From 457f7c31c3e481d08d640c36427bfe5daeb3624b Mon Sep 17 00:00:00 2001
From: Marisa Kirisame <marisa@sayachan.org>
Date: Mon, 27 Sep 2021 19:40:57 +0200
Subject: [PATCH] Allow WorldUnloaded events to know the next map name (if
 any).

---
 src/events.cpp                  | 8 +++++---
 src/events.h                    | 5 +++--
 src/g_level.cpp                 | 6 +++---
 wadsrc/static/zscript/events.zs | 2 ++
 4 files changed, 13 insertions(+), 8 deletions(-)

diff --git a/src/events.cpp b/src/events.cpp
index 623d22203..a9362e03b 100755
--- a/src/events.cpp
+++ b/src/events.cpp
@@ -294,11 +294,11 @@ void EventManager::WorldLoaded()
 	}
 }
 
-void EventManager::WorldUnloaded()
+void EventManager::WorldUnloaded(const FString& nextmap)
 {
 	for (DStaticEventHandler* handler = LastEventHandler; handler; handler = handler->prev)
 	{
-		handler->WorldUnloaded();
+		handler->WorldUnloaded(nextmap);
 	}
 }
 
@@ -629,6 +629,7 @@ DEFINE_FIELD_X(RenderEvent, FRenderEvent, Camera);
 
 DEFINE_FIELD_X(WorldEvent, FWorldEvent, IsSaveGame);
 DEFINE_FIELD_X(WorldEvent, FWorldEvent, IsReopen);
+DEFINE_FIELD_X(WorldEvent, FWorldEvent, NextMap);
 DEFINE_FIELD_X(WorldEvent, FWorldEvent, Thing);
 DEFINE_FIELD_X(WorldEvent, FWorldEvent, Inflictor);
 DEFINE_FIELD_X(WorldEvent, FWorldEvent, Damage);
@@ -769,13 +770,14 @@ void DStaticEventHandler::WorldLoaded()
 	}
 }
 
-void DStaticEventHandler::WorldUnloaded()
+void DStaticEventHandler::WorldUnloaded(const FString& nextmap)
 {
 	IFVIRTUAL(DStaticEventHandler, WorldUnloaded)
 	{
 		// don't create excessive DObjects if not going to be processed anyway
 		if (isEmpty(func)) return;
 		FWorldEvent e = owner->SetupWorldEvent();
+		e.NextMap = nextmap;
 		VMValue params[2] = { (DStaticEventHandler*)this, &e };
 		VMCall(func, params, 2, nullptr, 0);
 	}
diff --git a/src/events.h b/src/events.h
index 86e8e941e..f5ad75d88 100755
--- a/src/events.h
+++ b/src/events.h
@@ -78,7 +78,7 @@ public:
 
 	//
 	void WorldLoaded();
-	void WorldUnloaded();
+	void WorldUnloaded(const FString& nextmap);
 	void WorldThingSpawned(AActor* actor);
 	void WorldThingDied(AActor* actor, AActor* inflictor);
 	void WorldThingGround(AActor* actor, FState* st);
@@ -144,6 +144,7 @@ struct FWorldEvent
 	// for loaded/unloaded
 	bool IsSaveGame = false;
 	bool IsReopen = false;
+	FString NextMap;
 	// for thingspawned, thingdied, thingdestroyed
 	AActor* Thing = nullptr; // for thingdied
 	AActor* Inflictor = nullptr; // can be null - for damagemobj
@@ -232,7 +233,7 @@ struct EventManager
 	// called right after the map has loaded (approximately same time as OPEN ACS scripts)
 	void WorldLoaded();
 	// called when the map is about to unload (approximately same time as UNLOADING ACS scripts)
-	void WorldUnloaded();
+	void WorldUnloaded(const FString& nextmap);
 	// called around PostBeginPlay of each actor.
 	void WorldThingSpawned(AActor* actor);
 	// called after AActor::Die of each actor.
diff --git a/src/g_level.cpp b/src/g_level.cpp
index 6468dd29d..5247c4968 100644
--- a/src/g_level.cpp
+++ b/src/g_level.cpp
@@ -468,7 +468,7 @@ void G_InitNew (const char *mapname, bool bTitleLevel)
 
 	// did we have any level before?
 	if (primaryLevel->info != nullptr)
-		staticEventManager.WorldUnloaded();
+		staticEventManager.WorldUnloaded(FString());	// [MK] don't pass the new map, as it's not a level transition
 
 	if (!savegamerestore)
 	{
@@ -701,10 +701,10 @@ void FLevelLocals::ChangeLevel(const char *levelname, int position, int inflags,
 	for (auto Level : AllLevels())
 	{
 		// Todo: This must be exolicitly sandboxed!
-		Level->localEventManager->WorldUnloaded();
+		Level->localEventManager->WorldUnloaded(nextlevel);
 	}
 	// [ZZ] unsafe world unload (changemap != map)
-	staticEventManager.WorldUnloaded();
+	staticEventManager.WorldUnloaded(nextlevel);
 	unloading = false;
 
 	STAT_ChangeLevel(nextlevel, this);
diff --git a/wadsrc/static/zscript/events.zs b/wadsrc/static/zscript/events.zs
index 6db6fb1e2..7492ea2b0 100644
--- a/wadsrc/static/zscript/events.zs
+++ b/wadsrc/static/zscript/events.zs
@@ -15,6 +15,8 @@ struct WorldEvent native play version("2.4")
     native readonly bool IsSaveGame;
     // this will be true if we are re-entering the hub level.
     native readonly bool IsReopen;
+    // for unloaded, name of next map (if any)
+    native readonly String NextMap;
     // for thingspawned/thingdied/thingdestroyed/thingground
     native readonly Actor Thing;
     // for thingdied. can be null