Skip to content
Permalink
Browse files

Don't initialize the audio buffer passed to the application's audio c…

…allback,

 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.
  • Loading branch information
icculus committed Jul 5, 2007
1 parent a79e9d3 commit 4e47787a359ccb14e6b2384068785f11cf7661eb
Showing with 14 additions and 1 deletion.
  1. +14 −1 src/audio/SDL_audio.c
@@ -117,6 +117,13 @@ static AudioBootStrap *bootstrap[] = {
};
SDL_AudioDevice *current_audio = NULL;

/*
* If non-zero, use legacy behaviour (memset the callback buffer before call).
* Changed to NOT initializing the buffer before the callback in 1.2.12.
* Set environment SDL_AUDIO_MUST_INIT_BUFFERS=1 to get old behaviour.
*/
static int must_init_callback_buffer = 0;

/* Various local functions */
int SDL_AudioInit(const char *driver_name);
void SDL_AudioQuit(void);
@@ -190,7 +197,10 @@ int SDLCALL SDL_RunAudio(void *audiop)
stream = audio->fake_stream;
}
}
SDL_memset(stream, silence, stream_len);

if ( must_init_callback_buffer ) {
SDL_memset(stream, silence, stream_len);
}

if ( ! audio->paused ) {
SDL_mutexP(audio->mixer_lock);
@@ -300,6 +310,9 @@ int SDL_AudioInit(const char *driver_name)
{
SDL_AudioDevice *audio;
int i = 0, idx;
const char *envr = SDL_getenv("SDL_AUDIO_MUST_INIT_BUFFERS");

must_init_callback_buffer = ((envr != NULL) && (SDL_atoi(envr)));

/* Check to make sure we don't overwrite 'current_audio' */
if ( current_audio != NULL ) {

0 comments on commit 4e47787

Please sign in to comment.