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.

.TH "SDL_Flip" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_Flip \- Swaps screen buffers
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_Flip\fP\fR(\fBSDL_Surface *screen\fR);
.SH "DESCRIPTION"
.PP
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 \fISDL_UpdateRect\fR\fB(screen, 0, 0, 0, 0)\fR
.PP
The \fBSDL_DOUBLEBUF\fP flag must have been passed to \fISDL_SetVideoMode\fR, when setting the video mode for this function to perform hardware flipping\&.
.SH "RETURN VALUE"
.PP
This function returns \fB0\fR if successful, or \fB-1\fR if there was an error\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_SetVideoMode\fP\fR, \fI\fBSDL_UpdateRect\fP\fR, \fI\fBSDL_Surface\fR\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01