Expanded Pokémon Follower transformation functionality

include/config/overworld.h

@@ -55,8 +55,10 @@
 #define OW_MON_WANDER_WALK             TRUE       // If true, OW pokemon with MOVEMENT_TYPE_WANDER will walk-in-place in between steps.
 // Follower Pokémon
 #define OW_FOLLOWERS_ENABLED           FALSE      // Enables follower Pokémon, HGSS style. Requires OW_POKEMON_OBJECT_EVENTS. Note that additional scripting may be required for them to be fully supported!
-#define OW_FOLLOWERS_BOBBING           TRUE       // If true, follower pokemon will bob up and down during their idle & walking animations
-#define OW_FOLLOWERS_POKEBALLS         TRUE       // Followers will emerge from the pokeball they are stored in, instead of a normal pokeball
+#define OW_FOLLOWERS_BOBBING           TRUE       // If TRUE, follower Pokémon will bob up and down during their idle & walking animations
+#define OW_FOLLOWERS_POKEBALLS         TRUE       // If TRUE, follower Pokémon will emerge from the Poké Ball they are stored in, instead of a normal Poké Ball
+#define OW_FOLLOWERS_WEATHER_FORMS     FALSE      // If TRUE, Castform and Cherrim gain FORM_CHANGE_OVERWORLD_WEATHER, which will make them transform in the overworld based on the weather.
+#define OW_FOLLOWERS_COPY_WILD_PKMN    FALSE      // If TRUE, follower Pokémon that know Transform or have Illusion/Imposter will copy wild Pokémon at random.
 
 // Out-of-battle Ability effects
 #define OW_SYNCHRONIZE_NATURE       GEN_LATEST // In Gen8+, if a Pokémon with Synchronize leads the party, wild Pokémon will always have their same Nature as opposed to the 50% chance in previous games. Gift Pokémon excluded.

include/constants/form_change_types.h

@@ -144,4 +144,11 @@
 // param2: ability to check, optional
 #define FORM_CHANGE_BATTLE_BEFORE_MOVE_CATEGORY 25
 
+// Form change that activates when overworld weather changes.
+// param1: weather to check.
+#define FORM_CHANGE_OVERWORLD_WEATHER           26
+
+// Form change that activates when the Pokémon is deposited into the PC or Daycare.
+#define FORM_CHANGE_DEPOSIT                     27
+
 #endif // GUARD_CONSTANTS_FORM_CHANGE_TYPES_H

include/event_object_movement.h

@@ -148,6 +148,7 @@ void ClearObjectEventMovement(struct ObjectEvent *objectEvent, struct Sprite *sp
 void ObjectEventClearHeldMovement(struct ObjectEvent *);
 void ObjectEventClearHeldMovementIfActive(struct ObjectEvent *);
 struct Pokemon *GetFirstLiveMon(void);
+u16 GetOverworldWeatherSpecies(u16 species);
 void UpdateFollowingPokemon(void);
 void RemoveFollowingPokemon(void);
 struct ObjectEvent *GetFollowerObject(void);

src/battle_util.c

@@ -10909,21 +10909,18 @@ bool32 DoesSpeciesUseHoldItemToChangeForm(u16 species, u16 heldItemId)
     u32 i;
     const struct FormChange *formChanges = GetSpeciesFormChanges(species);
 
-    if (formChanges != NULL)
+    for (i = 0; formChanges != NULL && formChanges[i].method != FORM_CHANGE_TERMINATOR; i++)
     {
-        for (i = 0; formChanges[i].method != FORM_CHANGE_TERMINATOR; i++)
+        switch (formChanges[i].method)
         {
-            switch (formChanges[i].method)
-            {
-            case FORM_CHANGE_BATTLE_MEGA_EVOLUTION_ITEM:
-            case FORM_CHANGE_BATTLE_PRIMAL_REVERSION:
-            case FORM_CHANGE_BATTLE_ULTRA_BURST:
-            case FORM_CHANGE_ITEM_HOLD:
-            case FORM_CHANGE_BEGIN_BATTLE:
-                if (formChanges[i].param1 == heldItemId)
-                    return TRUE;
-                break;
-            }
+        case FORM_CHANGE_BATTLE_MEGA_EVOLUTION_ITEM:
+        case FORM_CHANGE_BATTLE_PRIMAL_REVERSION:
+        case FORM_CHANGE_BATTLE_ULTRA_BURST:
+        case FORM_CHANGE_ITEM_HOLD:
+        case FORM_CHANGE_BEGIN_BATTLE:
+            if (formChanges[i].param1 == heldItemId)
+                return TRUE;
+            break;
         }
     }
     return FALSE;
@@ -11054,103 +11051,98 @@ u16 GetBattleFormChangeTargetSpecies(u32 battler, u16 method)
     u32 targetSpecies = species;
     const struct FormChange *formChanges = GetSpeciesFormChanges(species);
     struct Pokemon *mon = &GetBattlerParty(battler)[gBattlerPartyIndexes[battler]];
-    u16 heldItem;
+    u16 heldItem = gBattleMons[battler].item;
 
