[Pokeemerald] Capture/Battle Combos

Diego Mertens · Sep 11, 2020

Hi! Sometime ago, when I graduated from a Whack a Hack! RGSS scripting school, I made a Catch Combo system for Essentials. And now, I ported it to pokeemerald! (big codes are put in spoilers for easier access and navigation through the page)
This version of the Catch Combo System includes:

Chain a Pokémon, with 30 as the maximum chain possible
Shiny Pokémon appear more often with the level of the chain!
A message box appears at the end of a Wild Battle when the chain is 3 or bigger, so it could appear and be noticed for all players
When a different Pokémon appears, you can run away and the chain continues!
Catching OR defeating the same Pokémon you did before will continue the chain

To do list:

Modify the encounter tables when going forward in the chain
Modify the IV's of the Pokemon (probably gonna add it tomorrow)
Make the chained Pokémon appear more often with the level of the chain
Make (a) special Pokémon sometimes appear at higher chain levels

The first thing you need to do is go to "src/battle_setup.c" and add this lines:

Code:

extern const u8 ChainNumber[]; 
extern const u8 AddChain[];

Below "static const u8 *GetTrainerCantBattleSpeech(void);"
Once we do that, we replace the whole "static void CB2_EndWildBattle(void)" definition with this one:

Spoiler:

Then, we add this variables in "include/constants/vars.h"
VAR_CHAIN
and
VAR_SPECIESCHAINED

We then go to src/pokemon.c and we replace the whole "
this if we don't have the Eggg item expansion and battle engine

Spoiler:

Code:

void CreateBoxMon(struct BoxPokemon *boxMon, u16 species, u8 level, u8 fixedIV, u8 hasFixedPersonality, u32 fixedPersonality, u8 otIdType, u32 fixedOtId)
{
    u8 speciesName[POKEMON_NAME_LENGTH + 1];
    u32 personality;
    u32 value;
    u16 checksum;

    ZeroBoxMonData(boxMon);

    if (hasFixedPersonality)
        personality = fixedPersonality;
    else
        personality = Random32();

    //Determine original trainer ID
    if (otIdType == OT_ID_RANDOM_NO_SHINY) //Pokemon cannot be shiny
    {
        u32 shinyValue;
        do
        {
            value = Random32();
            shinyValue = HIHALF(value) ^ LOHALF(value) ^ HIHALF(personality) ^ LOHALF(personality);
        } while (shinyValue < SHINY_ODDS);
    }
    else if (otIdType == OT_ID_PRESET) //Pokemon has a preset OT ID
    {
        value = fixedOtId;
    }
    else //Player is the OT
    {
        value = gSaveBlock2Ptr->playerTrainerId[0]
              | (gSaveBlock2Ptr->playerTrainerId[1] << 8)
              | (gSaveBlock2Ptr->playerTrainerId[2] << 16)
              | (gSaveBlock2Ptr->playerTrainerId[3] << 24);
        
        if (VarGet(VAR_CHAIN) >=2)
        {
            u32 shinyValue;
            u32 rolls = 0;
            do
            {
                personality = Random32();
                shinyValue = HIHALF(value) ^ LOHALF(value) ^ HIHALF(personality) ^ LOHALF(personality);
                rolls++;
            } while (shinyValue >= SHINY_ODDS && rolls <= (VarGet(VAR_CHAIN)));
        }
    }

    SetBoxMonData(boxMon, MON_DATA_PERSONALITY, &personality);
    SetBoxMonData(boxMon, MON_DATA_OT_ID, &value);

    checksum = CalculateBoxMonChecksum(boxMon);
    SetBoxMonData(boxMon, MON_DATA_CHECKSUM, &checksum);
    EncryptBoxMon(boxMon);
    GetSpeciesName(speciesName, species);
    SetBoxMonData(boxMon, MON_DATA_NICKNAME, speciesName);
    SetBoxMonData(boxMon, MON_DATA_LANGUAGE, &gGameLanguage);
    SetBoxMonData(boxMon, MON_DATA_OT_NAME, gSaveBlock2Ptr->playerName);
    SetBoxMonData(boxMon, MON_DATA_SPECIES, &species);
    SetBoxMonData(boxMon, MON_DATA_EXP, &gExperienceTables[gBaseStats[species].growthRate][level]);
    SetBoxMonData(boxMon, MON_DATA_FRIENDSHIP, &gBaseStats[species].friendship);
    value = GetCurrentRegionMapSectionId();
    SetBoxMonData(boxMon, MON_DATA_MET_LOCATION, &value);
    SetBoxMonData(boxMon, MON_DATA_MET_LEVEL, &level);
    SetBoxMonData(boxMon, MON_DATA_MET_GAME, &gGameVersion);
    value = ITEM_POKE_BALL;
    SetBoxMonData(boxMon, MON_DATA_POKEBALL, &value);
    SetBoxMonData(boxMon, MON_DATA_OT_GENDER, &gSaveBlock2Ptr->playerGender);

