view docs/html/sdlflip.html @ 3880:74e828c64315 SDL-1.2

Fixed bug #292 I might be on crack here. It looks like SDL_ConvertMono() in src/audio/SDL_audiocvt.c adds the left and right channels of a stereo stream together, and clamps the new mono channel if it would overflow. Shouldn't it be dividing by 2 to average the two sample points instead of clamping? Otherwise the mono sample point's volume doubles in the conversion. This would also make the conversion faster, as it replaces two branches per sample frame with a bitwise shift. --ryan.
author Sam Lantinga <slouken@libsdl.org>
date Sun, 24 Sep 2006 15:45:37 +0000
parents 355632dca928
children
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>SDL_Flip</TITLE
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><H1
><A
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>SDL_Flip</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN1426"
></A
><H2
>Name</H2
>SDL_Flip&nbsp;--&nbsp;Swaps screen buffers</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN1429"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN1430"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_Flip</B
></CODE
>(SDL_Surface *screen);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1436"
></A
><H2
>Description</H2
><P
>On hardware that supports double-buffering, this function sets up a flip
and returns.  The hardware will wait for vertical retrace, and then swap
video buffers before the next video surface blit or lock will return.
On hardware that doesn't support double-buffering, this is equivalent
to calling <A
HREF="sdlupdaterect.html"
>SDL_UpdateRect</A
><TT
CLASS="PARAMETER"
><I
>(screen, 0, 0, 0, 0)</I
></TT
></P
><P
>The <TT
CLASS="LITERAL"
>SDL_DOUBLEBUF</TT
> flag must have been passed to 
<A
HREF="sdlsetvideomode.html"
>SDL_SetVideoMode</A
>,
 when
setting the video mode for this function to perform hardware flipping.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1444"
></A
><H2
>Return Value</H2
><P
>This function returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> if successful, or 
<SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> if there was an error.</P
></DIV
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><A
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></A
><H2
>See Also</H2
><P
><A
HREF="sdlsetvideomode.html"
><TT
CLASS="FUNCTION"
>SDL_SetVideoMode</TT
></A
>,
<A
HREF="sdlupdaterect.html"
><TT
CLASS="FUNCTION"
>SDL_UpdateRect</TT
></A
>,
<A
HREF="sdlsurface.html"
><SPAN
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>SDL_Surface</SPAN
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