-    if (formChanges != NULL)
+    for (i = 0; formChanges != NULL && formChanges[i].method != FORM_CHANGE_TERMINATOR; i++)
     {
-        heldItem = gBattleMons[battler].item;
-
-        for (i = 0; formChanges[i].method != FORM_CHANGE_TERMINATOR; i++)
+        if (method == formChanges[i].method && species != formChanges[i].targetSpecies)
         {
-            if (method == formChanges[i].method && species != formChanges[i].targetSpecies)
+            switch (method)
             {
-                switch (method)
-                {
-                case FORM_CHANGE_BATTLE_MEGA_EVOLUTION_ITEM:
-                case FORM_CHANGE_BATTLE_PRIMAL_REVERSION:
-                case FORM_CHANGE_BATTLE_ULTRA_BURST:
-                    if (heldItem == formChanges[i].param1)
-                        targetSpecies = formChanges[i].targetSpecies;
-                    break;
-                case FORM_CHANGE_BATTLE_MEGA_EVOLUTION_MOVE:
-                    if (gBattleMons[battler].moves[0] == formChanges[i].param1
-                     || gBattleMons[battler].moves[1] == formChanges[i].param1
-                     || gBattleMons[battler].moves[2] == formChanges[i].param1
-                     || gBattleMons[battler].moves[3] == formChanges[i].param1)
-                        targetSpecies = formChanges[i].targetSpecies;
-                    break;
-                case FORM_CHANGE_BATTLE_SWITCH:
-                    if (formChanges[i].param1 == GetBattlerAbility(battler) || formChanges[i].param1 == ABILITY_NONE)
-                        targetSpecies = formChanges[i].targetSpecies;
-                    break;
-                case FORM_CHANGE_BATTLE_HP_PERCENT:
-                    if (formChanges[i].param1 == GetBattlerAbility(battler))
-                    {
-                        // We multiply by 100 to make sure that integer division doesn't mess with the health check.
-                        u32 hpCheck = gBattleMons[battler].hp * 100 * 100 / gBattleMons[battler].maxHP;
-                        switch(formChanges[i].param2)
-                        {
-                        case HP_HIGHER_THAN:
-                            if (hpCheck > formChanges[i].param3 * 100)
-                                targetSpecies = formChanges[i].targetSpecies;
-                            break;
-                        case HP_LOWER_EQ_THAN:
-                            if (hpCheck <= formChanges[i].param3 * 100)
-                                targetSpecies = formChanges[i].targetSpecies;
-                            break;
-                        }
-                    }
-                    break;
-                case FORM_CHANGE_BATTLE_GIGANTAMAX:
-                    if (GetMonData(mon, MON_DATA_GIGANTAMAX_FACTOR))
-                        targetSpecies = formChanges[i].targetSpecies;
-                    break;
-                case FORM_CHANGE_BATTLE_WEATHER:
-                    // Check if there is a required ability and if the battler's ability does not match it
-                    // or is suppressed. If so, revert to the no weather form.
-                    if (formChanges[i].param2
-                        && GetBattlerAbility(battler) != formChanges[i].param2
-                        && formChanges[i].param1 == B_WEATHER_NONE)
-                    {
-                        targetSpecies = formChanges[i].targetSpecies;
-                    }
-                    // We need to revert the weather form if the field is under Air Lock, too.
-                    else if (!WEATHER_HAS_EFFECT && formChanges[i].param1 == B_WEATHER_NONE)
-                    {
-                        targetSpecies = formChanges[i].targetSpecies;
-                    }
-                    // Otherwise, just check for a match between the weather and the form change table.
-                    // Added a check for whether the weather is in effect to prevent end-of-turn soft locks with Cloud Nine / Air Lock
-                    else if (((gBattleWeather & formChanges[i].param1) && WEATHER_HAS_EFFECT)
-                        || (gBattleWeather == B_WEATHER_NONE && formChanges[i].param1 == B_WEATHER_NONE))
+            case FORM_CHANGE_BATTLE_MEGA_EVOLUTION_ITEM:
+            case FORM_CHANGE_BATTLE_PRIMAL_REVERSION:
+            case FORM_CHANGE_BATTLE_ULTRA_BURST:
+                if (heldItem == formChanges[i].param1)
+                    targetSpecies = formChanges[i].targetSpecies;
+                break;
+            case FORM_CHANGE_BATTLE_MEGA_EVOLUTION_MOVE:
+                if (gBattleMons[battler].moves[0] == formChanges[i].param1
+                    || gBattleMons[battler].moves[1] == formChanges[i].param1
+                    || gBattleMons[battler].moves[2] == formChanges[i].param1
+                    || gBattleMons[battler].moves[3] == formChanges[i].param1)
+                    targetSpecies = formChanges[i].targetSpecies;
+                break;
+            case FORM_CHANGE_BATTLE_SWITCH:
+                if (formChanges[i].param1 == GetBattlerAbility(battler) || formChanges[i].param1 == ABILITY_NONE)
+                    targetSpecies = formChanges[i].targetSpecies;
+                break;
+            case FORM_CHANGE_BATTLE_HP_PERCENT:
+                if (formChanges[i].param1 == GetBattlerAbility(battler))
