Romhacking => ROM Hacking Discussion => Topic started by: Zynk on September 13, 2013, 04:15:41 am

Title: Game Boy Colorizer!
Post by: Zynk on September 13, 2013, 04:15:41 am
Heys! Has anyone tried to colorize any Game Boy games lately?

I found this ( and its relatively old and was downloaded over a thousand times now, yet there are only one ( or two ( hacks from it.

I read around that this utility gives bugs to most GB games when colorized. I might as well try this one out when I get home.  ;D


Before I colorize anything, I tried patching the Super Mario Land 2 gbp patch. It  seems that I can't patch it correctly & only get garbled colors on the game. What I do is:

File > Load ROM, then
File > Load GBP, then
File > Write ROM > Background Refresh Rate *64 > Type in ROM name with .gb file extension

Does anyone know how to patch it right?

I got it! You have to use a specific emulator to run the game properly. But its buggy, like when you die...
And yet its still buggy with trashed graphics after finishing the first stage! So annoying!  :banghead:

WHAT? There's a thread with a bugfix by Drakon?,16035.0.html  >:(
Title: Re: Game Boy Colorizer!
Post by: MegaManJuno on September 13, 2013, 11:59:11 am
It was an interesting project, but yes... it breaks a lot of games in the process of trying to colorize them, requiring additional hacking to fix. That's likely the biggest reason it didn't go too far. I remember working on Super Mario Land back when it (GB Colorizer) first released and getting it about half-done before I gave up due to the game-breaking bugs it introduced. :(
Title: Re: Game Boy Colorizer!
Post by: NES Boy on September 13, 2013, 11:21:15 pm
Well, this tool is a decade old. A more sophisticated tool should be possible.
Title: Re: Game Boy Colorizer!
Post by: Space King on September 14, 2013, 01:09:30 pm
Really any implementation of color would need a per-game custom solution... and I can throw a dart and hit a more attractive project to spend time on.
Title: Re: Game Boy Colorizer!
Post by: gadesx on September 24, 2013, 10:28:23 am
maybe Mystic quest in color  :crazy:
Title: Re: Game Boy Colorizer!
Post by: RomanWarrior on September 24, 2013, 02:08:39 pm
just use Virtual Boy
Title: Re: Game Boy Colorizer!
Post by: Spikeman on September 28, 2013, 04:33:37 pm
Hey I did much of the ASM work in fixing the Marioland patch with Drakon, as well as the Metroid II one. There are two main issues with the colorizer implementation: on many games it runs out of time in vblank so stuff doesn't update in time (this can sort of be fixed by lowering how many tiles it updates, but the result is slow updating colors) and that sometimes there are bank switching issues caused by the calls it adds (most of the severe bugs are caused by this). Oh and it only works on the most common mappers.

It is pretty clear that a custom solution is ideal, and I fooled around with this a few times (with Kirby's Dreamland and ZAS, check out my post history) with a decent amount of success, so I could give you some pointers on this if you're interested. I'd recommend against using Colorizer if you have the asssembly expertise.
Title: Re: Game Boy Colorizer!
Post by: Rhys on September 28, 2013, 04:43:37 pm
Would making it run at double speed solve the vblank issues? Or does it already do that anyway?
Title: Re: Game Boy Colorizer!
Post by: Spikeman on September 30, 2013, 04:09:57 am
Would making it run at double speed solve the vblank issues? Or does it already do that anyway?

I don't remember if it does it by default (if it did the sound would be messed up), but no, this doesn't solve the issues. The problem isn't that the length of vblank was neglected by colorizer, but that the way colorizer tries to handle it is too naive - it just has a certain number of tiles that it updates each vblank, and you can adjust that number if it appears glitchy. However, the amount of time you have in vblank is often variable, depending on the amount of objects on the screen, where on the map you are, etc. The first way I tried to fix this was by just making it run until vblank ended, and do as many tiles as possible. This still didn't fix everything because an entirely different colorizer function was trying to read from VRAM in order to update the color the tile will be set to in the next vblank. The problem with this is that you can only read from VRAM in vblank, so you have to apply a fix so this only happens in vblank, further slowing down the vblank handler. At this point I realized that a custom solution would be better, because colorizer just naively updates the map as often as it can, instead of only setting the color when the map has been scrolled for example. Similar problems exist with the sprites, but they are not as severe.

Anyway, I have a ton of notes on this that I might as well post, but I'm not on my computer that I have them on right now, so I'll have to post them later. I was considering making a successor to colorizer, but I'm thinking it'd be better to just have some assembly functions that can be copy pasted into the proper spots and modified to fit the game, along with a tutorial explaining how to do it. For any method to be truly universal (like colorizer tried to do), it would have to take a naive approach like colorizer did, and would run into similar problems with slowdown.
Title: Re: Game Boy Colorizer!
Post by: What Defines A Monster? on September 30, 2013, 06:43:34 pm

I was one of the people who was working with Thomas Blind on the GB Colorizer project... oh, that seems like... over a decade ago.

The problem is, to put it quite simply, for Tom life got in the way. He got a new job and we lost touch for years after that, and when I found him again he had no interest in continuing the project.

GBColorizer was a lovely concept that never truly saw its full potential.
Title: Re: Game Boy Colorizer!
Post by: Drakon on October 20, 2013, 08:01:24 am
It's ambitious for sure.  But I agree with spikeman it would be easier to be done on a per-game basis.  Most games eat themselves after patched with the software and then you have to go manually asm hunting to fix the things it fried.  Marioland 2 is one example.
Title: Re: Game Boy Colorizer!
Post by: Xalphenos on October 29, 2013, 01:03:58 am
I know it's not the same thing but I stumbled upon this ( a few weeks ago.  Been stuck in a tab waiting for me to read it until now.  I like the idea. 
Title: Re: Game Boy Colorizer!
Post by: talos91 on September 09, 2018, 03:32:51 am
It is a shame that nobody has fully colorized the Mega Man gameboy games, specifically Mega Man V one of the best Mega Man games ever, anyone knows of other tools to colorize gb games? I heard visual boy had some tool like that. Just look at how awesome mm colorized gameboy games look.