Calling all owners of Fantasy Zone II (System16C)

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donluca
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Calling all owners of Fantasy Zone II (System16C)

Post by donluca »

Hi everyone,

there's one thing which is driving me nuts and it's that there are small graphical glitches which happen on original hardware which are not reproduced in MAME (using the same ROMs).

I've tested and doublechecked everything and all is good and tight.

On youtube I managed to find only one guy which recorded the game from original hardware and, lo and behold, he has the exact same graphical glitches I have.

The glitches I've encountered so far are:

1 - During the attract mode (not shown in the video), upper part (the one with the score, etc...), some small horizontal black lines flickering when the image changes.

2 - When you start playing, before you take control of Opa-Opa, there are the same small horizontal black lines in the middle of the screen: https://youtu.be/vucC5RDi-Xg?t=13

3 - During the 4th zone boss, when you get closer to the boss and start attacking rapidly, the boss' sprite gets slightly corrupted: https://youtu.be/vucC5RDi-Xg?t=505

4 - Not shown in the video, but sometimes I manage to corrupt part of the shop graphics which will show some big white boxes going over the interface. I don't have a reliable way to trigger this, but it seems that if I shoot a lot and there are lots of sprites on screen when I open the shop, this will happen.

Apart from this last one, the other glitches can be reliably reproduced and are always the same: same lines, same spot, same duration, etc.

None of this happens in MAME or in the PS2 collection from which the ROMs are extracted.

I thought I messed up something, but since I've found another guy with the *exact same glitches* I have, I think there might be something wrong in the ROMs... maybe bad dumps?

Please, let me know if you have a working board if you have those glitches as well.

I might upload a better video to show you those issues at a later time.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by SavagePencil »

Not to derail too much, but I thought Fantasy Zone II was only available for the System E boards, not 16c?

EDIT: NM, this is the DX version done by M2, not the original.
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Shelcoof
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by Shelcoof »

Just curious though

Aside from the glitches
Are there any differences between playing this on original hardware vs the PS2 collection?
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donluca
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by donluca »

Haven't played the PS2 version yet, just watched it on youtube, but the data is the same. If you unpack the PS2 ISO, you find the game's ROMs.

The emulator on PS2 probably sets a dipswitch to freeplay and that should be all the differences you get.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by Shelcoof »

Now that I think about it I wonder if there's any lag at all with the PS2 emulation. Wonder if anyone would be interested in comparing this at all.

I'm happy with the PS2 seeing how I have it hooked up to a really nice CRT and the game outputs 240p beautifully on my Sony WEGA. Got my shmup stick for my PS2 as well and I'm all set to emulate that arcade experience at home :D
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donluca
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by donluca »

Eh, guess I could try a giving it a go, but right now the point of the thread is understanding why the hell those graphical glitches happen and if it's normal or something is amiss.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by bigbadboaz »

@Shel: the unique nature of FZIIDX means that, strictly speaking, the PS2 version is the original and not the board. M2 created the game specifically for the PS2 collection, aiming to capture the nature of the game if it had been built for System 16. The specs for this game include far more RAM than any of the actual S16 games had. The limited boards built were sort of promotional/exhibition items and were retrofitted around the game M2 had come up with.

So of course, the experience on an actual board is something to be interested in, but you don't have to worry about "emulation quality" in this case - you're definitely playing the game as intended by its creators the first time around.

@don: I don;'t have a factual answer for you, but I have to wonder if the glitching you describe - expecially since you cite at least one identical example - is entirely normal and due to the unique nature of these boards as described. Since they weren't mass-produced and had some unique components, perhaps this led to some quirks in the final boards?
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Shelcoof
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by Shelcoof »

Not worried about emulation quality at all but was curious as to see if lag did exist in the PS2 collection.

It was a curiosity thing to be honest :)
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by donluca »

bigbadboaz wrote:@Shel: the unique nature of FZIIDX means that, strictly speaking, the PS2 version is the original and not the board. M2 created the game specifically for the PS2 collection, aiming to capture the nature of the game if it had been built for System 16. The specs for this game include far more RAM than any of the actual S16 games had. The limited boards built were sort of promotional/exhibition items and were retrofitted around the game M2 had come up with.
I'm 100% positive it's exactly the other way around: I've read several times that M2 developed the game for the S16 system, but since it was able to address way more memory than it originally could, they decided to take advantage of it and build the game upon an improved board codenamed "HOSII" and then dubbed "System16C" which ran with 256KB of RAM and 8KB of Z80 RAM (with the latter being already on the board, as the game audio runs fine without any further modification).
Then they made an emulator for it on the PS2 and that was pretty much it.
So of course, the experience on an actual board is something to be interested in, but you don't have to worry about "emulation quality" in this case - you're definitely playing the game as intended by its creators the first time around.
I kind of agree, as they probably made an emulator specifically for this game.
@don: I don;'t have a factual answer for you, but I have to wonder if the glitching you describe - expecially since you cite at least one identical example - is entirely normal and due to the unique nature of these boards as described. Since they weren't mass-produced and had some unique components, perhaps this led to some quirks in the final boards?
That's what I was thinking and what's irking me even more is that there's no footage of those boards running to see if the glitches appeared also on the "official" System16C.
To me it almost looks like that the glitches are either:

