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  • Committer: Bazaar Package Importer
  • Author(s): Moritz Muehlenhoff
  • Date: 2011-05-25 19:02:23 UTC
  • mto: (21.1.2 sid)
  • mto: This revision was merged to the branch mainline in revision 24.
  • Revision ID: james.westby@ubuntu.com-20110525190223-fiqm0oaec714xk31
Tags: upstream-1.3.0
Import upstream version 1.3.0

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sound/softsynth/emumidi.h
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/* ScummVM - Graphic Adventure Engine
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 *
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 * ScummVM is the legal property of its developers, whose names
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 * are too numerous to list here. Please refer to the COPYRIGHT
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 * file distributed with this source distribution.
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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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 *
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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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 *
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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: https://scummvm.svn.sourceforge.net/svnroot/scummvm/scummvm/tags/release-1-2-1/sound/softsynth/emumidi.h $
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 * $Id: emumidi.h 40932 2009-05-27 00:34:31Z lordhoto $
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 */
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#ifndef SOUND_SOFTSYNTH_EMUMIDI_H
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#define SOUND_SOFTSYNTH_EMUMIDI_H
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#include "sound/audiostream.h"
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#include "sound/mididrv.h"
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#include "sound/mixer.h"
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#define FIXP_SHIFT 16
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class MidiDriver_Emulated : public Audio::AudioStream, public MidiDriver {
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protected:
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        bool _isOpen;
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        Audio::Mixer *_mixer;
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        Audio::SoundHandle _mixerSoundHandle;
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private:
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        Common::TimerManager::TimerProc _timerProc;
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        void *_timerParam;
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        int _nextTick;
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        int _samplesPerTick;
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protected:
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        virtual void generateSamples(int16 *buf, int len) = 0;
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        virtual void onTimer() {}
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        int _baseFreq;
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public:
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        MidiDriver_Emulated(Audio::Mixer *mixer) : _mixer(mixer) {
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                _isOpen = false;
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                _timerProc = 0;
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                _timerParam = 0;
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                _nextTick = 0;
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                _samplesPerTick = 0;
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                _baseFreq = 250;
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        }
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        int open() {
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                _isOpen = true;
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                int d = getRate() / _baseFreq;
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                int r = getRate() % _baseFreq;
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                // This is equivalent to (getRate() << FIXP_SHIFT) / BASE_FREQ
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                // but less prone to arithmetic overflow.
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                _samplesPerTick = (d << FIXP_SHIFT) + (r << FIXP_SHIFT) / _baseFreq;
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                return 0;
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        }
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        void setTimerCallback(void *timer_param, Common::TimerManager::TimerProc timer_proc) {
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                _timerProc = timer_proc;
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                _timerParam = timer_param;
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        }
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        uint32 getBaseTempo() { return 1000000 / _baseFreq; }
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        // AudioStream API
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        int readBuffer(int16 *data, const int numSamples) {
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                const int stereoFactor = isStereo() ? 2 : 1;
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                int len = numSamples / stereoFactor;
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                int step;
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                do {
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                        step = len;
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                        if (step > (_nextTick >> FIXP_SHIFT))
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                                step = (_nextTick >> FIXP_SHIFT);
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                        generateSamples(data, step);
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                        _nextTick -= step << FIXP_SHIFT;
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                        if (!(_nextTick >> FIXP_SHIFT)) {
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                                if (_timerProc)
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                                        (*_timerProc)(_timerParam);
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                                onTimer();
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                                _nextTick += _samplesPerTick;
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                        }
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                        data += step * stereoFactor;
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                        len -= step;
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                } while (len);
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                return numSamples;
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        }
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        bool endOfData() const { return false; }
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};
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#endif