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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 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() {}
/**
* The type of the timer callback functor.
*/
typedef Common::Functor0<void> TimerCallback;
/**
* Start the sound chip with callbacks.
*/
void start(TimerCallback *callback, int timerFrequency);
/**
* Stop the sound chip
*/
void stop();
/**
* Change the callback frequency. This must only be called from a
* timer proc.
*/
virtual void setCallbackFrequency(int timerFrequency) = 0;
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;
};
/**
* A Chip that represents a real sound chip, 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 RealChip : virtual public Chip {
public:
RealChip();
virtual ~RealChip();
// Chip API
void setCallbackFrequency(int timerFrequency);
protected:
// Chip API
void startCallbacks(int timerFrequency);
void stopCallbacks();
virtual void onTimer();
private:
static void timerProc(void *refCon);
uint _baseFreq;
uint _remainingTicks;
enum {
kMaxFreq = 100
};
};
/**
* A Chip that represents an emulated sound chip.
*
* This will send callbacks based on the number of samples
* decoded in readBuffer().
*/
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;
/**
* Read up to 'length' samples.
*
* Data will be in native endianess, 16 bit per sample, signed.
* For stereo chips, 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 chip, 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;
int _nextTick;
int _samplesPerTick;
Audio::SoundHandle *_handle;
};
} // End of namespace Audio
#endif
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