view docs/html/sdljoystickgetball.html @ 1643:51038e80ae59

More general fix for bug #189 The clipping is done at a higher level, and the low level functions are passed clipped rectangles. Drivers which don't support source clipping have not been changed, so the image will be squished instead of clipped, but at least they will no longer crash when the destination rect was out of bounds.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 17 Apr 2006 06:47:23 +0000
parents 355632dca928
children
line wrap: on
line source

<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
>