[DNM][DNM][WIP] Projectile backend code port and update

Ports#54924,  #65061, #59804 from /tg.
adds auxiliary code from /tg to make code work.

code/game/objects/structures/window.dm

@@ -18,6 +18,7 @@ GLOBAL_LIST_EMPTY(electrochromatic_window_lookup)
 	pressure_resistance = 4*ONE_ATMOSPHERE
 	anchored = TRUE //initially is 0 for tile smoothing
 	max_integrity = 25
+	pass_flags_self = PASSGLASS
 	var/ini_dir = null
 	var/state = WINDOW_OUT_OF_FRAME
 	var/reinf = FALSE
@@ -90,13 +91,13 @@ GLOBAL_LIST_EMPTY(electrochromatic_window_lookup)
 	. = ..()
 	if(direct)
 		setDir(direct)
-	
+
 	if(extra_reinforced && anchored)
 		state = PRWINDOW_SECURE
 
 	else if(reinf && anchored)
 		state = WINDOW_SCREWED_TO_FRAME
-	
+
 
 	if(mapload && electrochromatic_id && electrochromatic_id[1] == "!")
 		electrochromatic_id = SSmapping.get_obfuscated_id(electrochromatic_id)
@@ -159,13 +160,15 @@ GLOBAL_LIST_EMPTY(electrochromatic_window_lookup)
 	else
 		..(FULLTILE_WINDOW_DIR)
 
-/obj/structure/window/CanPass(atom/movable/mover, turf/target)
-	if(istype(mover) && (mover.pass_flags & PASSGLASS))
-		return 1
+/obj/structure/window/CanAllowThrough(atom/movable/mover, turf/target)
+	. = ..()
+	if(.)
+		return
 	if(dir == FULLTILE_WINDOW_DIR)
 		return 0	//full tile window, you can't move into it!
-	if(get_dir(loc, target) == dir)
-		return !density
+	var/attempted_dir = get_dir(loc, target)
+	if(attempted_dir == dir)
+		return
 	if(istype(mover, /obj/structure/window))
 		var/obj/structure/window/W = mover
 		if(!valid_window_location(loc, W.ini_dir))
@@ -176,7 +179,8 @@ GLOBAL_LIST_EMPTY(electrochromatic_window_lookup)
 			return FALSE
 	else if(istype(mover, /obj/machinery/door/window) && !valid_window_location(loc, mover.dir))
 		return FALSE
-	return 1
+	else if(attempted_dir != dir)
+		return TRUE
 
 /obj/structure/window/CheckExit(atom/movable/O, turf/target)
 	if(istype(O) && (O.pass_flags & PASSGLASS))