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1. NO BLATANT PIRACY. This includes reproducing homebrew less than 10 years old, with the exception of free software.
2. No advertising your reproductions, with the exception of free software.
3. Be nice. See RFC 1855 if you aren't sure what this means.



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PostPosted: Sat Apr 20, 2019 9:07 pm 
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Plutiedev has announced a set of guidelines for selling cartridges of original homebrew video games for Sega Genesis and Mega Drive. Here's my attempt to translate some of these guidelines to the NES platform, as a way to spark discussion on their practicality.

Compatibility
Game must be available as a Famicom cartridge and an NES cartridge.
- Famicom cartridge must work in all CPU and PPU revisions of Famicom, Famicom Titler, AV Famicom, and Dendy, as well as NTSC NES, PAL A NES, and PAL B NES through an adapter.
- NES cartridge must work in NTSC NES, PAL A NES, and PAL B NES, as well as Famicom, Famicom Titler, AV Famicom, and Dendy through an adapter.
Game must not rely on the microphone, player 2 Select and Start buttons, or any expansion controller that has not been released in all regions.

Cartridge
Don't use Nintendo branding on the box, on the cartridge, or in the game. No red oval logos, no design mimicking the black box of North American NES launch titles. It's OK to say a game is compatible with Nintendo systems, but don't go beyond that.
Cartridge must be 5 volt compatible, using either 5 volt parts or level shifters.

I doubt the practicality of testing "compatibility" for a studio's debut release, particularly given the difficulty of obtaining a 50 Hz CRT in the United States.

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PostPosted: Sat Apr 20, 2019 10:07 pm 
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Everything in your list under "compatibility" is an extremely onerous imposition, IMO. Regional differences for NES is an insanely different beast than it is for Genesis. Maybe some of these things are a cool goal to have, but as some sort of requirement standard? No, this is not good at all.

But of course, my response to any of this would be "or what?" What are you going to do if anything I release doesn't meet whatever your goals are here?


The 5V thing lots of people care about. That already has some pretty real consequences in PR.


The Nintendo branding thing... enh, I think you're going way too far with that too. I don't like things that lie. A fraudulent Nintendo seal of approval is stupid, and also illegal. That much I agree with.

Imitating the black box design though, that's totally fine in my view. Similarly I like the grid backgrounds for Genesis and SMS releases, and would think it's fun for a Homebrew to mimic them. Some people will think that's fun, some won't, but this is getting pretty far outside the duty of a guide like this.

And back to the consequences of this... I don't think anyone who's going to put a fake Nintendo seal on something is going to listen to your opinion about guidelines anyway, though, so that is probably pointless to begin with. On the rest of it where it's not about either a lie or something illegal, telling people how you expect their box art to look is extremely snobbish. There is nothing to gain from it except ill will.


Last edited by rainwarrior on Sun Apr 21, 2019 1:37 am, edited 3 times in total.

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PostPosted: Sun Apr 21, 2019 1:21 am 
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I wouldn't want to limit my designs to comply with the famicom titler. If it happens to do so; that's great, but i won't actively see to it. it's an obscure collectors' item. Iif you have it, you likely have another famicom/NES system too. And you probably have it because you're well aware of the PPU being different and wanted to have access those differences.

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PostPosted: Sun Apr 21, 2019 1:48 am 
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Looking over plutiedev's recommendations, none of them go as far as the things I object to in your list, tepples. Everything suggested is much more mild, and a lot of it is kind of a list of actual pitfalls someone might miss by accident. Your list is not really equivalent; it reads more like a prescriptive "style guide".

I don't really advise trying to publish something analogous here. It feels slightly in bad taste to me to call it guidelines...

However, I think there is room for a list of things to consider for multi-region releases. A compiled list of NTSC vs PAL differences, peripheral differences, remembering to read the expansion data lines for Famicom controllers, RGB emphasis, etc. would make a great article for the Wiki. That's already somewhat of a FAQ here. Why not do that instead? That'd be legitimately helpful, and wouldn't feel snobbish or pretentious to me.

Telling people not to use the Nintendo logo on things, or not to lie on their packaging, on the other hand, seems pointless to post some public notice about. This is not a common mistake. You can point this out when someone's actually doing it. People who want to are going to do it anyway, and for the rest of us... it feels to me like pre-emptively treating someone like an invalid. Similar with the 3V vs 5V thing. People that don't know about the issue should be informed, but as far as I've noticed the only people doing 3V in this scene are doing it intentionally. This category of "guidelines" feels more to me like trying to cast shade on some specific deliberately unnamed party, rather than being genuinely helpful to anyone trying to make homebrew.

(The 3V issue might be more insidious in Genesis stuff, I don't know, so I'm not really commenting on plutiedev's choice to mention it this way, only how it looks to me in the context of NESDev.)


Last edited by rainwarrior on Sun Apr 21, 2019 1:53 am, edited 1 time in total.

