Renamed VAR_TERRAIN to B_VAR_TERRAIN and added a var-based field terrain timer

include/config/battle.h

@@ -179,15 +179,15 @@
 
 // Var Settings
 // To use the following features in scripting, replace the 0s with the var ID you're assigning it to.
-// Eg: Replace with VAR_UNUSED_0x40F7 so you can use VAR_TERRAIN for that feature.
-#define VAR_TERRAIN                 0     // If this var has a value, assigning a STATUS_FIELD_xx_TERRAIN to it before battle causes the battle to start with that terrain active
+// Eg: Replace with VAR_UNUSED_0x40F7 so you can use B_VAR_TERRAIN for that feature.
+#define B_VAR_TERRAIN               0     // If this var has a value, assigning a STATUS_FIELD_xx_TERRAIN to it before battle causes the battle to start with that terrain active.
+#define B_VAR_TERRAIN_TIMER         0     // If this var has a value greater or equal than 1 field terrains will last that number of turns, otherwise they will last until they're overwritten.
 #define B_VAR_WILD_AI_FLAGS         0     // If not 0, you can use this var to add to default wild AI flags. NOT usable with flags above (1 << 15)
 
 // Sky Battles
-#define B_FLAG_SKY_BATTLE           0           // If this flag has a value, the player will be able to engage in scripted Sky Battles.
-#define B_VAR_SKY_BATTLE            0           // If this var has a value, the game will remember the positions of Pokémon used in Sky Battles.
-
-#define B_SKY_BATTLE_STRICT_ELIGIBILITY FALSE //If TRUE, Sky Battles will use the eligibility from Pokémon XY. If FALSE, all Flying-types or Pokémon with Levitate are allowed.
+#define B_FLAG_SKY_BATTLE                 0     // If this flag has a value, the player will be able to engage in scripted Sky Battles.
+#define B_VAR_SKY_BATTLE                  0     // If this var has a value, the game will remember the positions of Pokémon used in Sky Battles.
+#define B_SKY_BATTLE_STRICT_ELIGIBILITY   FALSE // If TRUE, Sky Battles will use the eligibility from Pokémon XY. If FALSE, all Flying-types or Pokémon with Levitate are allowed.
 
 // Flag and Var settings
 #define B_RESET_FLAGS_VARS_AFTER_WHITEOUT TRUE // If TRUE, Overworld_ResetBattleFlagsAndVars will reset battle-related Flags and Vars when the player whites out.