1 - The machine hitting the sprite limit, just like old NES did
2 - RAM or EPROMs not fast enough, but, hell, I've used the fastest I could find around, way faster than original System16 roms. And, just to rule this out, those RAMs and EPROMs work fine with other System16B games, no glitches at all.

If someone else comes up here saying that they have those glitches as well, I'll just call it a day and give for granted that there's some kind of limit by the hardware it runs on which produces those glitches.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by mikejmoffitt »

These are minor programming errors due to oversight in the creation of the game. I'm sure they did a lot of testing in emulators and did not see them as a result.

The lines that flicker on the screen are because of palette writes mid-frame. This would likely not be too hard to fix in software, and I'm working on a patch for that (among other things). The correct way for this to be done is to defer these palette writes into a queue, which gets committed during the vertical retrace interval.

The boss getting corrupted rapidly, and the shop interface having white boxes, are both the same problem, and it is simply sprite overdraw. Too much sprite data for a given line, just like on an NES game. The System 16 sprite system reacts interestingly to having too much sprite data requested on one line. Rather than simply dropping further data, the result is that the remaining data for the sprite gets pushed down by one line, while the total sprite height remains the same. System 16 sprites are stored per-line, not per-tile, so data fetches are iterative. A dropped line doesn't increment the line index, hence the strange movement of the boss's face. This'd be a bit harder to fix, as it is a consequence of a design oversight. A hotfix could be to detect too many bomb explosion sprites being drawn at once, and to omit them in that situation.

None of this happens in emulation because the emulators are not accurate enough. Nothing is wrong with your PCB or ROMs.
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donluca
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by donluca »

Wow, my wild guess was actually correct :mrgreen:
Feels good.

And it feels even better knowing that nothing's wrong on my end, thanks mike!

It surely makes you wonder about the accuracy of the emulators we use... we give for granted that emus like MAME are *very* accurate, but it seems like there are corner cases which haven't been figured out yet.

One thing still intrigues me: it's known that the game has been shown in some test locations, running on a System16C board in an arcade cabinet. How come those guys didn't notice those glitches? They just didn't care? It would make sense since their target were obviously PS2 users, but still...

Oh well, I'll be waiting patiently for your patches, so my OCD can find peace :mrgreen:
About the boss glitch: it's definitely the bomb explosions, today I died in a very stupid way on that boss and I couldn't trigger that glitch with just a single bomb, no matter how close/fast I spammed bomb and shot together.
Limiting the bomb explosions in this situation would be a viable solution for sure.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by Sumez »

donluca wrote: It surely makes you wonder about the accuracy of the emulators we use... we give for granted that emus like MAME are *very* accurate, but it seems like there are corner cases which haven't been figured out yet.
Definitely not. I do believe MAME (at least nowadays) has some sort of code involving accuracy, but I can't imagine that necessarily implies implementing all kinds of limitations that rarely have an effect on the actual games.
When you described the glitches, my theory was the exact same that mikejmoffitt comfirms - timing issues regarding writes to the video ram. That is such a classic error you see on a lot of homebrew written entirely for emulators, as emulators don't really have any reason to restrict when you can or can't access certain parts of memory if no official games ever did that.

Genuinely accurate emulators are few and very far between.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by orange808 »

To be truly accurate, you need transistor level emulation.

That's not coming any time soon.

In the meantime, what we have is pretty good. In most cases, you just want a hack thrown in to make you believe it's "accurate".
We apologise for the inconvenience
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by donluca »

Today I managed to trigger another glitch!
Spoiler
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All the sprites had vertical lines on them! Yay!

The sprites even retained the glitch between two levels, I had to go to the dark side and back to clear them up.

