Fixed Thing_ProjectileAimed being broken.

- It was calling the fallback aiming in the wrong place when it should have been outside the speed check.
- Credit to _mental_ for the base code, but no gotos involved.

src/p_things.cpp

@@ -163,16 +163,30 @@ bool P_Thing_Move (int tid, AActor *source, int mapspot, bool fog)
 	return false;
 }
 
+//==========================================================================
+//
+// VelIntercept
+//
+//==========================================================================
+
+void InterceptDefaultAim(AActor *mobj, AActor *targ, DVector3 aim, double speed)
+{
+	if (mobj == nullptr || targ == nullptr)	return;
+	mobj->Angles.Yaw = mobj->AngleTo(targ);
+	mobj->Vel = aim.Resized(speed);
+}
+
 // [MC] Was part of P_Thing_Projectile, now its own function for use in ZScript.
 // Aims mobj at targ based on speed and targ's velocity.
-void VelIntercept(AActor *targ, AActor *mobj, double speed, bool aimpitch = false, bool oldvel = false)
+static void VelIntercept(AActor *targ, AActor *mobj, double speed, bool aimpitch = false, bool oldvel = false, bool leadtarget = true)
 {
 	if (targ == nullptr || mobj == nullptr)	return;
 
-	if (speed > 0 && !targ->Vel.isZero())
-	{
 	DVector3 aim = mobj->Vec3To(targ);
 	aim.Z += targ->Height / 2;
+
+	if (leadtarget && speed > 0 && !targ->Vel.isZero())
+	{
 		// Aiming at the target's position some time in the future
 		// is basically just an application of the law of sines:
 		//     a/sin(A) = b/sin(B)
@@ -180,7 +194,6 @@ void VelIntercept(AActor *targ, AActor *mobj, double speed, bool aimpitch = fals
 		// with the math. I don't think I would have thought of using
 		// trig alone had I been left to solve it by myself.
 
-		bool nolead = false;
 		DVector3 tvel = targ->Vel;
 		if (!(targ->flags & MF_NOGRAVITY) && targ->waterlevel < 3)
 		{ // If the target is subject to gravity and not underwater,
@@ -188,10 +201,13 @@ void VelIntercept(AActor *targ, AActor *mobj, double speed, bool aimpitch = fals
 		  // even if we did consider the vertical component of the target's
 		  // velocity, we would still miss more often than not.
 			tvel.Z = 0.0;
-			nolead = !!(targ->Vel.X == 0 && targ->Vel.Y == 0);
+
-		}
+			if (targ->Vel.X == 0 && targ->Vel.Y == 0)
-		if (!nolead)
 			{
+				InterceptDefaultAim(mobj, targ, aim, speed);
+				return;
+			}
+		}
 		double dist = aim.Length();
 		double targspeed = tvel.Length();
 		double ydotx = -aim | tvel;
@@ -224,9 +240,7 @@ void VelIntercept(AActor *targ, AActor *mobj, double speed, bool aimpitch = fals
 	}
 	else
 	{
-			mobj->Angles.Yaw = mobj->AngleTo(targ);
+		InterceptDefaultAim(mobj, targ, aim, speed);
-			mobj->Vel = aim.Resized(speed);
-		}
 	}
 }
 
@@ -325,10 +339,8 @@ bool P_Thing_Projectile (int tid, AActor *source, int type, const char *type_nam
 
 					if (targ != nullptr)
 					{
-						if (leadTarget)
+						VelIntercept(targ, mobj, speed, false, false, leadTarget);
-						{
+
-							VelIntercept(targ, mobj, speed);
-						}
 						if (mobj->flags2 & MF2_SEEKERMISSILE)
 						{
 							mobj->tracer = targ;