Subsystem created... works!

code/__HELPERS/icon_smoothing.dm

@@ -111,12 +111,15 @@
 /proc/smooth_icon(atom/A)
 	if(QDELETED(A))
 		return
-	if(A && (A.smooth & SMOOTH_TRUE) || (A.smooth & SMOOTH_MORE))
-		var/adjacencies = calculate_adjacencies(A)
-		if(A.smooth & SMOOTH_DIAGONAL)
-			A.diagonal_smooth(adjacencies)
-		else
-			cardinal_smooth(A, adjacencies)
+	if(!A || !A.smooth)
+		return
+	spawn(0)
+		if((A.smooth & SMOOTH_TRUE) || (A.smooth & SMOOTH_MORE))
+			var/adjacencies = calculate_adjacencies(A)
+			if(A.smooth & SMOOTH_DIAGONAL)
+				A.diagonal_smooth(adjacencies)
+			else
+				cardinal_smooth(A, adjacencies)
 
 /atom/proc/diagonal_smooth(adjacencies)
 	switch(adjacencies)
@@ -244,23 +247,11 @@
 		A.bottom_left_corner = se
 		A.overlays += se
 
-/proc/find_type_in_direction(atom/source, direction, range=1)
-	var/x_offset = 0
-	var/y_offset = 0
-
-	if(direction & NORTH)
-		y_offset = range
-	else if(direction & SOUTH)
-		y_offset -= range
-
-	if(direction & EAST)
-		x_offset = range
-	else if(direction & WEST)
-		x_offset -= range
-
-	var/turf/target_turf = locate(source.x + x_offset, source.y + y_offset, source.z)
+/proc/find_type_in_direction(atom/source, direction)
+	var/turf/target_turf = get_step(source, direction)
 	if(!target_turf)
 		return NULLTURF_BORDER
+
 	if(source.canSmoothWith)
 		var/atom/A
 		if(source.smooth & SMOOTH_MORE)
@@ -287,22 +278,22 @@
 
 //Icon smoothing helpers
 
-/proc/smooth_icon_neighbors(atom/A)
-	for(var/V in orange(1,A))
-		var/atom/T = V
-		if(T.smooth)
-			smooth_icon(T)
-
-/proc/smooth_zlevel(var/zlevel)
+/proc/smooth_zlevel(var/zlevel, now = FALSE)
 	var/list/away_turfs = block(locate(1, 1, zlevel), locate(world.maxx, world.maxy, zlevel))
 	for(var/V in away_turfs)
 		var/turf/T = V
 		if(T.smooth)
-			smooth_icon(T)
+			if(now)
+				smooth_icon(T)
+			else
+				queue_smooth(T)
 		for(var/R in T)
 			var/atom/A = R
 			if(A.smooth)
-				smooth_icon(A)
+				if(now)
+					smooth_icon(A)
+				else
+					queue_smooth(A)
 
 /atom/proc/clear_smooth_overlays()
 	overlays -= top_left_corner
@@ -362,6 +353,31 @@
 		else
 			return 0
 
+//SSicon_smooth
+/proc/ss_smooth_icon(atom/A)
+	if(QDELETED(A))
+		return
+	if(!istype(A) || (A && !A.smooth))
+		return
+	if((A.smooth & SMOOTH_TRUE) || (A.smooth & SMOOTH_MORE))
+		var/adjacencies = calculate_adjacencies(A)
+		if(A.smooth & SMOOTH_DIAGONAL)
+			A.diagonal_smooth(adjacencies)
+		else
+			cardinal_smooth(A, adjacencies)
+ //SSicon_smooth
+/proc/queue_smooth_neighbors(atom/A)
+	for(var/V in orange(1,A))
+		var/atom/T = V
+		if(T.smooth)
+			queue_smooth(T)
+ //SSicon_smooth
+/proc/queue_smooth(atom/A)
+	if(SSicon_smooth)
+		SSicon_smooth.smooth_queue |= A
+	else
+		smooth_icon(A)
+
 //Example smooth wall
 /turf/simulated/wall/smooth
 	name = "smooth wall"

