OpenTTD: src/sound/allegro_s.cpp Source File

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allegro_s.cpp
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1 /* $Id: allegro_s.cpp 26482 2014-04-23 20:13:33Z rubidium $ */
2
3 /*
4 * This file is part of OpenTTD.
5 * 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.
6 * 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.
7 * 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/>.
8 */
9
12 #ifdef WITH_ALLEGRO
13
14 #include "../stdafx.h"
15
16 #include "../mixer.h"
17 #include "../debug.h"
18 #include "allegro_s.h"
19 #include <allegro.h>
20
21 #include "../safeguards.h"
22
23 static FSoundDriver_Allegro iFSoundDriver_Allegro;
25 static AUDIOSTREAM *_stream = NULL;
27 static int _buffer_size;
28
29 void SoundDriver_Allegro::MainLoop()
30 {
31 /* We haven't opened a stream yet */
32 if (_stream == NULL) return;
33
34 void *data = get_audio_stream_buffer(_stream);
35 /* We don't have to fill the stream yet */
36 if (data == NULL) return;
37
38 /* Mix the samples */
39 MxMixSamples(data, _buffer_size);
40
41 /* Allegro sound is always unsigned, so we need to correct that */
42 uint16 *snd = (uint16*)data;
43 for (int i = 0; i < _buffer_size * 2; i++) snd[i] ^= 0x8000;
44
45 /* Tell we've filled the stream */
46 free_audio_stream_buffer(_stream);
47 }
48
53 extern int _allegro_instance_count;
54
55 const char *SoundDriver_Allegro::Start(const char * const *parm)
56 {
57 if (_allegro_instance_count == 0 && install_allegro(SYSTEM_AUTODETECT, &errno, NULL)) {
58 DEBUG(driver, 0, "allegro: install_allegro failed '%s'", allegro_error);
59 return "Failed to set up Allegro";
60 }
61 _allegro_instance_count++;
62
63 /* Initialise the sound */
64 if (install_sound(DIGI_AUTODETECT, MIDI_AUTODETECT, NULL) != 0) {
65 DEBUG(driver, 0, "allegro: install_sound failed '%s'", allegro_error);
66 return "Failed to set up Allegro sound";
67 }
68
69 /* Okay, there's no soundcard */
70 if (digi_card == DIGI_NONE) {
71 DEBUG(driver, 0, "allegro: no sound card found");
72 return "No sound card found";
73 }
74
75 int hz = GetDriverParamInt(parm, "hz", 44100);
76 _buffer_size = GetDriverParamInt(parm, "samples", 1024) * hz / 11025;
77 _stream = play_audio_stream(_buffer_size, 16, true, hz, 255, 128);
78 MxInitialize(hz);
79 return NULL;
80 }
81
82 void SoundDriver_Allegro::Stop()
83 {
84 if (_stream != NULL) {
85 stop_audio_stream(_stream);
86 _stream = NULL;
87 }
88 remove_sound();
89
90 if (--_allegro_instance_count == 0) allegro_exit();
91 }
92
93 #endif /* WITH_ALLEGRO */