src/battle_util.c

@@ -4016,50 +4016,79 @@ u32 AbilityBattleEffects(u32 caseID, u32 battler, u32 ability, u32 special, u32
     switch (caseID)
     {
     case ABILITYEFFECT_SWITCH_IN_TERRAIN:
-        gBattleScripting.battler = battler;
-        if (VarGet(VAR_TERRAIN) & STATUS_FIELD_TERRAIN_ANY)
         {
-            u16 terrainFlags = VarGet(VAR_TERRAIN) & STATUS_FIELD_TERRAIN_ANY;    // only works for status flag (1 << 15)
-            gFieldStatuses = terrainFlags | STATUS_FIELD_TERRAIN_PERMANENT; // terrain is permanent
-            switch (VarGet(VAR_TERRAIN) & STATUS_FIELD_TERRAIN_ANY)
+            u8 varTerrainTimer = VarGet(B_VAR_TERRAIN_TIMER);
+
+            gBattleScripting.battler = battler;
+            if (VarGet(B_VAR_TERRAIN) & STATUS_FIELD_TERRAIN_ANY)
             {
-            case STATUS_FIELD_ELECTRIC_TERRAIN:
+                u16 terrainFlags = VarGet(B_VAR_TERRAIN) & STATUS_FIELD_TERRAIN_ANY;    // only works for status flag (1 << 15)
+
+                if (varTerrainTimer == 0)
+                {
+                    gFieldStatuses = terrainFlags | STATUS_FIELD_TERRAIN_PERMANENT; // terrain is permanent
+                }
+                else
+                {
+                    gFieldStatuses |= terrainFlags;
+                    gFieldTimers.terrainTimer = varTerrainTimer;
+                }
+
+                switch (VarGet(B_VAR_TERRAIN) & STATUS_FIELD_TERRAIN_ANY)
+                {
+                case STATUS_FIELD_ELECTRIC_TERRAIN:
+                    gBattleCommunication[MULTISTRING_CHOOSER] = B_MSG_TERRAIN_SET_ELECTRIC;
+                    break;
+                case STATUS_FIELD_MISTY_TERRAIN:
+                    gBattleCommunication[MULTISTRING_CHOOSER] = B_MSG_TERRAIN_SET_MISTY;
+                    break;
+                case STATUS_FIELD_GRASSY_TERRAIN:
+                    gBattleCommunication[MULTISTRING_CHOOSER] = B_MSG_TERRAIN_SET_GRASSY;
+                    break;
+                case STATUS_FIELD_PSYCHIC_TERRAIN:
+                    gBattleCommunication[MULTISTRING_CHOOSER] = B_MSG_TERRAIN_SET_PSYCHIC;
+                    break;
+                }
+                BattleScriptPushCursorAndCallback(BattleScript_OverworldTerrain);
+                effect++;
+            }
+            else if (B_THUNDERSTORM_TERRAIN == TRUE
+                && GetCurrentWeather() == WEATHER_RAIN_THUNDERSTORM
+                && !(gFieldStatuses & STATUS_FIELD_ELECTRIC_TERRAIN))
+            {
+                // overworld weather started rain, so just do electric terrain anim
+                if (varTerrainTimer == 0)
+                {
+                    gFieldStatuses = (STATUS_FIELD_ELECTRIC_TERRAIN | STATUS_FIELD_TERRAIN_PERMANENT);
+                }
+                else
+                {
+                    gFieldStatuses |= STATUS_FIELD_ELECTRIC_TERRAIN;
+                    gFieldTimers.terrainTimer = varTerrainTimer;
+                }
                 gBattleCommunication[MULTISTRING_CHOOSER] = B_MSG_TERRAIN_SET_ELECTRIC;
-                break;
-            case STATUS_FIELD_MISTY_TERRAIN:
+                BattleScriptPushCursorAndCallback(BattleScript_OverworldTerrain);
+                effect++;
+            }
+            else if (B_FOG_TERRAIN == TRUE
+                && (GetCurrentWeather() == WEATHER_FOG_HORIZONTAL || GetCurrentWeather() == WEATHER_FOG_DIAGONAL)
+                && !(gFieldStatuses & STATUS_FIELD_MISTY_TERRAIN))
+            {
+                if (varTerrainTimer == 0)
+                {
+                    gFieldStatuses = (STATUS_FIELD_MISTY_TERRAIN | STATUS_FIELD_TERRAIN_PERMANENT);
+                }
+                else
+                {
+                    gFieldStatuses |= STATUS_FIELD_ELECTRIC_TERRAIN;
+                    gFieldTimers.terrainTimer = varTerrainTimer;
+                }
                 gBattleCommunication[MULTISTRING_CHOOSER] = B_MSG_TERRAIN_SET_MISTY;
-                break;
-            case STATUS_FIELD_GRASSY_TERRAIN:
-                gBattleCommunication[MULTISTRING_CHOOSER] = B_MSG_TERRAIN_SET_GRASSY;
-                break;
-            case STATUS_FIELD_PSYCHIC_TERRAIN:
-                gBattleCommunication[MULTISTRING_CHOOSER] = B_MSG_TERRAIN_SET_PSYCHIC;
-                break;
+                BattleScriptPushCursorAndCallback(BattleScript_OverworldTerrain);
+                effect++;
             }
-
-            BattleScriptPushCursorAndCallback(BattleScript_OverworldTerrain);
-            effect++;
         }
-        else if (B_THUNDERSTORM_TERRAIN == TRUE
-            && GetCurrentWeather() == WEATHER_RAIN_THUNDERSTORM
-            && !(gFieldStatuses & STATUS_FIELD_ELECTRIC_TERRAIN))
-        {
-            // overworld weather started rain, so just do electric terrain anim
-            gFieldStatuses = (STATUS_FIELD_ELECTRIC_TERRAIN | STATUS_FIELD_TERRAIN_PERMANENT);
-            gBattleCommunication[MULTISTRING_CHOOSER] = B_MSG_TERRAIN_SET_ELECTRIC;
-            BattleScriptPushCursorAndCallback(BattleScript_OverworldTerrain);
-            effect++;
-        }
-        else if (B_FOG_TERRAIN == TRUE
-            && (GetCurrentWeather() == WEATHER_FOG_HORIZONTAL || GetCurrentWeather() == WEATHER_FOG_DIAGONAL)
-            && !(gFieldStatuses & STATUS_FIELD_MISTY_TERRAIN))
-        {
-            gFieldStatuses = (STATUS_FIELD_MISTY_TERRAIN | STATUS_FIELD_TERRAIN_PERMANENT);
-            gBattleCommunication[MULTISTRING_CHOOSER] = B_MSG_TERRAIN_SET_MISTY;
-            BattleScriptPushCursorAndCallback(BattleScript_OverworldTerrain);
-            effect++;
-        }
-    break;
+        break;
     case ABILITYEFFECT_SWITCH_IN_WEATHER:
         gBattleScripting.battler = battler;
         if (!(gBattleTypeFlags & BATTLE_TYPE_RECORDED))

src/overworld.c

@@ -399,10 +399,14 @@ void Overworld_ResetStateAfterDigEscRope(void)
 }
 
 #if B_RESET_FLAGS_VARS_AFTER_WHITEOUT  == TRUE
-    void Overworld_ResetBattleFlagsAndVars(void)
+void Overworld_ResetBattleFlagsAndVars(void)
 {
-    #if VAR_TERRAIN != 0
-        VarSet(VAR_TERRAIN, 0);
+    #if B_VAR_TERRAIN != 0
+        VarSet(B_VAR_TERRAIN, 0);
+    #endif
+
+    #if B_VAR_TERRAIN_TIMER != 0
+        VarSet(B_VAR_TERRAIN_TIMER, 0);
     #endif
 
     #if B_VAR_WILD_AI_FLAGS != 0