# allegro_s.cpp

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    00001 /* $Id: allegro_s.cpp 16804 2009-07-13 10:16:50Z rubidium $ */
    00002
    00005 #ifdef WITH_ALLEGRO
    00006
    00007 #include "../stdafx.h"
    00008
    00009 #include "../driver.h"
    00010 #include "../mixer.h"
    00011 #include "../sdl.h"
    00012 #include "../debug.h"
    00013 #include "allegro_s.h"
    00014 #include <allegro.h>
    00015
    00016 static FSoundDriver_Allegro iFSoundDriver_Allegro;
    00018 static AUDIOSTREAM *_stream = NULL;
    00020 static const int BUFFER_SIZE = 512;
    00021
    00022 void SoundDriver_Allegro::MainLoop()
    00023 {
    00024   /* We haven't opened a stream yet */
    00025   if (_stream == NULL) return;
    00026
    00027   void *data = get_audio_stream_buffer(_stream);
    00028   /* We don't have to fill the stream yet */
    00029   if (data == NULL) return;
    00030
    00031   /* Mix the samples */
    00032   MxMixSamples(data, BUFFER_SIZE);
    00033
    00034   /* Allegro sound is always unsigned, so we need to correct that */
    00035   uint16 *snd = (uint16*)data;
    00036   for (int i = 0; i < BUFFER_SIZE * 2; i++) snd[i] ^= 0x8000;
    00037
    00038   /* Tell we've filled the stream */
    00039   free_audio_stream_buffer(_stream);
    00040 }
    00041
    00044 extern int _allegro_instance_count;
    00045
    00046 const char *SoundDriver_Allegro::Start(const char * const *parm)
    00047 {
    00048   if (_allegro_instance_count == 0 && install_allegro(SYSTEM_AUTODETECT, &errno, NULL)) return "Failed to set up Allegro";
    00049   _allegro_instance_count++;
    00050
    00051   /* Initialise the sound */
    00052   if (install_sound(DIGI_AUTODETECT, MIDI_AUTODETECT, NULL) != 0) return "Failed to set up Allegro sound";
    00053
    00054   /* Okay, there's no soundcard */
    00055   if (digi_card == DIGI_NONE) {
    00056     DEBUG(driver, 0, "allegro: no sound card found");
    00057     return "No sound card found";
    00058   }
    00059
    00060   _stream = play_audio_stream(BUFFER_SIZE, 16, true, 11025, 255, 128);
    00061   MxInitialize(11025);
    00062   return NULL;
    00063 }
    00064
    00065 void SoundDriver_Allegro::Stop()
    00066 {
    00067   if (_stream != NULL) {
    00068     stop_audio_stream(_stream);
    00069     _stream = NULL;
    00070   }
    00071   remove_sound();
    00072
    00073   if (--_allegro_instance_count == 0) allegro_exit();
    00074 }
    00075
    00076 #endif /* WITH_ALLEGRO */