Vertical Super Mario Bros.!? Not exactly... - Talkin' Code Episode 3.1

[@matesafranka6110]

Okay, so this is both hilarious and cathartic to me, because I actually played "Vertical Mario" as a kid. Growing up in Eastern Europe in the early 90s, most kids didn't own actual Nintendo consoles, but rather some Chinese knockoff that also came with a bunch of built-in games. The boxes often boasted as many as "1000 games", which in actuality were like 12 different games with minor variations (nothing more complex than what you could get with a Game Genie: different starting level, number of lives, etc.). The games always included Super Mario Bros, as that was basically the selling point, plus a bunch of others like Tetris, Contra, Mighty Bomb Jack, Hokuto No Ken, etc. One of these games in the list was labeled "Fancy Mario", and was identical to SMB, except for its glitched graphics -- which I now recognized in your video. So, you have basically solved a 27-year-old mystery for me, and I really appreciate that :D

[@nightbirdds]

I had run across this on bootleg multicarts back when I was a kid, too. I had no idea why it was so messed up back then, but now I know. As I recall there was also a non-glitched version on the cart, which is what I ended up playing.

[@beastworm]

Same here, but I grow up in South America. As soon the started the game after the modification, I had on my head "That's fancy mario!"

[@FranciscoFoco]

Yes! I played that Fancy Mario hack too as a kid in the early 90's. I had a "Micro Genius" NES bootleg console that came with a "Contra 100 in 1" multicart. Among the several variations of the same games there was this weird version of Mario, in which you saw a preview of the background. Since we didn't had much to play back in the day, I stuck with it a lot. I think I was even able to finish it!

[@user-sl6gn1ss8p]

it's not a prank, it's a product!

[@craigluft7453]

Jasper: Slow down! The sidewalk is for regular Mario, not Fancy Mario.

[@QkiJose]

I played this version as a kid. it was in a 52-in-1 cart and the name was "fancy bros."

[@MaaZeus]

So did I! It was on one of those light grey Supervision multicarts. I always thought the cart was malfunctioning and that game was broken (and it sort of is) but now that I saw this video I realised what was going on, two decades later... 😂

[@mrmimeisfunny]

Everyone who grew up with Famiclones in the comments: "Hey, I've seen this one, this is a classic."

[@MyScorpion42]

everyone who didn't: "What do you mean you've seen this, it's brand new"

[@Vincent.Anthony]

This had been done in 90s with pirated cartridges, they named the game Fancy Mario

[@brentvecchi4893]

He did it! And solved the mystery of Fancy Mario? Incredible!

[@dominikmurz]

In Poland, we had pirated cartridges from Taiwan, often as "99999999 in 1" with some Game Genie-like hacks like big-only Mario or more lives. We also had "Fancy Mario" which did exactly what you have shown (future on left side of the screen).

[@makeitrein7366]

I swear Chris is a mind reader. I was thinking to myself "I wonder what would happen if someone soldered that pin just to see what happens" and sure enough... a whole episode about it. Kudos my friend.

[@GermanFleitas1989]

Wow!!! I'm from Uruguay (South America) and here we had a lot of Famiclones with multi cart games. My cousins had one of those multi cart with a game called "Ghost Super Mario Bros." or similar.... and was exactly this!

[@captainnavigator6534]

We really need to get kosmic to speed run this """""version"""".

[@Blankult]

He barely backtracks in the game so it wouldn't make a difference

[@ZipplyZane]

@@Blankult It's not backtracking that gets messed up, though. I think it would mess him up until he go the hang of it, and that he might mistime some things because he'll go fast.

[@vinterbjork4128]

I wonder how this effects wrongwarp in say for example 4-2, it shouldn’t I think?

[@Hattes]

@@vinterbjork4128 Assuming the same input, no, since this "hack" just affects the graphics

[@DisplacedGamers]

At one point I had written a note about blindfolded SMB players being able to play this version of the game easily without any knowledge of the cart being altered. I searched for blindfolded kosmic, but it looks like he hasn't done a blindfolded run? (...yet?) I think a SMB speedrunner's skills and muscle memory would probably make this alteration a non-factor.

