21 files changed, 366 insertions, 212 deletions

diff --git a/src/Bindings/CMakeLists.txt b/src/Bindings/CMakeLists.txt
index b1a19beca..17f2bdf39 100644
--- a/src/Bindings/CMakeLists.txt
+++ b/src/Bindings/CMakeLists.txt
@@ -164,7 +164,8 @@ set_source_files_properties(${BINDING_OUTPUTS} PROPERTIES GENERATED TRUE)
 set_source_files_properties(${CMAKE_SOURCE_DIR}/src/Bindings/Bindings.cpp PROPERTIES COMPILE_FLAGS -Wno-error)
 
 if(CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
-	set_source_files_properties(Bindings.cpp PROPERTIES COMPILE_FLAGS "-Wno-old-style-cast -Wno-missing-prototypes")
+	set_source_files_properties(Bindings.cpp PROPERTIES COMPILE_FLAGS
+		"-Wno-old-style-cast -Wno-missing-prototypes -Wno-deprecated-declarations")
 endif()
 
 if(NOT MSVC)
diff --git a/src/ClientHandle.cpp b/src/ClientHandle.cpp
index 49a882c77..ce6d4c981 100644
--- a/src/ClientHandle.cpp
+++ b/src/ClientHandle.cpp
@@ -189,7 +189,7 @@ void cClientHandle::Destroy(void)
 				// If ownership was transferred, our own smart pointer should be unset
 				ASSERT(!m_PlayerPtr);
 
-				m_PlayerPtr = world->RemovePlayer(*player, true);
+				m_PlayerPtr = world->RemovePlayer(*player);
 
 				// And RemovePlayer should have returned a valid smart pointer
 				ASSERT(m_PlayerPtr);
diff --git a/src/Entities/Boat.cpp b/src/Entities/Boat.cpp
index c05e67275..c88df4952 100644
--- a/src/Entities/Boat.cpp
+++ b/src/Entities/Boat.cpp
@@ -60,7 +60,7 @@ bool cBoat::DoTakeDamage(TakeDamageInfo & TDI)
 				m_World->SpawnItemPickups(Pickups, GetPosX(), GetPosY(), GetPosZ(), 0, 0, 0, true);
 			}
 		}
-		Destroy(true);
+		Destroy();
 	}
 	return true;
 }
diff --git a/src/Entities/Entity.cpp b/src/Entities/Entity.cpp
index 57a4680bd..44808e2a5 100644
--- a/src/Entities/Entity.cpp
+++ b/src/Entities/Entity.cpp
@@ -47,7 +47,6 @@ cEntity::cEntity(eEntityType a_EntityType, Vector3d a_Pos, double a_Width, doubl
 	m_LastPosition(a_Pos),
 	m_EntityType(a_EntityType),
 	m_World(nullptr),
-	m_IsWorldChangeScheduled(false),
 	m_IsFireproof(false),
 	m_TicksSinceLastBurnDamage(0),
 	m_TicksSinceLastLavaDamage(0),
@@ -158,19 +157,29 @@ bool cEntity::Initialize(OwnedEntity a_Self, cWorld & a_EntityWorld)
 
 	cPluginManager::Get()->CallHookSpawnedEntity(a_EntityWorld, *this);
 
+	return true;
+}
+
+
+
+
+
+void cEntity::OnAddToWorld(cWorld & a_World)
+{
 	// Spawn the entity on the clients:
-	a_EntityWorld.BroadcastSpawnEntity(*this);
+	m_LastSentPosition = GetPosition();
+	a_World.BroadcastSpawnEntity(*this);
+	BroadcastLeashedMobs();
+}
 
-	// If has any mob leashed broadcast every leashed entity to this
-	if (HasAnyMobLeashed())
-	{
-		for (auto LeashedMob : m_LeashedMobs)
-		{
-			m_World->BroadcastLeashEntity(*LeashedMob, *this);
-		}
-	}
 
-	return true;
+
+
+
+void cEntity::OnRemoveFromWorld(cWorld & a_World)
+{
+	RemoveAllLeashedMobs();
+	a_World.BroadcastDestroyEntity(*this);
 }
 
 
@@ -216,7 +225,7 @@ void cEntity::SetParentChunk(cChunk * a_Chunk)
 
 
 
-void cEntity::Destroy(bool a_ShouldBroadcast)
+void cEntity::Destroy()
 {
 	SetIsTicking(false);
 
@@ -226,11 +235,6 @@ void cEntity::Destroy(bool a_ShouldBroadcast)
 		m_LeashedMobs.front()->Unleash(true, true);
 	}
 
-	if (a_ShouldBroadcast)
-	{
-		m_World->BroadcastDestroyEntity(*this);
-	}
-
 	auto ParentChunkCoords = cChunkDef::BlockToChunk(GetPosition());
 	m_World->QueueTask([this, ParentChunkCoords](cWorld & a_World)
 	{
@@ -1166,7 +1170,7 @@ void cEntity::ApplyFriction(Vector3d & a_Speed, double a_SlowdownMultiplier, flo
 void cEntity::TickBurning(cChunk & a_Chunk)
 {
 	// If we're about to change worlds, then we can't accurately determine whether we're in lava (#3939)
-	if (m_IsWorldChangeScheduled)
+	if (IsWorldChangeScheduled())
 	{
 		return;
 	}
@@ -1310,34 +1314,11 @@ void cEntity::DetectCacti(void)
 
 
 
-void cEntity::ScheduleMoveToWorld(cWorld * a_World, Vector3d a_NewPosition, bool a_SetPortalCooldown, bool a_ShouldSendRespawn)
-{
-	m_NewWorld = a_World;
-	m_NewWorldPosition = a_NewPosition;
-	m_IsWorldChangeScheduled = true;
-	m_WorldChangeSetPortalCooldown = a_SetPortalCooldown;
-	m_WorldChangeSendRespawn = a_ShouldSendRespawn;
-}
-
-
-
-
-
 bool cEntity::DetectPortal()
 {
-	// If somebody scheduled a world change with ScheduleMoveToWorld, change worlds now.
-	if (m_IsWorldChangeScheduled)
+	// If somebody scheduled a world change, do nothing.
+	if (IsWorldChangeScheduled())
 	{
-		m_IsWorldChangeScheduled = false;
-
-		if (m_WorldChangeSetPortalCooldown)
-		{
-			// Delay the portal check.
-			m_PortalCooldownData.m_TicksDelayed = 0;
-			m_PortalCooldownData.m_ShouldPreventTeleportation = true;
-		}
-
-		MoveToWorld(m_NewWorld, m_WorldChangeSendRespawn, m_NewWorldPosition);
 		return true;
 	}
 
