A question about lightguns.

[Mischief Maker]

Why is it the Nintendo Zapper worked just fine as a stand-alone unit, but all the models since have all required some sort of sensor mounted to the top of your screen?

[trap15]

Because CRT scan position can be tracked easily with a cheap external sensor, whereas it's impossible to track an LCD. Since nobody uses CRTs anymore, traditional lightguns aren't marketable (and the zapper won't work on your new flat screen! give it a shot ).

[BryanM]

The zapper scans for light. When you press the button, the screen turns black, and white hitboxes on things you can hit are displayed in a quick sequence. If it detects white, it registers a hit.

The timing on this has to be precise - if the white box is displayed too late or too soon or not at all, the gun won't register a hit in sync with what the game requires. Since we have no standard television tech these days (plasma, LCD, OLED, CRT, maybe more?), and, jesus knows you can't rely on even LCD's to have a standard frequency (they don't even have the color BLACK for crying out loud), there's no way you can make a light gun accessory that "just works" with any tv. Though I suppose you could have one with a calibration menu if you want a game that has the screen flashing black twenty times a minute.

I don't think it would look too great in House Von Deaders though. I don't even think the light gun can register more than like 15 shots a minute, can it?

[BryanM]

Maybe scratch the lightgun calibration idea. We're probably talking something like a difference of 10 or less milliseconds here. Would take hundreds of tries through trial and error.

[BrianC]

Why is it the Nintendo Zapper worked just fine as a stand-alone unit, but all the models since have all required some sort of sensor mounted to the top of your screen?

Is this a trick question? The only ones I can think of before HD that require a sensor are the Menacer and Super Scope. Guncon 1 and 2 use a plug through the video, and others like the DC lightguns, the Saturn lightgun, the SMS lightgun, and the justifier don't require a sensor.

[trap15]

The zapper scans for light. When you press the button, the screen turns black, and white hitboxes on things you can hit are displayed in a quick sequence. If it detects white, it registers a hit.

Actually this is incorrect.

The way it works is: when you are holding the button, the sensor in the gun turns on. When the CRT raster triggers the sensor in the gun, the gun sends a signal to the console immediately. The console then turns this information back into an X,Y coordinate, which can then be used in the game to do collision checking or whatever. If I recall correctly, the reason for the white-box-on-black flash is to improve detection in areas that matter.

This doesn't work on anything other than a CRT because there's no raster beam to trigger the sensor.

[Fudoh]

This doesn't work on anything other than a CRT because there's no raster beam to trigger the sensor.

I think this actually applies to all classic CRT lightguns except the Nintendo zapper. Isn't that why you can simply point the zapper at any light source (e.g. a lamp), pull the trigger and it will detect a hit?

[BryanM]

When the CRT raster triggers the sensor in the gun, the gun sends a signal to the console immediately. The console then turns this information back into an X,Y coordinate, which can then be used in the game to do collision checking or whatever.

This is a different method than was used with the NES and Master System guns. It was used with the Super Scope and such. I remember it requiring some calibration before it would work... and it absolutely does not use white boxes.

If I recall correctly, the reason for the white-box-on-black flash is to improve detection in areas that matter.

It's solely to register a hit or not, and which object was hit. It is the only way the NES zapper can function, as it has one button and a sensor that either detects light or does not.

A really goddamn sensitive device it is, too. Killed mine just by opening the shell and looking at its insides. It's amazing any of the damn things still work.

This doesn't work on anything other than a CRT because there's no raster beam to trigger the sensor.

This is incorrect.

The white boxes turn on and off over a period of milliseconds. Timing must be precise. On an NES the time window needed to sync with the cycle the game checks for a hit will be long passed on an LCD. You could make a piece of zapper hardware that'd work for a specific TV, but not universally.


Edit: Sometimes I forget that humans are people and not robots, and those last couple sentences probably sound like incomprehensible gibberish to norms. They translate to "The nes zapper doesn't work on LCD screens because the white boxes appear later than the game expects them to. And LCD's have different specs, so the boxes won't appear at the same time on different LCD screens."

[BryanM]

And I'm not certain, but am reasonably sure LCDs still draw a picture top to bottom line by line. Mostly an assumption from the stuff in DirectX I've done, can't really google a clear answer at this point of sleepiness.

The Super Scope fails on LCDs due to pixel persistence, says the internet whom I'm too tired to find fault with at this hour.

[RocketKnight]

What if the white-turning screen used in the more precise one of the CRT detection methods would be replaced by a fullscreen pattern of white dots that differs in every area of the screen, similar to a QR code? Couldn't a light gun with a good quality photo lens detect the shot screen area by comparing its picture with the known dot pattern? Comparing 5x5 pixels (25 bit=approx. 33 million combinations) in the center of the photo should be enough.

