diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 5a3351880..a5164e84b 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -842,7 +842,6 @@ set( NOT_COMPILED_SOURCE_FILES
 	g_doom/a_keen.cpp
 	g_doom/a_lostsoul.cpp
 	g_doom/a_painelemental.cpp
-	g_doom/a_possessed.cpp
 	g_doom/a_revenant.cpp
 	g_doom/a_scriptedmarine.cpp
 	g_doom/a_spidermaster.cpp
diff --git a/src/g_doom/a_doommisc.cpp b/src/g_doom/a_doommisc.cpp
index de53dc3af..4c8be07f1 100644
--- a/src/g_doom/a_doommisc.cpp
+++ b/src/g_doom/a_doommisc.cpp
@@ -29,7 +29,6 @@
 #include "a_keen.cpp"
 #include "a_lostsoul.cpp"
 #include "a_painelemental.cpp"
-#include "a_possessed.cpp"
 #include "a_revenant.cpp"
 #include "a_spidermaster.cpp"
 #include "a_scriptedmarine.cpp"
diff --git a/src/g_doom/a_possessed.cpp b/src/g_doom/a_possessed.cpp
deleted file mode 100644
index 0b9a9ecfd..000000000
--- a/src/g_doom/a_possessed.cpp
+++ /dev/null
@@ -1,134 +0,0 @@
-/*
-#include "actor.h"
-#include "info.h"
-#include "m_random.h"
-#include "s_sound.h"
-#include "p_local.h"
-#include "p_enemy.h"
-#include "gstrings.h"
-#include "a_action.h"
-#include "vm.h"
-*/
-
-static FRandom pr_posattack ("PosAttack");
-static FRandom pr_sposattack ("SPosAttack");
-static FRandom pr_cposattack ("CPosAttack");
-static FRandom pr_cposrefire ("CPosRefire");
-
-//
-// A_PosAttack
-//
-DEFINE_ACTION_FUNCTION(AActor, A_PosAttack)
-{
-	PARAM_SELF_PROLOGUE(AActor);
-
-	int damage;
-	DAngle angle;
-	DAngle slope;
-		
-	if (!self->target)
-		return 0;
-				
-	A_FaceTarget (self);
-	angle = self->Angles.Yaw;
-	slope = P_AimLineAttack (self, angle, MISSILERANGE);
-
-	S_Sound (self, CHAN_WEAPON, "grunt/attack", 1, ATTN_NORM);
-	angle += pr_posattack.Random2() * (22.5 / 256);
-	damage = ((pr_posattack()%5)+1)*3;
-	P_LineAttack (self, angle, MISSILERANGE, slope, damage, NAME_Hitscan, NAME_BulletPuff);
-	return 0;
-}
-
-static void A_SPosAttack2 (AActor *self)
-{
-	int i;
-	DAngle bangle;
-	DAngle slope;
-		
-	A_FaceTarget (self);
-	bangle = self->Angles.Yaw;
-	slope = P_AimLineAttack (self, bangle, MISSILERANGE);
-
-	for (i=0 ; i<3 ; i++)
-    {
-		DAngle angle = bangle + pr_sposattack.Random2() * (22.5 / 256);
-		int damage = ((pr_sposattack()%5)+1)*3;
-		P_LineAttack(self, angle, MISSILERANGE, slope, damage, NAME_Hitscan, NAME_BulletPuff);
-    }
-}
-
-DEFINE_ACTION_FUNCTION(AActor, A_SPosAttackUseAtkSound)
-{
-	PARAM_SELF_PROLOGUE(AActor);
-
-	if (!self->target)
-		return 0;
-
-	S_Sound (self, CHAN_WEAPON, self->AttackSound, 1, ATTN_NORM);
-	A_SPosAttack2 (self);
-	return 0;
-}
-
-// This version of the function, which uses a hard-coded sound, is
-// meant for Dehacked only.
-DEFINE_ACTION_FUNCTION(AActor, A_SPosAttack)
-{
-	PARAM_SELF_PROLOGUE(AActor);
-
-	if (!self->target)
-		return 0;
-
-	S_Sound (self, CHAN_WEAPON, "shotguy/attack", 1, ATTN_NORM);
-	A_SPosAttack2 (self);
-	return 0;
-}
-
-DEFINE_ACTION_FUNCTION(AActor, A_CPosAttack)
-{
-	PARAM_SELF_PROLOGUE(AActor);
-
-	DAngle angle;
-	DAngle bangle;
-	int damage;
-	DAngle slope;
-		
-	if (!self->target)
-		return 0;
-
-	// [RH] Andy Baker's stealth monsters
-	if (self->flags & MF_STEALTH)
-	{
-		self->visdir = 1;
-	}
-
-	S_Sound (self, CHAN_WEAPON, self->AttackSound, 1, ATTN_NORM);
-	A_FaceTarget (self);
-	bangle = self->Angles.Yaw;
-	slope = P_AimLineAttack (self, bangle, MISSILERANGE);
-
-	angle = bangle + pr_cposattack.Random2() * (22.5 / 256);
-	damage = ((pr_cposattack()%5)+1)*3;
-	P_LineAttack (self, angle, MISSILERANGE, slope, damage, NAME_Hitscan, NAME_BulletPuff);
-	return 0;
-}
-
-DEFINE_ACTION_FUNCTION(AActor, A_CPosRefire)
-{
-	PARAM_SELF_PROLOGUE(AActor);
-
-	// keep firing unless target got out of sight
-	A_FaceTarget (self);
-
-	if (pr_cposrefire() < 40)
-		return 0;
-
-	if (!self->target
-		|| P_HitFriend (self)
-		|| self->target->health <= 0
-		|| !P_CheckSight (self, self->target, SF_SEEPASTBLOCKEVERYTHING|SF_SEEPASTSHOOTABLELINES))
-	{
-		self->SetState (self->SeeState);
-	}
-	return 0;
-}
diff --git a/src/info.cpp b/src/info.cpp
index 5e267b39c..268d4f91c 100644
--- a/src/info.cpp
+++ b/src/info.cpp
@@ -77,7 +77,7 @@ bool FState::CallAction(AActor *self, AActor *stateowner, FStateParamInfo *info,
 	{
 		ActionCycles.Clock();
 
