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view docs/man3/SDL_Palette.3 @ 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 | e5bc29de3f0a |
| children | 546f7c1eb755 |
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.TH "SDL_Palette" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_Palette\- Color palette for 8-bit pixel formats .SH "STRUCTURE DEFINITION" .PP .nf \f(CWtypedef struct{ int ncolors; SDL_Color *colors; } SDL_Palette;\fR .fi .PP .SH "STRUCTURE DATA" .TP 20 \fBncolors\fR Number of colors used in this palette .TP 20 \fBcolors\fR Pointer to \fI\fBSDL_Color\fR\fR structures that make up the palette\&. .SH "DESCRIPTION" .PP Each pixel in an 8-bit surface is an index into the \fBcolors\fR field of the \fBSDL_Palette\fR structure store in \fI\fBSDL_PixelFormat\fR\fR\&. A \fBSDL_Palette\fR should never need to be created manually\&. It is automatically created when SDL allocates a \fBSDL_PixelFormat\fR for a surface\&. The colors values of a \fI\fBSDL_Surface\fR\fRs palette can be set with the \fI\fBSDL_SetColors\fP\fR\&. .SH "SEE ALSO" .PP \fI\fBSDL_Color\fR\fR, \fI\fBSDL_Surface\fR\fR, \fI\fBSDL_SetColors\fP\fR \fI\fBSDL_SetPalette\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01