Atari XG-1 light gun
The Atari XG-1 light gun is a controller bundled with the Atari XEGS which was released in 1987 and was compatible with the Atari 7800 and Atari 2600. The XEGS, where "GS" stands for "game system," is an Atari 65XE computer reworked cosmetically to give the appearance of a game console. The light gun was bundled to compete with the Nintendo Entertainment System. The XEGS shipped with one light gun game, Bug Hunt. Atari eventually released five games on the 7800 that use the controller: Alien Brigade, Barnyard Blaster, Crossbow, Meltdown, and Sentinel.
The XG-1 is a specialized light pen. Light pen support was built into the earliest Atari 8-bit computers.
Technical details
The Atari 400/800 Hardware Technical Reference recommends a "calibration procedure" each time the light pen is used, so that the software can compensate for this offset. A calibration procedure would improve the accuracy of the light gun. But both Bug Hunt and Barnyard Blaster for the XEGS both have "hard-coded" values, different ones in fact. While Bug Hunt appears to shoot slightly to the left, Barnyard Blaster seems to shoot slightly to the right. The Y readings for the gun are more predictable, equal to half the number of the currently displayed scan line.
The gun won't return reliable readings at all if the intensity of the display is too low. That's why the screens for Atari light gun games may be brighter than usual. The game screen will momentarily flash white whenever the trigger is pressed in either Bug Hunt or Barnyard Blaster. While the screen is all white, the software reads the gun position and provides the most accurate values.
Games designed for the XG-1
- Alien Brigade (7800)
- Bug Hunt (XEGS)
- Barnyard Blaster (7800/XEGS)
- Crossbow (7800/XEGS)
- Crime Buster (XEGS)
- Meltdown (7800)
- Operation Blood disk (XEGS)
- Operation Blood II - Special Forces (XEGS)
- Gangsterville (XEGS)
- Sentinel (2600/7800)
Unreleased
- Shooting Gallery (2600)