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/* 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 2
* 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, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
*/
#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)
};
/**
* OPL type to emulate.
*/
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
};
/**
* Get a list of all available OPL emulators.
* @return list of all available OPL emulators, terminated by a zero entry
*/
static const EmulatorDescription *getAvailable() { return _drivers; }
/**
* Returns the driver id of a given name.
*/
static DriverId parse(const Common::String &name);
/**
* @return The driver description for the given id or 0 in case it is not
* available.
*/
static const EmulatorDescription *findDriver(DriverId id);
/**
* Detects a driver for the specific type.
*
* @return Returns a valid driver id on success, -1 otherwise.
*/
static DriverId detect(OplType type);
/**
* Creates the specific driver with a specific type setup.
*/
static OPL *create(DriverId driver, OplType type);
/**
* Wrapper to easily init an OPL chip, without specifing an emulator.
* By default it will try to initialize an OPL2 emulator, thus an AdLib card.
*/
static OPL *create(OplType type = kOpl2);
private:
static const EmulatorDescription _drivers[];
};
/**
* The type of the OPL timer callback functor.
*/
typedef Common::Functor0<void> TimerCallback;
/**
* A representation of a Yamaha OPL chip.
*/
class OPL {
private:
static bool _hasInstance;
public:
OPL();
virtual ~OPL() { _hasInstance = false; }
/**
* Initializes the OPL emulator.
*
* @return true on success, false on failure
*/
virtual bool init() = 0;
/**
* Reinitializes the OPL emulator
*/
virtual void reset() = 0;
/**
* Writes a byte to the given I/O port.
*
* @param a port address
* @param v value, which will be written
*/
virtual void write(int a, int v) = 0;
/**
* Reads a byte from the given I/O port.
*
* @param a port address
* @return value read
*/
virtual byte read(int a) = 0;
/**
* Function to directly write to a specific OPL register.
* This writes to *both* chips for a Dual OPL2. We allow
* writing to secondary OPL registers by using register
* values >= 0x100.
*
* @param r hardware register number to write to
* @param v value, which will be written
*/
virtual void writeReg(int r, int v) = 0;
/**
* Start the OPL with callbacks.
*/
void start(TimerCallback *callback, int timerFrequency = kDefaultCallbackFrequency);
/**
* Stop the OPL
*/
void stop();
/**
* Change the callback frequency. This must only be called from a
* timer proc.
*/
virtual void setCallbackFrequency(int timerFrequency) = 0;
enum {
/**
* The default callback frequency that start() uses
*/
kDefaultCallbackFrequency = 250
};
protected:
/**
* Start the callbacks.
*/
virtual void startCallbacks(int timerFrequency) = 0;
/**
* Stop the callbacks.
*/
virtual void stopCallbacks() = 0;
/**
* The functor for callbacks.
*/
Common::ScopedPtr<TimerCallback> _callback;
};
/**
* An OPL that represents a real OPL, as opposed to an emulated one.
*
* This will use an actual timer instead of using one calculated from
* the number of samples in an AudioStream::readBuffer call.
*/
class RealOPL : public OPL {
public:
RealOPL();
virtual ~RealOPL();
// OPL API
void setCallbackFrequency(int timerFrequency);
protected:
// OPL API
void startCallbacks(int timerFrequency);
void stopCallbacks();
private:
static void timerProc(void *refCon);
void onTimer();
uint _baseFreq;
uint _remainingTicks;
enum {
kMaxFreq = 100
};
};
/**
* An OPL that represents an emulated OPL.
*
* This will send callbacks based on the number of samples
* decoded in readBuffer().
*/
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();
/**
* Read up to 'length' samples.
*
* Data will be in native endianess, 16 bit per sample, signed.
* For stereo OPL, buffer will be filled with interleaved
* left and right channel samples, starting with a left sample.
* Furthermore, the samples in the left and right are summed up.
* So if you request 4 samples from a stereo OPL, you will get
* a total of two left channel and two right channel samples.
*/
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
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