From 7a4927fdf5b9fdf85407c1441f461be50ffa18f4 Mon Sep 17 00:00:00 2001
From: Boondorl <boondorl@live.com>
Date: Tue, 28 Jan 2025 09:15:56 -0500
Subject: [PATCH] Added TransferredOwner virtual

Allows for proper cleaning up of behaviors when moving between Actors. Important for player respawn handling and morphing.
---
 src/playsim/actor.h                   |  4 ++++
 src/playsim/p_mobj.cpp                | 34 +++++++++++++++++++++++----
 wadsrc/static/zscript/actors/actor.zs |  1 +
 3 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/src/playsim/actor.h b/src/playsim/actor.h
index cbc2781de..3339adeb9 100644
--- a/src/playsim/actor.h
+++ b/src/playsim/actor.h
@@ -1453,6 +1453,10 @@ public:
 		auto b = Behaviors.CheckKey(type);
 		return b != nullptr ? b->Get() : nullptr;
 	}
+	bool IsValidBehavior(const DBehavior& b) const
+	{
+		return !(b.ObjectFlags & OF_EuthanizeMe) && b.Owner.ForceGet() == this;
+	}
 	DBehavior* AddBehavior(PClass& type);
 	bool RemoveBehavior(FName type);
 	void TickBehaviors();
diff --git a/src/playsim/p_mobj.cpp b/src/playsim/p_mobj.cpp
index c6ebe85e4..d040f3de0 100644
--- a/src/playsim/p_mobj.cpp
+++ b/src/playsim/p_mobj.cpp
@@ -541,7 +541,7 @@ DBehavior* AActor::AddBehavior(PClass& type)
 			VMValue params[] = { b };
 			VMCall(func, params, 1, nullptr, 0);
 
-			if (b->ObjectFlags & OF_EuthanizeMe)
+			if (!IsValidBehavior(*b))
 			{
 				RemoveBehavior(type.TypeName);
 				return nullptr;
@@ -555,7 +555,7 @@ DBehavior* AActor::AddBehavior(PClass& type)
 			VMValue params[] = { b };
 			VMCall(func, params, 1, nullptr, 0);
 
-			if (b->ObjectFlags & OF_EuthanizeMe)
+			if (!IsValidBehavior(*b))
 			{
 				RemoveBehavior(type.TypeName);
 				return nullptr;
@@ -599,7 +599,7 @@ void AActor::TickBehaviors()
 
 	for (auto& b : toTick)
 	{
-		if ((b->ObjectFlags & OF_EuthanizeMe) || b->Owner != this)
+		if (!IsValidBehavior(*b))
 		{
 			toRemove.Push(b->GetClass()->TypeName);
 			continue;
@@ -610,7 +610,7 @@ void AActor::TickBehaviors()
 			VMValue params[] = { b };
 			VMCall(func, params, 1, nullptr, 0);
 
-			if (b->ObjectFlags & OF_EuthanizeMe)
+			if (!IsValidBehavior(*b))
 				toRemove.Push(b->GetClass()->TypeName);
 		}
 	}
@@ -645,12 +645,16 @@ DEFINE_ACTION_FUNCTION_NATIVE(AActor, FindBehavior, FindBehavior)
 
 void AActor::MoveBehaviors(AActor& from)
 {
+	if (&from == this)
+		return;
+
 	// Clean these up properly before transferring.
 	ClearBehaviors();
 
 	Behaviors.TransferFrom(from.Behaviors);
 
 	TArray<FName> toRemove = {};
+	TArray<DBehavior*> toTransfer = {};
 	
 	// Clean up any empty behaviors that remained as well while
 	// changing the owner.
@@ -671,6 +675,26 @@ void AActor::MoveBehaviors(AActor& from)
 			b->Level->RemoveActorBehavior(*b);
 			Level->AddActorBehavior(*b);
 		}
+
+		toTransfer.Push(b);
+	}
+
+	for (auto& b : toTransfer)
+	{
+		if (!IsValidBehavior(*b))
+		{
+			toRemove.Push(b->GetClass()->TypeName);
+			continue;
+		}
+
+		IFOVERRIDENVIRTUALPTRNAME(b, NAME_Behavior, TransferredOwner)
+		{
+			VMValue params[] = { b, &from };
+			VMCall(func, params, 2, nullptr, 0);
+
+			if (!IsValidBehavior(*b))
+				toRemove.Push(b->GetClass()->TypeName);
+		}
 	}
 
 	for (auto& type : toRemove)
@@ -5990,6 +6014,8 @@ AActor *FLevelLocals::SpawnPlayer (FPlayerStart *mthing, int playernum, int flag
 	const auto heldWeap = state == PST_REBORN && (dmflags3 & DF3_REMEMBER_LAST_WEAP) ? p->ReadyWeapon : nullptr;
 	if (state == PST_REBORN || state == PST_ENTER)
 	{
+		if (state == PST_REBORN && oldactor != nullptr)
+			p->mo->MoveBehaviors(*oldactor);
 		PlayerReborn (playernum);
 	}
 	else if (oldactor != NULL && oldactor->player == p && !(flags & SPF_TEMPPLAYER))
diff --git a/wadsrc/static/zscript/actors/actor.zs b/wadsrc/static/zscript/actors/actor.zs
index 1471dec61..56fa7ad10 100644
--- a/wadsrc/static/zscript/actors/actor.zs
+++ b/wadsrc/static/zscript/actors/actor.zs
@@ -80,6 +80,7 @@ class Behavior native play abstract
 
 	virtual void Initialize() {}
 	virtual void Reinitialize() {}
+	virtual void TransferredOwner(Actor oldOwner) {}
 	virtual void Tick() {}
 }