Pokémon quetzal following pokemon?

[C.J.TheDragonKingX]

Does anyone happen to know how following pokemon works In pokemon quetzal? I'm trying to make an emerald rom hack that includes pokemon that follow from gens 1-6 while creating a decomp expansion project, and I know that pokemon quetzal has basically every pokemon following the player. There's tons and tons of different ways people have implemented this for sure, however pokemon quetzal has pokemon from Gen 5,6 and onwards so that would possibly be the best for me to figure out. If anyone knows I would appreciate it.

 

[Lunos]

Does anyone happen to know how following pokemon works In pokemon quetzal?

Tenma, its creator, does.
While the project was presumably created using the Pokeemerald-expansion, it's not open source.
If you want to learn how anything was done on it, you will have to examine the ROM file.

You're better off using one of the public implementations you seem to be aware of, introducing new OW sprites on your own and then linking them in a table with species Ids or something.
That is likely to be both, faster and easier.

 

[C.J.TheDragonKingX]

Oh I see, what would be the best way to examine a roms files is there a way to decompile already created rom hacks? I've tried to find some information on this and I kinda just assumed that you couldn't since it's an already compiled rom.

 

[Lunos]

Oh I see, what would be the best way to examine a roms files is there a way to decompile already created rom hacks?

Well, yes, just like the GBA ROMs of Game Freak's base games were decompiled.
Keep in mind that decompiling a videogame is not exactly easy, or fast. It's a task that takes many years and the help and support of people with the appropriate knowledge and will to do it.
You need to dump all the code that composes a ROM file using a disassembler, and then translate each piece of code into another language, one that is easier to work with.
That can be done manually, or it can be automatized to an extent using a decompiler.
There's much more to it, but I don't have the expertize to explain the entire process.