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author | Max Horn | 2004-10-17 17:49:45 +0000 |
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committer | Max Horn | 2004-10-17 17:49:45 +0000 |
commit | 267144e69c09862c230506ec1550b6b1ac8437f3 (patch) | |
tree | 0115f95a43c141541c2f05bf209a9d9cfe1db910 /backends/midi/emumidi.h | |
parent | 649eb19a3ed45dbea8b2796a57190ff18534fffe (diff) | |
download | scummvm-rg350-267144e69c09862c230506ec1550b6b1ac8437f3.tar.gz scummvm-rg350-267144e69c09862c230506ec1550b6b1ac8437f3.tar.bz2 scummvm-rg350-267144e69c09862c230506ec1550b6b1ac8437f3.zip |
added MidiDriver_Emulated base class used by the adlib & ym2612 midi 'drivers'
svn-id: r15589
Diffstat (limited to 'backends/midi/emumidi.h')
-rw-r--r-- | backends/midi/emumidi.h | 96 |
1 files changed, 96 insertions, 0 deletions
diff --git a/backends/midi/emumidi.h b/backends/midi/emumidi.h new file mode 100644 index 0000000000..e5daa40647 --- /dev/null +++ b/backends/midi/emumidi.h @@ -0,0 +1,96 @@ +/* ScummVM - Scumm Interpreter + * Copyright (C) 2001-2004 The ScummVM project + * + * 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., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * $Header$ + */ + +#include "stdafx.h" +#include "sound/audiostream.h" +#include "sound/mididrv.h" +#include "sound/mixer.h" + +#define BASE_FREQ 250 +#define FIXP_SHIFT 16 + +class MidiDriver_Emulated : public AudioStream, public MidiDriver { +protected: + bool _isOpen; + SoundMixer *_mixer; + +private: + Timer::TimerProc _timer_proc; + void *_timer_param; + + int _next_tick; + int _samples_per_tick; + +protected: + virtual void generate_samples(int16 *buf, int len) = 0; + +public: + MidiDriver_Emulated(SoundMixer *mixer) : _mixer(mixer) { + _isOpen = false; + + _timer_proc = 0; + _timer_param = 0; + + _next_tick = 0; + _samples_per_tick = 0; + } + + int open() { + _isOpen = true; + _samples_per_tick = (getRate() << FIXP_SHIFT) / BASE_FREQ; + } + + void setTimerCallback(void *timer_param, Timer::TimerProc timer_proc) { + _timer_proc = timer_proc; + _timer_param = timer_param; + } + + uint32 getBaseTempo() { return 1000000 / BASE_FREQ; } + + + // AudioStream API + int readBuffer(int16 *data, const int numSamples) { + const int stereoFactor = isStereo() ? 2 : 1; + int len = numSamples / stereoFactor; + int step; + + do { + step = len; + if (step > (_next_tick >> FIXP_SHIFT)) + step = (_next_tick >> FIXP_SHIFT); + generate_samples(data, step); + + _next_tick -= step << FIXP_SHIFT; + if (!(_next_tick >> FIXP_SHIFT)) { + if (_timer_proc) + (*_timer_proc)(_timer_param); + _next_tick += _samples_per_tick; + } + data += step * stereoFactor; + len -= step; + } while (len); + + return numSamples; + } + int16 read() { + error("ProcInputStream::read not supported"); + } + bool endOfData() const { return false; } +}; |