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

OpenTTD Source 15.0-RC2

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 <https://www.gnu.org/licenses/old-licenses/gpl-2.0>.
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
21static FSoundDriver_Allegro iFSoundDriver_Allegro;
23static AUDIOSTREAM *_stream = nullptr;
25static int _buffer_size;
26
27void 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_t *snd = (uint16_t*)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
51extern int _allegro_instance_count;
52
53std::optional<std::string_view> 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 std::nullopt;
78}
79
80void 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 */
allegro_s.h
Base for playing sound via Allegro.
FSoundDriver_Allegro
Factory for the allegro sound driver.
Definition allegro_s.h:27
SoundDriver_Allegro::Stop
void Stop() override
Stop this driver.
SoundDriver_Allegro::MainLoop
void MainLoop() override
Called once every tick.
SoundDriver_Allegro::Start
std::optional< std::string_view > Start(const StringList &param) override
Start this driver.
Debug
#define Debug(category, level, format_string,...)
Output a line of debugging information.
Definition debug.h:37
GetDriverParamInt
int GetDriverParamInt(const StringList &parm, std::string_view name, int def)
Get an integer parameter the list of parameters.
Definition driver.cpp:79
StringList
std::vector< std::string > StringList
Type for a list of strings.
Definition string_type.h:60