PC Hardware in a Nutshell, 3rd Edition [Electronic resources] نسخه متنی

21.1 Game Controller Characteristics

Here
are the important characteristics of game controllers:

The first game controllers were joystick
controllers, which are still popular and still most
appropriate for playing flight simulator and air combat games. Some
are marginally usable for some driving, racing, action/adventure, and
sports games. Steering wheel controllers, many
of which include foot pedals, are ideal for driving/racing games and
some flight simulators, but ill-suited to other games.
Gamepad controllers are suitable for action
games, including first-person shooters, sports, and most arcade-style
games.

An axis is a line drawn through the center of
the joystick (or the D-pad on a gamepad) that defines the directions
that one can move by manipulating the controls. All controllers have
an x-axis (side-to-side movement) and a
y-axis (front to back). Some controllers add a
z-axis (up and down) and/or a throttle
axis. Depending on the controller type, the third and/or
fourth axes may also be called a yoke control or
rudder control, for their intended function, or
a twist control, for the method used to activate
the axis.

The throttle is a variable input, present on
most joysticks and some gamepads, and normally assigned to the third
or fourth axis on the controller. The throttle is usually used to
control vehicle speed, and may be a slider, wheel, pedal, or
variable-pull trigger, depending on the controller.

Motion along an axis can be tracked in two ways.
Proportional response (common with joysticks)
offers finer control because small stick movements result in small
incremental movements on screen. Nonproportional
response (common with gamepads) is
all-or-nothingany movement of the control along an axis
results in full motion on that axis, offering faster response at the
expense of fine control. Some controllers are programmable to allow
choosing between proportional and nonproportional modes.

All controllers have buttons, which are momentary-on switches used to
fire weapons and perform similar on/off functions. Pure analog
controllers are limited to two or four buttons by the gameport
itself. Digital controllers and the Microsoft DirectInput API allow
using any number of buttons.

A hat switch, sometimes called a POV
hat, a Point of View hat, or just a
hat, is so called because it usually resides on
the head of the joystick, where it's easily
manipulated by the thumb. The hat switch is a directional rocker
switch (usually four-way, but sometimes eight-way) that allows you to
rapidly change your POV to face front, rear, left, or right. Games
that do not support POV may use the hat to provide four extra
buttons.

Recent high-end game controllers have force-feedback technology,
which uses small servo motors built into the game controller itself
to provide physical feedback under the control of game software
designed to use force feedback. For example, with a force-feedback
joystick, as you pull a 7G turn you feel the joystick jerk and jitter
as the aircraft control surfaces lose laminar flow, but as you extend
to gain airspeed, the controls settle down again. When you come up on
the six of a bandit and begin hosing him down with your 30mm rotary
cannon, the joystick stutters as the gun recoils.

Well-implemented force feedback greatly enhances the ambiance of
games that support it properly, but the quality of force-feedback
hardware varies greatly between controllers. Even more important,
games vary greatly in how well they integrate force feedback.
Well-designed games use it elegantly to make the game more immersive.
Many games, however, have simply grafted on minimal force-feedback
support, and use it in only the most basic ways. This problem seems
to be disappearing as new releases of such games usually make better
use of force feedback. The only real drawback to force feedback is
that it is expensive. A $50 controller without force feedback might
cost $100 with it. Interestingly, this same technology (in much
enhanced form) is used in current fly-by-wire combat aircraft.

All
current game controllers include DirectInput drivers or are
compatible with standard Windows 9X drivers. A DirectInput-compliant
controller can be programmed within any DirectInput-compliant game.
However, DirectInput provides only basic functionality, so many
controllers come with their own programming software that provides
extended functionality, including:

By default, games may use different buttons for similar purposes. For
example, one air combat game may use button 1 to fire guns, button 2
to launch a Sidewinder, and button 3 to launch a Sparrow. Another air
combat game may offer similar weapons selection, but use different
buttons. Programmable game controllers allow you to redefine button
functions so that the same button performs similar actions in
different games.

Many modern game controllers are quite flexible and may be used with
diverse games. Optimal controller configuration for one game,
however, may be less desirable for another. Better game controllers
can store multiple groups of configuration settings, called
macros or profiles, that
allow you to quickly load whichever settings are most appropriate for
the game you're about to play, rather than having to
reprogram the controller manually each time. Most such controllers
come with predefined settings for various popular games.

Analog game controllers connect to
the gameport. Digital game controllers connect to the gameport or to
a USB port. Analog controllers are obsolete, although millions of
them are still in service. Analog controllers provide limited
functionality require frequent calibration, and using them degrades
system performance. Digital game controllers provide greater
functionality, seldom or never require calibration, and do not
degrade system performance, so all game controller development now
focuses on digital, and in particular on USB.