allegro_m.cpp

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/*
 * This file is part of OpenTTD.
 * 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.
 * 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.
 * 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/>.
 */
 
#ifdef WITH_ALLEGRO
 
#include "../stdafx.h"
#include "../debug.h"
#include "allegro_m.h"
#include "midifile.hpp"
#include <allegro.h>
 
#include "../safeguards.h"
 
static FMusicDriver_Allegro iFMusicDriver_Allegro;
static MIDI *_midi = nullptr;
 
extern int _allegro_instance_count;
 
std::optional<std::string_view> MusicDriver_Allegro::Start(const StringList &)
{
  if (_allegro_instance_count == 0 && install_allegro(SYSTEM_AUTODETECT, &errno, nullptr)) {
    Debug(driver, 0, "allegro: install_allegro failed '{}'", allegro_error);
    return "Failed to set up Allegro";
  }
  _allegro_instance_count++;
 
  /* Initialise the sound */
  if (install_sound(DIGI_AUTODETECT, MIDI_AUTODETECT, nullptr) != 0) {
    Debug(driver, 0, "allegro: install_sound failed '{}'", allegro_error);
    return "Failed to set up Allegro sound";
  }
 
  /* Okay, there's no soundcard */
  if (midi_card == MIDI_NONE) {
    Debug(driver, 0, "allegro: no midi card found");
    return "No sound card found";
  }
 
  return std::nullopt;
}
 
void MusicDriver_Allegro::Stop()
{
  if (_midi != nullptr) destroy_midi(_midi);
  _midi = nullptr;
 
  if (--_allegro_instance_count == 0) allegro_exit();
}
 
void MusicDriver_Allegro::PlaySong(const MusicSongInfo &song)
{
  std::string filename = MidiFile::GetSMFFile(song);
 
  if (_midi != nullptr) destroy_midi(_midi);
  if (!filename.empty()) {
    _midi = load_midi(filename.c_str());
    play_midi(_midi, false);
  } else {
    _midi = nullptr;
  }
}
 
void MusicDriver_Allegro::StopSong()
{
  stop_midi();
}
 
bool MusicDriver_Allegro::IsSongPlaying()
{
  return midi_pos >= 0;
}
 
void MusicDriver_Allegro::SetVolume(uint8_t vol)
{
  set_volume(-1, vol);
}
 
#endif /* WITH_ALLEGRO */