Arcade Light Guns with a super low latency LCD?

[xoypox]

Alright, Linus Tech Tips covered that light guns don't work with (most?) LCDs because of input lag, and hence didn't include it with his MAME Arcade box, but could he replace it with a modern super low latency LCD?

but looking at this slow motion shot, it seems that not all lcd monitors do a frame-at-once,*1 and based on display lag observations, a 9ms lag LCD with 1ms response time would be comparable to "Using this [displaylag.com] metric, even a CRT would not have zero lag – it would have 8.3 ms of lag. This is because it takes a full 16.66 ms to display the entire frame from top to bottom."*2 and using this test https://youtu.be/Q3gaic8-Gf8 with the ViewSonic XG2401, the top of the screen is at 2.9ms, but bottom of the screen draws at 17.6ms, leaving only a Delta of 2.9ms at the top and 1ms at the top of the LCD compared to a perfect crt. So are light guns are really that sensitive to timing? Is there another problem that LCDs cause not related to input latency?

 

*1: https://youtu.be/wts8f1bNnbo

 

*2: http://www.meleeitonme.com/this-tv-lags-a-guide-on-input-and-display-lag/

 

I think to know for sure though, someone needs to have one of these monitors and actually test it out, and with all the monitors Linus must've collected, there's no other person better than him to test it.

 

Here are 2 tests that need to be done.

 

1. Use an IPS 9ms lag and a 5ms response time, like the ViewSonic VP2468

 

2. Use a TN panel with a 10ms lag and 1ms response time, like the ViewSonic XG2401

 

Will one of them work, will both of them work, or none of them? LTT, I hope you really consider this for a proper video.

[TrigrH]

http://electronics.howstuffworks.com/question273.htm

 

it wont work, till we get OLED monitors or TVs with super low input lag then maybe.

[Mira Yurizaki]

Traditional light guns don't work because they relied on how CRTs worked with the scanning electron beam (i.e., the game calculates from a start of a frame happens to when the gun picks up light from the electron beam refreshing a phosphor). The only to get a light gun to work on an LCD is through an IR camera, similar to the Wiimote.

 

See:

 

[AshleyAshes]

Most light guns don't work the way the Nintendo Zapper does.  The Zapper uses simple flashing squares on screen and a photo diode.  However most light guns since then use a more advanced method called 'Cathode Ray Timing'.  In this case the light gun has access to the sync signal of the display, allowing it to know when the CRT's electron gun will start scanning across the screen, it then knows when the electron gun shines down the barrel of the light gun as it scans, it simply does the math to compare when the scan started and when the light gun saw the beam and it can derive X and Y from that.  This actually allows the Cathode Ray Timing guns to do real time tracking, much like a mouse.  There is literally no way to build an LCD that would allow for a Cathode Ray Timing gun to work.

 

If you're wondering why most light gun games in the arcade or at home still 'flash' it's to increase the brightness to ensure the gun more reliably sees it's position since it can get 'lost' in darker spaces even though it's tracking at all times.

 

Examples of Cathode Ray Timing guns would include the Namco Guncon 1 and Guncon 2.  The Classic Xbox light gun (Yes, it had a gun, and an arcade perfect port of House Of The Dead 3!)  The Konami Justifier worked this way too.  As do most arcade light guns you see on machines ranging from Time Crisis to Point Blank to Area 51 and many, many other games up until LCD panels started being used in games.

 

I kinda know my stuff.  I'm a huge fan of light gun games.  I have a collection of light guns.  I converted some spare Guncon 1's with Aimtrak kits for use on modern screens.  And one of the LTT writers was consulting me on light gun stuff early on in LTT's arcade machine project.  (And the JERK would not tell me why LTT needed to know about light guns. )

 

 

[AshleyAshes]

No joke, I might have a problem...

 

 

[phly95]

19 minutes ago, M.Yurizaki said:

Traditional light guns don't work because they relied on how CRTs worked with the scanning electron beam (i.e., the game calculates from a start of a frame happens to when the gun picks up light from the electron beam refreshing a phosphor). The only to get a light gun to work on an LCD is through an IR camera, similar to the Wiimote.

 

See:

 

At 9:10, it will show that the light gun would be much less dependent on it being a crt than the light pen is (though this may vary for different types of light guns) since all it does is sees a flash of black one frame, and a flash of white the next, making it theoretically possible on an LCD, while the light pen depends on detecting exactly where the light phosphor is at the time. So while a light pen would definitely not work on an LCD, it's less clear about light guns.

 

The biggest issue then becomes whether different games used methods closer to the light pen instead, rendering those games unplayable. Thing is, maybe a modified version of lightboost could solve this issue as well, especially on OLEDs.

[AshleyAshes]

4 minutes ago, phly95 said:

At 9:10, it will show that the light gun would be much less dependent on it being a crt than the light pen is (though this may vary for different types of light guns) since all it does is sees a flash of black one frame, and a flash of white the next, making it theoretically possible on an LCD, while the light pen depends on detecting exactly where the light phosphor is at the time. So while a light pen would definitely not work on an LCD, it's less clear about light guns.

