From: "Alex Volkov" Date: Thu, 10 Nov 2005 21:53:40 -0500 Subject: [SDL] BUG[?]: 32bpp RGBA->RGB colorkey blit, no SDL_SRCALPHA It seems there is either a documentation vs. reality mismatch or a real bug in SDL_blit_N.c:BlitNtoNKey(). The exact blit in question is a 32bpp RGBA->RGB, where RGBA has SDL_COLORKEY and *no* SDL_SRCALPHA flags. The doc in SDL_video.h states: * RGBA->RGB: * SDL_SRCALPHA not set: * copy RGB. * if SDL_SRCCOLORKEY set, only copy the pixels matching the * RGB values of the source colour key, ignoring alpha in the * comparison. BlitNtoNKey(), however, forgets to "ignore alpha in the comparison". The documentation makes perfect sense, so I think it is the code that is faulty. The attached patch corrects the code.

.TH "SDL_Color" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_Color\- Format independent color description
.SH "STRUCTURE DEFINITION"
.PP
.nf
\f(CWtypedef struct{
  Uint8 r;
  Uint8 g;
  Uint8 b;
  Uint8 unused;
} SDL_Color;\fR
.fi
.PP
.SH "STRUCTURE DATA"
.TP 20
\fBr\fR
Red intensity
.TP 20
\fBg\fR
Green intensity
.TP 20
\fBb\fR
Blue intensity
.TP 20
\fBunused\fR
Unused
.SH "DESCRIPTION"
.PP
\fBSDL_Color\fR describes a color in a format independent way\&. You can convert a \fBSDL_Color\fR to a pixel value for a certain pixel format using \fI\fBSDL_MapRGB\fP\fR\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_PixelFormat\fR\fR, \fI\fBSDL_SetColors\fP\fR, \fI\fBSDL_Palette\fP\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01