code/controllers/subsystem/icon_smooth.dm

@@ -0,0 +1,24 @@
+var/datum/controller/subsystem/icon_smooth/SSicon_smooth
+
+/datum/controller/subsystem/icon_smooth
+	name = "Icon Smoothing"
+	priority = -5
+	wait = 5
+	var/list/smooth_queue = list()
+
+/datum/controller/subsystem/icon_smooth/New()
+	NEW_SS_GLOBAL(SSicon_smooth)
+
+/datum/controller/subsystem/icon_smooth/fire()
+	for(var/atom in smooth_queue)
+		ss_smooth_icon(atom)
+		smooth_queue -= atom
+
+/datum/controller/subsystem/icon_smooth/Initialize()
+	smooth_zlevel(1,TRUE)
+	smooth_zlevel(2,TRUE)
+	for(var/V in smooth_queue)
+		var/atom/A = V
+		if(A.z == 1 || A.z == 2)
+			smooth_queue -= A
+	..()

code/game/objects/structures.dm

@@ -32,8 +32,8 @@
 	..()
 	if(smooth)
 		if(ticker && ticker.current_state == GAME_STATE_PLAYING)
-			smooth_icon(src)
-			smooth_icon_neighbors(src)
+			queue_smooth(src)
+			queue_smooth_neighbors(src)
 		icon_state = ""
 	if(climbable)
 		verbs += /obj/structure/proc/climb_on
@@ -46,7 +46,7 @@
 	if(smooth)
 		var/turf/T = get_turf(src)
 		spawn(0)
-			smooth_icon_neighbors(T)
+			queue_smooth_neighbors(T)
 	return ..()
 
 /obj/structure/proc/climb_on()

code/game/objects/structures/false_walls.dm

@@ -82,7 +82,7 @@
 	if(density)
 		icon_state = initial(icon_state)
 		smooth = SMOOTH_TRUE
-		smooth_icon(src)
+		queue_smooth(src)
 	else
 		icon_state = "fwall_open"
 
@@ -322,4 +322,4 @@
 	mineral = /obj/item/stack/sheet/mineral/plastitanium
 	walltype = /turf/simulated/wall/mineral/plastitanium
 	smooth = SMOOTH_MORE
-	canSmoothWith = list(/turf/simulated/wall/mineral/plastitanium, /obj/machinery/door/airlock/shuttle, /obj/machinery/door/airlock, /obj/structure/window/full/shuttle, /obj/structure/shuttle/engine/heater)
+	canSmoothWith = list(/turf/simulated/wall/mineral/plastitanium, /obj/machinery/door/airlock/shuttle, /obj/machinery/door/airlock, /obj/structure/window/full/shuttle, /obj/structure/shuttle/engine/heater)

code/game/objects/structures/tables_racks.dm

@@ -50,8 +50,8 @@
 /obj/structure/table/update_icon()
 	if(smooth && !flipped)
 		icon_state = ""
-		smooth_icon(src)
-		smooth_icon_neighbors(src)
+		queue_smooth(src)
+		queue_smooth_neighbors(src)
 
 	if(flipped)
 		clear_smooth_overlays()

code/game/objects/structures/window.dm

@@ -425,7 +425,7 @@ var/global/wcCommon = pick(list("#379963", "#0d8395", "#58b5c3", "#49e46e", "#8f
 /obj/structure/window/proc/update_nearby_icons()
 	update_icon()
 	if(smooth)
-		smooth_icon_neighbors(src)
+		queue_smooth_neighbors(src)
 
 /obj/structure/window/update_icon()
 	if(!QDELETED(src))
@@ -434,7 +434,7 @@ var/global/wcCommon = pick(list("#379963", "#0d8395", "#58b5c3", "#49e46e", "#8f
 		var/ratio = obj_integrity / max_integrity
 		ratio = CEILING(ratio*4, 1) * 25
 		if(smooth)
-			smooth_icon(src)
+			queue_smooth(src)
 		overlays -= crack_overlay
 		if(ratio > 75)
 			return
@@ -714,4 +714,4 @@ obj/structure/window/full/reinforced/ice
 	dir = FULLTILE_WINDOW_DIR
 	max_integrity = 120
 	level = 3
-	glass_amount = 2
+	glass_amount = 2

code/game/turfs/simulated.dm

@@ -85,6 +85,6 @@
 
 /turf/simulated/ChangeTurf(var/path)
 	. = ..()
-	smooth_icon_neighbors(src)
+	queue_smooth_neighbors(src)
 
