I’m working on adding Shinies to Pokémon Rumble Blast (3DS) – progress update

https://reddit.com/link/1rmhnr7/video/futltei95gng1/player

About two weeks ago I was complaining that Pokémon Rumble Blast never had shiny Pokémon. The Wii version did, but the 3DS one didn’t for some reason. That got me thinking: what if I could reverse engineer the game and mod shinies into it?

So I started digging into the ROM and reverse engineering the game code. As expected, it turned out to be a pretty complex project, but I’ve actually made some good progress so far.

Right now I have a working prototype where shiny Pokémon can spawn in stages. For testing I’ve only implemented it for Patrat so far (since the other Pokémon don’t have shiny models yet), but adding those later should be straightforward.

The mod works by patching the code binary of the ROM. I wrote a small Python script that applies the patch automatically. The shiny rate is configurable, but for development purposes I’ve set it to 1/16 right now so shinies appear frequently while testing.

Currently the shiny logic is implemented for regular spawns in areas. It might also work for bosses because they seem to use the same spawn system, but I haven’t been able to test that yet.

Next things I want to work on:

• Adding shiny indicators to the UI
• Showing shinies correctly in the Pokémon list / “Pokédex”-like screen
• Adding sparkle effects similar to the trait Pokémon effects

I’m not sure yet how complicated those parts will be, but I think the hardest part (reverse engineering the spawn system) is already done.

Also a big thanks to the creators of CtrStudio and HackingToolkit9DS — those tools made exploring and modifying the games assets much easier and probably saved a lot of time already.