@@ -1519,69 +1500,81 @@ bool cEntity::DetectPortal()
 
 
 
-bool cEntity::DoMoveToWorld(cWorld * a_World, bool a_ShouldSendRespawn, Vector3d a_NewPosition)
+void cEntity::DoMoveToWorld(const sWorldChangeInfo & a_WorldChangeInfo)
 {
-	UNUSED(a_ShouldSendRespawn);
-	ASSERT(a_World != nullptr);
+	ASSERT(a_WorldChangeInfo.m_NewWorld != nullptr);
 
-	if (GetWorld() == a_World)
+	if (a_WorldChangeInfo.m_SetPortalCooldown)
 	{
-		// Don't move to same world
-		return false;
+		m_PortalCooldownData.m_TicksDelayed = 0;
+		m_PortalCooldownData.m_ShouldPreventTeleportation = true;
 	}
 
-	//  Ask the plugins if the entity is allowed to changing the world
-	if (cRoot::Get()->GetPluginManager()->CallHookEntityChangingWorld(*this, *a_World))
+	if (GetWorld() == a_WorldChangeInfo.m_NewWorld)
 	{
-		// A Plugin doesn't allow the entity to changing the world
-		return false;
+		// Moving to same world, don't need to remove from world
+		SetPosition(a_WorldChangeInfo.m_NewPosition);
+		return;
 	}
 
+	LOGD("Warping entity #%i (%s) from world \"%s\" to \"%s\". Source chunk: (%d, %d) ",
+		GetUniqueID(), GetClass(),
+		m_World->GetName(), a_WorldChangeInfo.m_NewWorld->GetName(),
+		GetChunkX(), GetChunkZ()
+	);
+
 	// Stop ticking, in preperation for detaching from this world.
 	SetIsTicking(false);
 
-	// Tell others we are gone
-	GetWorld()->BroadcastDestroyEntity(*this);
+	// Remove from the old world
+	auto Self = m_World->RemoveEntity(*this);
 
-	// Take note of old chunk coords
-	auto OldChunkCoords = cChunkDef::BlockToChunk(GetPosition());
+	// Update entity before calling hook
+	ResetPosition(a_WorldChangeInfo.m_NewPosition);
+	SetWorld(a_WorldChangeInfo.m_NewWorld);
 
-	// Set position to the new position
-	ResetPosition(a_NewPosition);
+	cRoot::Get()->GetPluginManager()->CallHookEntityChangedWorld(*this, *m_World);
 
-	// Stop all mobs from targeting this entity
-	// Stop this entity from targeting other mobs
-	if (this->IsMob())
-	{
-		cMonster * Monster = static_cast<cMonster*>(this);
-		Monster->SetTarget(nullptr);
-		Monster->StopEveryoneFromTargetingMe();
-	}
-
-	// Queue add to new world and removal from the old one
-	cWorld * OldWorld = GetWorld();
-	SetWorld(a_World);  // Chunks may be streamed before cWorld::AddPlayer() sets the world to the new value
-	OldWorld->QueueTask([this, OldChunkCoords, a_World](cWorld & a_OldWorld)
-	{
-		LOGD("Warping entity #%i (%s) from world \"%s\" to \"%s\". Source chunk: (%d, %d) ",
-			this->GetUniqueID(), this->GetClass(),
-			a_OldWorld.GetName().c_str(), a_World->GetName().c_str(),
-			OldChunkCoords.m_ChunkX, OldChunkCoords.m_ChunkZ
-		);
-		UNUSED(OldChunkCoords);  // Non Debug mode only
-		a_World->AddEntity(a_OldWorld.RemoveEntity(*this));
-		cRoot::Get()->GetPluginManager()->CallHookEntityChangedWorld(*this, a_OldWorld);
-	});
-	return true;
+	// Don't do anything after adding as the old world's CS no longer protects us
+	a_WorldChangeInfo.m_NewWorld->AddEntity(std::move(Self));
 }
 
 
 
 
 
-bool cEntity::MoveToWorld(cWorld * a_World, bool a_ShouldSendRespawn, Vector3d a_NewPosition)
+bool cEntity::MoveToWorld(cWorld * a_World, Vector3d a_NewPosition, bool a_SetPortalCooldown, bool a_ShouldSendRespawn)
 {
-	return DoMoveToWorld(a_World, a_ShouldSendRespawn, a_NewPosition);
+	ASSERT(a_World != nullptr);
+
+	// Ask the plugins if the entity is allowed to change world
+	if (cRoot::Get()->GetPluginManager()->CallHookEntityChangingWorld(*this, *a_World))
+	{
+		// A Plugin isn't allowing the entity to change world
+		return false;
+	}
+
+	// Create new world change info
+	auto NewWCI = cpp14::make_unique<sWorldChangeInfo>();
+	*NewWCI = { a_World,  a_NewPosition, a_SetPortalCooldown, a_ShouldSendRespawn };
+
+	// Publish atomically
+	auto OldWCI = m_WorldChangeInfo.exchange(std::move(NewWCI));
+
+	if (OldWCI == nullptr)
+	{
+		// Schedule a new world change.
+		GetWorld()->QueueTask(
+			[this](cWorld & a_CurWorld)
+			{
+				auto WCI = m_WorldChangeInfo.exchange(nullptr);
+				cWorld::cLock Lock(a_CurWorld);
+				DoMoveToWorld(*WCI);
+			}
+		);
+	}
+
+	return true;
 }
 