-		static VMFrameStack stack;
+		VMFrameStack stack;
 		VMValue params[3] = { self, stateowner, VMValue(info, ATAG_STATEINFO) };
 		// If the function returns a state, store it at *stateret.
 		// If it doesn't return a state but stateret is non-NULL, we need
diff --git a/src/p_enemy.cpp b/src/p_enemy.cpp
index 0c2cb8e28..fbdc1a212 100644
--- a/src/p_enemy.cpp
+++ b/src/p_enemy.cpp
@@ -461,6 +461,12 @@ bool P_HitFriend(AActor * self)
 	return false;
 }
 
+DEFINE_ACTION_FUNCTION(AActor, HitFriend)
+{
+	PARAM_SELF_PROLOGUE(AActor);
+	ACTION_RETURN_BOOL(P_HitFriend(self));
+}
+
 //
 // P_Move
 // Move in the current direction,
diff --git a/src/p_map.cpp b/src/p_map.cpp
index 849f8dd24..ef46f6566 100644
--- a/src/p_map.cpp
+++ b/src/p_map.cpp
@@ -4043,6 +4043,18 @@ DAngle P_AimLineAttack(AActor *t1, DAngle angle, double distance, FTranslatedLin
 	return result->linetarget ? result->pitch : t1->Angles.Pitch;
 }
 
+DEFINE_ACTION_FUNCTION(AActor, AimLineAttack)
+{
+	PARAM_SELF_PROLOGUE(AActor);
+	PARAM_ANGLE(angle);
+	PARAM_FLOAT(distance);
+	PARAM_POINTER_OPT(pLineTarget, FTranslatedLineTarget) { pLineTarget = nullptr; }
+	PARAM_ANGLE_OPT(vrange) { vrange = 0.; }
+	PARAM_INT_OPT(flags) { flags = 0; }
+	PARAM_OBJECT_OPT(target, AActor) { target = nullptr; }
+	PARAM_OBJECT_OPT(friender, AActor) { friender = nullptr; }
+	ACTION_RETURN_FLOAT(P_AimLineAttack(self, angle, distance, pLineTarget, vrange, flags, target, friender).Degrees);
+}
 
 //==========================================================================
 //
@@ -4410,6 +4422,25 @@ AActor *P_LineAttack(AActor *t1, DAngle angle, double distance,
 	}
 }
 