Perhaps the gun could measure the TV's input lag when displaying the pattern before starting the actual game. In the game the gun could wait this period of time between receiving the console's report about sending the pattern to the TV and taking the photo to prevent taking a photo of the in-game graphics. Additionally, telling the program the position of dead or stuck pixels could help with minimizing faulty detections.

http://www.directupload.net/file/d/4435 ... bn_png.htm

[quash]

This doesn't work on anything other than a CRT because there's no raster beam to trigger the sensor.

This is incorrect.

The white boxes turn on and off over a period of milliseconds. Timing must be precise. On an NES the time window needed to sync with the cycle the game checks for a hit will be long passed on an LCD. You could make a piece of zapper hardware that'd work for a specific TV, but not universally.

For the majority of light guns, I would imagine these would both be issues. The Zapper in particular might not require a raster beam, but I'm pretty certain anything PS/SS onward does. I seem to remember the PS Guncon having a separate video wire for this very reason, as well as it not working on certain models of projection screens.

[null1024]

What if the white-turning screen used in the more precise one of the CRT detection methods would be replaced by a fullscreen pattern of white dots that differs in every area of the screen, similar to a QR code? Couldn't a light gun with a good quality photo lens detect the shot screen area by comparing its picture with the known dot pattern? Comparing 5x5 pixels (25 bit=approx. 33 million combinations) in the center of the photo should be enough.

Perhaps the gun could measure the TV's input lag when displaying the pattern before starting the actual game. In the game the gun could wait this period of time between receiving the console's report about sending the pattern to the TV and taking the photo to prevent taking a photo of the in-game graphics. Additionally, telling the program the position of dead or stuck pixels could help with minimizing faulty detections.

http://www.directupload.net/file/d/4435 ... bn_png.htm

There's a couple of things you can do if you were building a lightgun for modern TVs. Easiest would involve an autocalibration screen that looks at the image on the screen and uses whatever frame is being shown at the time the button is pressed to determine the delay required, and for detecting shots, you could do it exactly like on the NES Zapper [flashing squares and an optical sensor -- which would work as-is on modern LCD screens if they updated with zero delay]. Hell, you have the advantage that you could use colored squares so you only need to show the black screen for a frame and determine which target was hit based on that instead of multiplexing over targets over separate frames. You'd need a clear frame to make the player not aim away from the screen and hit the enemy marked with whatever color they painted their wall with, too.
You'd also consider storing the position of the targets from however many frames back so the player doesn't need to lead shots to account for TV lag, and maybe even adjusting things like incoming attacks so they only deal damage after the lag time has completely passed.

Doing dot-patterns on the screen could be a good solution too. You'd need to do a fair bit of processing on the image the gun takes [which is now another latency source], but as long as all of the markers were in frame, you could figure out where the gun was pointed based on angle/shift. You get the "bonus" of requiring the gun to be far enough from the screen for the markers to all be there, so you can't just push the gun up to the screen like with older methods.
The obvious disadvantage is the very visible markers you'd have to use, but otherwise, it's not a bad solution -- you'd use the same techniques commonly employed in AR image tracking. Getting good accuracy might be tricky though.

It wouldn't be a dense grid [that'd obscure visibility a bunch, unless you triggered it like the NES zapper method above], you could reasonably do it with a pretty simple loose grid overlay on the game screen.

And I'm not certain, but am reasonably sure LCDs still draw a picture top to bottom line by line. Mostly an assumption from the stuff in DirectX I've done, can't really google a clear answer at this point of sleepiness.

LCDs effectively update all at once [like, not entirely, but it's fast enough that you really can't reliably detect a specific position from it, there's slow-mo vids of LCD refreshing on youtube, it like fades between each frame from top to bottom, there's no nicely defined beam position to track].

[RocketKnight]

There's a couple of things you can do if you were building a lightgun for modern TVs.

So when it's possible to make an accurate light gun for LCDs, why doesn't anybody build one?
Shmups forum's engineers, it's your turn!

[Obiwanshinobi]

Gun games from Sega for the Wii were typically pretty great... and sold about as well there as anything that wasn't published by Nintendo for their home consoles. So, if the very genre is commercially this successful anymore, who's gonna pedlle another hunk of gizmo to whom, for the sake of supporting... what was it again?

[BryanM]

Gun games from Sega for the Wii were typically pretty great... and sold about as well there as anything that wasn't published by Nintendo for their home consoles. So, if the very genre is commercially this successful anymore, who's gonna pedlle another hunk of gizmo to whom, for the sake of supporting... what was it again?

Did they make a game where you can move around with a joystick in your left hand and the gun in your right?

Gallery shooters are fun, I enjoyed House Von Deaders and Time Crisis as much as the next guy, but..

[BrianC]

Gallery shooters are fun, I enjoyed House Von Deaders and Time Crisis as much as the next guy, but..

That's why I like games like Hogan's Alley, Duck Hunt, Barker Bill's Trick Shooting, Safari Hunt, Shooting Gallery SMS, and Wild Gunmen quite a bit.

[Obiwanshinobi]

Did they make a game where you can move around with a joystick in your left hand and the gun in your right?

