[Battle] Catch Trainer's Pokemon? (decomp)

[Disclaim]

Hi all,

Wanted to do a nuzlocke called a "Theiflocke", where I can only use Pokemon caught from other trainer's teams. Anyone know how to change the mechanics to allowing this? I understand there is an action replay code for this but I would like the battle to continue AFTER catching an opponents pokemon. Any way to implement this as well? Preferably in Emerald or Fire Red. thank you so much.

 

[ellabrella]

hi there, i got interested in this and spent a little time working on it. i think i have something for pokeemerald that works, but it's not been tested very thoroughly.

you can install it from my github into a clean pokeemerald project like this:

git remote add ellabrella https://github.com/ellabrella/pokeemerald
git pull ellabrella steal-trainer-mon

if you have trouble with that, you can add it manually, here's how to do that:

Spoiler:

step 1: disable blocking the ball

Spoiler:

in src/battle_script_commands.c, go to the function Cmd_handleballthrow.
change all this:

    if (gBattleTypeFlags & BATTLE_TYPE_TRAINER)
    {
        BtlController_EmitBallThrowAnim(BUFFER_A, BALL_TRAINER_BLOCK);
        MarkBattlerForControllerExec(gActiveBattler);
        gBattlescriptCurrInstr = BattleScript_TrainerBallBlock;
    }
    else if (gBattleTypeFlags & BATTLE_TYPE_WALLY_TUTORIAL)

to just this:

    if (gBattleTypeFlags & BATTLE_TYPE_WALLY_TUTORIAL)

this removes the "trainer blocked the ball" mechanic from the game.
you could alternatively keep the first part of the code in, and change the condition inside the first if statement, e.g. if you want to enable/disable stealing with a scriptable flag.

step 2: fix bad eggs

Spoiler:

when you catch any pokemon, its original trainer data is replaced with yours. normally this isn't an issue, since wild pokemon are generated with your original trainer data anyway. but trainer pokemon are generated with random ID numbers, and overwriting a pokemon's ID triggers the detection mechanism that turns them into bad eggs.

my solution to this was to give custom OT information to the stolen pokemon, corresponding to the NPC trainer you stole from, and to preserve this on capture.

first, go to src/pokemon.c. in the function GiveMonToPlayer, comment or remove the following lines:

    SetMonData(mon, MON_DATA_OT_NAME, gSaveBlock2Ptr->playerName);
    SetMonData(mon, MON_DATA_OT_GENDER, &gSaveBlock2Ptr->playerGender);
    SetMonData(mon, MON_DATA_OT_ID, gSaveBlock2Ptr->playerTrainerId);

next, go to src/battle_main.c. find the function CreateNPCTrainerParty.
at the start of the function:

     u8 fixedIV;
     s32 i, j;
     u8 monsCount;

[COLOR="Green"]+   u32 fixedOTID;[/COLOR]
[COLOR="Green"]+   u8 otGender;[/COLOR]

     if (trainerNum == TRAINER_SECRET_BASE)
         return 0;

before the "monsCount" loop:

     {
         monsCount = gTrainers[trainerNum].partySize;
     }

[COLOR="Green"]+     fixedOTID = Random32();[/COLOR]

     for (i = 0; i < monsCount; i++)
     {

just inside the "monsCount" loop:

    for (i = 0; i < monsCount; i++)
    {

         if (gTrainers[trainerNum].doubleBattle == TRUE)
[COLOR="Green"]+         {[/COLOR]
             personalityValue = 0x80;
[COLOR="Green"]+             otGender = gSaveBlock2Ptr->playerGender;[/COLOR]
[COLOR="Green"]+         }[/COLOR]
         else if (gTrainers[trainerNum].encounterMusic_gender & F_TRAINER_FEMALE)
[COLOR="Green"]+         {[/COLOR]
             personalityValue = 0x78; // Use personality more likely to result in a female Pokémon
[COLOR="Green"]+             otGender = FEMALE;[/COLOR]
[COLOR="Green"]+         }[/COLOR]
         else
[COLOR="Green"]+         {[/COLOR]
             personalityValue = 0x88; // Use personality more likely to result in a male Pokémon
[COLOR="Green"]+             otGender = MALE;[/COLOR]
[COLOR="Green"]+         }[/COLOR]

replace ALL FOUR CreateMon lines in the function like so:

