Mercurial > sdl-ios-xcode
changeset 1543:98f9b16f565c
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.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Wed, 15 Mar 2006 15:43:15 +0000 |
| parents | a8bf1aa21020 |
| children | ab1e4c41ab71 |
| files | src/video/SDL_blit_N.c |
| diffstat | 1 files changed, 5 insertions(+), 1 deletions(-) [+] |
line wrap: on
line diff
--- a/src/video/SDL_blit_N.c Wed Mar 15 15:39:29 2006 +0000 +++ b/src/video/SDL_blit_N.c Wed Mar 15 15:43:15 2006 +0000 @@ -2194,6 +2194,10 @@ int srcbpp = srcfmt->BytesPerPixel; int dstbpp = dstfmt->BytesPerPixel; unsigned alpha = dstfmt->Amask ? srcfmt->alpha : 0; + Uint32 rgbmask = ~srcfmt->Amask; + + /* Set up some basic variables */ + ckey &= rgbmask; while ( height-- ) { DUFFS_LOOP( @@ -2203,7 +2207,7 @@ unsigned sG; unsigned sB; RETRIEVE_RGB_PIXEL(src, srcbpp, Pixel); - if ( Pixel != ckey ) { + if ( (Pixel & rgbmask) != ckey ) { RGB_FROM_PIXEL(Pixel, srcfmt, sR, sG, sB); ASSEMBLE_RGBA(dst, dstbpp, dstfmt, sR, sG, sB, alpha);