Looks like mike will have quite a bit of work cleaning up the code for it to work correctly on the System16C :P
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by mikejmoffitt »

I don't see how that could possibly be a software glitch. Sounds like your board could use a little attention. The lines are spaced every four pixels, and only affect certain colors. I bet it is an intermittent data connection to your sprite data ROMs.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by donluca »

I've been playing the board for weeks and this is the first time this happens and it went away as soon as I cycled to Dark side level and back.

From experience, issues like this are permanent if there's a fault in the board, they do not go away like that. This is why I'm thinking about a software bug.

I'll keep playing it until I've cleared it (got through the boss rush zone and to the last boss where I lost my last life, sad times) and see if anything similar happens again.

Just to rule out any possibilities: the board has always been inside the cab since I started playing it, the cab has not been moved or kicked or anything, so, from a physical point of view, there haven't been any kind of changes.

If this keep happening I'll definitely take a look at the board, but AFAIK the only thing which could have happened is an EPROM going bad, since no changes have happened.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by mikejmoffitt »

Well, I've cleared the game on both sides and 4-looped it, and have never seen it do that once, so I'm pretty sure you have an intermittent hardware thing going on :P
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by donluca »

Good Lord, this game have 4 loops??? That's... disheartening, lol. I'll probably go for the first loop and call it a day. :P

I'll take out the board then and take a look, although I keep all my boards really clean, something might have gone over the EPROM pins and maybe shorted two address lines for a brief time, which was then retained into RAM until it was overwritten when I went to dark side and back.

I really hope it's not an EPROM going bad because I have only 1 more available.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by mikejmoffitt »

It might have more, but I choked halfway through the last loop.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by donluca »

I have a suicidal tendency to get really close to the bosses to get max damage, which often ends up killing me.

I should just relax and play it safe.

By the way, yesterday had another shot at it and, surprisingly, it only happened in a couple of cases and for a fraction of second, like a single flash. So there's definitely something wrong, I need to check the EPROMs and make sure everything is nice and clean.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by XtraSmiley »

Hey guys, any update on this? I know Mike is working on ROM fixes, but did you ever determine if those lines were your board?

Good find by the way!
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by donluca »

Which lines are you talking about? :P
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by Ikaruga11 »

I'm so glad I downloaded Fantasy Zone II: The Tears of Opa-Opa from the Nintendo Wii Shop Channel hours before it closed.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by mikejmoffitt »

The Wii shop channel only had the SMS / System E game, didn't it?
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by Greenalink »

Only the Master System version, not System E. That version did get a release for PS2's SEGA AGES Collection (yep, 3 versions of Fantasy Zone 2 on that disc).
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by Ikaruga11 »

mikejmoffitt wrote:The Wii shop channel only had the SMS / System E game, didn't it?
Yeah
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by XtraSmiley »

donluca wrote:Which lines are you talking about? :P
The ones that might have been your EPROMS.

Having said that, I guess there are no updates. I also asked on the other site, but no reply yet!
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by donluca »

There are several different "lines" discussed here in this thread.

If you're referring to the ones shown in the last image I've posted, that were a badly seated EPROM.

If you're referring to the others, that's a timing issue we all have.
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by XtraSmiley »

donluca wrote:There are several different "lines" discussed here in this thread.

If you're referring to the ones shown in the last image I've posted, that were a badly seated EPROM.

If you're referring to the others, that's a timing issue we all have.
I was asking about your last photo, so the badly seated EPROM, I'm glad it was an easy fix!

As for the other graphical problems, yup, I have the exact same ones!
mikejmoffitt wrote: The lines that flicker on the screen are because of palette writes mid-frame. This would likely not be too hard to fix in software, and I'm working on a patch for that (among other things).
Looking forward to Mike's fix, however, I'm curious about the "among other things" he said he's working on.

Mike, what else were you planning on fixing, or did you mean other games?
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Re: Calling all owners of Fantasy Zone II (System16C)

Post by mikejmoffitt »

I have a few things planned:

* Optional Free Play via DIPs (my hack just hardcodes it right now)
* Option to turn off attract sound
* Deferred palette writes (fix that color issue)
* Possibly limit the explosion sprite count during some bosses to fix sprite overflow
* Fix bug where on loop 2 and onwards, Opa-Opa is able to turn around in all boss battles, not just the designated ones. (must confirm this isn't intended behavior)
* Loop / stage select for practice
* Not fix an endearing typo on the item select, that mistakenly reads "H MOMB" instead of "H BOMB"

Right now, I am pretty preoccupied with my job (embedded automotive work) and am working on a real, commercial game project in a lot of my spare time, so it's hard to find a window of time to do more extensive things like this. The time will come, but it won't be quick. I might bang it out in a weekend before CAX so it's ready.
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