joystick_getaxis

NAME

joystick_getaxis, joystick_getbutton - query the current state of a joystick.

SYNOPSIS

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. Actually 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 position. 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 button clicks. The button press is only detected during a call to joystick_update(3) (at least in the 0.* protocol).

NOTE: The functions simply return the data passed to the default joystick 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.

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.