view docs/man3/SDL_UpdateRects.3 @ 4168:69bcba65c388 SDL-1.2

Fixed bug #526 Comment #1 From Simon Howard 2009-03-20 16:50:56 Hi, I'm the author of Chocolate Doom, one of the other source ports that James mentioned. This is a patch against the current SVN version of SDL 1.2 that fixes the bug. It has been tested and hopefully should be obviously correct from examining the changes. I'll give a brief explanation. When the palette is set with SDL_SetPalette, the IDirectDrawPalette_SetEntries DirectX function is invoked. However, when this happens, a WM_PALETTECHANGED message is sent to the window. A WM_PALETTECHANGED message can also be received if the palette is changed for some other reason, like if the system palette is changed. Therefore, the palette change handler (DX5_PaletteChanged) has code to deal with this case. It distinguishes "expected" palette changes (set with SDL_SetPalette) from "unexpected" palette changes using the colorchange_expected variable, which is set before calling IDirectDrawPalette_SetEntries. However, the code to set this variable is missing in the fullscreen code path. By setting this variable, the palette change is handled properly and the freezes go away.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 13 Apr 2009 00:53:12 +0000
parents 4e3b250c950e
children 1238da4a7112
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.TH "SDL_UpdateRects" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_UpdateRects \- Makes sure the given list of rectangles is updated on the given screen\&.
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBvoid \fBSDL_UpdateRects\fP\fR(\fBSDL_Surface *screen, int numrects, SDL_Rect *rects\fR);
.SH "DESCRIPTION"
.PP
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)\&.
.PP
This function should not be called while \fBscreen\fR is \fIlocked\fR\&.
.PP
.RS
\fBNote:  
.PP
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\&.
.PP
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\&.
.RE
.SH "SEE ALSO"
.PP
\fI\fBSDL_UpdateRect\fP\fR, \fI\fBSDL_Rect\fR\fR, \fI\fBSDL_Surface\fR\fR, \fI\fBSDL_LockSurface\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01