Mercurial > sdl-ios-xcode
view docs/man3/SDL_SetGamma.3 @ 1555:780fd5b61df1
Fixed bug #89
Date: Sun, 23 Oct 2005 16:39:03 +0200
From: "A. Schmid" <sahib@phreaker.net>
Subject: [SDL] no software surfaces with svgalib driver?
Hi,
I noticed that the SDL (1.2.9) svgalib driver only makes use of linear
addressable (framebuffer) video modes. On older systems (like one of
mine), linear addressable modes are often not available.
Especially for cards with VESA VBE < 2.0 the svgalib vesa driver is
unusable, since VESA only supports framebuffering for VBE 2.0 and later.
The changes necessary to add support for software surfaces seem to be
relatively small. I only had to hack src/video/svga/SDL_svgavideo.c (see
attached patch). The code worked fine for me, but it is no more than a
proof of concept and should be reviewed (probably has a memory leak when
switching modes). It also uses the vgagl library (included in the
svgalib package) and needs to be linked against it.
-Alex
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 19 Mar 2006 12:05:16 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
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.TH "SDL_SetGamma" "3" "Tue 11 Sep 2001, 23:01" "SDL" "SDL API Reference" .SH "NAME" SDL_SetGamma\- Sets the color gamma function for the display .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBint \fBSDL_SetGamma\fP\fR(\fBfloat redgamma, float greengamma, float bluegamma\fR); .SH "DESCRIPTION" .PP Sets the "gamma function" for the display of each color component\&. Gamma controls the brightness/contrast of colors displayed on the screen\&. A gamma value of 1\&.0 is identity (i\&.e\&., no adjustment is made)\&. .PP This function adjusts the gamma based on the "gamma function" parameter, you can directly specify lookup tables for gamma adjustment with \fISDL_SetGammaRamp\fR\&. .PP Not all display hardware is able to change gamma\&. .SH "RETURN VALUE" .PP Returns -1 on error (or if gamma adjustment is not supported)\&. .SH "SEE ALSO" .PP \fISDL_GetGammaRamp\fR \fISDL_SetGammaRamp\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:01