    if (fixedIV < 32)
    {
        SetBoxMonData(boxMon, MON_DATA_HP_IV, &fixedIV);
        SetBoxMonData(boxMon, MON_DATA_ATK_IV, &fixedIV);
        SetBoxMonData(boxMon, MON_DATA_DEF_IV, &fixedIV);
        SetBoxMonData(boxMon, MON_DATA_SPEED_IV, &fixedIV);
        SetBoxMonData(boxMon, MON_DATA_SPATK_IV, &fixedIV);
        SetBoxMonData(boxMon, MON_DATA_SPDEF_IV, &fixedIV);
    }
    else
    {
        u32 iv;
        value = Random();

        iv = value & 0x1F;
        SetBoxMonData(boxMon, MON_DATA_HP_IV, &iv);
        iv = (value & 0x3E0) >> 5;
        SetBoxMonData(boxMon, MON_DATA_ATK_IV, &iv);
        iv = (value & 0x7C00) >> 10;
        SetBoxMonData(boxMon, MON_DATA_DEF_IV, &iv);

        value = Random();

        iv = value & 0x1F;
        SetBoxMonData(boxMon, MON_DATA_SPEED_IV, &iv);
        iv = (value & 0x3E0) >> 5;
        SetBoxMonData(boxMon, MON_DATA_SPATK_IV, &iv);
        iv = (value & 0x7C00) >> 10;
        SetBoxMonData(boxMon, MON_DATA_SPDEF_IV, &iv);
    }

    if (gBaseStats[species].abilities[1])
    {
        value = personality & 1;
        SetBoxMonData(boxMon, MON_DATA_ABILITY_NUM, &value);
    }

    GiveBoxMonInitialMoveset(boxMon);
}

But if we do have them, we replace it with this one:

Spoiler:

Code:

void CreateBoxMon(struct BoxPokemon *boxMon, u16 species, u8 level, u8 fixedIV, u8 hasFixedPersonality, u32 fixedPersonality, u8 otIdType, u32 fixedOtId)
{
    u8 speciesName[POKEMON_NAME_LENGTH + 1];
    u32 personality;
    u32 value;
    u16 checksum;

    ZeroBoxMonData(boxMon);

    if (hasFixedPersonality)
        personality = fixedPersonality;
    else
        personality = Random32();

    //Determine original trainer ID
    if (otIdType == OT_ID_RANDOM_NO_SHINY) //Pokemon cannot be shiny
    {
        u32 shinyValue;
        do
        {
            value = Random32();
            shinyValue = HIHALF(value) ^ LOHALF(value) ^ HIHALF(personality) ^ LOHALF(personality);
        } while (shinyValue < SHINY_ODDS);
    }
    else if (otIdType == OT_ID_PRESET) //Pokemon has a preset OT ID
    {
        value = fixedOtId;
    }
    else //Player is the OT
    {
        value = gSaveBlock2Ptr->playerTrainerId[0]
              | (gSaveBlock2Ptr->playerTrainerId[1] << 8)
              | (gSaveBlock2Ptr->playerTrainerId[2] << 16)
              | (gSaveBlock2Ptr->playerTrainerId[3] << 24);
        
        if (CheckBagHasItem(ITEM_SHINY_CHARM, 1) && (VarGet(VAR_CHAIN) >=2))
        {
            u32 shinyValue;
            u32 rolls = 0;
            do
            {
                personality = Random32();
                shinyValue = HIHALF(value) ^ LOHALF(value) ^ HIHALF(personality) ^ LOHALF(personality);
                rolls++;
            } while (shinyValue >= SHINY_ODDS && rolls < (SHINY_CHARM_REROLLS + (VarGet(VAR_CHAIN))));
        }
        else if (CheckBagHasItem(ITEM_SHINY_CHARM, 1))
        {
            u32 shinyValue;
            u32 rolls = 0;
            do
            {
                personality = Random32();
                shinyValue = HIHALF(value) ^ LOHALF(value) ^ HIHALF(personality) ^ LOHALF(personality);
                rolls++;
            } while (shinyValue >= SHINY_ODDS && rolls < SHINY_CHARM_REROLLS);
        }
		else if (VarGet(VAR_CHAIN) >=2)
        {
            u32 shinyValue;
            u32 rolls = 0;
            do
            {
                personality = Random32();
                shinyValue = HIHALF(value) ^ LOHALF(value) ^ HIHALF(personality) ^ LOHALF(personality);
                rolls++;
            } while (shinyValue >= SHINY_ODDS && rolls <= (VarGet(VAR_CHAIN)));
        }
    }

