Mercurial > sdl-ios-xcode
view docs/man3/SDL_JoystickGetBall.3 @ 872:e7be95d758e8
Date: Fri, 05 Mar 2004 16:08:01 +0000
From: Alan Swanson
Subject: Re: [SDL] Fatal signal when initiaize with USB joystick on 2.6.2 kern
On Fri, 2004-03-05 at 15:09, Sam Lantinga wrote:
> > Fred, how does the attached patch work for you? Do all your axes work?
>
> I think you meant the two lines to be reversed.
> I checked a more robust version of this into CVS. Fred, can you see if
> it works?
You've misread the code. :-/
For coef[0] and coef[1], it is (values[2]+values[1]) / 2 and then add
or subtract values[4] to the answer.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sat, 06 Mar 2004 02:58:06 +0000 |
| parents | e5bc29de3f0a |
| children | 546f7c1eb755 |
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.TH "SDL_JoystickGetBall" "3" "Tue 11 Sep 2001, 23:00" "SDL" "SDL API Reference" .SH "NAME" SDL_JoystickGetBall\- Get relative trackball motion .SH "SYNOPSIS" .PP \fB#include "SDL\&.h" .sp \fBint \fBSDL_JoystickGetBall\fP\fR(\fBSDL_Joystick *joystick, int ball, int *dx, int *dy\fR); .SH "DESCRIPTION" .PP Get the \fBball\fR axis change\&. .PP Trackballs can only return relative motion since the last call to \fBSDL_JoystickGetBall\fP, these motion deltas a placed into \fBdx\fR and \fBdy\fR\&. .SH "RETURN VALUE" .PP Returns \fB0\fR on success or \fB-1\fR on failure .SH "EXAMPLES" .PP .PP .nf \f(CWint delta_x, delta_y; SDL_Joystick *joy; \&. \&. \&. SDL_JoystickUpdate(); if(SDL_JoystickGetBall(joy, 0, &delta_x, &delta_y)==-1) printf("TrackBall Read Error! "); printf("Trackball Delta- X:%d, Y:%d ", delta_x, delta_y);\fR .fi .PP .SH "SEE ALSO" .PP \fI\fBSDL_JoystickNumBalls\fP\fR ...\" created by instant / docbook-to-man, Tue 11 Sep 2001, 23:00