Unique Egg Graphics for Pokémon Platinum

This mod allows eggs to have a palette swap or custom sprites based on Pokémon species. The way things are set up currently, every species has a custom palette assigned to it, but a table defines species that get a custom graphic as well.

This hack is compatible with the Individually-Unique Pokémon Colors Mod.

If you would like to use this in your own hacks, please feel free to do so!

Building

1. Install devkitARM.
2. Install a D compiler.
3. Download PokeEditor, extract it into the root folder of this repo, and rename folder that got extracted to PokEditor.
4. Use a program like Nitro Explorer 3 to extract arm9.bin, overlay9-119.bin, and demo/egg/data/egg_data.narc from your Platinum ROM.
5. Place them in the root folder of this repo, and name them to arm9_vanilla.bin, overlay119_vanilla.bin, and egg_data_vanilla.narc respectively.
6. Run ./build_egg_data.sh.
7. Run ./build.sh.
8. Inject arm9_patched.bin, overlay119_patched.bin, egg_data_patched.bin, and overlay87_patched.bin back into arm9.bin, overlay9-119.bin, and demo/egg/data/egg_data.narc, respectively.

Adding New Palettes

Simply replace the .nclr file in egg_data/pals corresponding to the species ID of the Pokémon. Make sure that the palette contains 16 colors! I think the game and various tools will get upset if there are fewer, for example. When in doubt, base your file off of the other 90-byte palette files currently in that folder.

Adding New Graphics

• Add the species ID to the table defined in Hijack_SpecialPokemon.s.

  • (Note: The address of this table is near the limit of the unused space found for inserting this mod. Too many may overflow into data actually used by the game. This mod thus needs to be reworked in the future to run off a synthetic overlay so that this won't occur.)

• Add the name of the species into the table called special_pokemon in build_egg_data.sh. An entry such as togepishould correspond with two files in egg_data/gfx/ named togepi.sprite.ncgr and togepi.hatching.bin.

  • The .sprite.ncgr file would be in the exact same format as would be found in pl_pokegra.narc or pl_otherpoke.narc - you can insert one into a dummy file using PokeDSPicPlatinum and then extract it with Tinke.

  • The .hatching.bin file is modeled after the compressed egg animation image found in demo/egg/data/egg_data.narc, subfile 4.

  • Getting the graphics data of both images synced up with the single palette can be a little tricky... I'm still not sure yet what the most streamlined method for doing this is. Experiment and send me a message or write up an issue if you have a good way!

How It Works

We basically shove a bunch of new stuff into demo/egg/data/egg_data.narc and change some code to load it!

The new subfiles that are added to the NARC:

11  - Normal egg sprite data (ncgr, copied from pl_pokegra.narc)
12  - Bulbasaur egg palette (nclr)
...
504 - Arceus egg palette (nclr)
505 - Special egg #1 sprite (ncgr, same format as pl_pokegra.narc)
506 - Special egg #1 hatching animation (compressed bin, same format as subfile 4)
507 - Special egg #2 sprite
508 - Special egg #2 hatching animation
...

A rundown of the code files involved:

• Hijack_Include.s - Just some common constants to be included by all other files.

• Hijack_PkmnPtrSave.s - * This code is jumped to from hijacks in both GetPkmnData and GetBoxPkmnData. It just grabs the pointer to the Pokémon data structure passed into these function calls and puts it at 0x020501DC to be used later by Hijack_ColoredEggs.s and Hijack_Hatching.s.

• Hijack_ColoredEggs.s - Hijacks in the code arbitrating what graphic and palette to use for drawing a Pokémon's sprite, specifically in the case for 494 (ID for a Pokémon egg). It uses the pointer to the last read Pokémon data structure at 0x020501DC in order to call GetBoxPkmnData to find out what Pokémon is inside the egg. The NARC file ID changed to the one for demo/egg/data/egg_data.narc (0x76). The palette chosen is indexed by species ID from a big block of palette subfiles, starting at subfile 12. The graphic subfile ID is chosen by searching through a table defined in Hijack_SpecialPokemon.s, looking for the species ID. If it's found, the position it was found in the list is used as an index into the narc (past all of the palettes) . For Manaphy specifically, instead of doing all of that, we just let it load from its usual location. Code from 0x7614E to 0x76156 is replaced with NOPs since its functionality is replaced.

• Hijack_Hatching.s - Hijacks a function in overlay 119, that loads the egg hatching animation spritesheet from demo/egg/data/egg_data.narc. It largely does the same stuff as Hijack_ColoredEggs.s. Though, no special case is needed for Manaphy, as this code is not reached when it's hatching.

• Hijack_SpecialPokemon.s - Table of species that have their own GFX. Each entry is two bytes. The order matters, and must match the special_pokemon list in build_egg_data.sh. The table must end with a 0.

Credits

• turtleisaac - Idea
• QuakenPixels - Togepi egg sprite
• DescendedFromUllr - Igglybuff egg sprite
• LJSTAR - Some spriting help