    SetBoxMonData(boxMon, MON_DATA_PERSONALITY, &personality);
    SetBoxMonData(boxMon, MON_DATA_OT_ID, &value);

    checksum = CalculateBoxMonChecksum(boxMon);
    SetBoxMonData(boxMon, MON_DATA_CHECKSUM, &checksum);
    EncryptBoxMon(boxMon);
    GetSpeciesName(speciesName, species);
    SetBoxMonData(boxMon, MON_DATA_NICKNAME, speciesName);
    SetBoxMonData(boxMon, MON_DATA_LANGUAGE, &gGameLanguage);
    SetBoxMonData(boxMon, MON_DATA_OT_NAME, gSaveBlock2Ptr->playerName);
    SetBoxMonData(boxMon, MON_DATA_SPECIES, &species);
    SetBoxMonData(boxMon, MON_DATA_EXP, &gExperienceTables[gBaseStats[species].growthRate][level]);
    SetBoxMonData(boxMon, MON_DATA_FRIENDSHIP, &gBaseStats[species].friendship);
    value = GetCurrentRegionMapSectionId();
    SetBoxMonData(boxMon, MON_DATA_MET_LOCATION, &value);
    SetBoxMonData(boxMon, MON_DATA_MET_LEVEL, &level);
    SetBoxMonData(boxMon, MON_DATA_MET_GAME, &gGameVersion);
    value = ITEM_POKE_BALL;
    SetBoxMonData(boxMon, MON_DATA_POKEBALL, &value);
    SetBoxMonData(boxMon, MON_DATA_OT_GENDER, &gSaveBlock2Ptr->playerGender);

    if (fixedIV < 32)
    {
        SetBoxMonData(boxMon, MON_DATA_HP_IV, &fixedIV);
        SetBoxMonData(boxMon, MON_DATA_ATK_IV, &fixedIV);
        SetBoxMonData(boxMon, MON_DATA_DEF_IV, &fixedIV);
        SetBoxMonData(boxMon, MON_DATA_SPEED_IV, &fixedIV);
        SetBoxMonData(boxMon, MON_DATA_SPATK_IV, &fixedIV);
        SetBoxMonData(boxMon, MON_DATA_SPDEF_IV, &fixedIV);
    }
    else
    {
        u32 iv;
        value = Random();

        iv = value & 0x1F;
        SetBoxMonData(boxMon, MON_DATA_HP_IV, &iv);
        iv = (value & 0x3E0) >> 5;
        SetBoxMonData(boxMon, MON_DATA_ATK_IV, &iv);
        iv = (value & 0x7C00) >> 10;
        SetBoxMonData(boxMon, MON_DATA_DEF_IV, &iv);

        value = Random();

        iv = value & 0x1F;
        SetBoxMonData(boxMon, MON_DATA_SPEED_IV, &iv);
        iv = (value & 0x3E0) >> 5;
        SetBoxMonData(boxMon, MON_DATA_SPATK_IV, &iv);
        iv = (value & 0x7C00) >> 10;
        SetBoxMonData(boxMon, MON_DATA_SPDEF_IV, &iv);
    }

    if (gBaseStats[species].abilities[1])
    {
        value = personality & 1;
        SetBoxMonData(boxMon, MON_DATA_ABILITY_NUM, &value);
    }

    GiveBoxMonInitialMoveset(boxMon);
}

Then, we go to "data/scripts/" and we create there an archive named "chain.inc", and inside we add this;

Code:

ChainNumber::
	addvar VAR_CHAIN, 1
	buffernumberstring 0, VAR_CHAIN
	msgbox TextoCool, 2
	end
	
TextoCool::
	.string "Chain Level: {STR_VAR_1}\n chained :{STR_VAR_2}.$"
	
AddChain::
	addvar VAR_CHAIN, 1
	end

And we have to define it on "data/event_scripts.s", adding this at the end:
.include "data/scripts/chain.inc"

And with that, we have it all done. If I missed something or if there's a way to improve the code, let me know!

opakedragon · Jan 23, 2021

Diego Mertens said:
...
Then, we add this variables in "include/constants/vars.h"
VAR_CHAIN
and
VAR_SPECIESCHAINED

...

Can you be more specific? how does one add it?

Diego Mertens said:

...

We then go to src/pokemon.c and we replace the whole "
this if we don't have the Eggg item expansion and battle engine

Spoiler:

...

Why do you turn the dynamic values (USE_RANDOM_IVS, MAX_IV_MASK; seen below) with static values (quoted) in src/pokemon.c?

Spoiler:

The values are effectively identical. Are your edits from a previous pret/pokeemerald commit?

Diego Mertens said:
Then, we move on to "include/strings.h" and we add this at the end:
extern const u8 gText_Chain[];
And we define it on "src/strings.c"
const u8 gText_Chain[] = _("Cadena: {STR_VAR_1}, de {STR_VAR_1}.");

Does not appear to be used. All of your text appears to be in "data/scripts/chain.inc"

Diego Mertens · Feb 3, 2021

opakedragon said:
Can you be more specific? how does one add it?

You add them just like any other var, you go to include/constants/vars.h, replacing an old, unused var (theres ton of them) with those (just the name)

opakedragon said:
Why do you turn the dynamic values (USE_RANDOM_IVS, MAX_IV_MASK; seen below) with static values (quoted) in src/pokemon.c?

It appears that i was using an old copy. I also know i was going for better IV's the better the chain was, but i dont really remember why the code in that part looks like that.

opakedragon said:
Does not appear to be used. All of your text appears to be in "data/scripts/chain.inc"

That's simple. I forgot to delete it from the tutorial. Soon I'll update this, and I'll try to make it easier to access and use, I'll also make a repo so i can follow it.