 

The biggest issue then becomes whether different games used methods closer to the light pen instead, rendering those games unplayable. Thing is, maybe a modified version of lightboost could solve this issue as well, especially on OLEDs.

As I already said, no.  Any light gun newer than the NES or Sega Master System relies on Cathode Ray TIming like the light pen.  The tech used in the Nintendo Zapper was antiquated by 1990.

[phly95]

What if a modified version of lightboost (artificial backlight flicker for LCDs, which could probably be synced to the timing of a CRT) could solve this issue as well, especially on OLEDs if each led is timed correctly (since input lag is almost resolved at this point)? Though it would specifically have to be programed to simulate the timing of a CRT, and the market is probably too small right now, but I bet if demand was shown, monitor manufacturers could make it.

[AshleyAshes]

Just now, phly95 said:

What if a modified version of lightboost (artificial backlight flicker) could solve this issue as well, especially on OLEDs if each led is timed correctly, though it would specifically have to be programed to simulate the timing of a CRT, and the market is probably too small right now, but I bet if demand was shown, monitor manufacturers could make it.

The electron gun in a CRT literally scans lines from the top corner to the bottom opposite of the screen every 60th of second.  You would need a MONSTERIOUS refresh rate to even simulate the movement of e CRT's electron beam.  Like, even at 240hz, you could only manage to flash every quarter of the entire screen just once each in a 60th of a second.

 

It's not possible.  The solution is IR LED tracking.  It's what modern arcade machines use now too.

[Mira Yurizaki]

11 minutes ago, AshleyAshes said:

As I already said, no.  Any light gun newer than the NES or Sega Master System relies on Cathode Ray TIming like the light pen.  The tech used in the Nintendo Zapper was antiquated by 1990.

The video also shows light pens, which use the same principle that light guns after the NES used. So the latter half of the video is not really important, but the first half is.

 

9 minutes ago, phly95 said:

What if a modified version of lightboost (artificial backlight flicker for LCDs, which could probably be synced to the timing of a CRT) could solve this issue as well, especially on OLEDs if each led is timed correctly (since input lag is almost resolved at this point)? Though it would specifically have to be programed to simulate the timing of a CRT, and the market is probably too small right now, but I bet if demand was shown, monitor manufacturers could make it.

No, because Lightboost and ULMB blank the entire screen, it does not do a scanning line like a CRT electron beam.

 

Actually, it wouldn't be possible anyway because most back lights are not "high resolution" enough. i.e., you have either side lit screens or array lit that only covers an area. You need pixel perfect scanning

[Maxpphire]

1 minute ago, AshleyAshes said:

The solution is IR LED tracking.  It's what modern arcade machines use now too.

This was what I was going to suggest as well as an arcade game enthusiast (but Light Gun Games are not my forte in that area). It's a lot easier to just use a CRT as those are easier to come by, either that or buy a machine of the light gun game(s) you wish to own. It's cheaper to just use a CRT, not to mention most older arcade games look better on a CRT anyway.

[phly95]

1 minute ago, M.Yurizaki said:

No, because Lightboost and ULMB blank the entire screen, it does not do a scanning line like a CRT electron beam

But assuming each pixel on the panel was backlit by independent leds, it would be possible to use a similar concept to only blank specific pixels, and since each LED is independent, each one only has to refresh at 60hz at slightly different times as the others to simulate the electron gun's (inside the CRT) movement.

[AshleyAshes]

Just now, Maxpphire said:

This was what I was going to suggest as well as an arcade game enthusiast (but Light Gun Games are not my forte in that area). It's a lot easier to just use a CRT as those are easier to come by, either that or buy a machine of the light gun game(s) you wish to own. It's cheaper to just use a CRT, not to mention most older arcade games look better on a CRT anyway.

Sadly, I have no CRTs of my own, I got rid of my beautiful Sony Wega 27" in 2013 when I moved due to not having space for it.  I wish I had a bigger place so I could have a dedicated setup with some consoles and my guns.

[Mira Yurizaki]

1 minute ago, phly95 said:

But assuming each pixel on the panel was backlit by independent leds, it would be possible to use a similar concept to only blank specific pixels, and since each LED is independent, each one only has to refresh at 60hz at slightly different times as the others to simulate the electron gun's (inside the CRT) movement.

In theory, yes, it could work.

 

However as far as I know, no such backlit LCD exists. Not that it would work that way anyway.

[Not_Sean]

@AshleyAshes man nice collection, If anything were to make me Run out and buy a Oculus/Vive it would be a Time Crisis Reboot with VR.. I don't need to walk around, but would be awesome to duck and stand out in the same motion.. 

 

We can only dream :'( 

[AshleyAshes]

1 minute ago, phly95 said:

But assuming each pixel on the panel was backlit by independent leds, it would be possible to use a similar concept to only blank specific pixels, and since each LED is independent, each one only has to refresh at 60hz at slightly different times as the others to simulate the electron gun's (inside the CRT) movement.