I believe you can TECHNICALLY do this in Rogue Trooper and Sniper Elite ports using Nyko Perfect Shot peripheral*. Not sure if these can be completed this way, though.
*) Assuming you consider "nunchuck" a joystick, but if you don't, well, it can be modded into one I guess.

P.S. As a matter of fact, I see both Sniper Elite and S&P2 officially support Wii Zapper

but it's not saying much, is it?

[quash]

Did they make a game where you can move around with a joystick in your left hand and the gun in your right?

That was supposedly the concept behind the Dreamcast version of GunValkyrie that never came to be. You'd think there would have been more attempts at this since.

[PC Engine Fan X!]

Did they make a game where you can move around with a joystick in your left hand and the gun in your right?

That was supposedly the concept behind the Dreamcast version of GunValkyrie that never came to be. You'd think there would have been more attempts at this since.

For the arcade scene back in 1992 in Japan and abroad (including the USA courtesy of Taito of America arcade subsidy), Taito released it's hybird gun shooter called Operation GunBuster (a dedicated arcade cabinet that could be linked up with two cabs for a grand total of four players duking it out with each other). Each player had an 8-way digital joystick + X/Y fixed axis light gun setup to move around in/shoot. http://flyers.arcade-museum.com/?page=f ... 71&image=1

The promotional OG flyer shows two guns per player but the actual production cab sported a single x/y axis light gun (located on the right side) & single 8-way digital joystick (located on the left side) for each player. There was a shield that covered the screen and your view (when duking out with your opponent next to you during a serious session but the player could easily take a peek over it to see where the other player was when playing a 1P vs. 2P deathmatch stint).

The Japanese version of Gunbuster had that heavy Terminator Endoskeleton vibe/visual flair going on, especially during the attract demo run/cycle. It's playable in Mame but it really doesn't do it justice as it requires a dedicated 8-way digital joystick + the aforementioned fixed x/y axis light gun setup to be able to play it properly.

I used to play Operation Gunbuster at my local Regency Game Palace aracde hangout back in 1992 and into 1994 back in the day. Very cool hybrid arcade gun shootiing game with a heavy sci-fi/cyberpunk vibe going on.

At first, when I heard about this new Gunbuster arcade game, I wasn't sure if it was related to the cool Ganiax released Gunbuster OAV out on VHS & LD formats a tad bit earlier (but later found out that that wasn't the case here as they were two completely different IPs but with the similar Gunbuster name moniker).

PC Engine Fan X! ^_~

[Imhotep]

Did they make a game where you can move around with a joystick in your left hand and the gun in your right?

Namco's Lucky & Wild is like that, only that it's a racing game and you handle a wheel instead of a joystick. The second player gets only a gun, but the cabinet allows him to handle both guns at once and leave just the navigation to the first player, which is quite cool I think.

[Obscura]

Re: how the Zapper works, the easiest way to prove that it's just a light sensor and doesn't require a raster beam is to try aiming it at a lamp bulb. You'll register hits in-game even though you're not even aiming it at the TV.

[null1024]

Re: how the Zapper works, the easiest way to prove that it's just a light sensor and doesn't require a raster beam is to try aiming it at a lamp bulb. You'll register hits in-game even though you're not even aiming it at the TV.

that doesn't actually work in any actual Zapper games, since the game checks frame timings to determine what was shot -- if there isn't a black frame at the right spot, the game rejects the shot [read: sensor needs to not detect light at a specific point in the shot]

If you ran a test program and aimed the Zapper at a lightbulb, it'll show that yes, it's detecting light.
display latency is the entire reason Zapper games don't work on a modern LCD -- the timings are several frames out of sync

[Obscura]

Really? I'd always heard you could easily "perfect" Duck Hunt that way, and at least one blog seems to back it up: http://retrogamingnation.blogspot.com/2 ... apper.html

Or have I just been taken in by an urban legend? I had always heard the reason the Zapper didn't work on an LCD was that they didn't put out enough light for the sensor to pick up.

[BryanM]

Wikipedia claims the black check was intrinsic to later versions of the hardware, hell if I know.

[Astraea FGA Mk. I]

[null1024]

Wikipedia claims the black check was intrinsic to later versions of the hardware, hell if I know.

That sounds needlessly complicated to do in hardware instead of just polling the sensor to do the check in the game, but I dunno. At the absolute least, it didn't work with my Zapper to just point at a bulb as a kid playing on the SMB/Duck Hunt cartridge.

[BryanM]

It's been driving me crazy, so let's chalk the lightbulb trick into the myth bag. I can't find a single legitimate source on it.

The patent on the zapper claims a capacitor and a coil is used to filter input that lacks that black masking... I'd like to look at a documented ROM map of Duck Hunt, but I guess it's not as beloved as Super Mario Bros. and Pokemon Crystal are. Anyone who's familiar with ASM wanna check this for us?

[BIL]

I just tried the lightbulb trick in MADDO SHITTY aka BAYOU BIRRY and got my ass handed to me! :O

Spoiler

[atheistgod1999]

I tried the lightbulb trick in Duck Hunt and no dice.