loopwavequeue.c
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/*
Copyright (C) 1997-2014 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 sound queueing */
#include <stdio.h>
#include <stdlib.h>
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#ifdef __EMSCRIPTEN__
#include <emscripten/emscripten.h>
#endif
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#include "SDL.h"
#if HAVE_SIGNAL_H
#include <signal.h>
#endif
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);
}
static int done = 0;
void
poked(int sig)
{
done = 1;
}
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void
loop()
{
#ifdef __EMSCRIPTEN__
if (done || (SDL_GetAudioStatus() != SDL_AUDIO_PLAYING)) {
emscripten_cancel_main_loop();
}
else
#endif
{
/* The device from SDL_OpenAudio() is always device #1. */
const Uint32 queued = SDL_GetQueuedAudioSize(1);
SDL_Log("Device has %u bytes queued.\n", (unsigned int) queued);
if (queued <= 8192) { /* time to requeue the whole thing? */
if (SDL_QueueAudio(1, wave.sound, wave.soundlen) == 0) {
SDL_Log("Device queued %u more bytes.\n", (unsigned int) wave.soundlen);
} else {
SDL_Log("Device FAILED to queue %u more bytes: %s\n", (unsigned int) wave.soundlen, SDL_GetError());
}
}
}
}
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int
main(int argc, char *argv[])
{
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 = NULL; /* we'll push audio. */
#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) {
SDL_LogError(SDL_LOG_CATEGORY_APPLICATION, "Couldn't open audio: %s\n", SDL_GetError());
SDL_FreeWAV(wave.sound);
quit(2);
}
/*static x[99999]; SDL_QueueAudio(1, x, sizeof (x));*/
/* Let the audio run */
SDL_PauseAudio(0);
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done = 0;
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/* Note that we stuff the entire audio buffer into the queue in one
shot. Most apps would want to feed it a little at a time, as it
plays, but we're going for simplicity here. */
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#ifdef __EMSCRIPTEN__
emscripten_set_main_loop(loop, 0, 1);
#else
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while (!done && (SDL_GetAudioStatus() == SDL_AUDIO_PLAYING))
{
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loop();
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SDL_Delay(100); /* let it play for awhile. */
}
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#endif
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/* Clean up on signal */
SDL_CloseAudio();
SDL_FreeWAV(wave.sound);
SDL_Quit();
return 0;
}
/* vi: set ts=4 sw=4 expandtab: */