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view docs/man3/SDL_JoyBallEvent.3 @ 4431:d660ca4f7b1f SDL-1.2

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Fixed bug 944 Tatu Kilappa 2010-02-11 12:13:20 PST When compiling with -Wconversion, gcc complains about a cast in SDL_endian.h that might change the result as we are casting from an int into an Uint16. This is of course not visible unless we are on a non-x86 platform where the assembler is not available. While it's not really an error, the warning is really annoying. To fix, change SDL_endian.h line 87 to: return(Uint16)((x<<8)|(x>>8)); Thank you.
author Sam Lantinga <slouken@libsdl.org>
date Tue, 13 Apr 2010 21:46:10 -0700
parents 1238da4a7112
children
line wrap: on
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.TH "SDL_JoyBallEvent" "3" "Tue 11 Sep 2001, 22:59" "SDL" "SDL API Reference" 
.SH "NAME"
SDL_JoyBallEvent \- Joystick trackball motion event structure
.SH "STRUCTURE DEFINITION"
.PP
.nf
\f(CWtypedef struct{
  Uint8 type;
  Uint8 which;
  Uint8 ball;
  Sint16 xrel, yrel;
} SDL_JoyBallEvent;\fR
.fi
.PP
.SH "STRUCTURE DATA"
.TP 20
\fBtype\fR
\fBSDL_JOYBALLMOTION\fP
.TP 20
\fBwhich\fR
Joystick device index
.TP 20
\fBball\fR
Joystick trackball index
.TP 20
\fBxrel\fR, \fByrel\fR
The relative motion in the X/Y direction
.SH "DESCRIPTION"
.PP
\fBSDL_JoyBallEvent\fR is a member of the \fI\fBSDL_Event\fR\fR union and is used when an event of type \fBSDL_JOYBALLMOTION\fP is reported\&.
.PP
A \fBSDL_JOYBALLMOTION\fP event occurs when a user moves a trackball on the joystick\&. The field \fBwhich\fR is the index of the joystick that reported the event and \fBball\fR is the index of the trackball (for a more detailed explaination see the \fIJoystick section\fR)\&. Trackballs only return relative motion, this is the change in position on the ball since it was last polled (last cycle of the event loop) and it is stored in \fBxrel\fR and \fByrel\fR\&.
.SH "SEE ALSO"
.PP
\fI\fBSDL_Event\fR\fR, \fIJoystick Functions\fR, \fI\fBSDL_JoystickEventState\fP\fR, \fI\fBSDL_JoystickGetBall\fP\fR
.\" created by instant / docbook-to-man, Tue 11 Sep 2001, 22:59