+DEFINE_ACTION_FUNCTION(AActor, LineAttack)
+{
+	PARAM_SELF_PROLOGUE(AActor);
+	PARAM_ANGLE(angle);
+	PARAM_FLOAT(distance);
+	PARAM_ANGLE(pitch);
+	PARAM_INT(damage);
+	PARAM_NAME(damageType);
+	PARAM_CLASS(puffType, AActor);
+	PARAM_INT_OPT(flags) { flags = 0; }
+	PARAM_POINTER_OPT(victim, FTranslatedLineTarget) { victim = nullptr; }
+
+	int acdmg;
+	auto puff = P_LineAttack(self, angle, distance, pitch, damage, damageType, puffType, flags, victim, &acdmg);
+	if (numret > 0) ret[0].SetPointer(puff, ATAG_OBJECT);
+	if (numret > 1) ret[1].SetInt(acdmg), numret = 2;
+	return numret;
+}
+
 //==========================================================================
 //
 // P_LinePickActor
diff --git a/src/p_mobj.cpp b/src/p_mobj.cpp
index 5d40d1ed3..7398fa29f 100644
--- a/src/p_mobj.cpp
+++ b/src/p_mobj.cpp
@@ -510,6 +510,14 @@ bool AActor::SetState (FState *newstate, bool nofunction)
 	return true;
 }
 
+DEFINE_ACTION_FUNCTION(AActor, SetState)
+{
+	PARAM_SELF_PROLOGUE(AActor);
+	PARAM_STATE(state);
+	PARAM_BOOL_OPT(nofunction) { nofunction = false; }
+	ACTION_RETURN_BOOL(self->SetState(state, nofunction));
+};
+
 //============================================================================
 //
 // AActor :: AddInventory
diff --git a/src/p_sight.cpp b/src/p_sight.cpp
index c10365eea..fefe9eb27 100644
--- a/src/p_sight.cpp
+++ b/src/p_sight.cpp
@@ -905,6 +905,14 @@ done:
 	return res;
 }
 
+DEFINE_ACTION_FUNCTION(AActor, CheckSight)
+{
+	PARAM_SELF_PROLOGUE(AActor);
+	PARAM_OBJECT(target, AActor);
+	PARAM_INT_OPT(flags) { flags = 0; }
+	ACTION_RETURN_BOOL(P_CheckSight(self, target, flags));
+}
+
 ADD_STAT (sight)
 {
 	FString out;
diff --git a/src/scripting/codegeneration/codegen.cpp b/src/scripting/codegeneration/codegen.cpp
index de7048d88..8fec40113 100644
--- a/src/scripting/codegeneration/codegen.cpp
+++ b/src/scripting/codegeneration/codegen.cpp
@@ -1519,9 +1519,8 @@ ExpEmit FxUnaryNotBoolean::Emit(VMFunctionBuilder *build)
 	assert(ValueType == TypeBool);
 	ExpEmit from = Operand->Emit(build);
 	assert(!from.Konst);
-	// ~x & 1
-	build->Emit(OP_NOT, from.RegNum, from.RegNum, 0);
-	build->Emit(OP_AND_RK, from.RegNum, from.RegNum, build->GetConstantInt(1));
+	// boolean not is the same as XOR-ing the lowest bit
+	build->Emit(OP_XOR_RK, from.RegNum, from.RegNum, build->GetConstantInt(1));
 	return from;
 }
 
@@ -1734,32 +1733,54 @@ ExpEmit FxPostIncrDecr::Emit(VMFunctionBuilder *build)
 	int zero = build->GetConstantInt(0);
 	int regtype = ValueType->GetRegType();
 	ExpEmit pointer = Base->Emit(build);
-	ExpEmit out = pointer;
 