 
@@ -1606,7 +1599,7 @@ bool cEntity::MoveToWorld(const AString & a_WorldName, bool a_ShouldSendRespawn)
 		return false;
 	}
 
-	return DoMoveToWorld(World, a_ShouldSendRespawn, Vector3d(World->GetSpawnX(), World->GetSpawnY(), World->GetSpawnZ()));
+	return MoveToWorld(World, Vector3d(World->GetSpawnX(), World->GetSpawnY(), World->GetSpawnZ()), false, a_ShouldSendRespawn);
 }
 
 
@@ -2253,6 +2246,34 @@ void cEntity::RemoveLeashedMob(cMonster * a_Monster)
 
 
 
+void cEntity::RemoveAllLeashedMobs()
+{
+	while (!m_LeashedMobs.empty())
+	{
+		m_LeashedMobs.front()->Unleash(false, true);
+	}
+}
+
+
+
+
+
+void cEntity::BroadcastLeashedMobs()
+{
+	// If has any mob leashed broadcast every leashed entity to this
+	if (HasAnyMobLeashed())
+	{
+		for (auto LeashedMob : m_LeashedMobs)
+		{
+			m_World->BroadcastLeashEntity(*LeashedMob, *this);
+		}
+	}
+}
+
+
+
+
+
 float cEntity::GetExplosionExposureRate(Vector3d a_ExplosionPosition, float a_ExlosionPower)
 {
 	double EntitySize = m_Width * m_Width * m_Height;
diff --git a/src/Entities/Entity.h b/src/Entities/Entity.h
index 2805ee9e0..b151f745d 100644
--- a/src/Entities/Entity.h
+++ b/src/Entities/Entity.h
@@ -2,6 +2,7 @@
 #pragma once
 
 #include "../Item.h"
+#include "../OSSupport/AtomicUniquePtr.h"
 
 
 
@@ -72,6 +73,16 @@ struct TakeDamageInfo
 // tolua_begin
 class cEntity
 {
+protected:
+	/** State variables for MoveToWorld. */
+	struct sWorldChangeInfo
+	{
+		cWorld * m_NewWorld;
+		Vector3d m_NewPosition;
+		bool m_SetPortalCooldown;
+		bool m_SendRespawn;
+	};
+
 public:
 
 	enum eEntityType
@@ -163,6 +174,16 @@ public:
 	Adds the entity to the world. */
 	virtual bool Initialize(OwnedEntity a_Self, cWorld & a_EntityWorld);
 
+	/** Called when the entity is added to a world.
+	e.g after first spawning or after successfuly moving between worlds.
+	\param a_World The world being added to. */
+	virtual void OnAddToWorld(cWorld & a_World);
+
+	/** Called when the entity is removed from a world.
+	e.g. When the entity is destroyed or moved to a different world.
+	\param a_World The world being removed from. */
+	virtual void OnRemoveFromWorld(cWorld & a_World);
+
 	// tolua_begin
 
 	eEntityType GetEntityType(void) const { return m_EntityType; }
@@ -268,8 +289,14 @@ public:
 	If this returns false, you must stop using the cEntity pointer you have. */
 	bool IsTicking(void) const;
 
-	/** Destroys the entity and schedules it for memory freeing; if a_ShouldBroadcast is set to true, broadcasts the DestroyEntity packet */
-	virtual void Destroy(bool a_ShouldBroadcast = true);
+	/** Destroys the entity, schedules it for memory freeing and broadcasts the DestroyEntity packet */
+	virtual void Destroy();
+
+	OBSOLETE void Destroy(bool a_ShouldBroadcast)
+	{
+		LOGWARNING("cEntity:Destory(bool) is deprecated, use cEntity:Destroy() instead.");
+		Destroy();
+	}
 
 	/** Makes this pawn take damage from an attack by a_Attacker. Damage values are calculated automatically and DoTakeDamage() called */
 	void TakeDamage(cEntity & a_Attacker);
@@ -442,9 +469,18 @@ public:
 	virtual void TeleportToCoords(double a_PosX, double a_PosY, double a_PosZ);
 
 	/** Schedules a MoveToWorld call to occur on the next Tick of the entity */
-	void ScheduleMoveToWorld(cWorld * a_World, Vector3d a_NewPosition, bool a_ShouldSetPortalCooldown = false, bool a_ShouldSendRespawn = false);
+	OBSOLETE void ScheduleMoveToWorld(cWorld * a_World, Vector3d a_NewPosition, bool a_ShouldSetPortalCooldown = false, bool a_ShouldSendRespawn = false)
+	{
+		LOGWARNING("ScheduleMoveToWorld is deprecated, use MoveToWorld instead");
+		MoveToWorld(a_World, a_NewPosition, a_ShouldSetPortalCooldown, a_ShouldSendRespawn);
+	}
+
+	bool MoveToWorld(cWorld * a_World, Vector3d a_NewPosition, bool a_ShouldSetPortalCooldown = false, bool a_ShouldSendRespawn = false);
 
-	bool MoveToWorld(cWorld * a_World, bool a_ShouldSendRespawn, Vector3d a_NewPosition);
+	bool MoveToWorld(cWorld * a_World, bool a_ShouldSendRespawn, Vector3d a_NewPosition)
+	{
+		return MoveToWorld(a_World, a_NewPosition, false, a_ShouldSendRespawn);
+	}
 
 	/** Moves entity to specified world, taking a world pointer */
 	bool MoveToWorld(cWorld * a_World, bool a_ShouldSendRespawn = true);
@@ -454,7 +490,11 @@ public:
 
 	// tolua_end
 
-	virtual bool DoMoveToWorld(cWorld * a_World, bool a_ShouldSendRespawn, Vector3d a_NewPosition);
+	/** Returns true if a world change is scheduled to happen. */
+	bool IsWorldChangeScheduled() const
+	{
+		return (m_WorldChangeInfo.load() != nullptr);
+	}
 
 	/** Updates clients of changes in the entity. */
 	virtual void BroadcastMovementUpdate(const cClientHandle * a_Exclude = nullptr);
@@ -543,13 +583,16 @@ public:
 	/** Set the entity's status to either ticking or not ticking. */
 	void SetIsTicking(bool a_IsTicking);
 