[@thecastiel69]

That's fancy mario

[@AtKiba]

I finally understand why this game existed as a kid, I thought they actually made a weird hacked version of Super Mario, but they simply changed the scrolling value.

[@MaxOakland]

3:40 this makes me amazed that Mario 3 can scroll in all directions

[@danieljimenez1989]

It had a chip in the cart to allow that.

[@tylisirn]

Unfortunately 8 way scrolling can't be done perfectly on NES because you can only have extra screen space horizontally or vertically, but not in both directions at the same time. On actual CRT TV the glitch is usually hidden behind the TV overscan, but on LCD TV or emulator you can see the rightmost column splitting the attribute table cells with the cells on the left side of the screen.

[@mrmimeisfunny]

​@@tylisirn actually it can if you add some extra VRAM in the cartridge. an example of a game that does is the unlicensed game Rocman[sic] X

[@northsta]

This channel is like a dream come true. Anyone involved in graphics programming can now imagine how to create a classic platformer 👍

[@awesomedata8973]

This is why I love your channel. Stuff like this is great to see how/why it works! :D

[@EebstertheGreat]

Mario actually stands 112 pixels from the left edge of the screen if you are moving normally to the right, not quite halfway. And the seam appears to show up slightly behind him. So I'm guessing it's not quite 1.5 screens that are loaded into VRAM at a time, more like 1.4.

[@HJkos]

Next episode gotta be 3.11 for workgroups

[@renakunisaki]

📎 looks like you're trying to screw up Mario! Do you need some help?

[@araigumakiruno]

this actually answered the lingering question i have about famiclones containing SMB, i found the exact same one with that kind of graphical glitches and i was shocked to find out it was just a simple vertical or horizontal configuration error

[@vitalsign0]

This is slowly becoming my favorite channel.

[@hokostudios]

The confounded doubt at 6:52 really spoke to me. Anyway, a few videos later, it's nice to get to see what Super Mario Bros. with horizontal mirroring looks like! Not being wired to think in nametables, it was tricky to wrap my head around what that would actually look like.

[@LethalBubbles]

i seem to remember when VERY dirty cartridges would trigger things like this and invalid levels and such. similar to zelda 2's "f power"

[@jamesallen74]

dude your videos are the best. This is a PERFECT example of the power of video over the internet powered by people like you, not corporate-driven. Yeah I know KZbin is corporate and FAR from perfect, but stuff like this would NEVER see the light on corporate owned tv/cable stations. Cable public access at best. Great work dude.

[@BainesMkII]

The reason why disabling the built-in database isn't recommended is that there is no guarantee that the headers included within NES ROM files are accurate. Header information doesn't come directly from the cart, it is filled in by the dumping hardware and the person performing the dump. People creating and distributing dumps would too often simply guess as to what the mirroring was, or even ignored it entirely. You'd see people complaining online about emulation issues, when in reality they were just using a ROM that had the wrong mirroring setting in its header, which was a mess back when coders were still figuring out NES emulation. Now NES emulators mostly rely on built-in databases, and rom verification utilities and dat sets are often designed to ignore NES headers entirely. There was a push for simply scrapping NES headers entirely a while back (just having a file containing only the actual chip data), but it never caught on.

[@BainesMkII]

@@pineberryfox That's not really an issue, emulators already fall back on the supplied header if the game's ROM isn't matched to a database entry. You can even argue to varying degrees that preservation, hacking, and homebrew all would have benefited from a move to headerless ROMs. The NES header format was designed pretty much for piracy, and falls short pretty much every other use. But it is too heavily entrenched to be replaced by an alternative format. The widespread adoption of "headerless" could have been the middle step that let preservationists, homebrew enthusiasts, and rom hackers push through their own special case alternative information delivery format. (Whether it be an alternative "header" or "footer" attached within the rom file, or a separate "description" file.)

