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Author Topic: A guide for ROM hacking original Game Boy games?  (Read 1505 times)

Henrryparth

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A guide for ROM hacking original Game Boy games?
« on: December 28, 2018, 03:03:11 am »
I love the Game Boy, and I would eventually like to make my own games for it; movies download movies at forum  but for now, I want to learn to how to ROM hack games. I only know how to program in Java and Python, but I want to know if there's a definitive place to learn how ROM hack games with a hex editor or something. Where should I start?

« Last Edit: December 29, 2018, 11:57:03 pm by Henrryparth »

KingMike

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Re: A guide for ROM hacking original Game Boy games?
« Reply #1 on: December 28, 2018, 06:12:52 pm »
I'm sure there's plenty of tutorials for at least NES but the same basic concepts apply to Game Boy.

Except that instead of looking graphics in "NES 2BPP mode" in a tile editor, you're looking in "SNES/GB 2BPP mode".
And instead of adjusting text pointers to be in the 8000-FFFF range (usually), you're adjusting them to the 4000-7FFF range (usually).
"My watch says 30 chickens" Google, 2018

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Re: A guide for ROM hacking original Game Boy games?
« Reply #2 on: December 29, 2018, 07:29:47 am »

FAST6191

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Re: A guide for ROM hacking original Game Boy games?
« Reply #3 on: December 29, 2018, 10:19:05 am »
All the info you need: https://github.com/gbdev/awesome-gbdev

If you wanted to develop homebrew that is a great resource. However ROM hacking tends to take a slightly different approach, or at least new people to it can achieve good results without having to learn an awful lot of that and do things that such things likely skim over at best. Or if you prefer there is little point in contemplating the deeper aspects of the graphics system when a tile editor will do a lot (compression was kind of a thing but also still old enough to not be as prominent), to say nothing of you don't really need to know the first thing about assembly to effect a text hack.

A full bore assembly hacker could probably recount the relevant sections of http://bgb.bircd.org/pandocs.htm from memory or something close to it, however not all ROM hacking needs assembly hacking.

Psyklax

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Re: A guide for ROM hacking original Game Boy games?
« Reply #4 on: December 29, 2018, 11:37:19 am »
If you already know some high-level programming languages, you can learn a little Z80 assembly and that will get you started with the Game Boy. I recommend downloading BGB emulator due to its excellent debugger. You didn't actually mention what you wanted to do with your hacking: it's hard to recommend anything when you don't say what you want to do. :) Hacking is a broad topic, but most of us got started by messing with the ROMs and seeing what happens.

The simplest way to start, I suppose, is to hack some graphics. Load Super Mario Land in Tile Molester and turn Mario into Daisy. :D Or you could make an infinite lives hack by using the RAM search function then use breakpoints to pinpoint the exact instruction where your life is deducted, and change that instruction. The important thing is to just do it. ROM hacking ain't like flying a plane: you can mess up as much as you like before you get it right. ;)

KingMike

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Re: A guide for ROM hacking original Game Boy games?
« Reply #5 on: December 29, 2018, 11:41:28 pm »
The important thing is to just do it. ROM hacking ain't like flying a plane: you can mess up as much as you like before you get it right. ;)
Just remember to back up stuff regularly because you will crash it many times and you don't want an irreversible mistake to take out months of work with it.
"My watch says 30 chickens" Google, 2018