-	/** Adds a mob to the leashed list of mobs */
+	/** Adds a mob to the leashed list of mobs. */
 	void AddLeashedMob(cMonster * a_Monster);
 
-	/** Removes a mob from the leashed list of mobs */
+	/** Removes a mob from the leashed list of mobs. */
 	void RemoveLeashedMob(cMonster * a_Monster);
 
-	/** Returs whether the entity has any mob leashed to */
+	/** Removes all mobs from the leashed list of mobs. */
+	void RemoveAllLeashedMobs();
+
+	/** Returs whether the entity has any mob leashed to it. */
 	bool HasAnyMobLeashed() const { return m_LeashedMobs.size() > 0; }
 
 	/** a lightweight calculation approach to get explosion exposure rate
@@ -619,12 +662,8 @@ protected:
 
 	cWorld * m_World;
 
-	/** State variables for ScheduleMoveToWorld. */
-	bool m_IsWorldChangeScheduled;
-	bool m_WorldChangeSetPortalCooldown;
-	bool m_WorldChangeSendRespawn;
-	cWorld * m_NewWorld;
-	Vector3d m_NewWorldPosition;
+	/** If not nullptr, a world change is scheduled and a task is queued in the current world. */
+	cAtomicUniquePtr<sWorldChangeInfo> m_WorldChangeInfo;
 
 	/** Whether the entity is capable of taking fire or lava damage. */
 	bool m_IsFireproof;
@@ -671,6 +710,10 @@ protected:
 	overrides can provide further processing, such as forcing players to move at the given speed. */
 	virtual void DoSetSpeed(double a_SpeedX, double a_SpeedY, double a_SpeedZ);
 
+	/** Handles the moving of this entity between worlds.
+	Should handle degenerate cases such as moving to the same world. */
+	virtual void DoMoveToWorld(const sWorldChangeInfo & a_WorldChangeInfo);
+
 	virtual void Destroyed(void) {}  // Called after the entity has been destroyed
 
 	/** Applies friction to an entity
@@ -689,6 +732,8 @@ protected:
 	Only to be used when the caller will broadcast a teleport or equivalent to clients. */
 	virtual void ResetPosition(Vector3d a_NewPos);
 
+	/** If has any mobs are leashed, broadcasts every leashed entity to this. */
+	void BroadcastLeashedMobs();
 
 private:
 
diff --git a/src/Entities/ExpOrb.cpp b/src/Entities/ExpOrb.cpp
index ad6f6e97d..3d0c9e2b8 100644
--- a/src/Entities/ExpOrb.cpp
+++ b/src/Entities/ExpOrb.cpp
@@ -49,7 +49,7 @@ void cExpOrb::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 			a_Player.DeltaExperience(m_Reward);
 
 			m_World->BroadcastSoundEffect("entity.experience_orb.pickup", GetPosition(), 0.5f, (0.75f + (static_cast<float>((GetUniqueID() * 23) % 32)) / 64));
-			Destroy(true);
+			Destroy();
 			return true;
 		}
 
@@ -84,7 +84,7 @@ void cExpOrb::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 	m_Timer += a_Dt;
 	if (m_Timer >= std::chrono::minutes(5))
 	{
-		Destroy(true);
+		Destroy();
 	}
 }
 
@@ -96,7 +96,7 @@ bool cExpOrb::DoTakeDamage(TakeDamageInfo & a_TDI)
 {
 	if (a_TDI.DamageType == dtCactusContact)
 	{
-		Destroy(true);
+		Destroy();
 		return true;
 	}
 
diff --git a/src/Entities/FallingBlock.cpp b/src/Entities/FallingBlock.cpp
index 55b9e81e1..132acd09a 100644
--- a/src/Entities/FallingBlock.cpp
+++ b/src/Entities/FallingBlock.cpp
@@ -46,7 +46,7 @@ void cFallingBlock::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 		// Fallen out of this world, just continue falling until out of sight, then destroy:
 		if (BlockY < VOID_BOUNDARY)
 		{
-			Destroy(true);
+			Destroy();
 		}
 		return;
 	}
@@ -64,7 +64,7 @@ void cFallingBlock::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 		// Fallen onto a block that breaks this into pickups (e. g. half-slab)
 		// Must finish the fall with coords one below the block:
 		cSandSimulator::FinishFalling(m_World, BlockX, BlockY, BlockZ, m_BlockType, m_BlockMeta);
-		Destroy(true);
+		Destroy();
 		return;
 	}
 	else if (!cSandSimulator::CanContinueFallThrough(BlockBelow))
@@ -83,14 +83,14 @@ void cFallingBlock::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 		{
 			cSandSimulator::FinishFalling(m_World, BlockX, BlockY + 1, BlockZ, m_BlockType, m_BlockMeta);
 		}
-		Destroy(true);
+		Destroy();
 		return;
 	}
 	else if ((m_BlockType == E_BLOCK_CONCRETE_POWDER) && IsBlockWater(BlockBelow))
 	{
 		// Concrete powder falling into water solidifies on the first water it touches
 		cSandSimulator::FinishFalling(m_World, BlockX, BlockY, BlockZ, E_BLOCK_CONCRETE, m_BlockMeta);
-		Destroy(true);
+		Destroy();
 		return;
 	}
 
diff --git a/src/Entities/Floater.cpp b/src/Entities/Floater.cpp
index c9cc526a7..7b0314ae5 100644
--- a/src/Entities/Floater.cpp
+++ b/src/Entities/Floater.cpp
@@ -179,7 +179,7 @@ void cFloater::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 
 	if (!m_World->DoWithEntityByID(m_PlayerID, [](cEntity &) { return true; }))  // The owner doesn't exist anymore. Destroy the floater entity.
 	{
-		Destroy(true);
+		Destroy();
 	}
 