 	if (!pointer.Target)
 	{
-		out = ExpEmit(build, regtype);
+		ExpEmit out(build, regtype);
 		build->Emit(ValueType->GetLoadOp(), out.RegNum, pointer.RegNum, zero);
+		ExpEmit assign(build, regtype);
+		if (regtype == REGT_INT)
+		{
+			build->Emit((Token == TK_Incr) ? OP_ADD_RK : OP_SUB_RK, assign.RegNum, out.RegNum, build->GetConstantInt(1));
+		}
+		else
+		{
+			build->Emit((Token == TK_Incr) ? OP_ADDF_RK : OP_SUBF_RK, assign.RegNum, out.RegNum, build->GetConstantFloat(1.));
+		}
+		build->Emit(ValueType->GetStoreOp(), pointer.RegNum, out.RegNum, zero);
+		pointer.Free(build);
+		assign.Free(build);
+		return out;
 	}
-
-	ExpEmit assign(build, regtype);
-	if (regtype == REGT_INT)
+	else if (NeedResult)
 	{
-		build->Emit((Token == TK_Incr) ? OP_ADD_RK : OP_SUB_RK, assign.RegNum, out.RegNum, build->GetConstantInt(1));
+		ExpEmit out(build, regtype);
+		if (regtype == REGT_INT)
+		{
+			build->Emit(OP_MOVE, out.RegNum, pointer.RegNum);
+			build->Emit((Token == TK_Incr) ? OP_ADD_RK : OP_SUB_RK, pointer.RegNum, pointer.RegNum, build->GetConstantInt(1));
+		}
+		else
+		{
+			build->Emit(OP_MOVEF, out.RegNum, pointer.RegNum);
+			build->Emit((Token == TK_Incr) ? OP_ADDF_RK : OP_SUBF_RK, pointer.RegNum, pointer.RegNum, build->GetConstantFloat(1.));
+		}
+		pointer.Free(build);
+		return out;
 	}
 	else
 	{
-		build->Emit((Token == TK_Incr) ? OP_ADDF_RK : OP_SUBF_RK, assign.RegNum, out.RegNum, build->GetConstantFloat(1.));
+		if (regtype == REGT_INT)
+		{
+			build->Emit((Token == TK_Incr) ? OP_ADD_RK : OP_SUB_RK, pointer.RegNum, pointer.RegNum, build->GetConstantInt(1));
+		}
+		else
+		{
+			build->Emit((Token == TK_Incr) ? OP_ADDF_RK : OP_SUBF_RK, pointer.RegNum, pointer.RegNum, build->GetConstantFloat(1.));
+		}
+		pointer.Free(build);
+		return ExpEmit();
 	}
-
-	if (!pointer.Target)
-	{
-		build->Emit(ValueType->GetStoreOp(), pointer.RegNum, assign.RegNum, zero);
-	}
-
-	pointer.Free(build);
-	assign.Free(build);
-	return out;
 }
 
 //==========================================================================
@@ -5795,7 +5816,8 @@ FxExpression *FxSwitchStatement::Resolve(FCompileContext &ctx)
 			auto x = Condition;
 			Condition = nullptr;
 			delete this;
-			return Condition;
+			x->NeedResult = false;
+			return x;
 		}
 	}
 
@@ -5805,6 +5827,7 @@ FxExpression *FxSwitchStatement::Resolve(FCompileContext &ctx)
 		if (line->ExprType != EFX_JumpStatement || static_cast<FxJumpStatement *>(line)->Token != TK_Break)
 		{
 			SAFE_RESOLVE(line, ctx);
+			line->NeedResult = false;
 		}
 	}
 
@@ -5999,6 +6022,8 @@ FxIfStatement::FxIfStatement(FxExpression *cond, FxExpression *true_part,
 	Condition = cond;
 	WhenTrue = true_part;
 	WhenFalse = false_part;
+	if (WhenTrue != nullptr) WhenTrue->NeedResult = false;
+	if (WhenFalse != nullptr) WhenFalse->NeedResult = false;
 	assert(cond != NULL);
 }
 
@@ -6338,6 +6363,8 @@ FxForLoop::FxForLoop(FxExpression *init, FxExpression *condition, FxExpression *
 : FxLoopStatement(EFX_ForLoop, pos), Init(init), Condition(condition), Iteration(iteration), Code(code)
 {
 	ValueType = TypeVoid;
+	if (Iteration != nullptr) Iteration->NeedResult = false;
+	if (Code != nullptr) Code->NeedResult = false;
 }
 
