OpenTTD Source: src/sound/allegro_s.cpp Source File

OpenTTD Source 12.2

allegro_s.cpp
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1 /*
2 * This file is part of OpenTTD.
3 * 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.
4 * 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.
5 * 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/>.
6 */
7
10 #ifdef WITH_ALLEGRO
11
12 #include "../stdafx.h"
13
14 #include "../mixer.h"
15 #include "../debug.h"
16 #include "allegro_s.h"
17 #include <allegro.h>
18
19 #include "../safeguards.h"
20
21 static FSoundDriver_Allegro iFSoundDriver_Allegro;
23 static AUDIOSTREAM *_stream = nullptr;
25 static int _buffer_size;
26
27 void SoundDriver_Allegro::MainLoop()
28 {
29 /* We haven't opened a stream yet */
30 if (_stream == nullptr) return;
31
32 void *data = get_audio_stream_buffer(_stream);
33 /* We don't have to fill the stream yet */
34 if (data == nullptr) return;
35
36 /* Mix the samples */
37 MxMixSamples(data, _buffer_size);
38
39 /* Allegro sound is always unsigned, so we need to correct that */
40 uint16 *snd = (uint16*)data;
41 for (int i = 0; i < _buffer_size * 2; i++) snd[i] ^= 0x8000;
42
43 /* Tell we've filled the stream */
44 free_audio_stream_buffer(_stream);
45 }
46
51 extern int _allegro_instance_count;
52
53 const char *SoundDriver_Allegro::Start(const StringList &parm)
54 {
55 if (_allegro_instance_count == 0 && install_allegro(SYSTEM_AUTODETECT, &errno, nullptr)) {
56 Debug(driver, 0, "allegro: install_allegro failed '{}'", allegro_error);
57 return "Failed to set up Allegro";
58 }
59 _allegro_instance_count++;
60
61 /* Initialise the sound */
62 if (install_sound(DIGI_AUTODETECT, MIDI_AUTODETECT, nullptr) != 0) {
63 Debug(driver, 0, "allegro: install_sound failed '{}'", allegro_error);
64 return "Failed to set up Allegro sound";
65 }
66
67 /* Okay, there's no soundcard */
68 if (digi_card == DIGI_NONE) {
69 Debug(driver, 0, "allegro: no sound card found");
70 return "No sound card found";
71 }
72
73 int hz = GetDriverParamInt(parm, "hz", 44100);
74 _buffer_size = GetDriverParamInt(parm, "samples", 1024) * hz / 11025;
75 _stream = play_audio_stream(_buffer_size, 16, true, hz, 255, 128);
76 MxInitialize(hz);
77 return nullptr;
78 }
79
80 void SoundDriver_Allegro::Stop()
81 {
82 if (_stream != nullptr) {
83 stop_audio_stream(_stream);
84 _stream = nullptr;
85 }
86 remove_sound();
87
88 if (--_allegro_instance_count == 0) allegro_exit();
89 }
90
91 #endif /* WITH_ALLEGRO */
StringList
std::vector< std::string > StringList
Type for a list of strings.
Definition: string_type.h:58
allegro_s.h
SoundDriver_Allegro::MainLoop
void MainLoop()
Called once every tick.
GetDriverParamInt
int GetDriverParamInt(const StringList &parm, const char *name, int def)
Get an integer parameter the list of parameters.
Definition: driver.cpp:73
Debug
#define Debug(name, level, format_string,...)
Ouptut a line of debugging information.
Definition: debug.h:37
FSoundDriver_Allegro
Factory for the allegro sound driver.
Definition: allegro_s.h:27
SoundDriver_Allegro::Stop
void Stop()
Stop this driver.
SoundDriver_Allegro::Start
const char * Start(const StringList &param)
Start this driver.