 	if (m_AttachedMobID != cEntity::INVALID_ID)
diff --git a/src/Entities/Pickup.cpp b/src/Entities/Pickup.cpp
index be64e9e2f..679e9d5ff 100644
--- a/src/Entities/Pickup.cpp
+++ b/src/Entities/Pickup.cpp
@@ -156,7 +156,7 @@ void cPickup::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 				m_Timer += a_Dt;  // In case we have to destroy the pickup in the same tick.
 				if (m_Timer > std::chrono::milliseconds(500))
 				{
-					Destroy(true);
+					Destroy();
 					return;
 				}
 			}
@@ -180,14 +180,14 @@ void cPickup::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 	{
 		if (m_Timer > std::chrono::milliseconds(500))  // 0.5 second
 		{
-			Destroy(true);
+			Destroy();
 			return;
 		}
 	}
 
 	if (m_Timer > m_Lifetime)
 	{
-		Destroy(true);
+		Destroy();
 		return;
 	}
 }
@@ -200,7 +200,7 @@ bool cPickup::DoTakeDamage(TakeDamageInfo & a_TDI)
 {
 	if (a_TDI.DamageType == dtCactusContact)
 	{
-		Destroy(true);
+		Destroy();
 		return true;
 	}
 
diff --git a/src/Entities/Player.cpp b/src/Entities/Player.cpp
index e7b6ade15..421eddbd5 100644
--- a/src/Entities/Player.cpp
+++ b/src/Entities/Player.cpp
@@ -193,9 +193,6 @@ bool cPlayer::Initialize(OwnedEntity a_Self, cWorld & a_World)
 
 	cPluginManager::Get()->CallHookSpawnedEntity(*GetWorld(), *this);
 
-	// Spawn the entity on the clients:
-	GetWorld()->BroadcastSpawnEntity(*this);
-
 	return true;
 }
 
@@ -243,6 +240,9 @@ void cPlayer::SpawnOn(cClientHandle & a_Client)
 	{
 		return;
 	}
+
+	LOGD("Spawing %s on %s", GetName().c_str(), a_Client.GetUsername().c_str());
+
 	a_Client.SendPlayerSpawn(*this);
 	a_Client.SendEntityHeadLook(*this);
 	a_Client.SendEntityEquipment(*this, 0, m_Inventory.GetEquippedItem());
@@ -1225,7 +1225,7 @@ void cPlayer::Respawn(void)
 
 	if (GetWorld() != m_SpawnWorld)
 	{
-		ScheduleMoveToWorld(m_SpawnWorld, GetLastBedPos(), false);
+		MoveToWorld(m_SpawnWorld, GetLastBedPos(), false);
 	}
 	else
 	{
@@ -2003,92 +2003,70 @@ void cPlayer::TossItems(const cItems & a_Items)
 
 
 
-bool cPlayer::DoMoveToWorld(cWorld * a_World, bool a_ShouldSendRespawn, Vector3d a_NewPosition)
+void cPlayer::DoMoveToWorld(const cEntity::sWorldChangeInfo & a_WorldChangeInfo)
 {
-	ASSERT(a_World != nullptr);
-	ASSERT(IsTicking());
+	ASSERT(a_WorldChangeInfo.m_NewWorld != nullptr);
 
-	if (GetWorld() == a_World)
+	// Reset portal cooldown
+	if (a_WorldChangeInfo.m_SetPortalCooldown)
 	{
-		// Don't move to same world
-		return false;
+		m_PortalCooldownData.m_TicksDelayed = 0;
+		m_PortalCooldownData.m_ShouldPreventTeleportation = true;
 	}
 
-	//  Ask the plugins if the player is allowed to change the world
-	if (cRoot::Get()->GetPluginManager()->CallHookEntityChangingWorld(*this, *a_World))
+	if (m_World == a_WorldChangeInfo.m_NewWorld)
 	{
-		// A Plugin doesn't allow the player to change the world
-		return false;
+		// Moving to same world, don't need to remove from world
+		SetPosition(a_WorldChangeInfo.m_NewPosition);
+		return;
 	}
 
-	GetWorld()->QueueTask([this, a_World, a_ShouldSendRespawn, a_NewPosition](cWorld & a_OldWorld)
-	{
-		// The clienthandle caches the coords of the chunk we're standing at. Invalidate this.
-		GetClientHandle()->InvalidateCachedSentChunk();
-
-		// Prevent further ticking in this world
-		SetIsTicking(false);
+	LOGD("Warping player \"%s\" from world \"%s\" to \"%s\". Source chunk: (%d, %d) ",
+		GetName(), GetWorld()->GetName(), a_WorldChangeInfo.m_NewWorld->GetName(),
+		GetChunkX(), GetChunkZ()
+	);
 
-		// Tell others we are gone
-		GetWorld()->BroadcastDestroyEntity(*this);
+	// Stop all mobs from targeting this player
+	StopEveryoneFromTargetingMe();
 
-		// Remove player from world
-		// Make sure that RemovePlayer didn't return a valid smart pointer, due to the second parameter being false
-		// We remain valid and not destructed after this call
-		VERIFY(!GetWorld()->RemovePlayer(*this, false));
+	// Prevent further ticking in this world
+	SetIsTicking(false);
 
-		// Set position to the new position
-		ResetPosition(a_NewPosition);
-		FreezeInternal(a_NewPosition, false);
+	// Remove from the old world
+	auto & OldWorld = *GetWorld();
+	auto Self = OldWorld.RemovePlayer(*this);
 
-		// Stop all mobs from targeting this player
-		StopEveryoneFromTargetingMe();
+	ResetPosition(a_WorldChangeInfo.m_NewPosition);
+	FreezeInternal(a_WorldChangeInfo.m_NewPosition, false);
+	SetWorld(a_WorldChangeInfo.m_NewWorld);  // Chunks may be streamed before cWorld::AddPlayer() sets the world to the new value
 
-		// Deal with new world
-		SetWorld(a_World);
+	// Set capabilities based on new world
+	SetCapabilities();
 
-		// Set capabilities based on new world
-		SetCapabilities();
+	cClientHandle * ch = GetClientHandle();
+	if (ch != nullptr)
+	{
+		// The clienthandle caches the coords of the chunk we're standing at. Invalidate this.
+		ch->InvalidateCachedSentChunk();
 
