From: divverent <divverent@d7cf8633-e32d-0410-b094-e92efae38249>
Date: Fri, 20 Sep 2019 15:27:46 +0000 (+0000)
Subject: Fix issue with noise during startup
X-Git-Tag: xonotic-v0.8.5~35
X-Git-Url: https://git.rm.cloudns.org/?a=commitdiff_plain;h=f03abce85e464df6f067cf11e677e2a2d8f7b62d;p=xonotic%2Fdarkplaces.git

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
::stable-branch::merge=83f8124af58307eae378846c9746b5d769673474
---

diff --git a/snd_sdl.c b/snd_sdl.c
index 21341dce..d5cca856 100644
--- 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)