XE lightgun: Real 7800 vs MiSTer, XE vs Sega Phaser, offset, accuracy, adapters, etc.

[RockLobster]

So plenty have been posted about how the Sega Master System Phaser is superior in terms of accuracy to the now pricey and hard to find XE light gun.   Enough that there are variants of schematics to make an adapter for Atari systems to use Phasers.

 

Not that I doubted the claims about the gun differences but I haven't experienced it myself until yesterday after acquiring a copy of 7800 Crossbow.  Indeed the difference was noticeable across the two XE guns and two Phasers I have.   I've had Barnyard Blaster and Bug Hunt but the difference wasn't nearly as stark.  Has anyone else experienced this?

 

In addition, I notice a slight but consistent offset of the XE gun to the right and a little down by maybe a half an inch in the shot grouping (as it's a little inconsistent with shots).  I have no such problems with the SMS Phaser.

 

-- here's where it gets a little weird...

 

On the MiSTer using both Sega and Atari SNAC adapters (it's a direct pin to pin connection to the FPGA core accessing the device), the XE guns are significantly more accurate than on a real 7800 or Atari8bit computer.   So much so that prior to getting an Atari XEGS, 130XE and 7800 that I thought the accuracy thing was exaggerated.

 

However, on the MiSTer, there was an offset for the SMS Phaser whether I was using the home made adapter or the virtual SMS compatibility adapter in the core.   After digging/testing, one of the core devs shared a version of the core with delayed timing of reading the SNAC pins and that resolved the offset with the Phaser.

 

All this time, I just thought the XE guns were inferior by design and/or build.  But clearly they just fine and there's something on the programming or hardware of real Atari hardware?

 

--

 

So I guess the question/comments are:

 

1) Why are the XE guns so much less accurate than SMS Phasers on real hardware than on the MiSTer?

 

2) Any way to address the XE guns offset on real hardware?

[+MrFish]

I owned a couple XE lightguns at the same time, a few years back. From what I recall, one was slightly off to one side and either down or up a little, while the other one was dead on. I think I tested them on all the XE game cartridges with lightgun support: Crossbow, Bug Hunt, Barnyard Blaster, and Crime Buster. I also played some Special Forces (a German title) and a few of the Polish games that work with it. There's also a utility on the 8-bit computers that will test your lightgun.

 

From my experience, since the ones that are off are consistently off in the same direction, any software would just need to have a setup/calibration screen where it adjusts itself to how your lightgun plays.

 

I think there are a few topics on the subject in the 8-bit computer forums; and some comparisons between the XE and Sega guns. I might see if I can dig some up tomorrow.

 

I still have a lightgun (sold the other two I had and got a third). I don't use it much, because I don't find the game offerings too compelling to spend time with. But... I would really like to see Duck Hunt on the 8-bit computers some day. So, I started working on how the graphics might work out in 160 pixel width multi-color character mode (Antic 4). The same graphics should be suitable for the 7800.

 

Here's a little GIF animation I did for the converted graphics.

[Note: The grass, shrubbery, and trees are all quick & dirty conversions, with almost no hand editing; everything else was hand pixeled.]

 

 

[+DrVenkman]

I bought a Sega Light Phaser a couple years ago and had to take it apart to repair a broken wire inside the cable. The insides are quite similar to photos I’ve seen of the inside of the XEGS gun, and the cases are nearly identical except for color. I’m sure none of that is a coincidence - I expect most of both guns were built by the same one or two subcontractors, using the same design (aside from the inverted trigger circuit of the Light Phaser).

