Mercurial > sdl-ios-xcode
view docs/man3/SDL_MapRGB.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_MapRGB" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_MapRGB \- Map a RGB color value to a pixel format\&. .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBUint32 \fBSDL_MapRGB\fP\fR(\fBSDL_PixelFormat *fmt, Uint8 r, Uint8 g, Uint8 b\fR); .SH "DESCRIPTION" .PP Maps the RGB color value to the specified pixel format and returns the pixel value as a 32-bit int\&. .PP If the format has a palette (8-bit) the index of the closest matching color in the palette will be returned\&. .PP If the specified pixel format has an alpha component it will be returned as all 1 bits (fully opaque)\&. .SH "RETURN VALUE" .PP A pixel value best approximating the given RGB color value for a given pixel format\&. If the pixel format bpp (color depth) is less than 32-bpp then the unused upper bits of the return value can safely be ignored (e\&.g\&., with a 16-bpp format the return value can be assigned to a \fBUint16\fP, and similarly a \fBUint8\fP for an 8-bpp format)\&. .SH "SEE ALSO" .PP \fI\fBSDL_GetRGB\fP\fR, \fI\fBSDL_GetRGBA\fP\fR, \fI\fBSDL_MapRGBA\fP\fR, \fI\fBSDL_PixelFormat\fR\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01