Awesome

About oracles-disasm

This is a complete, documented disassembly of Oracle of Ages and Seasons for the Gameboy Color. When combined with LynnaLab, it is a level editing suite.

This repository builds US version ROMS. JP and EU versions are not supported.

See the wiki for detailed setup instructions.

Current status

The disassembly complete enough to be reassembled with ROM addresses shifted around arbitrarily. This is fairly well tested through the randomizer.

However there is still work to be done:

• Support for Japanese and European version ROMs. This could be done either in this repository or with a fork. Documenting the version differences could be invaluable for glitch hunting, as Nintendo of Europe had a crack team of grizzled QA testers working on these games (that's how it seems anyway...)
• RAM address shifting is not well-tested. There are still some references to hardcoded RAM addresses scattered around.
• Documentation and variable/function naming can always be improved; in particular, Seasons documentation is relatively lacking compared to Ages. Areas to focus on include:
  • Most stuff under object_code/seasons
  • Functions named "seasonsFunc_[...]" or just "func_[...]"
  • Things marked as TODO
• If some genius could figure out how the original compression algorithms worked we could get rid of the whole precompressed asset nonsense!

Branches

I've been extensively (ab)using branches in the main repository (https://github.com/stewmath/oracles-disasm) for various features and experiments. Most of these are stale branches for one-off experiments or hacks that I didn't bother creating separate repositories for.

The following branches are maintained (or at least updated every once in a while):

• master: Builds vanilla ROMs.
• hack-base: Has some tweaks to make hacking with LynnaLab easier, mainly deduplicated tilesets.
• rando/ng: Contains patches used by the randomizer. Tracked as a submodule.
• hack/crossitems: Ages items available in Seasons and vice-versa. Merged into rando/ng (and hack-base eventually).

Other notable branches (not necessarily maintained):

• vwf: Variable-width font hack

In order to keep track of which patches are applied to a particular branch I'm using certain "tags" prefixed to each commit name, for example:

• HACK-BASE: Patches for hack-base branch
• CROSSITEMS: Patches for hack/crossitems branch
• RANDO: Patches for rando/ng branch
• DEBUG: Debugging features (could be cherry-picked to other branches)
• MUSIC: Music-related patches, mostly new tracks in rando/ng branch

These tags also used in comments for the corresponding commits, which helps to understand when the code you're looking at has been modified from the master branch (without needing to use fancy git-fu).

Required tools to build

• Python 3
• python3-yaml (python module)
• WLA-DX v10.6
• On windows: Must use MSYS2 or some other linux-y environment.

Note: WLA will not produce an exact matching Seasons ROM due to quirks with how empty space is handled; however, this has no effect on how the game functions. If you need to work around this for some reason, This branch of WLA can be used instead (but it needs to be updated!)

Build instructions

Once the dependencies are installed, running make will build both games. To build a specific game, run make ages or make seasons.

By default, the rom is built with precompressed assets, so that an exact copy of the original game is produced. In order to edit text, graphics, and other things, switch to the "hack-base" branch. Alternatively, run the "./swapbuild.sh" script in the root of the repository. This will switch the build mode to "modifiable" instead of "precompressed".

There are 4 build directories in total (for ages and seasons, vanilla or editable), selected by the makefile at build time. See Makefile for details.

See the wiki for detailed setup instructions.

Graphics files

(Note: Graphics editing will only work if you're on the "hack-base" branch or have disabled the use of precompressed graphics)

Graphics are stored as 4-color indexed PNG files. Other formats (RGB) are supported, as long as you stick to using the original 4 colors. But the indexed format works particularly well with editors such as Aseprite, which show you the 4-color palette available to you.

Some graphics have a corresponding .properties file (ie. spr_link.png has spr_link.properties). These are YAML files which specify certain properties about how they should be converted from PNG format to BIN (raw) format, and vice-versa.

The following parameters are accepted in .properties files:

• width (int): Width of the resulting PNG file, in tiles. Only affects .BIN -> .PNG conversion.
• interleave (bool): Whether to treat the image with an 8x16 layout instead of an 8x8 layout (mainly for sprites).
• invert (bool): Whether to invert the color order of the PNG palettes. When "false", the order is light-to-dark (white = color 0). When "true", the order is dark-to-light (black = color 0).
• tile_padding (int): Number of tiles of padding at the end of the image. This many tiles will be truncated before conversion to .BIN format, or this many tiles will be added during conversion to .PNG format.
• format (string): Set this to "1bpp" for 1 bit-per-pixel files (only the font uses this).

Sprite graphics files (files beginning with spr_ instead of gfx_) are assumed to have the properties invert: true and interleave: true. However, these can be overridden by creating a .properties file.

If you wish to edit the files in raw .BIN format with an editor such as YY-CHR, run the following command from the root of the repository (using spr_link.png as an example):

python3 tools/gfx/gfx.py auto gfx/common/spr_link.png

This will create gfx/common/spr_link.bin, a raw 2bpp gameboy image. However you shouldn't have both a .bin and .png file with the same name; this will confuse the Makefile rules. You can simply remove gfx/spr_link.png, in which case the disassembly will read from gfx/spr_link.bin instead. Or, you may convert it back to PNG when you're done, then delete the .bin file. The following command will convert the .bin file back to .png:

python3 tools/gfx/gfx.py png gfx/common/spr_link.bin

Both of these commands will check the .properties file, if it exists, to decode and encode the image properly.

Disclaimer

The reverse-engineered code and assets in this repository belong largely to Capcom and Nintendo. While I can't really stop you from doing what you want with it, I strongly disavow its use for any commercial purposes. The purpose of this project is to research the inner workings of the Zelda Oracle games and facilitate the creation of non-commercial ROM hacks.

Scripts which do not contain any Nintendo/Capcom code (ie. python scripts in the "tools/" folder) may be considered "public domain" unless stated otherwise.