sdl

FORK: Simple Directmedia Layer
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loopwavequeue.c (3805B)

      1 /*
      2   Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
      3 
      4   This software is provided 'as-is', without any express or implied
      5   warranty.  In no event will the authors be held liable for any damages
      6   arising from the use of this software.
      7 
      8   Permission is granted to anyone to use this software for any purpose,
      9   including commercial applications, and to alter it and redistribute it
     10   freely.
     11 */
     12 
     13 /* Program to load a wave file and loop playing it using SDL sound queueing */
     14 
     15 #include <stdio.h>
     16 #include <stdlib.h>
     17 
     18 #ifdef __EMSCRIPTEN__
     19 #include <emscripten/emscripten.h>
     20 #endif
     21 
     22 #include "SDL.h"
     23 
     24 #if HAVE_SIGNAL_H
     25 #include <signal.h>
     26 #endif
     27 
     28 static struct
     29 {
     30     SDL_AudioSpec spec;
     31     Uint8 *sound;               /* Pointer to wave data */
     32     Uint32 soundlen;            /* Length of wave data */
     33 } wave;
     34 
     35 
     36 /* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
     37 static void
     38 quit(int rc)
     39 {
     40     SDL_Quit();
     41     exit(rc);
     42 }
     43 
     44 static int done = 0;
     45 void
     46 poked(int sig)
     47 {
     48     done = 1;
     49 }
     50 
     51 void
     52 loop()
     53 {
     54 #ifdef __EMSCRIPTEN__
     55     if (done || (SDL_GetAudioStatus() != SDL_AUDIO_PLAYING)) {
     56         emscripten_cancel_main_loop();
     57     }
     58     else
     59 #endif
     60     {
     61         /* The device from SDL_OpenAudio() is always device #1. */
     62         const Uint32 queued = SDL_GetQueuedAudioSize(1);
     63         SDL_Log("Device has %u bytes queued.\n", (unsigned int) queued);
     64         if (queued <= 8192) {  /* time to requeue the whole thing? */
     65             if (SDL_QueueAudio(1, wave.sound, wave.soundlen) == 0) {
     66                 SDL_Log("Device queued %u more bytes.\n", (unsigned int) wave.soundlen);
     67             } else {
     68                 SDL_Log("Device FAILED to queue %u more bytes: %s\n", (unsigned int) wave.soundlen, SDL_GetError());
     69             }
     70         }
     71     }
     72 }
     73 
     74 int
     75 main(int argc, char *argv[])
     76 {
     77     char filename[4096];
     78 
     79     /* Enable standard application logging */
     80     SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);
     81 
     82     /* Load the SDL library */
     83     if (SDL_Init(SDL_INIT_AUDIO) < 0) {
     84         SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
     85         return (1);
     86     }
     87 
     88     if (argc > 1) {
     89         SDL_strlcpy(filename, argv[1], sizeof(filename));
     90     } else {
     91         SDL_strlcpy(filename, "sample.wav", sizeof(filename));
     92     }
     93     /* Load the wave file into memory */
     94     if (SDL_LoadWAV(filename, &wave.spec, &wave.sound, &wave.soundlen) == NULL) {
     95         SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't load %s: %s\n", filename, SDL_GetError());
     96         quit(1);
     97     }
     98 
     99     wave.spec.callback = NULL;  /* we'll push audio. */
    100 
    101 #if HAVE_SIGNAL_H
    102     /* Set the signals */
    103 #ifdef SIGHUP
    104     signal(SIGHUP, poked);
    105 #endif
    106     signal(SIGINT, poked);
    107 #ifdef SIGQUIT
    108     signal(SIGQUIT, poked);
    109 #endif
    110     signal(SIGTERM, poked);
    111 #endif /* HAVE_SIGNAL_H */
    112 
    113     /* Initialize fillerup() variables */
    114     if (SDL_OpenAudio(&wave.spec, NULL) < 0) {
    115         SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open audio: %s\n", SDL_GetError());
    116         SDL_FreeWAV(wave.sound);
    117         quit(2);
    118     }
    119 
    120     /*static x[99999]; SDL_QueueAudio(1, x, sizeof (x));*/
    121 
    122     /* Let the audio run */
    123     SDL_PauseAudio(0);
    124 
    125     done = 0;
    126 
    127     /* Note that we stuff the entire audio buffer into the queue in one
    128        shot. Most apps would want to feed it a little at a time, as it
    129        plays, but we're going for simplicity here. */
    130     
    131 #ifdef __EMSCRIPTEN__
    132     emscripten_set_main_loop(loop, 0, 1);
    133 #else
    134     while (!done && (SDL_GetAudioStatus() == SDL_AUDIO_PLAYING))
    135     {
    136         loop();
    137 
    138         SDL_Delay(100);  /* let it play for awhile. */
    139     }
    140 #endif
    141 
    142     /* Clean up on signal */
    143     SDL_CloseAudio();
    144     SDL_FreeWAV(wave.sound);
    145     SDL_Quit();
    146     return 0;
    147 }
    148 
    149 /* vi: set ts=4 sw=4 expandtab: */