 

That said, there are details internally that can account for difference in accuracy between models and between individual units. First, these guns have a plastic lens at the front of the barrel which sits inside a little molded slot. That lens can easily get dirty or fogged, affecting accuracy. If the gun is handled roughly it might even get slightly misaligned or nudged in its slot, especially if the plastics are worn or the plastic barrel is flexed. Next there is a photodiode that sits behind the lens. It too is held in place with little molded bits inside the case, and so the same conditions apply: rough handling or flexing of the gun might cause it to become slightly misaligned. Finally, there are a slew of discrete components inside including capacitors and transistors, If any of those are out of spec or wearing out, response time for both sensor and trigger circuit can vary a tiny bit, affecting perceived accuracy. 

[Eagle]

3 hours ago, MrFish said:

Here's a little GIF animation I did for the converted graphics.

Nice. Few months ago I tried conversion from nes to 320C mode  

Should look better if you will draw from the scratch 

 

[+Muddyfunster]

I think @SmittyB's version is better. Needs more MethDog.

[Eagle]

Yep. My dog looks too sober 😂

[+SmittyB]

 

But yes I am working on a duck-themed lightgun project called Ducks Away. It is not Duck Hunt because frankly DH is dull as dishwater and I can do better.

For the lightgun I use a target selection method like DH which flashes individual targets on screen and it means the gun only needs to tell me if it saw something that frame. I tried the screen-flash method but while I could reliably get the Y position, the X position requires precision timing to be anything close to accurate and I just couldn't make it work.

If the response times are affected by those components aging as @DrVenkman mentioned then that will throw off the accuracy by quite a lot. I know the 8-bits read the gun as an analogue device but I don't know the specifics, but on the 2600 /7800 the screen-flash method means polling the gun in a tight loop. I believe Crossbow only manages to poll it about 16 times per line giving an accuracy of down to the nearest 20 pixels give or take. If the gun responds late it could miss being polled and be out by nearly 40 pixels.

 

[+MrFish]

15 hours ago, MrFish said:

Here's a little GIF animation I did for the converted graphics.

Man, Atariage really monkeys with the background colors for its in-line image-post previews for GIF's... click the preview to view the original (and have some visual peace).

 

[+MrFish]

5 hours ago, Eagle said:

Nice. Few months ago I tried conversion from nes to 320C mode  

Should look better if you will draw from the scratch

Thanks. I haven't done any work on the dog yet. It shouldn't be too tough though. The background shouldn't be hard either. All the duck animations are done.

 

I'm not too familiar with the restrictions for the various modes on the 7800. Although I did produce an updated version of someone's charts of mode specs (just haven't looked at them much).

 

 

7800 Sprite Data to Color Mapping 1.xlsx

(Excel spreadsheet version)

 

[+MrFish]

3 hours ago, SmittyB said:

DH is dull as dishwater

It's not the kind of game you want to play all the time. But we always found the game entertaining and worth playing every once in a while, to break up the typical gaming sessions. It's simple but well-done with a nice touch of humor. I like it.

 

[+DrVenkman]

22 minutes ago, MrFish said:

It's not the kind of game you want to play all the time. But we always found the game entertaining and worth playing every once in a while, to break up the typical gaming sessions. It's simple but well-done with a nice touch of humor. I like it.

 

It was a college fave of ours, especially after a few drinks while “pre-gaming” for a party or an actual football game. We had a small on-campus apartment but my roommate was rather well-to-do for the time. He had an enormous Mitsubishi console TV that we sat about 3 feet away from due to the small size of our apartment. Hip-shooting contests after 2-3 drinks was great fun. 

 

 

[+MrFish]

My idea for doing Duck Hunt is to enhance it some, by adding a variety of backgrounds/environments (overlooking a lake, fall time of year colors, etc.). This would make it a bit less monotonous.

 

I think the skeet shooting is worth keeping too; but could also use some background variations.

 

[+MrFish]

I found these graphics from the original. The scene is the lower-right is nice; but I'm not sure how you reach it in the original game; maybe some kind of bonus round?

 

 

[+Mitch]

It has been a long time since I played Duck Hunt but isn't the bottom right screen from the skeet shooting variation?