-		cClientHandle * ch = this->GetClientHandle();
-		if (ch != nullptr)
+		// Send the respawn packet:
+		if (a_WorldChangeInfo.m_SendRespawn)
 		{
-			// Send the respawn packet:
-			if (a_ShouldSendRespawn)
-			{
-				m_ClientHandle->SendRespawn(a_World->GetDimension());
-			}
-
-			// Update the view distance.
-			ch->SetViewDistance(m_ClientHandle->GetRequestedViewDistance());
-
-			// Send current weather of target world to player
-			if (a_World->GetDimension() == dimOverworld)
-			{
-				ch->SendWeather(a_World->GetWeather());
-			}
+			ch->SendRespawn(a_WorldChangeInfo.m_NewWorld->GetDimension());
 		}
 
-		// Broadcast the player into the new world.
-		a_World->BroadcastSpawnEntity(*this);
-
-		// Queue add to new world and removal from the old one
+		// Update the view distance.
+		ch->SetViewDistance(ch->GetRequestedViewDistance());
 
-		// Chunks may be streamed before cWorld::AddPlayer() sets the world to the new value
-		cChunk * ParentChunk = this->GetParentChunk();
-
-		LOGD("Warping player \"%s\" from world \"%s\" to \"%s\". Source chunk: (%d, %d) ",
-			this->GetName().c_str(),
-			a_OldWorld.GetName().c_str(), a_World->GetName().c_str(),
-			ParentChunk->GetPosX(), ParentChunk->GetPosZ()
-		);
-
-		// New world will take over and announce client at its next tick
-		auto PlayerPtr = static_cast<cPlayer *>(ParentChunk->RemoveEntity(*this).release());
-		a_World->AddPlayer(std::unique_ptr<cPlayer>(PlayerPtr), &a_OldWorld);
-	});
+		// Send current weather of target world to player
+		if (a_WorldChangeInfo.m_NewWorld->GetDimension() == dimOverworld)
+		{
+			ch->SendWeather(a_WorldChangeInfo.m_NewWorld->GetWeather());
+		}
+	}
 
-	return true;
+	// New world will take over and announce client at its next tick
+	a_WorldChangeInfo.m_NewWorld->AddPlayer(std::move(Self), &OldWorld);
 }
 
 
@@ -2515,7 +2493,7 @@ void cPlayer::HandleFloater()
 	}
 	m_World->DoWithEntityByID(m_FloaterID, [](cEntity & a_Entity)
 		{
-			a_Entity.Destroy(true);
+			a_Entity.Destroy();
 			return true;
 		}
 	);
diff --git a/src/Entities/Player.h b/src/Entities/Player.h
index c9249b2f1..1ce2c5d9d 100644
--- a/src/Entities/Player.h
+++ b/src/Entities/Player.h
@@ -387,10 +387,6 @@ public:
 	void SetVisible( bool a_bVisible);  // tolua_export
 	bool IsVisible(void) const { return m_bVisible; }  // tolua_export
 
-	/** Moves the player to the specified world.
-	Returns true if successful, false on failure (world not found). */
-	virtual bool DoMoveToWorld(cWorld * a_World, bool a_ShouldSendRespawn, Vector3d a_NewPosition) override;
-
 	/** Saves all player data, such as inventory, to JSON */
 	bool SaveToDisk(void);
 
@@ -735,6 +731,8 @@ protected:
 	/** The main hand of the player */
 	eMainHand m_MainHand;
 
+	virtual void DoMoveToWorld(const cEntity::sWorldChangeInfo & a_WorldChangeInfo) override;
+
 	/** Sets the speed and sends it to the client, so that they are forced to move so. */
 	virtual void DoSetSpeed(double a_SpeedX, double a_SpeedY, double a_SpeedZ) override;
 
diff --git a/src/Entities/TNTEntity.cpp b/src/Entities/TNTEntity.cpp
index c76b09119..fa17296cf 100644
--- a/src/Entities/TNTEntity.cpp
+++ b/src/Entities/TNTEntity.cpp
@@ -34,7 +34,7 @@ void cTNTEntity::SpawnOn(cClientHandle & a_ClientHandle)
 void cTNTEntity::Explode(void)
 {
 	m_FuseTicks = 0;
-	Destroy(true);
+	Destroy();
 	FLOGD("BOOM at {0}", GetPosition());
 	m_World->DoExplosionAt(4.0, GetPosX() + 0.49, GetPosY() + 0.49, GetPosZ() + 0.49, true, esPrimedTNT, this);
 }
diff --git a/src/Entities/WitherSkullEntity.cpp b/src/Entities/WitherSkullEntity.cpp
index 65e055e59..55f1ff32f 100644
--- a/src/Entities/WitherSkullEntity.cpp
+++ b/src/Entities/WitherSkullEntity.cpp
@@ -43,7 +43,7 @@ void cWitherSkullEntity::OnHitEntity(cEntity & a_EntityHit, Vector3d a_HitPos)
 	// TODO: Explode
 	// TODO: Apply wither effect to entity and others nearby
 
-	Destroy(true);
+	Destroy();
 }
 
 
diff --git a/src/Items/ItemFishingRod.h b/src/Items/ItemFishingRod.h
index 60e0617d6..2d42411e3 100644
--- a/src/Items/ItemFishingRod.h
+++ b/src/Items/ItemFishingRod.h
@@ -28,7 +28,7 @@ public:
 		m_Pos = Floater.GetPosition();
 		m_BitePos = Floater.GetBitePos();
 		m_AttachedMobID = Floater.GetAttachedMobID();
-		Floater.Destroy(true);
+		Floater.Destroy();
 		return true;
 	}
 
diff --git a/src/Mobs/Monster.cpp b/src/Mobs/Monster.cpp
index dfcd0dd6a..09f937564 100644
--- a/src/Mobs/Monster.cpp
+++ b/src/Mobs/Monster.cpp
@@ -132,12 +132,12 @@ cMonster::~cMonster()
 
 
 
