GBC to GB?

Discussion of programming and development for the original Game Boy and Game Boy Color.
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IRSUP2a03
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GBC to GB?

Post by IRSUP2a03 » Fri Apr 27, 2018 1:43 pm

Just a random thought, is it possible to convert a GBC exclusive title to DMG-001 compatible, and if it was done before, please put a link to it.
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Re: GBC to GB?

Post by tepples » Fri Apr 27, 2018 1:53 pm

It'd be a time-consuming manual port, as the Game Boy Color has more video memory, more work RAM, a faster CPU, a hardware-accelerated copy from ROM or work RAM to video memory, and a faster-responding LCD than that of the DMG-001. Do you want everything to be an undetailed, slow-moving, motion-blurry mess?

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Re: GBC to GB?

Post by IRSUP2a03 » Fri Apr 27, 2018 1:59 pm

I was thinking that it would be the GBC version when it is running on a GBC, and when running on the DMG-001, it would be the "Undetailed, motion-blurry mess".
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Re: GBC to GB?

Post by tepples » Fri Apr 27, 2018 2:03 pm

It would still be manual work to convert a GBC-exclusive game's engine to an adaptive one by removing those features that cannot be replicated on mono and converting those that can. Are you working with a publisher on making a monochrome-compatible (black cartridge) rerelease of its GBC-exclusive (clear cartridge) game?

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Re: GBC to GB?

Post by IRSUP2a03 » Fri Apr 27, 2018 2:06 pm

No... I am NOT working with a company(wish I was...) that is thinking of making a Black Cart game, I am just one person that likes making games either through a utility or editing source code(very bad at it...). I was just wondering if such a cart was even possible in the first place...
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Re: GBC to GB?

Post by nitro2k01 » Fri Apr 27, 2018 4:13 pm

It stands to reason that a game that was released as GBC exclusive is making use of the extra functionality in the GBC, and would be hard to port unless it was ridiculously unoptimized. If not, it would likely have been released as a dual platform game from the start.

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Re: GBC to GB?

Post by IRSUP2a03 » Fri Apr 27, 2018 4:19 pm

(kinda)Related: I wonder if you could port Super Mario Bros. Deluxe to the OGB(original Game Boy), and still keep the GBC functions when on GBC, and a more primitive version when running on the OGB?

What do you mean ridiculously unoptimized?
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Re: GBC to GB?

Post by adam_smasher » Fri Apr 27, 2018 5:18 pm

nitro2k01 wrote:It stands to reason that a game that was released as GBC exclusive is making use of the extra functionality in the GBC, and would be hard to port unless it was ridiculously unoptimized. If not, it would likely have been released as a dual platform game from the start.
Ehhhhh, you're giving gamedevs too much credit here. It's entirely believable that in many cases they looked at the size of the mono GB market vs. the GBC-only market and decided that it wasn't worth any extra effort (or ROM space) to build an engine that works for both - regardless of whether or not it would be possible on the former or if it'd take a lot of work to trim it down. It'd definitely be case-by-case but I can imagine that there are at least a few GBC-only games that could be ported without too much trouble.

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Re: GBC to GB?

Post by Shonumi » Fri Apr 27, 2018 10:21 pm

adam_smasher wrote: Ehhhhh, you're giving gamedevs too much credit here. It's entirely believable that in many cases they looked at the size of the mono GB market vs. the GBC-only market and decided that it wasn't worth any extra effort (or ROM space) to build an engine that works for both - regardless of whether or not it would be possible on the former or if it'd take a lot of work to trim it down. It'd definitely be case-by-case but I can imagine that there are at least a few GBC-only games that could be ported without too much trouble.
In my experience poking and prodding various Game Boy games to figure out how they work, it seems a majority of "black" carts (dual DMG/GBC compatibility) did not use any of the new features of the GBC besides colorized palettes. They don't use the new VRAM DMAs and don't use the expanded VRAM or WRAM. At most, they do use the GBC's double-speed mode, since it's a nice freebie. So in this regard, I think nitro2k1's statement is accurate: most games that are easy to backport to the DMG are already DMG compatible. A lot of GBC exclusive games are heavily dependent on the new DMAs in conjunction with 2x CPU speed. From what I've analyzed over the years, stripping that combo out severely limits some of the things GBC-exclusives were capable of.

However, I do agree that it's a case-by-case basis. Most GBC-only games extensively rely on the GBC-only stuff, but I can think of a handful that don't really fully utilize them. For example, I'm pretty sure you could backport Pokemon Crystal to the DMG without sacrificing much. Underneath the hood, it's Pokemon Gold/Silver, which worked just fine on the DMG. Seems like most of the GBC's features were used to spice up the graphics, and all of that can be undone. Probably Pokemon Puzzle Challenge too; since it's just a puzzle game graphics aren't anything the DMG couldn't handle, you'd have to rewrite the engine's WRAM usage, probably.

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Re: GBC to GB?

Post by NovaSquirrel » Tue May 01, 2018 6:58 pm

Shonumi wrote:Probably Pokemon Puzzle Challenge too; since it's just a puzzle game graphics aren't anything the DMG couldn't handle
In this case a non-Color version already exists in the form of Tetris Attack for Game Boy, released 4 years earlier. There's also the hidden game in Puzzle Challenge you can access from the "Only works on Game Boy Color" screen.

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