Mercurial > sdl-ios-xcode
view docs/html/sdlsetgamma.html @ 1157:baf35853ad54
Date: Mon, 10 Oct 2005 13:09:32 +0300
From: Tommi Kyntola <tommi.kyntola@ray.fi>
To: sdl@libsdl.org
Subject: [SDL] [RFC] get_ticks broken on linux
It uses gettimeofday to calculate the timedifference.
Gettimeofday returns current time which is seldom monotonous.
This breaks SDL timer subsystem. (time callbacks and all that
get borked when the time difference ms is suddenly ~ 2^32)
I posted a message about this earlier but got no response.
Some thoughts on this matter would be appreciated.
(Or even an explanation for the lack of interest.)
A patch below would use the posix timers that have been around
since posix 93 and do provide a good source of monotonous time
on linux boxes (and on few others too).
The following patch is also availabe at:
http://www.hut.fi/u/tkyntola/SDL-1.2.9-clockfix.patch
It's against 1.2.9, but I can easily rediffit against
the cvs branch is needed.
cheers,
Tommi Kyntola tommi.kyntola@ray.fi
author | Ryan C. Gordon <icculus@icculus.org> |
---|---|
date | Tue, 11 Oct 2005 18:16:12 +0000 |
parents | 355632dca928 |
children |
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<HTML ><HEAD ><TITLE >SDL_SetGamma</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ "><LINK REL="HOME" TITLE="SDL Library Documentation" HREF="index.html"><LINK REL="UP" TITLE="Video" HREF="video.html"><LINK REL="PREVIOUS" TITLE="SDL_SetPalette" HREF="sdlsetpalette.html"><LINK REL="NEXT" TITLE="SDL_GetGammaRamp" HREF="sdlgetgammaramp.html"></HEAD ><BODY CLASS="REFENTRY" BGCOLOR="#FFF8DC" TEXT="#000000" LINK="#0000ee" VLINK="#551a8b" ALINK="#ff0000" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >SDL Library Documentation</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="sdlsetpalette.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlgetgammaramp.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLSETGAMMA" ></A >SDL_SetGamma</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN1569" ></A ><H2 >Name</H2 >SDL_SetGamma -- Sets the color gamma function for the display</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN1572" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN1573" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >int <B CLASS="FSFUNC" >SDL_SetGamma</B ></CODE >(float redgamma, float greengamma, float bluegamma);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1579" ></A ><H2 >Description</H2 ><P >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 <TT CLASS="CONSTANT" >1.0</TT > is identity (i.e., no adjustment is made).</P ><P >This function adjusts the gamma based on the "gamma function" parameter, you can directly specify lookup tables for gamma adjustment with <A HREF="sdlsetgammaramp.html" >SDL_SetGammaRamp</A >.</P ><P >Not all display hardware is able to change gamma.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1586" ></A ><H2 >Return Value</H2 ><P >Returns -1 on error (or if gamma adjustment is not supported).</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN1589" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlgetgammaramp.html" >SDL_GetGammaRamp</A > <A HREF="sdlsetgammaramp.html" >SDL_SetGammaRamp</A ></P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="sdlsetpalette.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >Home</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="sdlgetgammaramp.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_SetPalette</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="video.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_GetGammaRamp</TD ></TR ></TABLE ></DIV ></BODY ></HTML >