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view docs/html/sdljoystickgetaxis.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_JoystickGetAxis</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="Joystick" HREF="joystick.html"><LINK REL="PREVIOUS" TITLE="SDL_JoystickUpdate" HREF="sdljoystickupdate.html"><LINK REL="NEXT" TITLE="SDL_JoystickGetHat" HREF="sdljoystickgethat.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="sdljoystickupdate.html" ACCESSKEY="P" >Prev</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="sdljoystickgethat.html" ACCESSKEY="N" >Next</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="SDLJOYSTICKGETAXIS" ></A >SDL_JoystickGetAxis</H1 ><DIV CLASS="REFNAMEDIV" ><A NAME="AEN6320" ></A ><H2 >Name</H2 >SDL_JoystickGetAxis -- Get the current state of an axis</DIV ><DIV CLASS="REFSYNOPSISDIV" ><A NAME="AEN6323" ></A ><H2 >Synopsis</H2 ><DIV CLASS="FUNCSYNOPSIS" ><A NAME="AEN6324" ></A ><P ></P ><PRE CLASS="FUNCSYNOPSISINFO" >#include "SDL.h"</PRE ><P ><CODE ><CODE CLASS="FUNCDEF" >Sint16 <B CLASS="FSFUNC" >SDL_JoystickGetAxis</B ></CODE >(SDL_Joystick *joystick, int axis);</CODE ></P ><P ></P ></DIV ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN6330" ></A ><H2 >Description</H2 ><P ><TT CLASS="FUNCTION" >SDL_JoystickGetAxis</TT > returns the current state of the given <TT CLASS="PARAMETER" ><I >axis</I ></TT > on the given <TT CLASS="PARAMETER" ><I >joystick</I ></TT >.</P ><P >On most modern joysticks the X axis is usually represented by <TT CLASS="PARAMETER" ><I >axis</I ></TT > 0 and the Y axis by <TT CLASS="PARAMETER" ><I >axis</I ></TT > 1. The value returned by <TT CLASS="FUNCTION" >SDL_JoystickGetAxis</TT > is a signed integer (-32768 to 32768) representing the current position of the <TT CLASS="PARAMETER" ><I >axis</I ></TT >, it maybe necessary to impose certain tolerances on these values to account for jitter. It is worth noting that some joysticks use axes 2 and 3 for extra buttons.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN6341" ></A ><H2 >Return Value</H2 ><P >Returns a 16-bit signed integer representing the current position of the <TT CLASS="PARAMETER" ><I >axis</I ></TT >.</P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN6345" ></A ><H2 >Examples</H2 ><P ><PRE CLASS="PROGRAMLISTING" >Sint16 x_move, y_move; SDL_Joystick *joy1; . . x_move=SDL_JoystickGetAxis(joy1, 0); y_move=SDL_JoystickGetAxis(joy1, 1);</PRE ></P ></DIV ><DIV CLASS="REFSECT1" ><A NAME="AEN6349" ></A ><H2 >See Also</H2 ><P ><A HREF="sdljoysticknumaxes.html" ><TT CLASS="FUNCTION" >SDL_JoystickNumAxes</TT ></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="sdljoystickupdate.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="sdljoystickgethat.html" ACCESSKEY="N" >Next</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >SDL_JoystickUpdate</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="joystick.html" ACCESSKEY="U" >Up</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >SDL_JoystickGetHat</TD ></TR ></TABLE ></DIV ></BODY ></HTML >