view docs/html/sdlupdaterects.html @ 997:3bf4103b2b89

Date: Sat, 27 Nov 2004 13:35:43 +0100 From: "Martin Bickel" Subject: [SDL] Patch: fixing uninitilized palette while running Valgrind over my application I found the following problem in SDL: The function MapNto1 allocates SDL_Color colors[256] but does not initialize it. SDL_DitherColors is then called which initialized the r, g and b component, but not the 'unused' component of each color. When Map1to1 is called from MapNto1, it runs a memcmp on the colors, which also evaluates the unused component and therefor returns differences much more often than necessary. So the 'unused' component of SDL_Color should be initialized. This patch does this by calling memset for the whole array in MapNto1 .
author Sam Lantinga <slouken@libsdl.org>
date Tue, 30 Nov 2004 14:28:20 +0000
parents 355632dca928
children
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>SDL_UpdateRects</H1
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>Name</H2
>SDL_UpdateRects&nbsp;--&nbsp;Makes sure the given list of rectangles is updated on the given screen.</DIV
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><PRE
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>#include "SDL.h"</PRE
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><CODE
><CODE
CLASS="FUNCDEF"
>void <B
CLASS="FSFUNC"
>SDL_UpdateRects</B
></CODE
>(SDL_Surface *screen, int numrects, SDL_Rect *rects);</CODE
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>Description</H2
><P
>Makes sure the given list of rectangles is updated on the given screen.
The rectangles must all be confined within the screen boundaries (no
clipping is done).</P
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>This function should not be called while <TT
CLASS="PARAMETER"
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>screen</I
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> is
<A
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>locked</A
>.</P
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><B
>Note: </B
>It is adviced to call this function only once per frame, since each
call has some processing overhead. This is no restriction since you
can pass any number of rectangles each time.</P
><P
>The rectangles are not automatically merged or checked for overlap. In
general, the programmer can use his knowledge about his particular
rectangles to merge them in an efficient way, to avoid overdraw.</P
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><TT
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>SDL_UpdateRect</TT
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>SDL_Rect</SPAN
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