[Other] [Pokeemerald] Adding ONLY Hidden Abilities from Pokemon Expansion

[Kobazco]

As the title says, the project I'm currently working on doesn't need the Pokemon expansion, but I want to be able to use hidden abilities. Would someone be able to point me in the right directions either for what files in the Pokemon expansion add in hidden ability support, or a separate method of adding them in? For Pokeemerald btw.

I have the Battle engine upgrade v2 and item expansion in this decomp project if that information helps in anyway.

 

[Lunos]

As the title says, the project I'm currently working on doesn't need the Pokemon expansion, but I want to be able to use hidden abilities. Would someone be able to point me in the right directions either for what files in the Pokemon expansion add in hidden ability support, or a separate method of adding them in? For Pokeemerald btw.

I have the Battle engine upgrade v2 and item expansion in this decomp project if that information helps in anyway.

This is about all you need.
https://github.com/rh-hideout/pokeemerald-expansion/pull/1464/files

 

[Kobazco]

Thanks, I managed to implement it!

 

[Kobazco]

This is about all you need.
https://github.com/rh-hideout/pokeemerald-expansion/pull/1464/files

Unfortunately, it seems like I need additional assistance. It seems like I've managed to get it all working (hidden abilities are appearing in my dev menu implying they are properly being assigned), but attempts to use SetMonData to alter the ability to be the Hidden one don't work and default to Ability 00 for some reason.

As an example, this is the command I have been trying to use: SetMonData(&gPlayerParty[tMonId], MON_DATA_ABILITY_NUM, &tAbilityNum); with tAbilityNum being set to 2

 

[Lunos]

Unfortunately, it seems like I need additional assistance. It seems like I've managed to get it all working (hidden abilities are appearing in my dev menu implying they are properly being assigned), but attempts to use SetMonData to alter the ability to be the Hidden one don't work and default to Ability 00 for some reason.

As an example, this is the command I have been trying to use: SetMonData(&gPlayerParty[tMonId], MON_DATA_ABILITY_NUM, &tAbilityNum); with tAbilityNum being set to 2

For your information, that's not a command, it's a function call. You're calling the function SetMonData and passing specific parameters through it.

Anyway, where exactly did you do this?
Ideally, hidden abilities should be set in the function where all the basic data of a Pokémon is created, CreateBoxMon.

As you can see right here, in CreateBoxMon a Pokémon is given its 1st or 2nd ability based on their personality, if they do have a 2nd ability at all.
There's many ways you can make hidden abilities (that is 3rd abilities) usable and it solely depends on your own tastes.

Here's a quick example. I slightly modified the if statement I linked above.
This would make it so there's a 50% chance that a Pokémon is generated with its hidden ability if they have one:

    if (gBaseStats[species].abilities[2] && (Random() % 100) <= 50)
    {
        value = 2;
        SetBoxMonData(boxMon, MON_DATA_ABILITY_NUM, &value);
    }
    else if (gBaseStats[species].abilities[1])
    {
        value = personality & 1;
        SetBoxMonData(boxMon, MON_DATA_ABILITY_NUM, &value);
    }

EDIT (05/05/2023): It's actually 51% because Random() starts to count from 0 and I used <= instead of <, lel.

 

[Kobazco]

For your information, that's not a command, it's a function call. You're calling the function SetMonData and passing specific parameters through it.

Anyway, where exactly did you do this?
Ideally, hidden abilities should be set in the function where all the basic data of a Pokémon is created, CreateBoxMon.

As you can see right here, in CreateBoxMon a Pokémon is given its 1st or 2nd ability based on their personality, if they do have a 2nd ability at all.
There's many ways you can make hidden abilities (that is 3rd abilities) usable and it solely depends on your own tastes.

Here's a quick example. I slightly modified the if statement I linked above.
This would make it so there's a 50% chance that a Pokémon is generated with its hidden ability if they have one:

    if (gBaseStats[species].abilities[2] && (Random() % 100) <= 50)
    {
        value = 2;
        SetBoxMonData(boxMon, MON_DATA_ABILITY_NUM, &value);
    }
    else if (gBaseStats[species].abilities[1])
    {
        value = personality & 1;
        SetBoxMonData(boxMon, MON_DATA_ABILITY_NUM, &value);
    }

The function SetMonData is being used in the debug menu I got from here: https://github.com/TheXaman/pokeemerald/tree/tx_debug_system

It just feels a little odd, since it recognizes it as ability 02 but still gives ability 00 after the mon is given

Spoiler:

//Ability
    if (abilityNum == 0xFF || GetAbilityBySpecies(species, abilityNum) == 0)
    {
        do {
            abilityNum = Random() % 3;  // includes hidden abilities
        } while (GetAbilityBySpecies(species, abilityNum) == 0);
    }

    SetMonData(&mon, MON_DATA_ABILITY_NUM, &abilityNum);

So can I just not use SetMonData to set the hidden ability? I was going to try and make an item to change the pokemon's ability to (hidden) but the method I was going to try was also using SetMonData

 

[Kobazco]

Well... never mind in all this. It seems the issue was that /* 0x07 */ u32 abilityNum:2; was set to be 1 instead of 2 inside of include\pokemon.h

Thanks for your help!

 

[AlmightyK]

For your information, that's not a command, it's a function call. You're calling the function SetMonData and passing specific parameters through it.

Here's a quick example. I slightly modified the if statement I linked above.
This would make it so there's a 50% chance that a Pokémon is generated with its hidden ability if they have one:

    if (gBaseStats[species].abilities[2] && (Random() % 100) <= 50)
    {
        value = 2;
        SetBoxMonData(boxMon, MON_DATA_ABILITY_NUM, &value);
    }
    else if (gBaseStats[species].abilities[1])
    {
        value = personality & 1;
        SetBoxMonData(boxMon, MON_DATA_ABILITY_NUM, &value);
    }

Thanks for this, I got it working in my own version.

Is there a way to give a visual effect of some kind when a Pokemon with a Hidden Ability appears?