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Author Topic: Adding a VWF to a Gameboy game, how hard is it?  (Read 1810 times)

IamRifki

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Adding a VWF to a Gameboy game, how hard is it?
« on: September 10, 2019, 06:50:47 am »
I want to do a VWF hack for Final Fantasy Adventure as it's one of my favorite Gameboy games and nobody else seems to be interested in doing it. My question is how hard is it?, I already have some experience in ASM before, and I know people who can (probably) help me. I also need to know what tools are recommended to hack Gameboy games, I know Ghidra has a Gameboy plugin, but what else?

Cyneprepou4uk

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Re: Adding a VWF to a Gameboy game, how hard is it?
« Reply #1 on: September 10, 2019, 08:00:36 am »
What is VWF?
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Pennywise

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Re: Adding a VWF to a Gameboy game, how hard is it?
« Reply #2 on: September 10, 2019, 10:00:21 am »
Well, first off the game stores the entire font in VRAM. You'd have to hack the game to load the text directly into VRAM before you'd be able do a VWF hack. If you only have experience doing small, simple ASM hacks, it's probably going to be a challenge to pull off.

Jorpho

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Re: Adding a VWF to a Gameboy game, how hard is it?
« Reply #3 on: September 10, 2019, 09:40:29 pm »
What is VWF?
Variable Width Font. See for instance Link's Awakening:
https://www.romhacking.net/hacks/2414/

The difficulty of any such hack depends on exactly how the game writes its text to the text boxes.
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Cyneprepou4uk

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Re: Adding a VWF to a Gameboy game, how hard is it?
« Reply #4 on: September 10, 2019, 10:18:54 pm »
Thanks
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Psyklax

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Re: Adding a VWF to a Gameboy game, how hard is it?
« Reply #5 on: September 11, 2019, 12:18:35 pm »
Quite a few Game Boy games write the text to VRAM instead of simply pulling individual letters out, and VWF is an extension of that. The game looks at the tile for the next letter and previous letter, then does some bitwise calculation to decide where the new letter should go. For example, your routine might check that the last bit is zero for all eight bytes, meaning the right-most pixels are empty, and so it can do an arithmetic shift for the next letter to push it along. I could be wrong since I've never worked with a VWF before, but I presume this is how it works.

At least it's feasible on the GB, but the NES it's far more difficult, since the CPU doesn't have direct access to the VRAM, and the graphics are usually in ROM anyway so can't be changed. There would need to be RAM on the cartridge for it to work, so naturally virtually no games did it. I don't know how many GB games tried it, but if you have some ASM experience then it's probably not crazy hard. I'd like to try doing it myself someday... :D

Cyneprepou4uk

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Re: Adding a VWF to a Gameboy game, how hard is it?
« Reply #6 on: September 11, 2019, 01:04:41 pm »
Any nes games that have vwf? I have figured out how would I made it work, maybe to write an article about it.
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KingMike

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Re: Adding a VWF to a Gameboy game, how hard is it?
« Reply #7 on: September 12, 2019, 01:21:45 am »
The fan-translation of Romancia is the only one I know of.
I tried adding one to Zelda 1 but only got it half-working. It would crash and I never went further.

Like was said, for it to even be possible on NES it would need to be a game that uses CHR-RAM, but it would also have to be a game with enough unused tiles to draw the entire message window across it (as you are basically creating a graphic of the message box)
(Zelda could do it because the FDS original had English and katakana characters and the localization simply blanked out the katakana tiles and left them unused)
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Cyneprepou4uk

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Re: Adding a VWF to a Gameboy game, how hard is it?
« Reply #8 on: September 12, 2019, 07:15:34 am »
Thanks
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