[COLOR="DarkRed"]-    CreateMon(&party[i], partyData[i].species, partyData[i].lvl, fixedIV, TRUE, personalityValue, OT_ID_RANDOM_NO_SHINY, 0);[/COLOR]
[COLOR="Green"]+    CreateMon(&party[i], partyData[i].species, partyData[i].lvl, fixedIV, TRUE, personalityValue, OT_ID_PRESET, fixedOTID);[/COLOR]

[COLOR="Green"] +              SetMonData(&party[i], MON_DATA_OT_GENDER, &otGender);[/COLOR]
[COLOR="Green"] +              SetMonData(&party[i], MON_DATA_OT_NAME, gTrainers[trainerNum].trainerName);[/COLOR]

alternatively you might want to just give the stolen pokemon your own OT info. i think this would be a simpler (but less fun) solution, and all you'd have to do is change the CreateMon lines to be:

CreateMon(&party[i], partyData[i].species, partyData[i].lvl, fixedIV, TRUE, personalityValue, OT_ID_PRESET, gSaveBlock2Ptr->playerTrainerId);

(i think, but i haven't tested this!)

as a consequence of changing the ID number they're generated with, trainer pokemon should no longer be shiny-locked. but because the personality value is generated in an unusual way, i don't know what the actual shiny rates are.

step 3: continue the battle after capture

Spoiler:

the battle script for catching a pokemon does a few things that we want to avoid for this mechanic. so, on a successful capture, we will branch off the usual capture script and write our own.

in data/battle_scripts_2.s, find BattleScript_SuccessBallThrow.

    BattleScript_SuccessBallThrow::
        jumpifhalfword CMP_EQUAL, gLastUsedItem, ITEM_SAFARI_BALL, BattleScript_PrintCaughtMonInfo
        incrementgamestat GAME_STAT_POKEMON_CAPTURES
[COLOR="Green"]+        jumpifword CMP_COMMON_BITS, gBattleTypeFlags, BATTLE_TYPE_TRAINER, BattleScript_BallThrowSteal[/COLOR]

find somewhere to put the new script. i put mine in the space between BattleScript_SuccessBallThrowEnd's last line and the beginning of BattleScript_WallyBallThrow. then paste it in, it should look like this:

    BattleScript_BallThrowSteal::
        printstring STRINGID_GOTCHAPKMNCAUGHT
        givecaughtmon
        cleareffectsonfaint BS_TARGET
	goto BattleScript_HandleFaintedMon

lastly, we need to set the opponent's pokemon's hp so that it's made unusable by being considered fainted. go to cmd_givecaughtmon in src/battle_script_commands.c, and before the last line (gBattlescriptCurrInstr++;), add the following:

    if (gBattleTypeFlags & BATTLE_TYPE_TRAINER)
    {
        gBattleMons[gBattlerTarget].hp = 0;
        SetMonData(&gEnemyParty[gBattlerPartyIndexes[gBattlerAttacker ^ BIT_SIDE]], MON_DATA_HP, &gBattleMons[gBattlerTarget].hp);
    }

note that because we make stolen pokemon count as "fainted", NPCs that can use revives will be able to make these pokemon usable again. this isn't an issue in vanilla emerald, as it's impossible for an NPC to use a revive, but keep it in mind if you're using another mod which enables that.

the new script skips both the dex screen and nickname screen, due to graphical glitches that occur when you try to resume battle after viewing one of those. the result feels a bit like colosseum.

step 4: polish

Spoiler:

there are just a couple last details that can be easily changed to make this mod better.

firstly, the "caught" victory music begins playing after a pokemon is caught, and remains for the rest of the battle. there are a couple of things that must be done to fix this.

