* Generalized AStar check for objects preventing passability

* Fixed AStar not detecting plastic flaps as impassable for mobs that can't pass them (fixes #14616)

code/game/objects/objs.dm

@@ -199,3 +199,6 @@
 	tesla_zap(src, 3, power_bounced)
 	spawn(10)
 		being_shocked = 0
+
+/obj/proc/CanAStarPass()
+	. = !density

code/game/objects/structures/plasticflaps.dm

@@ -7,6 +7,17 @@
 	anchored = 1
 	layer = 4
 
+/obj/structure/plasticflaps/CanAStarPass(ID, to_dir, caller)
+	if(istype(caller, /mob/living))
+		if(istype(caller,/mob/living/simple_animal/bot/mulebot))
+			return 1
+
+		var/mob/living/M = caller
+		if(!M.ventcrawler && M.mob_size != MOB_SIZE_TINY)
+			return 0
+
+	return 1 //diseases, stings, etc can pass
+
 /obj/structure/plasticflaps/CanPass(atom/movable/A, turf/T)
 	if(istype(A) && A.checkpass(PASSGLASS))
 		return prob(60)

code/game/objects/structures/window.dm

@@ -439,6 +439,14 @@
 /obj/structure/window/storage_contents_dump_act(obj/item/weapon/storage/src_object, mob/user)
 	return 0
 
+/obj/structure/window/CanAStarPass(ID, to_dir)
+	if(!density)
+		return 1
+	if((dir == SOUTHWEST) || (dir == to_dir))
+		return 0
+
+	return 1
+
 /obj/structure/window/reinforced
 	name = "reinforced window"
 	icon_state = "rwindow"