 FxForLoop::~FxForLoop()
@@ -7139,19 +7166,19 @@ ExpEmit FxLocalVariableDeclaration::Emit(VMFunctionBuilder *build)
 			{
 			default:
 			case REGT_INT:
-				build->Emit(OP_LK, build->GetConstantInt(constval->GetValue().GetInt()), RegNum);
+				build->Emit(OP_LK, RegNum, build->GetConstantInt(constval->GetValue().GetInt()));
 				break;
 
 			case REGT_FLOAT:
-				build->Emit(OP_LKF, build->GetConstantFloat(constval->GetValue().GetFloat()), RegNum);
+				build->Emit(OP_LKF, RegNum, build->GetConstantFloat(constval->GetValue().GetFloat()));
 				break;
 
 			case REGT_POINTER:
-				build->Emit(OP_LKP, build->GetConstantAddress(constval->GetValue().GetPointer(), ATAG_GENERIC), RegNum);
+				build->Emit(OP_LKP, RegNum, build->GetConstantAddress(constval->GetValue().GetPointer(), ATAG_GENERIC));
 				break;
 
 			case REGT_STRING:
-				build->Emit(OP_LKS, build->GetConstantString(constval->GetValue().GetString()), RegNum);
+				build->Emit(OP_LKS, RegNum, build->GetConstantString(constval->GetValue().GetString()));
 			}
 			emitval.Free(build);
 		}
diff --git a/src/scripting/codegeneration/codegen.h b/src/scripting/codegeneration/codegen.h
index 3fb1b1576..d099daa22 100644
--- a/src/scripting/codegeneration/codegen.h
+++ b/src/scripting/codegeneration/codegen.h
@@ -300,6 +300,7 @@ public:
 	PType *ValueType = nullptr;
 
 	bool isresolved = false;
+	bool NeedResult = true;	// should be set to false if not needed and properly handled by all nodes for their subnodes to eliminate redundant code
 	EFxType ExprType;
 };
 
@@ -1246,7 +1247,7 @@ public:
 	FxSequence(const FScriptPosition &pos) : FxExpression(EFX_Sequence, pos) {}
 	FxExpression *Resolve(FCompileContext&);
 	ExpEmit Emit(VMFunctionBuilder *build);
-	void Add(FxExpression *expr) { if (expr != NULL) Expressions.Push(expr); }
+	void Add(FxExpression *expr) { if (expr != NULL) Expressions.Push(expr); expr->NeedResult = false; }
 	VMFunction *GetDirectFunction();
 };
 