[@renakunisaki]

I think the idea was to be something simple like a zip file, containing dumps of each chip plus a file describing how they were connected, what the game's title is, etc.

[@BainesMkII]

@@renakunisaki That's the preservationist approach, similar to how ROMs are handled for arcade games. Near had been pushing for this approach for SNES ROMs in Ares. With Near's death, I don't know if anyone of any influence is still pushing for such an approach, though.

[@Nikku4211]

It makes me wonder, what if there was an NROM game with 8-way scrolling that used a vertical arrangement of nametables like Super Mario Bros 3 does?

[@MarklarMusic]

You actually went back and did it. Wow. I love it.

[@SomeGuy712x]

I think I recall getting this kind of weird scrolling effect while fooling around with Game Genie codes in the past. So, whatever oddball code I entered to cause this must've changed the mirroring value from horizontal to vertical, I reckon.

[@Stratelier]

Carts with a mapper chip had to store the current mirroring state _somewhere_ in RAM, so it's entirely possible.

[@BrainSlugs83]

When you say "put the game back to normal", I really hope you mean that you are going to install a switch to toggle between the two modes. 😅 That would have been the ultimate prank! "How come when you play it, it's normal!?" 😂

[@jonathanpobst7093]

The next question is: what happens if neither horizontal nor vertical is soldered?

[@picc9000]

Miyamoto: "Please do not do that."

[@FoxerTails]

Perhaps nothing would show on screen since the connection isn't going anywhere?

[@Hattes]

That's actually how they did the multi-dimensional scrolling on SMB3

[@mazionach]

@@Hattes Not mario 3, that one uses horizontal mirroring. But kirby's adventure does use a single screen.

[@sentry4944]

@@Hattes SMB3 used a different mapper chip (MMC3) with a different PCB with no V or H solder pads.

[@stevenjlovelace]

I'm looking forward to "Talkin' Code for Workgroups 3.11".

[@Colonel-Llama]

Had this mirrored version on a 190 in 1 multi along side the original. The Bros. weren’t as fancy as the name suggested

[@xeostube]

This description of how scrolling works was actually easier to follow than the last video. Well, maybe that's because I saw the last video, but in any case it underlines how helpful a good demo can be for making complex topics clear.

[@themrpoopo]

I remember as a child, those "polystation" nes clones came with a game called Super Mario Fancy that look right like that. We used to belive it was a different game. Now i know what they do.

[@fluffycritter]

After the previous episode (where I was one of the folks commenting asking about the modification) I looked through my cartridge collection to see what mapperless games I even had to see if I could modify any of them for fun. It turns out the only mapperless game I have which involves any scrolling at all is Raid on Bungeling Bay, which I was surprised about, as it's a game which has 360° scrolling! So I played it for the first time in years and found it really interesting to see how they'd managed to implement 360° scrolling without a mapper. The horizontal scrolling is very smooth, but vertical is a little juddery, which I'd never noticed before. It'd be interesting to see an episode on how games like that implement their scrolling at the PPU level. Raid on Bungeling Bay in particular is overlooked as an interesting technical achievement and was also an interesting game on its own right; it's the game that directly led to the creation of SimCity, because Will Wright, the game's designer, kept on having too much fun adding capabilities to the map editor and decided to make a game based on that. (edited to fix some terminology, thanks to Dycedarg's Elder Brother)

[@dycedargselderbrother5353]

A minor correction, because I was briefly confused: Raid on Bungeling Bay's configuration is NROM, not UNROM. Despite the similar naming the configurations are completely different. NROM was a "no-mapper" used for launch era titles like Balloon Fight, Excitebike, and Ice Climber while UNROM was an early mapper configuration that was used in games like Castlevania, Contra, and Mega Man. Raid on Bungeling Bay appears to have the same mirroring configuration as Super Mario Bros. so that would match your observations. I'm betting software scrolling similar to what was used in platforms like the MSX1 was employed for the horizontal portion. That is it's probably overwriting background tiles in VRAM to produce the effect. This is a lot slower than hardware scrolling so it can't happen every frame which would be why it's choppy. It's still pretty impressive, though. The flying physics are also pretty impressive for a 16K code early NES game.

