Relay-Version: version B 2.10 5/3/83; site utzoo.UUCP Path: utzoo!mnetor!seismo!rutgers!ames!ucbcad!ucbvax!ucdavis!egg-id!ui3!dickow From: dickow@ui3.UUCP Newsgroups: comp.sys.cbm Subject: Re: Zapper for C64 Message-ID: <60008@ui3.UUCP> Date: Mon, 22-Dec-86 13:11:02 EST Article-I.D.: ui3.60008 Posted: Mon Dec 22 13:11:02 1986 Date-Received: Fri, 2-Jan-87 20:57:06 EST References: <60@popeye.UUCP> Organization: MRC, University of Idaho Lines: 19 ... Concerning the question about a ZAPPER light gun for the C64... I can't say for certain that there isn't a "light gun" such as this available, but I would be a little surprised. I say this only because light pens (direct contact to screen) to date have been slightly problematic on the C64. It takes extra hardware/fast photodiodes in order to reduce the horizontal 'jitter' that occurs. That is, getting readings on the verticle coordinate (even with cheapo $1.50 pens you can make from two parts purchased at Radio Shack) is a cinch. The horizontal readings are bonkers. Basically you have to deal with an 8 bit resolution to determine a point on a 320 pixel wide screen. You can get better hdwr and do interrupts and ML averaging and most-frequently-returned-data routines and still get erratic results in my experience. My work with the SYMTEC light pen on the Apple IIe is also prone to some of the same problems. All in all I might be quite dissapointed in a light target gun for game applications on any system, but I'm willing to be proved wrong. Bob Dickow, University of Idaho School of Music egg-id!ui3!dickow