Core/Movement: split SetCanFly for player and creature class and handle their part accordingly

src/server/game/Entities/Creature/Creature.cpp

@@ -1112,6 +1112,10 @@ bool Creature::SetDisableGravity(bool disable, bool packetOnly /*= false*/, bool
             SetAnimationTier(AnimationTier::Ground);
     }
 
+    WorldPacket data(disable ? SMSG_SPLINE_MOVE_GRAVITY_DISABLE : SMSG_SPLINE_MOVE_GRAVITY_ENABLE);
+    WriteMovementInfo(data);
+    SendMessageToSet(&data, false);
+
     return true;
 }
 
@@ -1133,6 +1137,16 @@ bool Creature::SetHover(bool enable, bool packetOnly /*= false*/, bool updateAni
     return true;
 }
 
+bool Creature::SetCanFly(bool enable, bool packetOnly /*= false*/)
+{
+    if (!Unit::SetCanFly(enable, packetOnly))
+        return false;
+
+    WorldPacket data(enable ? SMSG_SPLINE_MOVE_SET_FLYING : SMSG_SPLINE_MOVE_UNSET_FLYING);
+    WriteMovementInfo(data);
+    SendMessageToSet(&data, false);
+}
+
 void Creature::InitializeReactState()
 {
     if (IsTotem() || IsTrigger() || IsCritter() || IsSpiritService())

src/server/game/Entities/Creature/Creature.h

@@ -101,6 +101,7 @@ class TC_GAME_API Creature : public Unit, public GridObject<Creature>, public Ma
         bool CanHover() const { return GetMovementTemplate().IsHoverEnabled() || IsHovering(); }
         bool SetDisableGravity(bool disable, bool packetOnly = false, bool updateAnimationTier = true) override;
         bool SetHover(bool enable, bool packetOnly = false, bool updateAnimationTier = true) override;
+        bool SetCanFly(bool enable, bool packetOnly = false) override;
 
         bool IsDungeonBoss() const { return (GetCreatureTemplate()->flags_extra & CREATURE_FLAG_EXTRA_DUNGEON_BOSS) != 0; }
         bool IsAffectedByDiminishingReturns() const override { return Unit::IsAffectedByDiminishingReturns() || (GetCreatureTemplate()->flags_extra & CREATURE_FLAG_EXTRA_ALL_DIMINISH) != 0; }

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

@@ -13892,8 +13892,12 @@ void Unit::PurgeAndApplyPendingMovementChanges(bool informObservers /* = true */
             case MovementChangeType::SPEED_CHANGE_FLIGHT_SPEED:         moveType = MOVE_FLIGHT; break;
             case MovementChangeType::SPEED_CHANGE_FLIGHT_BACK_SPEED:    moveType = MOVE_FLIGHT_BACK; break;
             case MovementChangeType::RATE_CHANGE_PITCH:                 moveType = MOVE_PITCH_RATE; break;
-            case MovementChangeType::GRAVITY_DISABLE: break;
-            case MovementChangeType::SET_CAN_FLY: break;
+            case MovementChangeType::GRAVITY_DISABLE:
+                Unit::SetDisableGravity(pendingChange.second.apply);
+                break;
+            case MovementChangeType::SET_CAN_FLY:
+                Unit::SetCanFly(pendingChange.second.apply);
+                break;
             default:
                 ASSERT(false);
                 return;
@@ -13907,6 +13911,18 @@ void Unit::PurgeAndApplyPendingMovementChanges(bool informObservers /* = true */
             if (informObservers)
                 MovementPacketSender::SendSpeedChangeToObservers(this, *moveType, speedFlat);
         }
+        else if (informObservers)
+        {
+            switch (changeType)
+            {
+                case MovementChangeType::GRAVITY_DISABLE:
+                case MovementChangeType::SET_CAN_FLY:
+                    MovementPacketSender::SendMovementFlagChangeToObservers(this);
+                    break;
+                default:
+                    break;
+            }
+        }
     }
 
     m_pendingMovementChanges.clear();
@@ -14199,14 +14215,6 @@ bool Unit::SetDisableGravity(bool disable, bool packetOnly /*= false*/, bool /*u
         }
     }
 
-    WorldPacket data;
-    if (disable)
-        data.Initialize(IsMovedByClient() ? SMSG_MOVE_GRAVITY_DISABLE : SMSG_SPLINE_MOVE_GRAVITY_DISABLE);
-    else
-        data.Initialize(IsMovedByClient() ? SMSG_MOVE_GRAVITY_ENABLE : SMSG_SPLINE_MOVE_GRAVITY_ENABLE);
-
-    WriteMovementInfo(data);
-
     return true;
 }
 
@@ -14269,16 +14277,6 @@ bool Unit::SetCanFly(bool enable, bool packetOnly)
             if (GetTypeId() == TYPEID_PLAYER)
                 RemoveExtraUnitMovementFlag(MOVEMENTFLAG2_CAN_SWIM_TO_FLY_TRANS);
         }
-
-        if (Player* player = ToPlayer())
-            player->SendMovementSetCanTransitionBetweenSwimAndFly(enable);
-    }
-
-    if (IsCreature())
-    {
-        WorldPacket data(enable ? SMSG_SPLINE_MOVE_SET_FLYING : SMSG_SPLINE_MOVE_UNSET_FLYING);
-        WriteMovementInfo(data);
-        SendMessageToSet(&data, false);
     }
 
     return true;