[@fluffycritter]

@@dycedargselderbrother5353 Ah, good to know, I didn't know about NROM or that UNROM had a mapper at all.

[@daserfomalhaut9809]

This actually explains half of what was going on in an ANCIENT video called Super Glitch Bros.

[@jonothanthrace1530]

Next question: what happens if you do the same thing on Ice Climber, which is the only game I can think of right now with purely vertical scrolling.

[@YASYTU]

If it works by the same logic as Mario but with vertical instead of horizontal scrolling, it would probably show a "preview" of the what is just above the current screen where the lower half of the current screen should be. Can't wait! ;)

[@BagOfMagicFood]

Wrecking Crew?

[@gluttonousmaximus9048]

I'm not sure whether the free-scrolling Bungeling Bay can be messed with like this. The Famicom version even predates Super Mario Bros.

[@RaposaCadela]

Cool! I have seen SMB doing this when I played it in a bootleg multi-cart that had it

[@michaelpowell3204]

When I was little in like 1987 I had a dream about what Super Mario Bros 2 and 3 would be like, and for whatever reason my brain settled on the idea that SMB2 would be like 1 but you were being chased by a bulldozer, but 3 would be a true innovation where it would scroll vertically and you'd go up through the clouds...

[@TtEL]

Now we need to modify the code to point to the new registers.

[@BokBarber]

Now I must know: what if you solder both of them closed? What about neither?

[@jmalmsten]

I too was struck with that question. We need to find out. Maybe the NES will just see both flags as 1 or 0, determine that this shouldn't be possible and just get stuck in an error state. But I am curious to want to know nonetheless.

[@LynnDrumm]

Interesting! I have a 500-in-1 cart that has a game called “fancy Mario” that just looks exactly like this.

[@SamuraiPixelCats]

OK now I'm curious what would happen if you did this same thing to a vertically scrolling game like Kid Icarus

[@ohnoitschris]

Could try it yourself. Disable the database check in Mesen, and look on the Nesdev wiki to see how NES 2.0 headers work, find the bit to flip to horizontal mode, save it, and give it a shot

[@SomeGuy712x]

However, Kid Icarus can scroll both horizontally and vertically, depending on what level you're playing.

[@roymerkel8008]

yeah, sounds like changing sodder isn't going to be enough, sadly, but that DOES sound like an interesting mod someone with some time, an assembler, and a disassembly from online could do...

[@YTDeepshock]

This is exactly the kind of persistent glitch I saw on a multicart long before I was in a position to understand any of it.

[@PrinzessinRamode]

You can do this same thing on Nintendo World Championships. When the title starts, press start on player 2 to get Super Mario 1 going, scroll the screen a bit, then repeatedly press the reset button. Eventually, you will see a glitched version of Super Mario 1. The effect will be the same. Rad Racer will then either start normally, or be an unplayable mess. I have a video of this on my channel.

[@PrinzessinRamode]

This will not work on an emulator. You would need an actual cartridge.

[@dionelr]

Time to break out the soldering iron. Great video, as always!

[@youdontneedtoseehisidentif4939]

Count me in as one of the people who played this version of _Super Mario Bros._ as a child - I never owned a NES, but the father of friend brought a multicart back from… Hong Kong, I think..? …in the early 1990s, and this was on it

[@Mamiya645]

gruz who lives for Mario game genie code fun would love this.

[@klauskillski3881]

and a new speed run category is born

[@lucetubegplusstillsux2678]

Apparently early Mario 2/Doki Doki Panic prototypes were an actually vertically scrolling Mario game, so maybe they thought of this too.

[@KazoWAR]

i wonder what happens if both or neither solder pad is set

[@JB-mm5ff]

great vid. what model microphone do you use for your YTs?

[@solembum78]

Great content as always, thank you!

