X-Authentication-Warning: delorie.com: mailnull set sender to djgpp-bounces using -f X-Originating-IP: [209.213.43.188] From: "Chester Lowrey" To: djgpp AT delorie DOT com Subject: Light Gun Interfacing question Date: Tue, 04 Dec 2001 09:12:58 +0000 Mime-Version: 1.0 Content-Type: text/plain; format=flowed Message-ID: X-OriginalArrivalTime: 04 Dec 2001 09:12:58.0671 (UTC) FILETIME=[DDDAEBF0:01C17CA3] Reply-To: djgpp AT delorie DOT com Hello everyone, I have a quesion about interfacing my custom built light gun into programs i would like to make. I built the gun from scratch and it detects the light coming from the monitor, if light is sensed a pin on the parallel port goes high, another pin is used for the trigger on the gun. I have already made a simple target shooting game in cpp that just cheakes to see if light is sensed, and as there is only one source of light on the screen this means that the target was shot, it also counts down the ammo and stuff like that. What i would really like to do is be able to know where on the screen the gun was aimed, not just light/no light :) The way the arcade games do this is by flashing the screen white when the trigger is pulled (or mabe the screen is bright enough so they dont have to do this, i think there is more than one way) and then when the gun senses light the software cheaks where the video card was scanning the electron beam across the screen, so it knows at exactly what part of the screen you shot. As you can see the timeing has to be fairly fast, my gun is fast enough, what i dont know how to do is get any information from the video card as to where it was scanning when light was sensed ? I thought i could make some kind of timer start running when the screen was flashed, and then count the time it took to sense light, that would be a really crude way of telling where it was scanning, and probably not accurate enough to do anything with. But if the graphics card method is hopeless i may not have another choice. If you can help me at all i would greatly appreciate it. Thanks, Chester Lowrey Chester's Electronics Lab http://hot-streamer.com/hilo90mhz/ _________________________________________________________________ Get your FREE download of MSN Explorer at http://explorer.msn.com/intl.asp