/* * This example code creates a mixer, loads a single sound, and plays it, with * several playback options (fade-in, loop, etc). * * This code is public domain. Feel free to use it for any purpose! */ #define SDL_MAIN_USE_CALLBACKS 1 /* use the callbacks instead of main() */ #include #include #include /* We will use this renderer to draw into this window every frame. */ static SDL_Window *window = NULL; static SDL_Renderer *renderer = NULL; static MIX_Mixer *mixer = NULL; static MIX_Track *track = NULL; /* This function runs once at startup. */ SDL_AppResult SDL_AppInit(void **appstate, int argc, char *argv[]) { char *path = NULL; MIX_Audio *audio = NULL; SDL_PropertiesID options = 0; SDL_SetAppMetadata("Example Play With Options", "1.0", "com.example.play-with-options"); /* this doesn't have to run very much, so give up tons of CPU time between iterations. Optional! */ SDL_SetHint(SDL_HINT_MAIN_CALLBACK_RATE, "5"); /* we don't need video, but we'll make a window for smooth operation. */ if (!SDL_Init(SDL_INIT_VIDEO)) { SDL_Log("Couldn't initialize SDL: %s", SDL_GetError()); return SDL_APP_FAILURE; } if (!SDL_CreateWindowAndRenderer("examples/basic/play-with-options", 640, 480, SDL_WINDOW_RESIZABLE, &window, &renderer)) { SDL_Log("Couldn't create window/renderer: %s", SDL_GetError()); return SDL_APP_FAILURE; } if (!MIX_Init()) { SDL_Log("Couldn't init SDL_mixer library: %s", SDL_GetError()); return SDL_APP_FAILURE; } /* Create a mixer on the default audio device. Don't care about the specific audio format. */ mixer = MIX_CreateMixerDevice(SDL_AUDIO_DEVICE_DEFAULT_PLAYBACK, NULL); if (!mixer) { SDL_Log("Couldn't create mixer on default device: %s", SDL_GetError()); return SDL_APP_FAILURE; } /* load a sound file */ SDL_asprintf(&path, "%smusic.mp3", SDL_GetBasePath()); /* allocate a string of the full file path */ audio = MIX_LoadAudio(mixer, path, false); if (!audio) { SDL_Log("Couldn't load %s: %s", path, SDL_GetError()); SDL_free(path); return SDL_APP_FAILURE; } SDL_free(path); /* done with this, the file is loaded. */ /* we need a track on the mixer to play the audio. Each track has audio assigned to it, and all playing tracks are mixed together for the final output. */ track = MIX_CreateTrack(mixer); if (!track) { SDL_Log("Couldn't create a mixer track: %s", SDL_GetError()); return SDL_APP_FAILURE; } MIX_SetTrackAudio(track, audio); /* start the audio playing! */ options = SDL_CreateProperties(); if (!options) { SDL_Log("Couldn't create play options: %s", SDL_GetError()); return SDL_APP_FAILURE; } /* note these all use MILLISECONDS, since the track is generic, but you can use equivalent FRAMES properties, for frame-perfect mixing. */ SDL_SetNumberProperty(options, MIX_PROP_PLAY_START_MILLISECOND_NUMBER, 1000); /* start the first loop 1 second into the audio. */ SDL_SetNumberProperty(options, MIX_PROP_PLAY_MAX_MILLISECONDS_NUMBER, 10000); /* play at most 10 seconds of audio before ending/looping (since we started 1000 in, this will be the eleventh second). */ SDL_SetNumberProperty(options, MIX_PROP_PLAY_LOOPS_NUMBER, 2); /* loop 2 times, 3rd time through doesn't loop. */ SDL_SetNumberProperty(options, MIX_PROP_PLAY_LOOP_START_MILLISECOND_NUMBER, 2000); /* when looping, start again here instead of the start of the track. */ SDL_SetNumberProperty(options, MIX_PROP_PLAY_FADE_IN_MILLISECONDS_NUMBER, 5000); /* fade-in the first loop over five seconds. No fade on the loops, unless the initial fade is still in progress! */ MIX_PlayTrack(track, options); SDL_DestroyProperties(options); /* MIX_PlayTrack makes a copy of the options, so this can go away. */ /* we don't save `audio`; SDL_mixer will clean it up for us during MIX_Quit(). */ return SDL_APP_CONTINUE; /* carry on with the program! */ } /* This function runs when a new event (mouse input, keypresses, etc) occurs. */ SDL_AppResult SDL_AppEvent(void *appstate, SDL_Event *event) { if (event->type == SDL_EVENT_QUIT) { return SDL_APP_SUCCESS; /* end the program, reporting success to the OS. */ } return SDL_APP_CONTINUE; /* carry on with the program! */ } /* This function runs once per frame, and is the heart of the program. */ SDL_AppResult SDL_AppIterate(void *appstate) { /* draw a blank video frame to keep the OS happy */ SDL_RenderClear(renderer); SDL_RenderPresent(renderer); /* when the track has finished playing, end the program. */ if (!MIX_TrackPlaying(track)) { return SDL_APP_SUCCESS; } return SDL_APP_CONTINUE; /* carry on with the program! */ } /* This function runs once at shutdown. */ void SDL_AppQuit(void *appstate, SDL_AppResult result) { /* SDL will clean up the window/renderer for us, MIX_Quit() destroys any mixer objects we made. */ MIX_Quit(); }