Resident Evil GBC Fundraiser thread - 2 builds! (GOAL MET)

Hello everyone, this is my first post, but i was follow this thread some time ago, and I'm so glad this game is finally release, and i thought this would never happen, thanks to everyone who help to release it.

anyway, i was doing a research to both roms, and in a way to thank to all of you for this, i ripped all (i guess) background and scenes of both carts

http://www.mediafire.com/?ib1542opyrl0em5

during the ripping i noticed many differences between both carts, here are some of the most significant differences:

cart 1 cart 2



the first thing you notice in the cart2 is the slim and lighter sprites for jill and chris and the stylized alphabet

cart1 cart 2

most of the backgrounds in cart 2 has an opaque tone

cart 1 cart 2

some backgrounds have minor changes (falling roof room has no door and the roof is already collapsed in cart2)


there isn't the lion statue in cart 2, although you can use both jewels where use to be the statue


there isn't door in this room

cart 1 cart 2

and many backgrounds are a completely different version of cart 1 backgrounds


these look like beta versions of the cart 1 backgrounds


guardhouse backgrounds are the worst in cart 2, they look like to be early development versions


the fountain in cart 2 is rounded shaped like in the original


These background/camera angles are not present in cart1







Also i did a hack rom of cart 1 adding the slim sprites for chris and jill and the stylized alphabet of cart 2





http://www.mediafire.com/?obwwo4vke11pg6i

the hack was made using pacochan's bug fix patched rom, enjoy it

 

nice read lestar, thanks for doing that very interesting :thumbsup:

 

Nice work lester, i guess its safe to say cart 2 is the earlier version of the two carts we got. Just one question, is that hacked rom you uploaded cart 1 or cart 2, didn't seem to get that info out of what i was reading. Thanks for the hard work!

 

the hack i made is for cart 1 rom because is the most complete, but cart 2 has more stylized sprites and fonts, so i decided to include them into cart 1 rom

 

I tried the patch/hack and while it seems to add the slim sprites, it definitely doesn't do the same with the stylized alphabet. Can you check this?

 

oops, i'm sorry, here the correct patch http://www.mediafire.com/?obwwo4vke11pg6i

 

thanks for the new patch.

I want to do my own modifications to the cart I. What kind of tools (including a Hex Editor) you recommend me to do so?

 

depend on what do you want to do, in this patch i used a graphic editor (fatilety) to edit the fonts and to find where the sprites offsets are, then i used an hex editor to copy-paste all the sprites bytes from cart2 to cart1, it was an easy hack, but if you want to do a mayor hack like pacochan's patch you need to do an ASM hack using a disassembler and reverse engineer it to find the game routines a modify them, or include your owns, to do this you need gbz80 assembly knowledge and a debugger emulator, like BGB

 

Thanks. I was thinking about doing an simple graphics patch and a translation patch.

 

I wonder if there is any work being done on this in romhackig communities, such as dissasembling or studying how it works. I'm specially curious about how they scale the characters (if they are pre-scaled on VROM, or if they scale it in VRAM on loading... and things like that), how the scenarios are stored (compressed, I assume but each seems to not repeat a single tile).

 

Sprites get scaled in real time. Since sprites have a fixed size (8x8 px or 8x16, I don't remember) there will be more or less of them depending on the character position. That's why the game may slowdown if the character appears too big.

The scenarios and everything in the game is uncompressed. Just a bunch of tiles one after another containing all the backgrounds. The only thing they used to "compress" the backgrounds is to use plain colors in many backgrounds, so they could use one tile to fill many parts of the screen.

What I find very interesting, is the fact that the character actually hides if it is behind something. In GameBoy, NES and I guess every tile based console, the sprites are always in front of background. That's how it works. But this game erases parts of the sprites if you are behind something, giving the effect that the character is behind. I don't know how it works though. I didn't find any kind of mask map or something like that.

I don't know much about collisions either, but I think that they are simple invisible boxes. For my morgue room fix, I managed to find some coordinates that changed the boundaries of the room. Since they are boxes, it could explain why the fountain that gives you access to the laboratory changed from circle shaped to square.

I wanted to do some tool to extract or see the backgrounds from the game, but it was harder than I thought. I didn't manage to find a tile map. The game does a lot of stuff when it loads a background and not the usual stuff that every other game does, so I couldn't do a proper extraction. Without a tile map, I can only extract a bunch of garbled tiles that are difficult to recognize. Besides, you could see those sprites with any tile viewer.

That's all I can think off right now.

 

Strange; I didn't think the Gameboy Color was capable of sprite scaling.

 

It isn't. It's done by software, not by hardware. The game itself redraws every sprite as it needs.

 

I'm pretty sure that character movement and collision is dictated by square boxes, like it's done in old graphic adventures and such. On the graphic adventures by LucasArts and Sierra, the boxes are used for collision and have a scaling value associated so the can simulate better the perspective of the scene. I also suspected that the characters where scaled up and down depending on their distance to the camera and it still puzzles me because it's a costly operation for a console like a GBC, maybe it pre-scales the frames in VRAM at loading time since there are so few characters in the game (and some appear when there are no zombies).

The tile maps could be compressed... I don't see any structure at work here, the backgrounds seem to be still images tilefied and retouched to reduce the number of tiles in the areas with plain color. I wonder where they store the tilemaps...

 

If anyone needs a playthrough on actual hardware, I have a USB cartridge I can throw the game on for a weekend. I'll post updates while I'm playing.

 

Hopefully we'll see some interesting modifications in the coming months.
Is anyone planning on ripping the sprites for editing purposes? I'm having trouble doing this myself, due to the sprite scaling its pretty difficult to get a decent sprite sheet. Are there other ways of doing this besides printscreen+paint?

 

hello again, i bring you a new sprite hack, this one put the lighter palletes for chris and jill from cart2 to cart1, now, sprites in cart1 look like exactly like in cart2, some samples

how jill and chris look like in the original version of cart1


now how they look in cart1


graphics patch v1.1
http://www.mediafire.com/?yhdj3m5o164y7i5



and to answer any questions, all character sprites are compressed, they look like this in a graphic editor



the sprites' horizontal lines alternate on each tile, storing two sprites data into one tile, in the jill sprites set, the half-left part, the odd lines stores the body data, and the even lines store the arm data, on the other half, is the opposite, the even lines store the body data and the odd lines store arm data

i "decompressed" jill's front sprite by hand, and she looks like this


maybe someone can use this information to make a sprite editor, jill spriteset starts at $3c0000 offset if anyone is interested

and with respect to sprite scaling, making a dump of memory i discovered that sprites are first decompressed into wram first, then are scale to finally load them into vram, it seems that sprites are scale them using a kind of patern located at $28000 address, the pattern into an hex editor is a straight count from 00 to FF, but in a graphic editor it looks like this

the red highlighted area correspond to the left part of jill's sprite, it seems that the bigger the patter is, the bigger the sprite is

if anyone is intereted, i think that decompression and scaling routine is at $29B2 offset

i think i found map draw routine at $303A, the tittle screen tilemap data is from $94C0 to $9627, from $9628 is the palette data of each tilemap, and i'm trying to make a map editor too, but i have to find how it works the tile map construction yet for Room BG

 

thanks for the info mate, amazed how much you have managed in such little time

 

>< god damn sire.... blew me away... Cannot wait for the sprite sheet...

 

So I have to download the rom and the patch and patch the game with that program??? or is there a rom already patched I can download.

I am definitely going to put this on a cart somehow. If someone could provide help with that that be great.