-void cMonster::Destroy(bool a_ShouldBroadcast)
+void cMonster::OnRemoveFromWorld(cWorld & a_World)
 {
 	if (IsLeashed())
 	{
 		cEntity * LeashedTo = GetLeashedTo();
-		Unleash(false, a_ShouldBroadcast);
+		Unleash(false, true);
 
 		// Remove leash knot if there are no more mobs leashed to
 		if (!LeashedTo->HasAnyMobLeashed() && LeashedTo->IsLeashKnot())
@@ -146,7 +146,7 @@ void cMonster::Destroy(bool a_ShouldBroadcast)
 		}
 	}
 
-	super::Destroy(a_ShouldBroadcast);
+	super::OnRemoveFromWorld(a_World);
 }
 
 
@@ -282,7 +282,7 @@ void cMonster::Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 		m_DestroyTimer += a_Dt;
 		if (m_DestroyTimer > std::chrono::seconds(1))
 		{
-			Destroy(true);
+			Destroy();
 		}
 		return;
 	}
@@ -590,6 +590,20 @@ bool cMonster::DoTakeDamage(TakeDamageInfo & a_TDI)
 
 
 
+void cMonster::DoMoveToWorld(const cEntity::sWorldChangeInfo & a_WorldChangeInfo)
+{
+	// Stop all mobs from targeting this entity
+	// Stop this entity from targeting other mobs
+	SetTarget(nullptr);
+	StopEveryoneFromTargetingMe();
+
+	super::DoMoveToWorld(a_WorldChangeInfo);
+}
+
+
+
+
+
 void cMonster::KilledBy(TakeDamageInfo & a_TDI)
 {
 	super::KilledBy(a_TDI);
diff --git a/src/Mobs/Monster.h b/src/Mobs/Monster.h
index 11d49b82e..676e8ebe5 100644
--- a/src/Mobs/Monster.h
+++ b/src/Mobs/Monster.h
@@ -43,7 +43,7 @@ public:
 
 	virtual ~cMonster() override;
 
-	virtual void Destroy(bool a_ShouldBroadcast = true) override;
+	virtual void OnRemoveFromWorld(cWorld & a_World) override;
 
 	virtual void Destroyed() override;
 
@@ -319,6 +319,8 @@ protected:
 	/** Adds weapon that is equipped with the chance saved in m_DropChance[...] (this will be greter than 1 if picked up or 0.085 + (0.01 per LootingLevel) if born with) to the drop */
 	void AddRandomWeaponDropItem(cItems & a_Drops, unsigned int a_LootingLevel);
 
+	virtual void DoMoveToWorld(const cEntity::sWorldChangeInfo & a_WorldChangeInfo) override;
+
 private:
 	/** A pointer to the entity this mobile is aiming to reach.
 	The validity of this pointer SHALL be guaranteed by the pointee;
diff --git a/src/NetherPortalScanner.cpp b/src/NetherPortalScanner.cpp
index 9625ed7cf..78cdb2f02 100644
--- a/src/NetherPortalScanner.cpp
+++ b/src/NetherPortalScanner.cpp
@@ -296,7 +296,7 @@ void cNetherPortalScanner::OnDisabled(void)
 	}
 
 	FLOGD("Placing player at {0}", Position);
-	m_Entity->ScheduleMoveToWorld(m_World, Position, true);
+	m_Entity->MoveToWorld(m_World, Position, true);
 	delete this;
 }
 
diff --git a/src/OSSupport/AtomicUniquePtr.h b/src/OSSupport/AtomicUniquePtr.h
new file mode 100644
index 000000000..5b18763d3
--- /dev/null
+++ b/src/OSSupport/AtomicUniquePtr.h
@@ -0,0 +1,81 @@
+
+
+#pragma once
+
+
+/** An RAII wrapper for std::atomic<T*>. */
+template <typename T>
+class cAtomicUniquePtr
+{
+public:
+	static_assert(!std::is_array<T>::value, "cAtomicUniquePtr does not support arrays");
+	DISALLOW_COPY_AND_ASSIGN(cAtomicUniquePtr);
+
+	cAtomicUniquePtr() NOEXCEPT:
+		m_Ptr(nullptr)
+	{
+	}
+
+
+	cAtomicUniquePtr(std::unique_ptr<T> a_Ptr) NOEXCEPT:
+		m_Ptr(a_Ptr.release())
+	{
+	}
+
+	cAtomicUniquePtr & operator = (std::unique_ptr<T> a_Ptr) NOEXCEPT
+	{
+		store(std::move(a_Ptr));
+		return *this;
+	}
+
+	~cAtomicUniquePtr() NOEXCEPT
+	{
+		delete load();
+	}
+
+	operator T * () const NOEXCEPT
+	{
+		return load();
+	}
+
+	bool compare_exchange_weak(T *& a_Expected, std::unique_ptr<T> && a_Desired, std::memory_order a_Order = std::memory_order_seq_cst) NOEXCEPT
+	{
+		bool DidExchange = m_Ptr.compare_exchange_weak(a_Expected, a_Desired.get(), a_Order);
+		if (DidExchange)
+		{
+			// Only release ownership from the caller if the exchange occurred
+			a_Desired.release();
+		}
+		return DidExchange;
+	}
+
+	bool compare_exchange_strong(T *& a_Expected, std::unique_ptr<T> && a_Desired, std::memory_order a_Order = std::memory_order_seq_cst) NOEXCEPT
+	{
+		bool DidExchange = m_Ptr.compare_exchange_strong(a_Expected, a_Desired.get(), a_Order);
+		if (DidExchange)
+		{
+			// Only release ownership from the caller if the exchange occurred
+			a_Desired.release();
+		}
+		return DidExchange;
+	}
+
+	std::unique_ptr<T> exchange(std::unique_ptr<T> a_Ptr, std::memory_order a_Order = std::memory_order_seq_cst) NOEXCEPT
+	{
+		return std::unique_ptr<T>{ m_Ptr.exchange(a_Ptr.release(), a_Order) };
+	}
+
+	T * load(std::memory_order a_Order = std::memory_order_seq_cst) const NOEXCEPT
+	{
+		return m_Ptr.load(a_Order);
+	}
+
+	void store(std::unique_ptr<T> a_Ptr, std::memory_order a_Order = std::memory_order_seq_cst) NOEXCEPT
+	{
+		// Store new value and delete old value
+		delete m_Ptr.exchange(a_Ptr.release(), a_Order);
+	}
+
+private:
+	std::atomic<T*> m_Ptr;
+};
diff --git a/src/OSSupport/CMakeLists.txt b/src/OSSupport/CMakeLists.txt
index 332b880ed..9f3fcb8a0 100644
--- a/src/OSSupport/CMakeLists.txt
+++ b/src/OSSupport/CMakeLists.txt
@@ -19,6 +19,7 @@ SET (SRCS
 )
 
