From 7285c5aca8d421ce45617865bb2c4e67734293f2 Mon Sep 17 00:00:00 2001
From: nashmuhandes <nashbackslash@gmail.com>
Date: Sun, 6 Sep 2020 20:34:40 +0800
Subject: [PATCH] Added WorldThingGround event to hook into the actor at exact
 moment its corpse spawns gibs upon being crushed.

---
 src/events.cpp                  | 26 ++++++++++++++++++++++++++
 src/events.h                    |  3 +++
 src/playsim/p_mobj.cpp          |  2 ++
 wadsrc/static/zscript/events.zs |  3 ++-
 4 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/src/events.cpp b/src/events.cpp
index d07bfefe87..f71fd9e9ec 100755
--- a/src/events.cpp
+++ b/src/events.cpp
@@ -331,6 +331,18 @@ void EventManager::WorldThingDied(AActor* actor, AActor* inflictor)
 		handler->WorldThingDied(actor, inflictor);
 }
 
+void EventManager::WorldThingGround(AActor* actor)
+{
+	// don't call anything if actor was destroyed on PostBeginPlay/BeginPlay/whatever.
+	if (actor->ObjectFlags & OF_EuthanizeMe)
+		return;
+
+	if (ShouldCallStatic(true)) staticEventManager.WorldThingGround(actor);
+
+	for (DStaticEventHandler* handler = FirstEventHandler; handler; handler = handler->next)
+		handler->WorldThingGround(actor);
+}
+
 void EventManager::WorldThingRevived(AActor* actor)
 {
 	// don't call anything if actor was destroyed on PostBeginPlay/BeginPlay/whatever.
@@ -795,6 +807,20 @@ void DStaticEventHandler::WorldThingDied(AActor* actor, AActor* inflictor)
 	}
 }
 
+void DStaticEventHandler::WorldThingGround(AActor* actor)
+{
+	IFVIRTUAL(DStaticEventHandler, WorldThingGround)
+	{
+		// don't create excessive DObjects if not going to be processed anyway
+		if (isEmpty(func)) return;
+		FWorldEvent e = owner->SetupWorldEvent();
+		e.Thing = actor;
+		VMValue params[2] = { (DStaticEventHandler*)this, &e };
+		VMCall(func, params, 2, nullptr, 0);
+	}
+}
+
+
 void DStaticEventHandler::WorldThingRevived(AActor* actor)
 {
 	IFVIRTUAL(DStaticEventHandler, WorldThingRevived)
diff --git a/src/events.h b/src/events.h
index 816615823f..b803f76d6d 100755
--- a/src/events.h
+++ b/src/events.h
@@ -80,6 +80,7 @@ public:
 	void WorldUnloaded();
 	void WorldThingSpawned(AActor* actor);
 	void WorldThingDied(AActor* actor, AActor* inflictor);
+	void WorldThingGround(AActor* actor);
 	void WorldThingRevived(AActor* actor);
 	void WorldThingDamaged(AActor* actor, AActor* inflictor, AActor* source, int damage, FName mod, int flags, DAngle angle);
 	void WorldThingDestroyed(AActor* actor);
@@ -234,6 +235,8 @@ struct EventManager
 	void WorldThingSpawned(AActor* actor);
 	// called after AActor::Die of each actor.
 	void WorldThingDied(AActor* actor, AActor* inflictor);
+	// called inside AActor::Grind just before the corpse is destroyed
+	void WorldThingGround(AActor* actor);
 	// called after AActor::Revive.
 	void WorldThingRevived(AActor* actor);
 	// called before P_DamageMobj and before AActor::DamageMobj virtuals.
diff --git a/src/playsim/p_mobj.cpp b/src/playsim/p_mobj.cpp
index 56fcf47eac..b85ad78878 100644
--- a/src/playsim/p_mobj.cpp
+++ b/src/playsim/p_mobj.cpp
@@ -1204,6 +1204,7 @@ bool AActor::Grind(bool items)
 				S_Sound (this, CHAN_BODY, 0, "misc/fallingsplat", 1, ATTN_IDLE);
 				Translation = BloodTranslation;
 			}
+			Level->localEventManager->WorldThingGround(this);
 			return false;
 		}
 		if (!(flags & MF_NOBLOOD))
@@ -1246,6 +1247,7 @@ bool AActor::Grind(bool items)
 				gib->Translation = BloodTranslation;
 			}
 			S_Sound (this, CHAN_BODY, 0, "misc/fallingsplat", 1, ATTN_IDLE);
+			Level->localEventManager->WorldThingGround(this);
 		}
 		if (flags & MF_ICECORPSE)
 		{
diff --git a/wadsrc/static/zscript/events.zs b/wadsrc/static/zscript/events.zs
index aa4d620ec5..6792188004 100644
--- a/wadsrc/static/zscript/events.zs
+++ b/wadsrc/static/zscript/events.zs
@@ -15,7 +15,7 @@ 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 thingspawned/thingdied/thingdestroyed
+    // for thingspawned/thingdied/thingdestroyed/thingground
     native readonly Actor Thing;
     // for thingdied. can be null
     native readonly Actor Inflictor;
@@ -323,6 +323,7 @@ class StaticEventHandler : Object native play version("2.4")
     virtual void WorldUnloaded(WorldEvent e) {}
     virtual void WorldThingSpawned(WorldEvent e) {}
     virtual void WorldThingDied(WorldEvent e) {}
+    virtual void WorldThingGround(WorldEvent e) {}
     virtual void WorldThingRevived(WorldEvent e) {}
     virtual void WorldThingDamaged(WorldEvent e) {}
     virtual void WorldThingDestroyed(WorldEvent e) {}