Mercurial > sdl-ios-xcode
changeset 688:c0522010bb6d
Date: Tue, 12 Aug 2003 14:26:19 +0200 (MEST)
From: "Mattias Engdeg?rd"
Subject: bug in SDL_GetRGB/GetRGBA
There's an embarrassing bug in GetRGB/GetRGBA which apparently has been there
for years. It incorrectly converts colours with < 8 bits/channel.
It came to my attention today in #sdl.
What it does now is (for each channel):
rv = (pixel & fmt->Rmask) >> fmt->Rshift;
*r = (rv << fmt->Rloss) + (rv >> (8 - fmt->Rloss));
which is wrong; the last line should be
*r = (rv << fmt->Rloss) + (rv >> (8 - (fmt->Rloss << 1)));
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Tue, 12 Aug 2003 15:17:20 +0000 |
| parents | 91400ecf307d |
| children | 5bb080d35049 |
| files | src/video/SDL_pixels.c |
| diffstat | 1 files changed, 7 insertions(+), 7 deletions(-) [+] |
line wrap: on
line diff
--- a/src/video/SDL_pixels.c Mon Aug 11 22:28:13 2003 +0000 +++ b/src/video/SDL_pixels.c Tue Aug 12 15:17:20 2003 +0000 @@ -381,14 +381,14 @@ */ unsigned v; v = (pixel & fmt->Rmask) >> fmt->Rshift; - *r = (v << fmt->Rloss) + (v >> (8 - fmt->Rloss)); + *r = (v << fmt->Rloss) + (v >> (8 - (fmt->Rloss << 1))); v = (pixel & fmt->Gmask) >> fmt->Gshift; - *g = (v << fmt->Gloss) + (v >> (8 - fmt->Gloss)); + *g = (v << fmt->Gloss) + (v >> (8 - (fmt->Gloss << 1))); v = (pixel & fmt->Bmask) >> fmt->Bshift; - *b = (v << fmt->Bloss) + (v >> (8 - fmt->Bloss)); + *b = (v << fmt->Bloss) + (v >> (8 - (fmt->Bloss << 1))); if(fmt->Amask) { v = (pixel & fmt->Amask) >> fmt->Ashift; - *a = (v << fmt->Aloss) + (v >> (8 - fmt->Aloss)); + *a = (v << fmt->Aloss) + (v >> (8 - (fmt->Aloss << 1))); } else *a = SDL_ALPHA_OPAQUE; } else { @@ -405,11 +405,11 @@ /* the note for SDL_GetRGBA above applies here too */ unsigned v; v = (pixel & fmt->Rmask) >> fmt->Rshift; - *r = (v << fmt->Rloss) + (v >> (8 - fmt->Rloss)); + *r = (v << fmt->Rloss) + (v >> (8 - (fmt->Rloss << 1))); v = (pixel & fmt->Gmask) >> fmt->Gshift; - *g = (v << fmt->Gloss) + (v >> (8 - fmt->Gloss)); + *g = (v << fmt->Gloss) + (v >> (8 - (fmt->Gloss << 1))); v = (pixel & fmt->Bmask) >> fmt->Bshift; - *b = (v << fmt->Bloss) + (v >> (8 - fmt->Bloss)); + *b = (v << fmt->Bloss) + (v >> (8 - (fmt->Bloss << 1))); } else { *r = fmt->palette->colors[pixel].r; *g = fmt->palette->colors[pixel].g;