diff --git a/src/scripting/thingdef_data.cpp b/src/scripting/thingdef_data.cpp
index a4815cb33..601fb5e9a 100644
--- a/src/scripting/thingdef_data.cpp
+++ b/src/scripting/thingdef_data.cpp
@@ -680,6 +680,7 @@ void InitThingdef()
 	symt.AddSymbol(new PField(NAME_Threshold,		TypeSInt32,		VARF_Native|VARF_ReadOnly,	myoffsetof(AActor, threshold)));
 	symt.AddSymbol(new PField(NAME_DefThreshold,	TypeSInt32,		VARF_Native|VARF_ReadOnly,	myoffsetof(AActor, DefThreshold)));
 	symt.AddSymbol(new PField(NAME_Damage,			TypeSInt32,		VARF_Native|VARF_ReadOnly,  myoffsetof(AActor, DamageVal)));
+	symt.AddSymbol(new PField("visdir",				TypeSInt32,		VARF_Native,				myoffsetof(AActor, visdir)));
 	symt.AddSymbol(new PField(NAME_VisibleStartAngle, TypeFloat64,	VARF_Native,				myoffsetof(AActor, VisibleStartAngle)));
 	symt.AddSymbol(new PField(NAME_VisibleStartPitch, TypeFloat64,	VARF_Native,				myoffsetof(AActor, VisibleStartPitch)));
 	symt.AddSymbol(new PField(NAME_VisibleEndAngle,	TypeFloat64,	VARF_Native,				myoffsetof(AActor, VisibleEndAngle)));
@@ -688,6 +689,7 @@ void InitThingdef()
 	symt.AddSymbol(new PField("Pos",				TypeVector3,	VARF_Native|VARF_ReadOnly,  myoffsetof(AActor, __Pos)));
 	symt.AddSymbol(new PField("Vel",				TypeVector3,	VARF_Native,				myoffsetof(AActor, Vel)));
 	symt.AddSymbol(new PField("Scale",				TypeVector2,	VARF_Native,				myoffsetof(AActor, Scale)));
+	symt.AddSymbol(new PField("SeeState",			TypeState,		VARF_Native|VARF_ReadOnly,	myoffsetof(AActor, SeeState)));
 	symt.AddSymbol(new PField(NAME_Target,			TypeActor,		VARF_Native,				myoffsetof(AActor, target)));
 	symt.AddSymbol(new PField(NAME_Master,			TypeActor,		VARF_Native,				myoffsetof(AActor, master)));
 	symt.AddSymbol(new PField(NAME_Tracer,			TypeActor,		VARF_Native,				myoffsetof(AActor, tracer)));
diff --git a/src/scripting/vm/vm.h b/src/scripting/vm/vm.h
index 12ce01273..747d53c3b 100644
--- a/src/scripting/vm/vm.h
+++ b/src/scripting/vm/vm.h
@@ -915,7 +915,7 @@ void VMDisasm(FILE *out, const VMOP *code, int codesize, const VMScriptFunction
 #define PARAM_FLOAT_AT(p,x)			assert((p) < numparam); assert(param[p].Type == REGT_FLOAT); double x = param[p].f;
 #define PARAM_ANGLE_AT(p,x)		assert((p) < numparam); assert(param[p].Type == REGT_FLOAT); DAngle x = param[p].f;
 #define PARAM_STRING_AT(p,x)		assert((p) < numparam); assert(param[p].Type == REGT_STRING); FString x = param[p].s();
-#define PARAM_STATE_AT(p,x)			assert((p) < numparam); assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_STATE || param[p].a == NULL)); FState *x = (FState *)param[p].a;
+#define PARAM_STATE_AT(p,x)			assert((p) < numparam); assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_STATE || param[p].atag == ATAG_GENERIC  || param[p].a == NULL)); FState *x = (FState *)param[p].a;
 #define PARAM_POINTER_AT(p,x,type)	assert((p) < numparam); assert(param[p].Type == REGT_POINTER); type *x = (type *)param[p].a;
 #define PARAM_OBJECT_AT(p,x,type)	assert((p) < numparam); assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); type *x = (type *)param[p].a; assert(x == NULL || x->IsKindOf(RUNTIME_CLASS(type)));
 #define PARAM_CLASS_AT(p,x,base)	assert((p) < numparam); assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); base::MetaClass *x = (base::MetaClass *)param[p].a; assert(x == NULL || x->IsDescendantOf(RUNTIME_CLASS(base)));
@@ -932,8 +932,8 @@ void VMDisasm(FILE *out, const VMOP *code, int codesize, const VMScriptFunction
 #define PARAM_FLOAT_OPT_AT(p,x)			double x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_FLOAT); x = param[p].f; } else
 #define PARAM_ANGLE_OPT_AT(p,x)		DAngle x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_FLOAT); x = param[p].f; } else
 #define PARAM_STRING_OPT_AT(p,x)		FString x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_STRING); x = param[p].s(); } else
-#define PARAM_STATE_OPT_AT(p,x)			FState *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_STATE || param[p].a == NULL)); x = (FState *)param[p].a; } else
-#define PARAM_STATEINFO_OPT_AT(p,x)		FStateParamInfo *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_STATEINFO || param[p].a == NULL)); x = (FStateParamInfo *)param[p].a; } else
+#define PARAM_STATE_OPT_AT(p,x)			FState *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_STATE || param[p].atag == ATAG_GENERIC || param[p].a == NULL)); x = (FState *)param[p].a; } else
+#define PARAM_STATEINFO_OPT_AT(p,x)		FStateParamInfo *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_STATEINFO || param[p].atag == ATAG_GENERIC  || param[p].a == NULL)); x = (FStateParamInfo *)param[p].a; } else
 #define PARAM_POINTER_OPT_AT(p,x,type)	type *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER); x = (type *)param[p].a; } else
 #define PARAM_OBJECT_OPT_AT(p,x,type)	type *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); x = (type *)param[p].a; assert(x == NULL || x->IsKindOf(RUNTIME_CLASS(type))); } else
 #define PARAM_CLASS_OPT_AT(p,x,base)	base::MetaClass *x; if ((p) < numparam && param[p].Type != REGT_NIL) { assert(param[p].Type == REGT_POINTER && (param[p].atag == ATAG_OBJECT || param[p].a == NULL)); x = (base::MetaClass *)param[p].a; assert(x == NULL || x->IsDescendantOf(RUNTIME_CLASS(base))); } else
diff --git a/src/scripting/vm/vmbuilder.cpp b/src/scripting/vm/vmbuilder.cpp
index 1b7c4ce70..c72c2b567 100644
--- a/src/scripting/vm/vmbuilder.cpp
+++ b/src/scripting/vm/vmbuilder.cpp
@@ -665,6 +665,7 @@ VMFunction *FFunctionBuildList::AddFunction(PFunction *functype, FxExpression *c
 	it.Code = code;
 	it.PrintableName = name;
 	it.Function = new VMScriptFunction;
+	it.Function->Name = functype->SymbolName;
 	it.Function->ImplicitArgs = functype->GetImplicitArgs();
 	it.Proto = nullptr;
 	it.FromDecorate = fromdecorate;
diff --git a/wadsrc/static/zscript/actor.txt b/wadsrc/static/zscript/actor.txt
index 872a3ef98..027aaf7dc 100644
--- a/wadsrc/static/zscript/actor.txt
+++ b/wadsrc/static/zscript/actor.txt
@@ -51,6 +51,12 @@ class Actor : Thinker native
 	native void TraceBleed(int damage, Actor missile);
 	native bool CheckMeleeRange();
 	native int DamageMobj(Actor inflictor, Actor source, int damage, Name mod, int flags = 0, double angle = 0);
+	native double AimLineAttack(double angle, double distance, out FTranslatedLineTarget pLineTarget = null, double vrange = 0., int flags = 0, Actor target = null, Actor friender = null);
+	native Actor, int LineAttack(double angle, double distance, double pitch, int damage, Name damageType, class<Actor> pufftype, int flags = 0, out FTranslatedLineTarget victim = null);
+	native bool CheckSight(Actor target, int flags = 0);
+	native bool HitFriend();
+	native bool SetState(state st, bool nofunction = false);
+
 	
