From aea346f1f3bd85411ee9095099954c3dec554175 Mon Sep 17 00:00:00 2001
From: Boondorl <59555366+Boondorl@users.noreply.github.com>
Date: Thu, 10 Nov 2022 16:15:40 -0500
Subject: [PATCH] Improved Slam functionality: *Added ONLYSLAMSOLID flag to
 ignore non-solid Actors that aren't shootable while SKULLFLY is on. *Added
 Slam state that gets entered when slamming an Actor.

---
 src/namedef_custom.h            |  1 +
 src/playsim/actor.h             |  1 +
 src/playsim/p_mobj.cpp          | 15 +++++++++++++--
 src/scripting/thingdef_data.cpp |  1 +
 4 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/src/namedef_custom.h b/src/namedef_custom.h
index 371e94377..16f6a022a 100644
--- a/src/namedef_custom.h
+++ b/src/namedef_custom.h
@@ -348,6 +348,7 @@ xx(Idle)
 xx(GenericFreezeDeath)
 xx(GenericCrush)
 xx(DieFromSpawn)
+xx(Slam)
 
 // Bounce state names
 xx(Bounce)
diff --git a/src/playsim/actor.h b/src/playsim/actor.h
index 3bf44994d..731c97942 100644
--- a/src/playsim/actor.h
+++ b/src/playsim/actor.h
@@ -429,6 +429,7 @@ enum ActorFlag8
 	MF8_CROSSLINECHECK	= 0x10000000,	// [MC]Enables CanCrossLine virtual
 	MF8_MASTERNOSEE		= 0x20000000,	// Don't show object in first person if their master is the current camera.
 	MF8_ADDLIGHTLEVEL	= 0x40000000,	// [MC] Actor light level is additive with sector.
+	MF8_ONLYSLAMSOLID	= 0x80000000,	// [B] Things with skullfly will ignore non-solid Actors.
 };
 
 // --- mobj.renderflags ---
diff --git a/src/playsim/p_mobj.cpp b/src/playsim/p_mobj.cpp
index 588acf1ab..c731369b8 100644
--- a/src/playsim/p_mobj.cpp
+++ b/src/playsim/p_mobj.cpp
@@ -3140,6 +3140,12 @@ DEFINE_ACTION_FUNCTION(AActor, Howl)
 
 bool AActor::Slam (AActor *thing)
 {
+	if ((flags8 & MF8_ONLYSLAMSOLID)
+		&& !(thing->flags & MF_SOLID) && !(thing->flags & MF_SHOOTABLE))
+	{
+		return true;
+	}
+
 	flags &= ~MF_SKULLFLY;
 	Vel.Zero();
 	if (health > 0)
@@ -3152,8 +3158,13 @@ bool AActor::Slam (AActor *thing)
 			// The charging monster may have died by the target's actions here.
 			if (health > 0)
 			{
-				if (SeeState != NULL && !(flags8 & MF8_RETARGETAFTERSLAM)) SetState (SeeState);
-				else SetIdle();
+				FState *slam = FindState(NAME_Slam);
+				if (slam != NULL)
+					SetState(slam);
+				else if (SeeState != NULL && !(flags8 & MF8_RETARGETAFTERSLAM))
+					SetState (SeeState);
+				else
+					SetIdle();
 			}
 		}
 		else
diff --git a/src/scripting/thingdef_data.cpp b/src/scripting/thingdef_data.cpp
index 7eaebda6c..96a788da3 100644
--- a/src/scripting/thingdef_data.cpp
+++ b/src/scripting/thingdef_data.cpp
@@ -343,6 +343,7 @@ static FFlagDef ActorFlagDefs[]=
 	DEFINE_FLAG(MF8, CROSSLINECHECK, AActor, flags8),
 	DEFINE_FLAG(MF8, MASTERNOSEE, AActor, flags8),
 	DEFINE_FLAG(MF8, ADDLIGHTLEVEL, AActor, flags8),
+	DEFINE_FLAG(MF8, ONLYSLAMSOLID, AActor, flags8),
 
 	// Effect flags
 	DEFINE_FLAG(FX, VISIBILITYPULSE, AActor, effects),