# Classes of Peripherals

Peripherals supported by the 3DO Interactive Multiplayer system include:

- Light gun
- Extended joystick
- Mouse
- Control pad

Note: Examples for using the control pad are discussed in Getting User Input.

Peripheral devices are divided into two classes.

- digital
- analog

## Digital

Digital peripheral devices are best suited for applications involving on/off events with a limited range of motion. The control pad is a digital device.

## Analog

Analog peripheral devices are best suited for applications involving a broad and continuous range of motion. The joystick, light gun, and mouse are analog devices.

Analog peripheral devices work best with games that require smooth control. It is possible to emulate the functionality of an analog device, such as the joystick, with the digital control pad, but this ultimately frustrates the user and is not recommended.

This document is concerned primarily with analog peripheral devices.

### Personality

Each peripheral has a set of characteristics-a personality-that makes it more suitable for some types of applications than for others. Developers who take the time to understand the characteristics of the various peripherals are in the best position to pick the appropriate peripheral for their application, and to derive the maximum benefit from the personality of that device.

The following list matches peripherals supported by the 3DO Interactive Multiplayer system with games best suited to the personality of each:

- Extended light gun-most often used with shooting games and arcade games.

- Joystick-the varying degrees of movement possible with this peripheral ideally suit it for driving simulation and flight simulation games.

- Mouse-best suited for games that require the player to click on items on the screen, for example strategy-type games.

### Noise Level

Relative noise level is another distinguishing characteristic of peripherals. Noise level refers to the amount of superfluous information traveling back and forth between peripheral and game. A noisy peripheral is one that transfers a relatively large amount of irrelevant data. The extended joystick, for example, continues to send information about minute changes in its x and y coordinates even when idle.

The following is a comparative list of supported peripherals:

- Light gun-moderately noisy
- Extended joystick-noisy
- Mouse-quiet

Filtering is a way of setting the resolution of a peripheral, that is, of establishing a threshold at which information exchange between game and peripheral becomes significant.

Based on the minimal movement perceived by the device, some type of filtering is recommended to avoid jittering and expensive recomputations. The 3DO:Examples:Eventbroker folder contains sample peripheral filters.

The management of data transfer between peripheral and game is handled by the event broker. See Event broker for more information.