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PostPosted: Sun Apr 21, 2019 1:52 am 
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Famicom cart shells are still not widely available. Nobody cares about Dendy clones.


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PostPosted: Sun Apr 21, 2019 5:18 am 
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A bit like with the patreon thread, i'm wondering if the question is based on problems that someone has had (ie. "the game i ordered won't play on my system and noone made it clear this would be the case", or "the forums are being flooded with irrelevant self-advertisement"), or if it is hypothetical?

I think the question that would be nice to pin down answers to is "what information can be of use (and thus be readily available on a cheat sheet) to homebrewers planning on separate region or multi-region releases?"

I second rainwarriors' sentiment that such a list ought to seek advise voluntarily and conveniently, rather than being authoritative "must comply" type of thing, because.. lots of these values are either contextual, or subjective.

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PostPosted: Sun Apr 21, 2019 7:11 am 
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Apparently the Genesis scene has had a bunch of cart releases that only run on a subset of hardware. I asked @plutiedev on Twitter for some clarification, and they mentioned a few specific hazards that these games were exercising:

A. reading the wrong mirror of APU status (which appears to break on consoles without a headphone jack)
B. relying on memory areas whose behavior changes if a Sega CD or 32X accessory is connected
C. failing to adapt to NTSC's shorter vblank

The rough NES analogs of those might be these, all of which have been spotted in commercial games:

A. relying on open bus for CPU I/O ports (such as Paperboy requiring exactly $41 for controller presses)
B. relying on open bus for unmapped cart SRAM (such as Low G Man)
C. failing to adapt to NTSC's shorter vblank (such as Smurfs, Asterix, and PAL Battletoads)

What triggered my outrage was the implication that all developers ought to own all regional versions of the model 1, model 2, Sega CD, and 32X, or to be able to hire trustworthy testers who do. I can think of over two dozen combinations already: J, U, or E x model 1 or 2 x Sega CD or no x 32X or no, plus Mega Jet, Nomad, Wondermega, Genesis CDX, and Genesis 3 (U).

That and "the moment money is involved" (quotation source), a release has to be global.

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PostPosted: Sun Apr 21, 2019 10:11 am 
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Sega CD and 32x are the same hw in all regions, only differing in the bios or a solder point. You can load any region bios to the Sega CD using an Everdrive, and solder a switch to the 32x to let it be changed between PAL and NTSC.


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PostPosted: Sun Apr 21, 2019 8:34 pm 
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I would definitely appreciate a list of things to look out for to make my NES games accessible, collected in one place. All the requirements listed in the OP sound relevant to me. The only thing I'd really object to is the "must be available as a Famicom cartridge and an NES cartridge" requirement, because it's unnecessarily expensive, and the language barrier can make e.g. a Famicom release of a Scrabble game rather pointless to begin with.

CPU and PPU revisions are definitely important to check, and there are portable emulators to check them with, so I don't think this one's onerous at all. Including the RGB PPUs, because the emphasis bits can make the game a totally unplayable whiteout, not just wonky, while typically not being gameplay-essential themselves.

Controllers are similar; relying on the Famicom microphone or player 2 start/select can make the game completely unplayable. Obscure input devices... if your game needs one, then it needs one, and you're gonna label it as such. Not much can be done there. Stuff like Famicom multitap versus 4-score though, that's important, because there's really no reason (aside from more complex polling code, which may be an issue for deliberately constrained relases) not to support both.

No Nintendo logos - Nintendo is a notoriously laywer-happy company. I haven't heard of anyone getting sued over a NES game's packaging, but that doesn't mean they haven't, or that they won't start. An artist could easily slap a decades-old logo that they've seen so many times since they were born that it's faded into the background of nostalgia onto box art without realizing that it's still an active trademark, so it's worth mentioning.

5 volt parts - this one's a no-brainer. Damaging other people's consoles is not cool.


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PostPosted: Wed Apr 24, 2019 12:25 am 
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Rahsennor wrote:
Including the RGB PPUs, because the emphasis bits can make the game a totally unplayable whiteout, not just wonky, while typically not being gameplay-essential themselves.
One could check for their presence of an RGB PPU and limit the use of the emphasis bits on the result of that check. From what I have read, the RGB PPUs do not skip the odd-frame cycle on the pre-render scanline, so that is something one could check for, as blargg's PPU check ROMs demonstrate.

The more difficult thing about the RGB PPUs is choice of colors. Nintendo themselves changed the color numbers for at least two games between the Playchoice 10 and home cartridge releases (Punch Out and Volleyball), indicating that they were conscious of palette differences. Ideally, one would limit oneself to a set of color combinations that look okay on both 2C02 and 2C03 palettes, or modify the color choices based on the detected PPU type.

Another thing to consider is Sharp C1 compatibility. Several licensed Japanese games openly state on the packaging that they are not compatible with the C1, even as they do not use the emphasis bits. It seems to be related instead to the Audio In/Out pins on the 60-pin cartridge connector, though the details are not known exactly.


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