Mercurial > sdl-ios-xcode

<HTML
><HEAD
><TITLE
>SDL_JoystickGetBall</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_JoystickGetButton"
HREF="sdljoystickgetbutton.html"><LINK
REL="NEXT"
TITLE="SDL_JoystickClose"
HREF="sdljoystickclose.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="sdljoystickgetbutton.html"
ACCESSKEY="P"
>Prev</A
></TD
><TD
WIDTH="80%"
ALIGN="center"
VALIGN="bottom"
></TD
><TD
WIDTH="10%"
ALIGN="right"
VALIGN="bottom"
><A
HREF="sdljoystickclose.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
></TABLE
><HR
ALIGN="LEFT"
WIDTH="100%"></DIV
><H1
><A
NAME="SDLJOYSTICKGETBALL"
></A
>SDL_JoystickGetBall</H1
><DIV
CLASS="REFNAMEDIV"
><A
NAME="AEN6433"
></A
><H2
>Name</H2
>SDL_JoystickGetBall&nbsp;--&nbsp;Get relative trackball motion</DIV
><DIV
CLASS="REFSYNOPSISDIV"
><A
NAME="AEN6436"
></A
><H2
>Synopsis</H2
><DIV
CLASS="FUNCSYNOPSIS"
><A
NAME="AEN6437"
></A
><P
></P
><PRE
CLASS="FUNCSYNOPSISINFO"
>#include "SDL.h"</PRE
><P
><CODE
><CODE
CLASS="FUNCDEF"
>int <B
CLASS="FSFUNC"
>SDL_JoystickGetBall</B
></CODE
>(SDL_Joystick *joystick, int ball, int *dx, int *dy);</CODE
></P
><P
></P
></DIV
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN6443"
></A
><H2
>Description</H2
><P
>Get the <TT
CLASS="PARAMETER"
><I
>ball</I
></TT
> axis change.</P
><P
>Trackballs can only return relative motion since the last call to <TT
CLASS="FUNCTION"
>SDL_JoystickGetBall</TT
>, these motion deltas a placed into <TT
CLASS="PARAMETER"
><I
>dx</I
></TT
> and <TT
CLASS="PARAMETER"
><I
>dy</I
></TT
>.</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN6451"
></A
><H2
>Return Value</H2
><P
>Returns <SPAN
CLASS="RETURNVALUE"
>0</SPAN
> on success or <SPAN
CLASS="RETURNVALUE"
>-1</SPAN
> on failure</P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN6456"
></A
><H2
>Examples</H2
><P
><PRE
CLASS="PROGRAMLISTING"
>int delta_x, delta_y;
SDL_Joystick *joy;
.
.
.
SDL_JoystickUpdate();
if(SDL_JoystickGetBall(joy, 0, &#38;delta_x, &#38;delta_y)==-1)
  printf("TrackBall Read Error!\n");
printf("Trackball Delta- X:%d, Y:%d\n", delta_x, delta_y);</PRE
></P
></DIV
><DIV
CLASS="REFSECT1"
><A
NAME="AEN6460"
></A
><H2
>See Also</H2
><P
><A
HREF="sdljoysticknumballs.html"
><TT
CLASS="FUNCTION"
>SDL_JoystickNumBalls</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="sdljoystickgetbutton.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="sdljoystickclose.html"
ACCESSKEY="N"
>Next</A
></TD
></TR
><TR
><TD
WIDTH="33%"
ALIGN="left"
VALIGN="top"
>SDL_JoystickGetButton</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_JoystickClose</TD
></TR
></TABLE
></DIV
></BODY
></HTML
>
author	Sam Lantinga <slouken@libsdl.org>
date	Sun, 18 Oct 2009 17:31:37 +0000
parents	355632dca928
children