Mercurial > sdl-ios-xcode
view docs/html/sdlglsetattribute.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_GL_SetAttribute</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_GL_GetAttribute" HREF="sdlglgetattribute.html"><LINK REL="NEXT" TITLE="SDL_GL_SwapBuffers" HREF="sdlglswapbuffers.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="sdlglgetattribute.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdlglswapbuffers.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLGLSETATTRIBUTE" ></A >SDL_GL_SetAttribute</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN2742" ></A ><H2 >Name</H2 >SDL_GL_SetAttribute -- Set a special SDL/OpenGL attribute</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN2745" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN2746" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >int <B CLASS="FSFUNC" >SDL_GL_SetAttribute</B ></CODE >(SDL_GLattr attr, int value);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2752" ></A ><H2 >Description</H2 ><P >Sets the OpenGL <A HREF="sdlglattr.html" >attribute</A > <TT CLASS="PARAMETER" ><I >attr</I ></TT > to <TT CLASS="PARAMETER" ><I >value</I ></TT >. The attributes you set don't take effect until after a call to <A HREF="sdlsetvideomode.html" ><TT CLASS="FUNCTION" >SDL_SetVideoMode</TT ></A >. You should use <A HREF="sdlglgetattribute.html" ><TT CLASS="FUNCTION" >SDL_GL_GetAttribute</TT ></A > to check the values after a <TT CLASS="FUNCTION" >SDL_SetVideoMode</TT > call.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2763" ></A ><H2 >Return Value</H2 ><P >Returns <SPAN CLASS="RETURNVALUE" >0</SPAN > on success, or <SPAN CLASS="RETURNVALUE" >-1</SPAN > on error.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2768" ></A ><H2 >Example</H2 ><PRE CLASS="PROGRAMLISTING" >SDL_GL_SetAttribute( SDL_GL_RED_SIZE, 5 ); SDL_GL_SetAttribute( SDL_GL_GREEN_SIZE, 5 ); SDL_GL_SetAttribute( SDL_GL_BLUE_SIZE, 5 ); SDL_GL_SetAttribute( SDL_GL_DEPTH_SIZE, 16 ); SDL_GL_SetAttribute( SDL_GL_DOUBLEBUFFER, 1 ); if ( (screen=SDL_SetVideoMode( 640, 480, 16, SDL_OPENGL )) == NULL ) { fprintf(stderr, "Couldn't set GL mode: %s\n", SDL_GetError()); SDL_Quit(); return; }</PRE ><DIV CLASS="NOTE" ><BLOCKQUOTE CLASS="NOTE" ><P ><B >Note: </B >The <TT CLASS="LITERAL" >SDL_DOUBLEBUF</TT > flag is not required to enable double buffering when setting an OpenGL video mode. Double buffering is enabled or disabled using the SDL_GL_DOUBLEBUFFER attribute.</P ></BLOCKQUOTE ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN2774" ></A ><H2 >See Also</H2 ><P ><A HREF="sdlglgetattribute.html" ><TT CLASS="FUNCTION" >SDL_GL_GetAttribute</TT ></A >, <A HREF="sdlglattr.html" >GL Attributes</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="sdlglgetattribute.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="sdlglswapbuffers.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_GL_GetAttribute</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_GL_SwapBuffers</TD ></TR ></TABLE ></DIV ></BODY ></HTML >