+                {
+                    // We multiply by 100 to make sure that integer division doesn't mess with the health check.
+                    u32 hpCheck = gBattleMons[battler].hp * 100 * 100 / gBattleMons[battler].maxHP;
+                    switch(formChanges[i].param2)
                     {
-                        targetSpecies = formChanges[i].targetSpecies;
+                    case HP_HIGHER_THAN:
+                        if (hpCheck > formChanges[i].param3 * 100)
+                            targetSpecies = formChanges[i].targetSpecies;
+                        break;
+                    case HP_LOWER_EQ_THAN:
+                        if (hpCheck <= formChanges[i].param3 * 100)
+                            targetSpecies = formChanges[i].targetSpecies;
+                        break;
                     }
-                    break;
-                case FORM_CHANGE_BATTLE_TURN_END:
-                case FORM_CHANGE_HIT_BY_MOVE:
-                    if (formChanges[i].param1 == GetBattlerAbility(battler))
-                        targetSpecies = formChanges[i].targetSpecies;
-                    break;
-                case FORM_CHANGE_STATUS:
-                    if (gBattleMons[battler].status1 & formChanges[i].param1)
-                        targetSpecies = formChanges[i].targetSpecies;
-                    break;
-                case FORM_CHANGE_BATTLE_TERASTALLIZATION:
-                    if (GetBattlerTeraType(battler) == formChanges[i].param1)
-                        targetSpecies = formChanges[i].targetSpecies;
-                    break;
-                case FORM_CHANGE_BATTLE_BEFORE_MOVE:
-                    if (formChanges[i].param1 == gCurrentMove
-                     && (formChanges[i].param2 == ABILITY_NONE || formChanges[i].param2 == GetBattlerAbility(battler)))
-                        targetSpecies = formChanges[i].targetSpecies;
-                    break;
-                case FORM_CHANGE_BATTLE_BEFORE_MOVE_CATEGORY:
-                    if (formChanges[i].param1 == GetBattleMoveCategory(gCurrentMove)
-                     && (formChanges[i].param2 == ABILITY_NONE || formChanges[i].param2 == GetBattlerAbility(battler)))
-                        targetSpecies = formChanges[i].targetSpecies;
-                    break;
                 }
+                break;
+            case FORM_CHANGE_BATTLE_GIGANTAMAX:
+                if (GetMonData(mon, MON_DATA_GIGANTAMAX_FACTOR))
+                    targetSpecies = formChanges[i].targetSpecies;
+                break;
+            case FORM_CHANGE_BATTLE_WEATHER:
+                // Check if there is a required ability and if the battler's ability does not match it
+                // or is suppressed. If so, revert to the no weather form.
+                if (formChanges[i].param2
+                    && GetBattlerAbility(battler) != formChanges[i].param2
+                    && formChanges[i].param1 == B_WEATHER_NONE)
+                {
+                    targetSpecies = formChanges[i].targetSpecies;
+                }
+                // We need to revert the weather form if the field is under Air Lock, too.
+                else if (!WEATHER_HAS_EFFECT && formChanges[i].param1 == B_WEATHER_NONE)
+                {
+                    targetSpecies = formChanges[i].targetSpecies;
+                }
+                // Otherwise, just check for a match between the weather and the form change table.
+                // Added a check for whether the weather is in effect to prevent end-of-turn soft locks with Cloud Nine / Air Lock
+                else if (((gBattleWeather & formChanges[i].param1) && WEATHER_HAS_EFFECT)
+                    || (gBattleWeather == B_WEATHER_NONE && formChanges[i].param1 == B_WEATHER_NONE))
+                {
+                    targetSpecies = formChanges[i].targetSpecies;
+                }
+                break;
+            case FORM_CHANGE_BATTLE_TURN_END:
+            case FORM_CHANGE_HIT_BY_MOVE:
+                if (formChanges[i].param1 == GetBattlerAbility(battler))
+                    targetSpecies = formChanges[i].targetSpecies;
+                break;
+            case FORM_CHANGE_STATUS:
+                if (gBattleMons[battler].status1 & formChanges[i].param1)
+                    targetSpecies = formChanges[i].targetSpecies;
+                break;
+            case FORM_CHANGE_BATTLE_TERASTALLIZATION:
+                if (GetBattlerTeraType(battler) == formChanges[i].param1)
+                    targetSpecies = formChanges[i].targetSpecies;
+                break;
+            case FORM_CHANGE_BATTLE_BEFORE_MOVE:
+                if (formChanges[i].param1 == gCurrentMove
+                    && (formChanges[i].param2 == ABILITY_NONE || formChanges[i].param2 == GetBattlerAbility(battler)))
+                    targetSpecies = formChanges[i].targetSpecies;
+                break;
+            case FORM_CHANGE_BATTLE_BEFORE_MOVE_CATEGORY:
+                if (formChanges[i].param1 == GetBattleMoveCategory(gCurrentMove)
+                    && (formChanges[i].param2 == ABILITY_NONE || formChanges[i].param2 == GetBattlerAbility(battler)))
+                    targetSpecies = formChanges[i].targetSpecies;
+                break;
             }
         }
     }