[@Nicholas_Steel]

You can also achieve this along with corrupt level layouts by an improper insertion of the game cartridge (contact pins on cartridge making incorrect contact with console pins). But only the NES version, SNES version just crashes.

[@danielleary7876]

My friend and I are both Systems Engineers by trade and amateur programmers. We're planning on learning Assembly language together by working on either a Z80 or NES program. It got me thinking that we should start by analyzing one of the smallest possible NES roms as a way to begin to grasp the standard structure and composition of a typical NES rom. 16k Donkey Kong seems like such a small, fathomable, manageable amount of data that it seems to me to be a good candidate for analysis. It would be awesome if you wanted to tackle the same subject. I'm thinking in terms of breaking down the entirety of the address locations into identifiable sections ie. "0x0000-0x1fff is the program rom", "0x2000-0x3fff is the sprite data", etc. With possible subdivisions within each section. It just seems to me that stepping back and having a macro view of the rom in it's entirety would be really helpful way to gain some perspective that makes things more conceivable. Or maybe just the fact that this seems possible to me betrays how little I understand the technology at all. Just thinking. Love all your videos, especially the newer Pacman Ai one. Keep up the good work.

[@danielleary7876]

Wow, I'm really embarrased cuz the video that i referenced above about Pacman Ai actually is not yours, its from the Retro Game Mechanics Explained channel here: kzbin.info/www/bejne/l6XEeKKqhpycqJo But you guys both make killer videos and the fact I confused your videos is a compliment to both of you I think.

[@TroyBlackford]

Absolutely love this. I've got a small soldering job on a Eurorack module to add a MIDI header, and I'm nervous. You want to do it for me? You're great and I love your work.

[@aner_bda]

Definitely need to see speedrunners try and speed run this version.

[@tmilker]

What if you solder... both? 🤣

[@sevenpastmidnight9542]

Just thought that was seeing if anyone else did xD

[@ImSquiggs]

This is super interesting... are the any other soldering points that can change how early games are configured? I'm about ready to break open some carts and start going nuts haha

[@patrickhawthorneLS]

I have seen a rom hack like this for a nes multicart from the 90s

[@FeralInferno]

Very neat trick. I wonder what would happen to Mario 2 (USA) if you flipped it around, as it has both horizontal and vertical levels.

[@heitortremor]

This is a really amusing and informative video lol

[@tdelfino2509]

Talkin' Code for Workgroups 3.1

[@krunkcleanup2949]

Would be interesting if someone made a 2 player simultaneous game by using one name table for each half of the screen. I wonder if any games like that exist on the NES already.

[@BIG_CLARKY]

this is something that commonly happens with corruptions

[@Kippykip]

lol after your first video i hex edited the iNes header rom to do this exact thing. I was too curious

[@HostiaRecords]

How to convert your original SMB to "Fancy Mario" jajaja

[@stevep9177]

I saw this "version" of the game on a multicart way back in the day

[@jswanhart]

If you were really Evil you could rent a cartridge and change the solder points before returning it. I had friends back in the 80s that would have been prone to such things if they knew about them.

[@mjc0961]

Okay, now for episode 3.2, solder both jumpers at the same time and see what happens. 🤪 For 3.3, neither of them.

[@renakunisaki]

3.4, add a toggle switch and change it on the fly!

[@yeolemillinial8295]

so basically since zelda 2 can scroll both directions but not at the same time, is this exactly what happens in the speedrun glitch that get used all the time, it pretty much looks like this.

[@Manabender]

I'm curious. What pins are being bridged when the Hscroll solder pads are connected? Same question for Vscroll? What would happen if you soldered both? What would happen if you soldered neither?

[@seeigecannon]

Great video. Now I am curious what would happen if both jumpers are selected, un-selected, and what would happen if the jumper configuration changed mid-game.

[@mrmimeisfunny]

Both jumpers means 4 way mirroring. No jumpers means it addresses unallocated memory, though you can fill it with cartridge ram and some games did. My favorite example is the unlicensed game "Rocman X".