 

Mitch

[+MrFish]

7 minutes ago, Mitch said:

isn't the bottom right screen from the skeet shooting variation?

I really don't know, because I haven't seen it before while playing. I guess I could check some YouTube videos. But... it doesn't match up with the lower graphics of the skeet shooting shown here. The skeet-shooting graphics have that gray panel at the bottom. So, it seems to match up more with the style of the duck hunting graphics on the lower portion (ground/dirt/earth).

 

[+MrFish]

  

1 hour ago, MrFish said:

maybe some kind of bonus round?

1 hour ago, Mitch said:

isn't the bottom right screen from the skeet shooting variation?

 

I found it. It's the bonus round on Vs. Duck Hunt (MAME/Arcade); and you get to shoot the dog!   So, you have to play it in MAME.

 

Here's a video of it from YouTube. The bonus round starts at 1:40.

 

 

Gotta include that!

 

[+MrFish]

I always liked Skeet Shooting from Summer Games on the XL/XE's a lot. It doesn't appear to be included with the 7800 version (nor does Pole Vaulting... too bad, fun stuff). It'd be cool to have a light gun version of it. The Joystick version works quite well; but I could see a light gun providing an even better experience (properly coded).

 

 

[Silver Back]

7 hours ago, SmittyB said:

 

But yes I am working on a duck-themed lightgun project called Ducks Away. It is not Duck Hunt because frankly DH is dull as dishwater and I can do better.

For the lightgun I use a target selection method like DH which flashes individual targets on screen and it means the gun only needs to tell me if it saw something that frame. I tried the screen-flash method but while I could reliably get the Y position, the X position requires precision timing to be anything close to accurate and I just couldn't make it work.

If the response times are affected by those components aging as @DrVenkman mentioned then that will throw off the accuracy by quite a lot. I know the 8-bits read the gun as an analogue device but I don't know the specifics, but on the 2600 /7800 the screen-flash method means polling the gun in a tight loop. I believe Crossbow only manages to poll it about 16 times per line giving an accuracy of down to the nearest 20 pixels give or take. If the gun responds late it could miss being polled and be out by nearly 40 pixels.

 

How is ducks away coming along?  I tested a bit for you on discord so if you'd like me to help test more I can 

[+SmittyB]

48 minutes ago, Silver Back said:

How is ducks away coming along? 

I don't want to derail the thread too much, but it's coming along very well thanks. I rewrote the original version from scratch to take advantage of some ideas I had and it's all the better for it. I'm pretty much where I was with the old version plus some new extras like quadtari support. I'm not sure how practical 4 lightguns will be with the screen flashing away all the time but the option is now there for whoever wants to play it that way.

[leech]

1 hour ago, SmittyB said:

I don't want to derail the thread too much, but it's coming along very well thanks. I rewrote the original version from scratch to take advantage of some ideas I had and it's all the better for it. I'm pretty much where I was with the old version plus some new extras like quadtari support. I'm not sure how practical 4 lightguns will be with the screen flashing away all the time but the option is now there for whoever wants to play it that way.

Ha, still think I need a large CRT for stuff like this.  Largest I have is a 21inch VGA one...

[+MrFish]

Last month: Man Robs Convenience Store With Nintendo ‘Duck Hunt’ Pistol

 

[bikeguychicago]

On a side note, is there an adapter to use the SMS light gun with the 7800? I tried the SMS gun in combination with a Seagull 78 and it recognized the gun as a joystick when I tried it with Crossbow. I prefer to use the gun unmodified with both consoles (SMS and 7800), if possible. 

Edited August 7 by bikeguychicago

[+DrVenkman]

43 minutes ago, bikeguychicago said:

On a side note, is there an adapter to use the SMS light gun with the 7800?

The Mega7800 from @SainT has adapter functionality built in if used with his 7800 Game Drive cart.

 

Otherwise, you have to make/build an adapter that corrects the inverted trigger circuit as compared to an Atari XE style gun.