+++ /dev/null
-/*
- * SDL_sound -- An abstract sound format decoding API.
- * Copyright (C) 2001 Ryan C. Gordon.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
- */
-
-/**
- * This is just a simple "decode sound, play it through SDL" example.
- * The much more complex, fancy, and robust code is playsound.c.
- *
- * Please see the file COPYING in the source's root directory.
- *
- * This file written by Ryan C. Gordon. (icculus@clutteredmind.org)
- */
-
-#include <SDL/SDL.h>
-#include <SDL/SDL_sound.h>
-
-/* global decoding state. */
-typedef struct
-{
- Sound_Sample *sample;
- SDL_AudioSpec devformat;
- Uint8 *decoded_ptr;
- Uint32 decoded_bytes;
-} PlaysoundAudioCallbackData;
-
-/*
- * This variable is flipped to non-zero when the audio callback has
- * finished playing the whole file.
- */
-static volatile int global_done_flag = 0;
-
-
-/*
- * The audio callback. SDL calls this frequently to feed the audio device.
- * We decode the audio file being played in here in small chunks and feed
- * the device as necessary. Other solutions may want to predecode more
- * (or all) of the file, since this needs to run fast and frequently,
- * but since we're only sitting here and waiting for the file to play,
- * the only real requirement is that we can decode a given audio file
- * faster than realtime, which isn't really a problem with any modern format
- * on even pretty old hardware at this point.
- */
-static void audio_callback(void *userdata, Uint8 *stream, int len)
-{
- PlaysoundAudioCallbackData *data = (PlaysoundAudioCallbackData *) userdata;
- Sound_Sample *sample = data->sample;
- int bw = 0; /* bytes written to stream this time through the callback */
-
- while (bw < len)
- {
- int cpysize; /* bytes to copy on this iteration of the loop. */
-
- if (data->decoded_bytes == 0) /* need more data! */
- {
- /* if there wasn't previously an error or EOF, read more. */
- if ( ((sample->flags & SOUND_SAMPLEFLAG_ERROR) == 0) &&
- ((sample->flags & SOUND_SAMPLEFLAG_EOF) == 0) )
- {
- data->decoded_bytes = Sound_Decode(sample);
- data->decoded_ptr = sample->buffer;
- } /* if */
-
- if (data->decoded_bytes == 0)
- {
- /* ...there isn't any more data to read! */
- memset(stream + bw, '\0', len - bw); /* write silence. */
- global_done_flag = 1;
- return; /* we're done playback, one way or another. */
- } /* if */
- } /* if */
-
- /* we have data decoded and ready to write to the device... */
- cpysize = len - bw; /* len - bw == amount device still wants. */
- if (cpysize > data->decoded_bytes)
- cpysize = data->decoded_bytes; /* clamp to what we have left. */
-
- /* if it's 0, next iteration will decode more or decide we're done. */
- if (cpysize > 0)
- {
- /* write this iteration's data to the device. */
- memcpy(stream + bw, (Uint8 *) data->decoded_ptr, cpysize);
-
- /* update state for next iteration or callback */
- bw += cpysize;
- data->decoded_ptr += cpysize;
- data->decoded_bytes -= cpysize;
- } /* if */
- } /* while */
-} /* audio_callback */
-
-
-
-static void playOneSoundFile(const char *fname)
-{
- PlaysoundAudioCallbackData data;
-
- memset(&data, '\0', sizeof (PlaysoundAudioCallbackData));
- data.sample = Sound_NewSampleFromFile(fname, NULL, 65536);
- if (data.sample == NULL)
- {
- fprintf(stderr, "Couldn't load '%s': %s.\n", fname, Sound_GetError());
- return;
- } /* if */
-
- /*
- * Open device in format of the the sound to be played.
- * We open and close the device for each sound file, so that SDL
- * handles the data conversion to hardware format; this is the
- * easy way out, but isn't practical for most apps. Usually you'll
- * want to pick one format for all the data or one format for the
- * audio device and convert the data when needed. This is a more
- * complex issue than I can describe in a source code comment, though.
- */
- data.devformat.freq = data.sample->actual.rate;
- data.devformat.format = data.sample->actual.format;
- data.devformat.channels = data.sample->actual.channels;
- data.devformat.samples = 4096; /* I just picked a largish number here. */
- data.devformat.callback = audio_callback;
- data.devformat.userdata = &data;
- if (SDL_OpenAudio(&data.devformat, NULL) < 0)
- {
- fprintf(stderr, "Couldn't open audio device: %s.\n", SDL_GetError());
- Sound_FreeSample(data.sample);
- return;
- } /* if */
-
- printf("Now playing [%s]...\n", fname);
- SDL_PauseAudio(0); /* SDL audio device is "paused" right after opening. */
-
- global_done_flag = 0; /* the audio callback will flip this flag. */
- while (!global_done_flag)
- SDL_Delay(10); /* just wait for the audio callback to finish. */
-
- /* at this point, we've played the entire audio file. */
- SDL_PauseAudio(1); /* so stop the device. */
-
- /*
- * Sleep two buffers' worth of audio before closing, in order
- * to allow the playback to finish. This isn't always enough;
- * perhaps SDL needs a way to explicitly wait for device drain?
- * Most apps don't have this issue, since they aren't explicitly
- * closing the device as soon as a sound file is done playback.
- * As an alternative for this app, you could also change the callback
- * to write silence for a call or two before flipping global_done_flag.
- */
- SDL_Delay(2 * 1000 * data.devformat.samples / data.devformat.freq);
-
- /* if there was an error, tell the user. */
- if (data.sample->flags & SOUND_SAMPLEFLAG_ERROR)
- fprintf(stderr, "Error decoding file: %s\n", Sound_GetError());
-
- Sound_FreeSample(data.sample); /* clean up SDL_Sound resources... */
- SDL_CloseAudio(); /* will reopen with next file's format. */
-} /* playOneSoundFile */
-
-
-int main(int argc, char **argv)
-{
- int i;
-
- if (!Sound_Init()) /* this calls SDL_Init(SDL_INIT_AUDIO) ... */
- {
- fprintf(stderr, "Sound_Init() failed: %s.\n", Sound_GetError());
- SDL_Quit();
- return(42);
- } /* if */
-
- for (i = 1; i < argc; i++) /* each arg is an audio file to play. */
- playOneSoundFile(argv[i]);
-
- /* Shutdown the libraries... */
- Sound_Quit();
- SDL_Quit();
- return(0);
-} /* main */
-
-/* end of playsound-simple.c ... */
-
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