[@Peffse]

hahaha, that half-screen ending card

[@TopShelfTheology]

Oh holy crap, this happened to me by complete accident in Mega Man 3 last week!! I was playing my physical cart, and it was doing the usual NES glitching/freezing thing, I blew in it a few times, shook it up... Then the next time I loaded it and it seemed stable, all the way through the menus, until I started a stage, Needle Man in my case. I'd never seen anything like that, and it was playing surprisingly stable, other than me being completely disoriented. And more oddly, MM3 scrolls different directions, so once I went down a ladder, it seemed fine again, until I'd start moving right. How in the hell did that happen?! Do I have a short in my cart? Did a loose chunk of solder happen to land right in the spot inside? I'm still bewildered, but I'm more spooked by the fact that this literally happened the week before you posted this, that's crazy. Thanks for some form of insight! I guess?

[@ohnoitschris]

A bit of your saliva from blowing in your cart might have bridged the solder point edit: get some canned air and start using that instead

[@DankRedditMemes]

Makes me wonder, how are pre-mapper games without scrolling (e.g. Galaga, Donkey Kong) configured on the PCB?

[@mrmimeisfunny]

Galaga has a Vertically scrolling title screen. So it uses Horizontal Mirroring. Donkey Kong just has Horizontal Mirroring for no reason and leaves one of the nametables uninitialized. Donkey Kong 3 is a bit more interesting, It uses vertical mirroring and puts the pause screen on nametable B, so when you pause it scrolls there. Despite that, if you leave both solder joints disconnected you should get "Single Screen" mirroring. That's what Tetris and Dr. Mario did (I think... at least that's what Mesen says)

[@MoustiluigiRandom]

Excellent

[@chrisd6287]

Hell yea were talkin code

[@miketate3445]

Now I can sleep. Thank you.

[@RSRetroStageVG]

Gran video explicando este curioso efecto. En los 90´s era común jugar el "Mario fantasma" en los multicarts piratas (bootlegs) también se podía conseguir el juego solo pero no era muy común de verlo. Pueden investigar en videos que tengan gameplay del multicart "SuperVision 52 in 1" y el ultimo juego se llama "Fancy Bros." con esta modificación. Saludos.

[@DrakkarCalethiel]

Wonder what would happen if you bridge both or neither. Latter one would probably be end in aa random choice of h or v scrolling based on interference?

[@jorgeluiscontreras5239]

Fancy Mario bootleg famiclone carts!

[@vaendryl]

first question that popped up was "but what happens if you move to the left" completely forgetting that in the first mario, you can't do that. but that leads to the second question - "why can't you move to the left in mario 1?". with all you've explained about the viewport it doesn't seem that hard to do. not that "reversing" the code that loads the level in front of you as you move would be trivial but nintendo clearly chose it wasn't worth the effort. maybe that was just a part of game design sensibilities at the time.

[@minirop]

1/ the same thing but in reverse. They would have chosen to keep half a screen in memory so both screens would be full (one with what's around Mario and the other half of what to come and half of what's behind) 2/ pretty sure it was game design decision (to force you to continue/finish the level)

[@shortcat]

is scrolling both left and right related with glitches on the very sides of the screen in some games?

[@thomasmathew13]

@@shortcat that has more to do with games that can scroll both vertically and horizontally, like smb3.

[@minirop]

@@shortcat if you think about SMB3 and it's colour glitch on the right side of the screen, yes. that game is in vertical mirroring. "retro game mechanic explained" has a video on that subject called "The Nintendo Entertainment System's Loading Seam"

[@GeneralBolas]

It isn't hard in theory to move to the left. However, that would assume that you actually store your level data in a way that allows you to access the level data that is "to the left". There are many compression techniques that don't allow you to randomly access data. That are required to start from the beginning and move in one direction only. The obvious solution here is to decompress the entire level and feed it in as needed. But the NES doesn't exactly have a ton of RAM lying around. It should also be noted that smooth scrolling *at all* on consoles of the day was kind of new. Not unheard of, but hardly the norm (vertical scrolling was *far* more common than horizontal scrolling, for scan-conversion reasons). So limiting the game to ratchet scrolling wasn't unreasonable, as people would be pleased to have horizontal scrolling at all.

