view test/loopwave.c @ 4001:6831b8723a85 SDL-1.2

Don't initialize the audio buffer passed to the application's audio callback, since they are expected to entirely fill it with data or silence. For legacy apps that might expect the buffer to already have silence and thus may not fill the buffer in the callback, there's an environment variable to expose the old behaviour. Fixes Bugzilla #416.
author Ryan C. Gordon <icculus@icculus.org>
date Thu, 05 Jul 2007 02:24:36 +0000
parents 290b5baf2fca
children 8b9d79e7eacf c121d94672cb e905bb5d9bc3
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/* Program to load a wave file and loop playing it using SDL sound */

/* 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

#include "SDL.h"
#include "SDL_audio.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_MixAudio(stream, waveptr, waveleft, SDL_MIX_MAXVOLUME);
		stream += waveleft;
		len -= waveleft;
		waveptr = wave.sound;
		waveleft = wave.soundlen;
		wave.soundpos = 0;
	}
	SDL_MixAudio(stream, waveptr, len, SDL_MIX_MAXVOLUME);
	wave.soundpos += len;
}

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

int main(int argc, char *argv[])
{
	char name[32];

	/* Load the SDL library */
	if ( SDL_Init(SDL_INIT_AUDIO) < 0 ) {
		fprintf(stderr, "Couldn't initialize SDL: %s\n",SDL_GetError());
		return(1);
	}
	if ( argv[1] == NULL ) {
		argv[1] = "sample.wav";
	}
	/* Load the wave file into memory */
	if ( SDL_LoadWAV(argv[1],
			&wave.spec, &wave.sound, &wave.soundlen) == NULL ) {
		fprintf(stderr, "Couldn't load %s: %s\n",
						argv[1], 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 */

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

	/* Let the audio run */
	printf("Using audio driver: %s\n", SDL_AudioDriverName(name, 32));
	while ( ! done && (SDL_GetAudioStatus() == SDL_AUDIO_PLAYING) )
		SDL_Delay(1000);

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