 SET (HDRS
+	AtomicUniquePtr.h
 	CriticalSection.h
 	Errors.h
 	Event.h
diff --git a/src/World.cpp b/src/World.cpp
index 312f5967a..a80cffbcc 100644
--- a/src/World.cpp
+++ b/src/World.cpp
@@ -1024,6 +1024,7 @@ void cWorld::Tick(std::chrono::milliseconds a_Dt, std::chrono::milliseconds a_La
 		Entity->SetWorld(this);
 		auto EntityPtr = Entity.get();
 		m_ChunkMap->AddEntity(std::move(Entity));
+		EntityPtr->OnAddToWorld(*this);
 		ASSERT(!EntityPtr->IsTicking());
 		EntityPtr->SetIsTicking(true);
 	}
@@ -1167,14 +1168,14 @@ void cWorld::TickMobs(std::chrono::milliseconds a_Dt)
 			{
 				if (Monster.GetMobType() != eMonsterType::mtWolf)
 				{
-					Monster.Destroy(true);
+					Monster.Destroy();
 				}
 				else
 				{
 					auto & Wolf = static_cast<cWolf &>(Monster);
 					if (!Wolf.IsAngry() && !Wolf.IsTame())
 					{
-						Monster.Destroy(true);
+						Monster.Destroy();
 					}
 				}
 			}
@@ -2454,23 +2455,34 @@ void cWorld::AddPlayer(std::unique_ptr<cPlayer> a_Player, cWorld * a_OldWorld)
 
 
 
-std::unique_ptr<cPlayer> cWorld::RemovePlayer(cPlayer & a_Player, bool a_RemoveFromChunk)
+std::unique_ptr<cPlayer> cWorld::RemovePlayer(cPlayer & a_Player)
 {
-	std::unique_ptr<cPlayer> PlayerPtr;
+	// Check the chunkmap
+	std::unique_ptr<cPlayer> PlayerPtr(static_cast<cPlayer *>(m_ChunkMap->RemoveEntity(a_Player).release()));
 
-	if (a_RemoveFromChunk)
+	if (PlayerPtr != nullptr)
 	{
-		// To prevent iterator invalidations when an entity goes through a portal and calls this function whilst being ticked by cChunk
-		// we should not change cChunk's entity list if asked not to
-		PlayerPtr = std::unique_ptr<cPlayer>(static_cast<cPlayer *>(m_ChunkMap->RemoveEntity(a_Player).release()));
+		// Player found in the world, tell it it's being removed
+		PlayerPtr->OnRemoveFromWorld(*this);
 	}
+	else  // Check the awaiting players list
 	{
 		cCSLock Lock(m_CSPlayersToAdd);
-		m_PlayersToAdd.remove_if([&](const decltype(m_PlayersToAdd)::value_type & value) -> bool
+		auto itr = std::find_if(m_PlayersToAdd.begin(), m_PlayersToAdd.end(),
+			[&](const decltype(m_PlayersToAdd)::value_type & value)
+			{
+				return (value.first.get() == &a_Player);
+			}
+		);
+
+		if (itr != m_PlayersToAdd.end())
 		{
-			return (value.first.get() == &a_Player);
-		});
+			PlayerPtr = std::move(itr->first);
+			m_PlayersToAdd.erase(itr);
+		}
 	}
+
+	// Remove from the player list
 	{
 		cCSLock Lock(m_CSPlayers);
 		LOGD("Removing player %s from world \"%s\"", a_Player.GetName().c_str(), m_WorldName.c_str());
@@ -3076,6 +3088,7 @@ OwnedEntity cWorld::RemoveEntity(cEntity & a_Entity)
 	auto Entity = m_ChunkMap->RemoveEntity(a_Entity);
 	if (Entity != nullptr)
 	{
+		Entity->OnRemoveFromWorld(*this);
 		return Entity;
 	}
 
@@ -3475,6 +3488,7 @@ void cWorld::AddQueuedPlayers(void)
 			// Add to chunkmap, if not already there (Spawn vs MoveToWorld):
 			auto PlayerPtr = Player.get();
 			m_ChunkMap->AddEntityIfNotPresent(std::move(Player));
+			PlayerPtr->OnAddToWorld(*this);
 			ASSERT(!PlayerPtr->IsTicking());
 			PlayerPtr->SetIsTicking(true);
 			AddedPlayerPtrs.emplace_back(PlayerPtr, AwaitingPlayer.second);
diff --git a/src/World.h b/src/World.h
index 159fa7d93..4363804c6 100644
--- a/src/World.h
+++ b/src/World.h
@@ -263,9 +263,8 @@ public:
 	/** Removes the player from the world.
 	Removes the player from the addition queue, too, if appropriate.
 	If the player has a ClientHandle, the ClientHandle is removed from all chunks in the world and will not be ticked by this world anymore.
-	@param a_RemoveFromChunk determines if the entity should be removed from its chunk as well. Should be false when ticking from cChunk.
 	@return An owning reference to the given player. */
-	std::unique_ptr<cPlayer> RemovePlayer(cPlayer & a_Player, bool a_RemoveFromChunk);
+	std::unique_ptr<cPlayer> RemovePlayer(cPlayer & a_Player);
 
 #ifdef _DEBUG
 	bool IsPlayerReferencedInWorldOrChunk(cPlayer & a_Player);