 DriverId;
    struct EmulatorDescription {
        const char *name;
        const char *description;

        DriverId id;    // A unique ID for each driver
        uint32 flags;   // Capabilities of this driver
    };

    static const EmulatorDescription *getAvailable() { return _drivers; }

    static DriverId parse(const Common::String &name);

    static const EmulatorDescription *findDriver(DriverId id);

    static DriverId detect(OplType type);

    static OPL *create(DriverId driver, OplType type);

    static OPL *create(OplType type = kOpl2);

private:
    static const EmulatorDescription _drivers[];
};

typedef Common::Functor0<void> TimerCallback;

class OPL {
private:
    static bool _hasInstance;
public:
    OPL();
    virtual ~OPL() { _hasInstance = false; }

    virtual bool init() = 0;

    virtual void reset() = 0;

    virtual void write(int a, int v) = 0;

    virtual byte read(int a) = 0;

    virtual void writeReg(int r, int v) = 0;

    void start(TimerCallback *callback, int timerFrequency = kDefaultCallbackFrequency);

    void stop();

    virtual void setCallbackFrequency(int timerFrequency) = 0;

    enum {
        kDefaultCallbackFrequency = 250
    };

protected:
    void initDualOpl2OnOpl3(Config::OplType oplType);

    bool emulateDualOpl2OnOpl3(int r, int v, Config::OplType oplType);

    virtual void startCallbacks(int timerFrequency) = 0;

    virtual void stopCallbacks() = 0;

    Common::ScopedPtr<TimerCallback> _callback;

    bool _rhythmMode;
    int _connectionFeedbackValues[3];
};

class RealOPL : public OPL {
public:
    RealOPL();
    virtual ~RealOPL();

    // OPL API
    void setCallbackFrequency(int timerFrequency);

protected:
    // OPL API
    void startCallbacks(int timerFrequency);
    void stopCallbacks();
    virtual void onTimer();

private:
    static void timerProc(void *refCon);

    uint _baseFreq;
    uint _remainingTicks;

    enum {
        kMaxFreq = 100
    };
};

class EmulatedOPL : public OPL, protected Audio::AudioStream {
public:
    EmulatedOPL();
    virtual ~EmulatedOPL();

    // OPL API
    void setCallbackFrequency(int timerFrequency);

    // AudioStream API
    int readBuffer(int16 *buffer, const int numSamples);
    int getRate() const;
    bool endOfData() const { return false; }

protected:
    // OPL API
    void startCallbacks(int timerFrequency);
    void stopCallbacks();

    virtual void generateSamples(int16 *buffer, int numSamples) = 0;

private:
    int _baseFreq;

    enum {
        FIXP_SHIFT = 16
    };

    int _nextTick;
    int _samplesPerTick;

    Audio::SoundHandle *_handle;
};
} // End of namespace OPL

#endif