In what UNIVERSE do you think that this is going to suddenly magically exist to solve such a tiny niche?

 

They don't even do this in the ARCADE anymore.  Do you know what they do in the arcades?  The arcade is literally the place where a publicly playable PC port of Mario Kart exists, where it's crammed into sit down boxes that cost $20 000 for a single player setup... And the ARCADE still hasn't done anything for light guns but move to LED tracking for light guns.

 

You are literally in the territory where you might a well be saying 'Yes, but what IF NASA started building a launch pad in my backyard because they thought I wanted to go to space that badly?"  You don't live in a universe where that happens.

[Maxpphire]

Just now, AshleyAshes said:

Sadly, I have no CRTs of my own, I got rid of my beautiful Sony Wega 27" in 2013 when I moved due to not having space for it.  I wish I had a bigger place so I could have a dedicated setup with some consoles and my guns.

Oh noooo! I'm lucky not only do the games I specialize more in come in HD, but in game they have menu settings to help offset any input lag and give a monitor refresh number before the game boots. I do have a Spare CRT I want to Set up a Retro Gaming corner for but I've been too Lazy/not enough room to set it up yet lmao.

[AshleyAshes]

Just now, Maxpphire said:

Oh noooo! I'm lucky not only do the games I specialize more in come in HD, but in game they have menu settings to help offset any input lag and give a monitor refresh number before the game boots. I do have a Spare CRT I want to Set up a Retro Gaming corner for but I've been too Lazy/not enough room to set it up yet lmao.

TO busy working.  I really need to finish my Aimtrak setup.  The problem is, well, you need a really BIG LED bar to get the Aimtrak to work on a 65" TV all the way from the couch.

[phly95]

well, I guess the only solution right now is to use an ir sensor with MAME. Kind of a shame there's no direct hardware solution as that would be awesome to have a lightweight LCD one could carry on a plane to play time, but yeah, there's little chance monitor makers will make it for such a small niche, unless they could market it to esports as being so low latency it even works with a lightgun, but that would be a side gimmik. Still, that side gimmik could sell a lot of monitors if esports players and smash tournaments buy into it, and might be very much worth it for a monitor company if they pulled it off successfully, and as a bonus, it could be implemented in all the new home arcade boxes, as well as allowing arcade companies to refresh/remaster old games without redoing the code. I think there is a lot of potential gain for a company doing this if they do it properly, but retro gamers would only be a means to an end (the esports market).

[Maxpphire]

1 minute ago, phly95 said:

 would be awesome to have a lightweight LCD one could carry on a plane to play time

I don't know where you live, but where I'm from, I don't think TSA would appreciate even a fake gun being out on a plane. In the Checked luggage, sure, but in the carryons or out and in use, lmao god no.

[AshleyAshes]

5 minutes ago, phly95 said:

well, I guess the only solution right now is to use an ir sensor with MAME.

Well, no, there are third party LED tracking guns for some consoles.  Even the Aimtrak has a Guncon 2 mode that enables it to operate on PS2 games in a PS3 or backwards compatible PS3.

[phly95]

On 7/17/2017 at 11:07 PM, AshleyAshes said:

Well, no, there are third party LED tracking guns for some consoles.  Even the Aimtrak has a Guncon 2 mode that enables it to operate on PS2 games in a PS3 or backwards compatible PS3.

How does that work? does it intercept the video feed before it reached the TV?

On 7/17/2017 at 11:03 PM, Maxpphire said:

I don't know where you live, but where I'm from, I don't think TSA would appreciate even a fake gun being out on a plane. In the Checked luggage, sure, but in the carryons or out and in use, lmao god no.

haha, true, it'd be more useful in a hotel than a plane.

[phly95]

And do you think the esports market would eat up an LCD that can be proven in a live demo to have the best latency ever? I think that would be a pretty good way to sell it, especially if you made some remasters that used the same method giving exclusive features to the product, since game remasters seem to sell pretty well these days.

[AshleyAshes]

5 minutes ago, phly95 said:

How does that work? does it intercept the video feed before it reached the TV?

Well, no.  Even for the Guncon's, the GUN determines it's lown location and then sends X,Y data to the console.  The Aimtrak just uses the LED markers to determine it's location, in PS2 mode it uses the same protocol as a stock guncon and sends X,Y data to the console.

 

You're grossly overthinking how it'd have to work.

 

THe EMS Top Gun series is a pretty common 'affordabe' gun kit compatible with a few consoles.

[phly95]

lol, I thought the console was what processed it. I guess it really would be pretty simple to set up an IR setup for an arcade box. CRTs and over-engineered LCDs are not necessary. So really, the only people who would "benefit" are esports arenas, given that the flicker is optional. Retro gamers are all good. How hard is it to calibrate an IR gun BTW?

 

Edit: probably not hard at all https://www.ultimarc.com/aimtrak.html

 

Edit2: holy shit those things are expensive, I guess the wiimote method would be a significantly more budget friendly option.