 	// DECORATE compatible functions
 	native bool CheckClass(class<Actor> checkclass, int ptr_select = AAPTR_DEFAULT, bool match_superclass = false);
@@ -88,10 +94,7 @@ class Actor : Thinker native
 	native void A_FaceTarget(float max_turn = 0, float max_pitch = 270, float ang_offset = 0, float pitch_offset = 0, int flags = 0, float z_ofs = 0);
 	native void A_FaceTracer(float max_turn = 0, float max_pitch = 270, float ang_offset = 0, float pitch_offset = 0, int flags = 0, float z_ofs = 0);
 	native void A_FaceMaster(float max_turn = 0, float max_pitch = 270, float ang_offset = 0, float pitch_offset = 0, int flags = 0, float z_ofs = 0);
-	native void A_PosAttack();
 	native void A_Scream();
-	native void A_SPosAttack();
-	native void A_SPosAttackUseAtkSound();
 	native void A_VileChase();
 	native void A_VileStart();
 	native void A_VileTarget(class<Actor> fire = "ArchvileFire");
@@ -108,8 +111,6 @@ class Actor : Thinker native
 	native void A_FatAttack2(class<Actor> spawntype = "FatShot");
 	native void A_FatAttack3(class<Actor> spawntype = "FatShot");
 	native void A_BossDeath();
-	native void A_CPosAttack();
-	native void A_CPosRefire();
 	native void A_SkullAttack(float speed = 20);
 	native void A_BetaSkullAttack();
 	native void A_Metal();
diff --git a/wadsrc/static/zscript/constants.txt b/wadsrc/static/zscript/constants.txt
index 41c4bfec9..f49264062 100644
--- a/wadsrc/static/zscript/constants.txt
+++ b/wadsrc/static/zscript/constants.txt
@@ -824,4 +824,41 @@ struct FStateParamInfo
 	int mPSPIndex;
 }
 
+// returned by AimLineAttack.
+struct FTranslatedLineTarget
+{
+	Actor linetarget;
+	double angleFromSource;
+	bool unlinked;	// found by a trace that went through an unlinked portal.
+}
 
