SDL/test/loopwave.c

/*
  Copyright (C) 1997-2017 Sam Lantinga <slouken@libsdl.org>

  This software is provided 'as-is', without any express or implied
  warranty.  In no event will the authors be held liable for any damages
  arising from the use of this software.

  Permission is granted to anyone to use this software for any purpose,
  including commercial applications, and to alter it and redistribute it
  freely.
*/

/* Program to load a wave file and loop playing it using SDL audio */

/* loopwaves.c is much more robust in handling WAVE files --
    This is only for simple WAVEs
*/
#include "SDL_config.h"

#include <stdio.h>
#include <stdlib.h>

#if HAVE_SIGNAL_H
#include <signal.h>
#endif

#ifdef __EMSCRIPTEN__
#include <emscripten/emscripten.h>
#endif

#include "SDL.h"

struct
{
    SDL_AudioSpec spec;
    Uint8 *sound;               /* Pointer to wave data */
    Uint32 soundlen;            /* Length of wave data */
    int soundpos;               /* Current play position */
} wave;


/* Call this instead of exit(), so we can clean up SDL: atexit() is evil. */
static void
quit(int rc)
{
    SDL_Quit();
    exit(rc);
}


void SDLCALL
fillerup(void *unused, Uint8 * stream, int len)
{
    Uint8 *waveptr;
    int waveleft;

    /* Set up the pointers */
    waveptr = wave.sound + wave.soundpos;
    waveleft = wave.soundlen - wave.soundpos;

    /* Go! */
    while (waveleft <= len) {
        SDL_memcpy(stream, waveptr, waveleft);
        stream += waveleft;
        len -= waveleft;
        waveptr = wave.sound;
        waveleft = wave.soundlen;
        wave.soundpos = 0;
    }
    SDL_memcpy(stream, waveptr, len);
    wave.soundpos += len;
}

static int done = 0;
void
poked(int sig)
{
    done = 1;
}

#ifdef __EMSCRIPTEN__
void
loop()
{
    if(done || (SDL_GetAudioStatus() != SDL_AUDIO_PLAYING))
        emscripten_cancel_main_loop();
}
#endif

int
main(int argc, char *argv[])
{
    int i;
    char filename[4096];

    /* Enable standard application logging */
    SDL_LogSetPriority(SDL_LOG_CATEGORY_APPLICATION, SDL_LOG_PRIORITY_INFO);

    /* Load the SDL library */
    if (SDL_Init(SDL_INIT_AUDIO) < 0) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't initialize SDL: %s\n", SDL_GetError());
        return (1);
    }

    if (argc > 1) {
        SDL_strlcpy(filename, argv[1], sizeof(filename));
    } else {
        SDL_strlcpy(filename, "sample.wav", sizeof(filename));
    }
    /* Load the wave file into memory */
    if (SDL_LoadWAV(filename, &wave.spec, &wave.sound, &wave.soundlen) == NULL) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't load %s: %s\n", filename, SDL_GetError());
        quit(1);
    }

    wave.spec.callback = fillerup;
#if HAVE_SIGNAL_H
    /* Set the signals */
#ifdef SIGHUP
    signal(SIGHUP, poked);
#endif
    signal(SIGINT, poked);
#ifdef SIGQUIT
    signal(SIGQUIT, poked);
#endif
    signal(SIGTERM, poked);
#endif /* HAVE_SIGNAL_H */

    /* Show the list of available drivers */
    SDL_Log("Available audio drivers:");
    for (i = 0; i < SDL_GetNumAudioDrivers(); ++i) {
        SDL_Log("%i: %s", i, SDL_GetAudioDriver(i));
    }

    /* Initialize fillerup() variables */
    if (SDL_OpenAudio(&wave.spec, NULL) < 0) {
        SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open audio: %s\n", SDL_GetError());
        SDL_FreeWAV(wave.sound);
        quit(2);
    }

    SDL_Log("Using audio driver: %s\n", SDL_GetCurrentAudioDriver());

    /* Let the audio run */
    SDL_PauseAudio(0);

#ifdef __EMSCRIPTEN__
    emscripten_set_main_loop(loop, 0, 1);
#else
    while (!done && (SDL_GetAudioStatus() == SDL_AUDIO_PLAYING))
        SDL_Delay(1000);
#endif

    /* Clean up on signal */
    SDL_CloseAudio();
    SDL_FreeWAV(wave.sound);
    SDL_Quit();
    return (0);
}

/* vi: set ts=4 sw=4 expandtab: */