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95 lines
2.5 KiB
C++
95 lines
2.5 KiB
C++
/* ScummVM - Scumm Interpreter
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* Copyright (C) 2007 The ScummVM project
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2
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* of the License, or (at your option) any later version.
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* $URL$
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* $Id$
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*
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*/
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#ifndef SOUND_MODS_PAULA_H
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#define SOUND_MODS_PAULA_H
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#include "sound/audiostream.h"
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#include "common/mutex.h"
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namespace Audio {
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/**
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* Emulation of the "Paula" Amiga music chip
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* The interrupt frequency specifies the number of mixed wavesamples between
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* calls of the interrupt method
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*/
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class Paula : public AudioStream {
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public:
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static const int NUM_VOICES = 4;
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Paula(bool stereo = false, int rate = 44100, int interruptFreq = 0);
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~Paula();
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bool playing() const { return _playing; }
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void setInterruptFreq(int freq) { _intFreq = freq; }
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void setPanning(byte voice, byte panning) {
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assert(voice < NUM_VOICES);
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_voice[voice].panning = panning;
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}
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void clearVoice(byte voice);
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void clearVoices() { for (int i = 0; i < NUM_VOICES; ++i) clearVoice(i); }
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virtual void startPlay(void) {}
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virtual void stopPlay(void) {}
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virtual void pausePlay(bool pause) {}
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// AudioStream API
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int readBuffer(int16 *buffer, const int numSamples);
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bool isStereo() const { return _stereo; }
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bool endOfData() const { return _end; }
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int getRate() const { return _rate; }
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protected:
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struct Channel {
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int8 *data;
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int8 *dataRepeat;
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uint32 length;
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uint32 lengthRepeat;
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int16 period;
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byte volume;
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double offset;
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byte panning; // For stereo mixing: 0 = far left, 255 = far right
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} _voice[NUM_VOICES];
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int _rate;
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int _intFreq;
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int _curInt;
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bool _stereo;
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bool _end;
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bool _playing;
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Common::Mutex _mutex;
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void mix(int16 *&buf, int8 data, int voice) {
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const int32 tmp = ((int32) data) * _voice[voice].volume;
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if (_stereo) {
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*buf++ += (tmp * (255 - _voice[voice].panning)) >> 7;
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*buf++ += (tmp * (_voice[voice].panning)) >> 7;
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} else
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*buf++ += tmp;
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}
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virtual void interrupt(void) {};
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};
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} // End of namespace Audio
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#endif
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