# allegro_s.cpp

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    00001 /* $Id: allegro_s.cpp 17787 2009-10-17 14:39:43Z rubidium $ */
    00002
    00003 /*
    00004  * This file is part of OpenTTD.
    00005  * OpenTTD 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, version 2.
    00006  * OpenTTD 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.
    00007  * See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with OpenTTD. If not, see <http://www.gnu.org/licenses/>.
    00008  */
    00009
    00012 #ifdef WITH_ALLEGRO
    00013
    00014 #include "../stdafx.h"
    00015
    00016 #include "../driver.h"
    00017 #include "../mixer.h"
    00018 #include "../debug.h"
    00019 #include "allegro_s.h"
    00020 #include <allegro.h>
    00021
    00022 static FSoundDriver_Allegro iFSoundDriver_Allegro;
    00024 static AUDIOSTREAM *_stream = NULL;
    00026 static const int BUFFER_SIZE = 4096;
    00027
    00028 void SoundDriver_Allegro::MainLoop()
    00029 {
    00030   /* We haven't opened a stream yet */
    00031   if (_stream == NULL) return;
    00032
    00033   void *data = get_audio_stream_buffer(_stream);
    00034   /* We don't have to fill the stream yet */
    00035   if (data == NULL) return;
    00036
    00037   /* Mix the samples */
    00038   MxMixSamples(data, BUFFER_SIZE);
    00039
    00040   /* Allegro sound is always unsigned, so we need to correct that */
    00041   uint16 *snd = (uint16*)data;
    00042   for (int i = 0; i < BUFFER_SIZE * 2; i++) snd[i] ^= 0x8000;
    00043
    00044   /* Tell we've filled the stream */
    00045   free_audio_stream_buffer(_stream);
    00046 }
    00047
    00050 extern int _allegro_instance_count;
    00051
    00052 const char *SoundDriver_Allegro::Start(const char * const *parm)
    00053 {
    00054   if (_allegro_instance_count == 0 && install_allegro(SYSTEM_AUTODETECT, &errno, NULL)) {
    00055     DEBUG(driver, 0, "allegro: install_allegro failed '%s'", allegro_error);
    00056     return "Failed to set up Allegro";
    00057   }
    00058   _allegro_instance_count++;
    00059
    00060   /* Initialise the sound */
    00061   if (install_sound(DIGI_AUTODETECT, MIDI_AUTODETECT, NULL) != 0) {
    00062     DEBUG(driver, 0, "allegro: install_sound failed '%s'", allegro_error);
    00063     return "Failed to set up Allegro sound";
    00064   }
    00065
    00066   /* Okay, there's no soundcard */
    00067   if (digi_card == DIGI_NONE) {
    00068     DEBUG(driver, 0, "allegro: no sound card found");
    00069     return "No sound card found";
    00070   }
    00071
    00072   _stream = play_audio_stream(BUFFER_SIZE, 16, true, 44100, 255, 128);
    00073   MxInitialize(44100);
    00074   return NULL;
    00075 }
    00076
    00077 void SoundDriver_Allegro::Stop()
    00078 {
    00079   if (_stream != NULL) {
    00080     stop_audio_stream(_stream);
    00081     _stream = NULL;
    00082   }
    00083   remove_sound();
    00084
    00085   if (--_allegro_instance_count == 0) allegro_exit();
    00086 }
    00087
    00088 #endif /* WITH_ALLEGRO */