view docs/man3/SDL_GetGammaRamp.3 @ 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 e5bc29de3f0a
children 546f7c1eb755
line wrap: on
line source

.TH "SDL_GetGammaRamp" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_GetGammaRamp\- Gets the color gamma lookup tables for the display
.SH "SYNOPSIS"
.PP
\fB#include "SDL\&.h"
.sp
\fBint \fBSDL_GetGammaRamp\fP\fR(\fBUint16 *redtable, Uint16 *greentable, Uint16 *bluetable\fR);
.SH "DESCRIPTION"
.PP
Gets the gamma translation lookup tables currently used by the display\&. Each table is an array of 256 Uint16 values\&.
.PP
Not all display hardware is able to change gamma\&.
.SH "RETURN VALUE"
.PP
Returns -1 on error\&.
.SH "SEE ALSO"
.PP
\fISDL_SetGamma\fR \fISDL_SetGammaRamp\fR
...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01