[@captainobvious7033]

So this was how Fancy Mario was made?

[@walmartcartpusher]

Time to activate both Horizontal and Verticals ;-)

[@WilliamEly]

Why isn't this a new speed running category?

[@Vextrove]

Awesome!

[@yod1213]

Hey whats up Displaced Gamers, just wondering if you're making that sprite comparison episode we talked about or not.

[@possible-realities]

Ok, so SMB1 must be keeping a copy of the tile data in RAM as well, which is what the game logic reads, since the behavior doesn't change when you do this, only the graphics. That's at least 360 bytes (16x15 blocks per screen x 1.5 screens) out of the NES' 2k of RAM. But it makes sense; I guess it's not so easy or fast to read back the tile data, the tile data is for 8x8 tiles, and it might not even be unambiguous (background castles made of brick tiles, etc...).

[@mazionach]

If you open the ram viewer on an emulator, you can actualy see the copy of the level loaded in ram as you move. And yes, reading from vram is tricky, has some bugs, and can only be done at vblank or you would corrupt the sceeen (but SMB1 still does it anyway for the title screen)

[@malik641]

This reminds me of the healer glitch in Zelda 2. Do you think you will cover this in a future video?

[@BlackBeltGamers88]

I have a glitchy cartridge just like this. It's more glitchy than your modified one though, it shows a LOT of crazy stuff like it's heavily corrupted. I have a video of it on my channel.

[@xeostube]

So does a game like zelda skip the mirroring based scrolling and just move data round the first of the 1 background pages?

[@possible-realities]

I'd bet that Zelda I uses mirroring based scrolling, and changes the mirroring based on whether you're going through a vertical or horizontal edge of the screen. Zelda I is originally a Famicom Disk System game, those must have been able to control the mirroring because different disk system games might use different mirroring. Not sure how Zelda II overworld map does it, that can scroll in both directions, right? But you don't strictly need the mirroring, that's true, SMB3 uses horizontal mirroring which lets it do vertical scrolling, and updates the leftmost/rightmost tile column of the screen for horizontal scrolling (with some color glitching as a result).

[@taskanawa9604]

whats happen if you bridge V and H at same time?

[@rsa5991]

Short circuit, with a possibility of frying your NES.

[@taskanawa9604]

@@rsa5991 try it, maybe works

[@MrTASer]

That green block can be seen in actual gameplay(TAS) also... Skip to 1-2 kzbin.info/www/bejne/qarToGB9itWDZ6s

[@f.k.b.16]

Is it possible to run left in Mario 1? Is it just a programming limitation?

[@kuulajarkkoperse]

what happens if you solder them both?

[@XxUltimateGodzXx]

Hmmm, wondering now how the emulators, if the database did not exist, would know how to scroll the screen without the physical circuit telling it how too per game. Wonder what it would do...

[@mazionach]

Thats why the ines header was invented, to store information about the pcb the rom is suposed to use. Without that, there is no way to tell. I have heard that really old emulators needed modified versions of the games to work, this could be one of the reasons.

[@Ragesauce]

3:13 wouldn't you want 2 to be ontop to load upcoming graphics as you scroll upwards vertically? or can the programer just change which graphics load in 1 or 2 depending on which direction they go (either up, or down)

[@minirop]

doesn't matter, since the scroll wraps around, so when in VRAM1, the "above" tiles are loaded at the "bottom" in VRAM2.

[@vitalsign0]

Can you look at the code on ET from the Atari 2600?

[@ManiacalForeigner]

Honestly, I was more surprised by the askew scanlines on that monitor than anything else. How on Earth does that work?

[@fluffycritter]

It's what rolling shutter does to the retrace of the screen.

[@LaatiMafia]

What happens if both or none are soldered?

[@trench01]

Since you can see ahead, then is their a way to see the entire level for the emulator to extend the window?