+enum EAimFlags
+{
+	ALF_FORCENOSMART = 1,
+	ALF_CHECK3D = 2,
+	ALF_CHECKNONSHOOTABLE = 4,
+	ALF_CHECKCONVERSATION = 8,
+	ALF_NOFRIENDS = 16,
+	ALF_PORTALRESTRICT = 32,	// only work through portals with a global offset (to be used for stuff that cannot remember the calculated FTranslatedLineTarget info)
+}
+
+enum ELineAttackFlags
+{
+	LAF_ISMELEEATTACK = 1,
+	LAF_NORANDOMPUFFZ = 2,
+	LAF_NOIMPACTDECAL = 4,
+	LAF_NOINTERACT =	8,
+}
+
+const MELEERANGE = 64;
+const SAWRANGE = (64.+(1./65536.));	// use meleerange + 1 so the puff doesn't skip the flash (i.e. plays all states)
+const MISSILERANGE = (32*64);
+const PLAYERMISSILERANGE = 8192;	// [RH] New MISSILERANGE for players
+
+enum ESightFlags
+{
+	SF_IGNOREVISIBILITY=1,
+	SF_SEEPASTSHOOTABLELINES=2,
+	SF_SEEPASTBLOCKEVERYTHING=4,
+	SF_IGNOREWATERBOUNDARY=8
+}
diff --git a/wadsrc/static/zscript/doom/possessed.txt b/wadsrc/static/zscript/doom/possessed.txt
index de1e50ff2..8b6612076 100644
--- a/wadsrc/static/zscript/doom/possessed.txt
+++ b/wadsrc/static/zscript/doom/possessed.txt
@@ -251,3 +251,93 @@ class WolfensteinSS : Actor
 		Goto See ;
 	}
 }
+
+//===========================================================================
+//
+// Code (must be attached to Actor)
+//
+//===========================================================================
+
+extend class Actor
+{
+	void A_PosAttack()
+	{
+		if (target)
+		{
+			A_FaceTarget();
+			double ang = angle;
+			double slope = AimLineAttack(ang, MISSILERANGE);
+			A_PlaySound("grunt/attack", CHAN_WEAPON);
+			ang  += Random2[PosAttack]() * (22.5/256);
+			int damage = Random[PosAttack](1, 5) * 3;
+			LineAttack(ang, MISSILERANGE, slope, damage, "Hitscan", "Bulletpuff");
+		}
+	}
+	
+	
+	private void A_SPosAttackInternal()
+	{
+		if (target)
+		{
+			A_FaceTarget();
+			double bangle = angle;
+			double slope = AimLineAttack(bangle, MISSILERANGE);
+		
+			for (int i=0 ; i<3 ; i++)
+			{
+				double ang = bangle + Random2[SPosAttack]() * (22.5/256);
+				int damage = Random[SPosAttack](1, 5) * 3;
+				LineAttack(ang, MISSILERANGE, slope, damage, "Hitscan", "Bulletpuff");
+			}
+		}
+    }
+	
+	void A_SPosAttackUseAtkSound()
+	{
+		if (target)
+		{
+			A_PlaySound(AttackSound, CHAN_WEAPON);
+			A_SPosAttackInternal();
+		}
+	}
+	
+	// This version of the function, which uses a hard-coded sound, is meant for Dehacked only.
+	void A_SPosAttack()
+	{
+		if (target)
+		{
+			A_PlaySound("shotguy/attack", CHAN_WEAPON);
+			A_SPosAttackInternal();
+		}
+	}
+	
+	void A_CPosAttack()
+	{
+		if (target)
+		{
+			if (bStealth) visdir = 1;
+			A_PlaySound(AttackSound, CHAN_WEAPON);
+			A_FaceTarget();
+			double slope = AimLineAttack(angle, MISSILERANGE);
+			double ang = angle + Random2[SPosAttack]() * (22.5/256);
+			int damage = Random[CPosAttack](1, 5) * 3;
+			LineAttack(ang, MISSILERANGE, slope, damage, "Hitscan", "Bulletpuff");
+		}
+	}
+	
+	void A_CPosRefire()
+	{
+		// keep firing unless target got out of sight
+		A_FaceTarget();
+		if (Random[CPosRefire](0, 255) >= 40)
+		{
+			if (!target
+				|| HitFriend()
+				|| target.health <= 0
+				|| !CheckSight(target, SF_SEEPASTBLOCKEVERYTHING|SF_SEEPASTSHOOTABLELINES))
+			{
+				SetState(SeeState);
+			}
+		}
+	}
+}