joystick_getaxis(3) Svgalib User Manual joystick_getaxis(3)NAME
joystick_getaxis, joystick_getbutton - query the current state of a
joystick.
SYNOPSIS
#include <vgajoystick.h>
char joystick_getaxis(int joydev, int a);
char joystick_getbutton(int joydev, int b);
DESCRIPTION
These functions query the current state of the joystick joydev. Actu‐
ally this is the state found during the last call to joystick_update(3)
with the default joystick event handler active.
joystick_getaxis(joydev, a) return the current state of the given axis
(usually it is x - 0, y - 1, z - 1, ...) in range -128 .. 127. Some
effort is made such that the center position is close to 0.
Note that especially the version 0.* protocol joystick calibration is
very bad. You won't usually see the extrem values on the extreme posi‐
tion. Also, the center position will be close to zero but often not be
exactly zero and return values will also vary slightly from call to
call even when the user did not move the joystick.
joystick_getbutton(joydev, b) returns the state of a button. It returns
1 for pressed button and 0 else. Note that no hardware checks for but‐
ton clicks. The button press is only detected during a call to joy‐
stick_update(3) (at least in the 0.* protocol).
NOTE: The functions simply return the data passed to the default joy‐
stick event handler!
For your convenience, the following stortcuts have been established by
use of the preprocessor:
joystick_button1(i) for joystick_getbutton(i, 0).
joystick_button2(i) for joystick_getbutton(i, 1).
joystick_button3(i) for joystick_getbutton(i, 2).
joystick_button4(i) for joystick_getbutton(i, 3).
joystick_x(i) for joystick_getaxis(i, 0).
joystick_y(i) for joystick_getaxis(i, 1).
joystick_z(i) for joystick_getaxis(i, 2).
joystick_getb1() for joystick_getbutton(0, 0).
joystick_getb2() for joystick_getbutton(0, 1).
joystick_getb3() for joystick_getbutton(0, 2).
joystick_getb4() for joystick_getbutton(0, 3).
joystick_getx() for joystick_getaxis(0, 0).
joystick_gety() for joystick_getaxis(0, 1).
joystick_getz() for joystick_getaxis(0, 2).
CAVEATS
This function is only available in ELF versions of svgalib. Due to
backwards compatibility issues it cannot be used with shared a.out
libs.
SEE ALSOsvgalib(7), vgagl(7), libvga.config(5), joytest(6), mjoytest(6), joy‐
stick_init(3), joystick_close(3), joystick_update(3), joy‐
stick_sethandler(3), joystick_setdefaulthandler(3), joystick_getnu‐
maxes(3), joystick_getnumbuttons(3).
AUTHOR
The svgalib joystick handler was mostly done by Daniel Engstr\"om
<daniel.engstrom@riksnett.no>. Multiple joystick, VC switching support
and code to glue it into svgalib by Michael Weller <eowmob@exp-
math.uni-essen.de>. Part of the code is based on code from C. Smith and
Vojtech Pavlik.
Svgalib 1.3.0 14 April 1998 joystick_getaxis(3)