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

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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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<HTML
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><TITLE
>SDL_UpdateRect</TITLE
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><H1
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>SDL_UpdateRect</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN1355"
></A
><H2
>Name</H2
>SDL_UpdateRect&nbsp;--&nbsp;Makes sure the given area is updated on the given screen.</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN1358"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN1359"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>void <B
CLASS="FSFUNC"
>SDL_UpdateRect</B
></CODE
>(SDL_Surface *screen, Sint32 x, Sint32 y, Sint32 w, Sint32 h);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1365"
></A
><H2
>Description</H2
><P
>Makes sure the given area is updated on the given screen. The rectangle must
be confined within the screen boundaries (no clipping is done).</P
><P
>If '<TT
CLASS="PARAMETER"
><I
>x</I
></TT
>', '<TT
CLASS="PARAMETER"
><I
>y</I
></TT
>', '<TT
CLASS="PARAMETER"
><I
>w</I
></TT
>'
and '<TT
CLASS="PARAMETER"
><I
>h</I
></TT
>' are all 0,
<TT
CLASS="FUNCTION"
>SDL_UpdateRect</TT
> will update the
entire screen.</P
><P
>This function should not be called while '<TT
CLASS="PARAMETER"
><I
>screen</I
></TT
>' is
<A
HREF="sdllocksurface.html"
>locked</A
>.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN1377"
></A
><H2
>See Also</H2
><P
><A
HREF="sdlupdaterects.html"
><TT
CLASS="FUNCTION"
>SDL_UpdateRects</TT
></A
>,
<A
HREF="sdlrect.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Rect</SPAN
></A
>,
<A
HREF="sdlsurface.html"
><SPAN
CLASS="STRUCTNAME"
>SDL_Surface</SPAN
></A
>,
<A
HREF="sdllocksurface.html"
><TT
CLASS="FUNCTION"
>SDL_LockSurface</TT
></A
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