feat(Core): add OnDisplayId hook (#12320)

src/server/game/Entities/Unit/Unit.cpp

@@ -16359,6 +16359,8 @@ void Unit::SetDisplayId(uint32 modelId)
     // Set Gender by modelId
     if (CreatureModelInfo const* minfo = sObjectMgr->GetCreatureModelInfo(modelId))
         SetByteValue(UNIT_FIELD_BYTES_0, 2, minfo->gender);
+
+    sScriptMgr->OnDisplayIdChange(this, modelId);
 }
 
 void Unit::RestoreDisplayId()

src/server/game/Scripting/ScriptDefines/UnitScript.cpp

@@ -210,3 +210,11 @@ void ScriptMgr::OnUnitUpdate(Unit* unit, uint32 diff)
         script->OnUnitUpdate(unit, diff);
     });
 }
+
+void ScriptMgr::OnDisplayIdChange(Unit* unit, uint32 displayId)
+{
+    ExecuteScript<UnitScript>([&](UnitScript* script)
+    {
+        script->OnDisplayIdChange(unit, displayId);
+    });
+}

src/server/game/Scripting/ScriptMgr.h

@@ -459,6 +459,8 @@ public:
      * @param diff Contains information about the diff time
      */
     virtual void OnUnitUpdate(Unit* /*unit*/, uint32 /*diff*/) { }
+
+    virtual void OnDisplayIdChange(Unit* /*unit*/, uint32 /*displayId*/) { }
 };
 
 class MovementHandlerScript : public ScriptObject
@@ -2400,6 +2402,7 @@ public: /* UnitScript */
     bool IsCustomBuildValuesUpdate(Unit const* unit, uint8 updateType, ByteBuffer& fieldBuffer, Player const* target, uint16 index);
     bool OnBuildValuesUpdate(Unit const* unit, uint8 updateType, ByteBuffer& fieldBuffer, Player* target, uint16 index);
     void OnUnitUpdate(Unit* unit, uint32 diff);
+    void OnDisplayIdChange(Unit* unit, uint32 displayId);
 
 public: /* MovementHandlerScript */
     void OnPlayerMove(Player* player, MovementInfo movementInfo, uint32 opcode);