 /turf/simulated/proc/is_shielded()

code/game/turfs/simulated/floor/fancy_floor.dm

@@ -131,11 +131,11 @@
 		return 0
 	if(!broken && !burnt)
 		if(smooth)
-			smooth_icon(src)
+			queue_smooth(src)
 	else
 		make_plating()
 		if(smooth)
-			smooth_icon_neighbors(src)
+			queue_smooth_neighbors(src)
 
 /turf/simulated/floor/carpet/break_tile()
 	broken = 1

code/game/turfs/simulated/walls.dm

@@ -72,7 +72,7 @@
 	if(!damage_overlays[1]) //list hasn't been populated
 		generate_overlays()
 
-	smooth_icon(src)
+	queue_smooth(src)
 	if(!damage)
 		if(damage_overlay)
 			overlays -= damage_overlays[damage_overlay]

code/game/turfs/simulated/walls_reinforced.dm

@@ -65,7 +65,7 @@
 
 				d_state = RWALL_INTACT
 				update_icon()
-				smooth_icon_neighbors(src)
+				queue_smooth_neighbors(src)
 				to_chat(user, "<span class='notice'>You repair the last of the damage.</span>")
 
 			return TRUE
@@ -84,7 +84,7 @@
 			to_chat(user, "<span class='notice'>You add an additional layer of coating to the wall.</span>")
 			ChangeTurf(/turf/simulated/wall/r_wall/coated)
 			update_icon()
-			smooth_icon_neighbors(src)
+			queue_smooth_neighbors(src)
 			can_be_reinforced = FALSE
 		return TRUE
 	return FALSE

code/game/turfs/turf.dm

@@ -39,18 +39,18 @@
 	for(var/atom/movable/AM in src)
 		Entered(AM)
 	if(smooth && ticker && ticker.current_state == GAME_STATE_PLAYING)
-		smooth_icon(src)
+		queue_smooth(src)
 
 /hook/startup/proc/smooth_world()
 	var/watch = start_watch()
 	log_startup_progress("Smoothing atoms...")
 	for(var/turf/T in world)
 		if(T.smooth)
-			smooth_icon(T)
+			queue_smooth(T)
 		for(var/A in T)
 			var/atom/AA = A
 			if(AA.smooth)
-				smooth_icon(AA)
+				queue_smooth(AA)
 	log_startup_progress(" Smoothed atoms in [stop_watch(watch)]s.")
 	return 1
 
@@ -477,4 +477,4 @@
 	SSair.add_to_active(T0,1)
 
 /turf/AllowDrop()
-	return TRUE
+	return TRUE

code/modules/awaymissions/zlevel.dm

@@ -17,11 +17,11 @@ var/global/list/potentialRandomZlevels = generateMapList(filename = "config/away
 	log_debug("Smoothing tiles")
 	for(var/turf/T in smoothTurfs)
 		if(T.smooth)
-			smooth_icon(T)
+			queue_smooth(T)
 		for(var/R in T)
 			var/atom/A = R
 			if(A.smooth)
-				smooth_icon(A)
+				queue_smooth(A)
 		if(istype(T, /turf/simulated/mineral)) // For the listening post, among other maps
 			var/turf/simulated/mineral/MT = T
 			MT.add_edges()

code/modules/shuttle/on_move.dm

@@ -52,7 +52,7 @@
 // After docking //
 /atom/proc/postDock(obj/docking_port/S1)
 	if(smooth)
-		smooth_icon(src)
+		queue_smooth(src)
 
 /obj/machinery/door/airlock/postDock(obj/docking_port/stationary/S1)
 	. = ..()

code/modules/shuttle/ripple.dm

@@ -15,5 +15,5 @@
 
 /obj/effect/temp_visual/ripple/New()
 	. = ..()
-	smooth_icon(src)
+	queue_smooth(src)
 	animate(src, alpha=255, time=SHUTTLE_RIPPLE_TIME)

paradise.dme

@@ -204,6 +204,7 @@
 #include "code\controllers\subsystem\atoms.dm"
 #include "code\controllers\subsystem\fires.dm"
 #include "code\controllers\subsystem\garbage.dm"
+#include "code\controllers\subsystem\icon_smooth.dm"
 #include "code\controllers\subsystem\machinery.dm"
 #include "code\controllers\subsystem\mobs.dm"
 #include "code\controllers\subsystem\nano_mob_hunter.dm"