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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.
*
* $URL$
* $Id$
*
*/
#ifndef SOUND_MODS_PAULA_H
#define SOUND_MODS_PAULA_H
#include "sound/audiostream.h"
#include "common/mutex.h"
namespace Audio {
/**
* Emulation of the "Paula" Amiga music chip
* The interrupt frequency specifies the number of mixed wavesamples between
* calls of the interrupt method
*/
class Paula : public AudioStream {
public:
static const int NUM_VOICES = 4;
Paula(bool stereo = false, int rate = 44100, int interruptFreq = 0);
~Paula();
bool playing() const { return _playing; }
void setInterruptFreq(int freq) { _curInt = _intFreq = freq; }
void setPanning(byte voice, byte panning) {
assert(voice < NUM_VOICES);
_voice[voice].panning = panning;
}
void clearVoice(byte voice);
void clearVoices() { for (int i = 0; i < NUM_VOICES; ++i) clearVoice(i); }
virtual void startPlay(void) {}
virtual void stopPlay(void) {}
virtual void pausePlay(bool pause) {}
// AudioStream API
int readBuffer(int16 *buffer, const int numSamples);
bool isStereo() const { return _stereo; }
bool endOfData() const { return _end; }
int getRate() const { return _rate; }
protected:
struct Channel {
const int8 *data;
const int8 *dataRepeat;
uint32 length;
uint32 lengthRepeat;
int16 period;
byte volume;
double offset;
byte panning; // For stereo mixing: 0 = far left, 255 = far right
} _voice[NUM_VOICES];
int _rate;
int _intFreq;
int _curInt;
bool _stereo;
bool _end;
bool _playing;
Common::Mutex _mutex;
void mix(int16 *&buf, int8 data, int voice) {
const int32 tmp = ((int32) data) * _voice[voice].volume;
if (_stereo) {
*buf++ += (tmp * (255 - _voice[voice].panning)) >> 7;
*buf++ += (tmp * (_voice[voice].panning)) >> 7;
} else
*buf++ += tmp;
}
virtual void interrupt(void) {}
};
} // End of namespace Audio
#endif
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