Opening the audio device
SDL_AudioSpec wanted;
+ extern void fill_audio(void *udata, Uint8 *stream, int len);
+
+ /* Set the audio format */
+ wanted.freq = 22050;
+ wanted.format = AUDIO_S16;
+ wanted.channels = 2; /* 1 = mono, 2 = stereo */
+ wanted.samples = 1024; /* Good low-latency value for callback */
+ wanted.callback = fill_audio;
+ wanted.userdata = NULL;
+
+ /* Open the audio device, forcing the desired format */
+ if ( SDL_OpenAudio(&wanted, NULL) < 0 ) {
+ fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError());
+ return(-1);
+ }
+ return(0);Playing audio
static Uint8 *audio_chunk;
+ static Uint32 audio_len;
+ static Uint8 *audio_pos;
+
+ /* The audio function callback takes the following parameters:
+ stream: A pointer to the audio buffer to be filled
+ len: The length (in bytes) of the audio buffer
+ */
+ void fill_audio(void *udata, Uint8 *stream, int len)
+ {
+ /* Only play if we have data left */
+ if ( audio_len == 0 )
+ return;
+
+ /* Mix as much data as possible */
+ len = ( len > audio_len ? audio_len : len );
+ SDL_MixAudio(stream, audio_pos, len, SDL_MIX_MAXVOLUME);
+ audio_pos += len;
+ audio_len -= len;
+ }
+
+ /* Load the audio data ... */
+
+ ;;;;;
+
+ audio_pos = audio_chunk;
+
+ /* Let the callback function play the audio chunk */
+ SDL_PauseAudio(0);
+
+ /* Do some processing */
+
+ ;;;;;
+
+ /* Wait for sound to complete */
+ while ( audio_len > 0 ) {
+ SDL_Delay(100); /* Sleep 1/10 second */
+ }
+ SDL_CloseAudio();