first, in include/constants/battle_string_ids.h, scroll down to the "BATTLESTRINGS_COUNT" line. we'll be adding a new string to this table, so we'll need to give it a #define with the next available ID, and we'll need to increase the size of the table also.

in my case, before the BATTLESTRINGS_COUNT line, the last string was "#define STRINGID_TRAINER2WINTEXT 380". i added my new string as 381 like so:

    #define STRINGID_GOTCHAPKMNCAUGHTNOBGM      381

and then, i increased the BATTLESTRINGS_COUNT number by one, from 381 to 382.

next, go to src/battle_message.c. just before "const u8 * const gBattleStringsTable[BATTLESTRINGS_COUNT - BATTLESTRINGS_TABLE_START] =", add a new line:

static const u8 sText_GotchaPkmnCaughtNoBgm[] = _("Gotcha!\n{B_OPPONENT_MON1_NAME} was caught!{WAIT_SE}{RESUME_MUSIC}\p");

this string on its own will resume the trainer battle music after the capture jingle is finished. feel free to rewrite the dialogue however you like.

to use this new message, go back to data/battle_scripts_2.s and find the BattleScript_BallThrowSteal we added earlier, and change printstring STRINGID_GOTCHAPKMNCAUGHT to printstring STRINGID_GOTCHAPKMNCAUGHTNOBGM. the battle music should continue on as expected.

finally, there's a super quick change you can make to deal with the opponent's health box, which currently sticks on the screen til the next pokemon overwrites it. in src/battle_script_commands.c, inside the if statement we added to cmd_givecaughtmon earlier, just add this one line:

    SetHealthboxSpriteInvisible(gHealthboxSpriteIds[gBattlerTarget]);

the health box in the top-left should now just vanish instantly.

and that's it!

one issue with this implementation is that it doesn't give you a chance to nickname the mon, and since they don't have your OT, you can't nickname them at the name rater. as a workaround, consider adding this mod as well: https://github.com/pret/pokeemerald/wiki/Nickname-your-Pokémon-from-the-party-menu this adds a party menu option for nicknaming, and as far as i can tell it doesn't check for OT.

 

[kolbinski32]

Can you still catch wild pokemon with this or only steal pokemon

 

[kolbinski32]

How do you makeit so stolen pokemon are added to pokedex

 

[LordOfOtatops]

How would I limit capturable Pokemon with this method to specific species?

 

[Anon822]

How would I limit capturable Pokemon with this method to specific species?

In ellabrella's post the code in the 1st step contains the condition for the trainer blocking the ball. You could modify that to check the opponent's species and block the ball only if it isn't correct.

 

[LordOfOtatops]

Alright thanks! I've been wanting to make a romhack similar to Pokemon Coliseum or Game of Darkness if that makes sense. This should be super helpful

 

[Kliss88]

I just stumbled upon this and it looks exactly like something I'd be interested in trying. Is there anyway to get it as a UPS file or some patch that I can apply to my emerald?

 

[Lunos]

I just stumbled upon this and it looks exactly like something I'd be interested in trying. Is there anyway to get it as a UPS file or some patch that I can apply to my emerald?

What ellabrella posted are snippets of code that have to be applied to a copy of Pokeemerald, Pret's decompilation project of Pokémon Emerald.
Once you apply the changes in each relevant file and save them, you build a ROM in a terminal that has the right packages, libraries and tools installed as instructed in the INSTALL.md document that will contain the changes.
The only way to get a .ups patch would be for someone else to do this for you and then build a patch file based on the generated ROM.

 

[Kliss88]

What ellabrella posted are snippets of code that have to be applied to a copy of Pokeemerald, Pret's decompilation project of Pokémon Emerald.
Once you apply the changes in each relevant file and save them, you build a ROM in a terminal that has the right packages, libraries and tools installed as instructed in the INSTALL.md document that will contain the changes.
The only way to get a .ups patch would be for someone else to do this for you and then build a patch file based on the generated ROM.

Ah ok! I've not dealt with a deconstructed mod before but I guess I'll follow the instructions and see if I can do it lol