Fix issue with noise during startup

After migrating to SDL2 interfaces there is noise during startup fix
this by initializng buffer as specification requires.

Per SDL_AudioCallback spec:
The callback must completely initialize the buffer; as of SDL 2.0, this buffer is not initialized before the callback is called. If there is nothing to play, the callback should fill the buffer with silence.

Signed-off-by: Amadeusz Sławiński <amade@asmblr.net>
git-svn-id: svn://svn.icculus.org/twilight/trunk/darkplaces@12480 d7cf8633-e32d-0410-b094-e92efae38249

diff --git a/snd_sdl.c b/snd_sdl.c
index 850ca773e4d4054ecdb56bc94e15401ce2d11a55..f7e0f4723065c73c8b73856257afe8aeaa42a005 100644 (file)
--- a/snd_sdl.c
+++ b/snd_sdl.c
@@ -68,10 +68,20 @@ static void Buffer_Callback (void *userdata, Uint8 *stream, int len)
 
                        PartialLength2 = FrameCount * factor - PartialLength1;
                        memcpy(&stream[PartialLength1], &snd_renderbuffer->ring[0], PartialLength2);
+
+                       // As of SDL 2.0 buffer needs to be fully initialized, so fill leftover part with silence
+                       // FIXME this is another place that assumes 8bit is always unsigned and others always signed
+                       memset(&stream[PartialLength1 + PartialLength2], snd_renderbuffer->format.width == 1 ? 0x80 : 0, len - (PartialLength1 + PartialLength2));
                }
                else
+               {
                        memcpy(stream, &snd_renderbuffer->ring[StartOffset * factor], FrameCount * factor);
 
+                       // As of SDL 2.0 buffer needs to be fully initialized, so fill leftover part with silence
+                       // FIXME this is another place that assumes 8bit is always unsigned and others always signed
+                       memset(&stream[FrameCount * factor], snd_renderbuffer->format.width == 1 ? 0x80 : 0, len - (FrameCount * factor));
+               }
+
                snd_renderbuffer->startframe += FrameCount;
 
                if (FrameCount < RequestedFrames && developer_insane.integer && vid_activewindow)