Localized fix to its own field

src/p_setup.cpp

@@ -285,7 +285,7 @@ void FLevelLocals::ClearLevelData(bool fullgc)
 		auto it = GetThinkerIterator<AActor>(NAME_None, STAT_TRAVELLING);
 		for (AActor *actor = it.Next(); actor != nullptr; actor = it.Next())
 		{
-			actor->BlockingLine = nullptr;
+			actor->BlockingLine = actor->MovementBlockingLine = nullptr;
 			actor->BlockingFloor = actor->BlockingCeiling = actor->Blocking3DFloor = nullptr;
 		}
 	}

src/playsim/actor.h

@@ -1223,6 +1223,7 @@ class AActor final : public DThinker
 
 	AActor			*BlockingMobj;	// Actor that blocked the last move
 	line_t			*BlockingLine;	// Line that blocked the last move
+	line_t			*MovementBlockingLine; // Line that stopped the Actor's movement in P_XYMovement
 	sector_t		*Blocking3DFloor;	// 3D floor that blocked the last move (if any)
 	sector_t		*BlockingCeiling;	// Sector that blocked the last move (ceiling plane slope)
 	sector_t		*BlockingFloor;		// Sector that blocked the last move (floor plane slope)

src/playsim/p_mobj.cpp

@@ -310,6 +310,7 @@ void AActor::Serialize(FSerializer &arc)
 		A("smokecounter", smokecounter)
 		("blockingmobj", BlockingMobj)
 		A("blockingline", BlockingLine)
+		A("movementblockingline", MovementBlockingLine)
 		A("blocking3dfloor", Blocking3DFloor)
 		A("blockingceiling", BlockingCeiling)
 		A("blockingfloor", BlockingFloor)
@@ -1971,7 +1972,6 @@ static double P_XYMovement (AActor *mo, DVector2 scroll)
 	FCheckPosition tm(!!(mo->flags2 & MF2_RIP));
 
 	DAngle oldangle = mo->Angles.Yaw;
-	line_t* blocker = nullptr;
 	do
 	{
 		if (mo->Level->i_compatflags & COMPATF_WALLRUN) pushtime++;
@@ -1987,7 +1987,7 @@ static double P_XYMovement (AActor *mo, DVector2 scroll)
 		{
 			// blocked move
 			AActor *BlockingMobj = mo->BlockingMobj;
-			line_t *BlockingLine = blocker = mo->BlockingLine;
+			line_t *BlockingLine = mo->MovementBlockingLine = mo->BlockingLine;
 
 			// [ZZ] 
 			if (!BlockingLine && !BlockingMobj) // hit floor or ceiling while XY movement - sector actions
@@ -2189,9 +2189,6 @@ static double P_XYMovement (AActor *mo, DVector2 scroll)
 		}
 	} while (++step <= steps);
 
-	// Correctly update whether the Actor was truly blocked by a wall or not
-	mo->BlockingLine = blocker;
-
 	// Friction
 
 	if (player && player->mo == mo && player->cheats & CF_NOVELOCITY)
@@ -4061,7 +4058,7 @@ void AActor::Tick ()
 
 		// Handle X and Y velocities
 		BlockingMobj = nullptr;
-		BlockingLine = nullptr;
+		MovementBlockingLine = nullptr;
 		sector_t* oldBlockingCeiling = BlockingCeiling;
 		sector_t* oldBlockingFloor = BlockingFloor;
 		Blocking3DFloor = nullptr;

src/scripting/vmthunks_actors.cpp

@@ -1539,20 +1539,21 @@ DEFINE_ACTION_FUNCTION_NATIVE(AActor, LookForPlayers, P_LookForPlayers)
 	ACTION_RETURN_BOOL(P_LookForPlayers(self, allaround, params));
 }
 
-static int CheckMonsterUseSpecials(AActor *self)
+static int CheckMonsterUseSpecials(AActor *self, line_t *blocking)
 {
 	spechit_t spec;
 	int good = 0;
 
 	if (!(self->flags6 & MF6_NOTRIGGER))
 	{
+		auto checkLine = blocking ? blocking : self->BlockingLine;
 		while (spechit.Pop (spec))
 		{
 			// [RH] let monsters push lines, as well as use them
 			if (((self->flags4 & MF4_CANUSEWALLS) && P_ActivateLine (spec.line, self, 0, SPAC_Use)) ||
 				((self->flags2 & MF2_PUSHWALL) && P_ActivateLine (spec.line, self, 0, SPAC_Push)))
 			{
-				good |= spec.line == self->BlockingLine ? 1 : 2;
+				good |= spec.line == checkLine ? 1 : 2;
 			}
 		}
 	}
@@ -1564,8 +1565,9 @@ static int CheckMonsterUseSpecials(AActor *self)
 DEFINE_ACTION_FUNCTION_NATIVE(AActor, CheckMonsterUseSpecials, CheckMonsterUseSpecials)
 {
 	PARAM_SELF_PROLOGUE(AActor);
+	PARAM_POINTER(blocking, line_t);
 
-	ACTION_RETURN_INT(CheckMonsterUseSpecials(self));
+	ACTION_RETURN_INT(CheckMonsterUseSpecials(self, blocking));
 }
 
 DEFINE_ACTION_FUNCTION_NATIVE(AActor, A_Wander, A_Wander)
@@ -2055,6 +2057,7 @@ DEFINE_FIELD(AActor, lastbump)
 DEFINE_FIELD(AActor, DesignatedTeam)
 DEFINE_FIELD(AActor, BlockingMobj)
 DEFINE_FIELD(AActor, BlockingLine)
+DEFINE_FIELD(AActor, MovementBlockingLine)
 DEFINE_FIELD(AActor, Blocking3DFloor)
 DEFINE_FIELD(AActor, BlockingCeiling)
 DEFINE_FIELD(AActor, BlockingFloor)

wadsrc/static/zscript/actors/actor.zs

@@ -202,6 +202,7 @@ class Actor : Thinker native
 	native int DesignatedTeam;
 	native Actor BlockingMobj;
 	native Line BlockingLine;
+	native Line MovementBlockingLine;
 	native Sector Blocking3DFloor;
 	native Sector BlockingCeiling;
 	native Sector BlockingFloor;
@@ -698,7 +699,7 @@ class Actor : Thinker native
 	native void CheckFakeFloorTriggers (double oldz, bool oldz_has_viewheight = false);
 	native bool CheckFor3DFloorHit(double z, bool trigger);
 	native bool CheckFor3DCeilingHit(double z, bool trigger);
-	native int CheckMonsterUseSpecials();
+	native int CheckMonsterUseSpecials(Line blocking = null);
 
 	native bool CheckMissileSpawn(double maxdist);
 	native bool CheckPosition(Vector2 pos, bool actorsonly = false, FCheckPosition tm = null);