Swap overlay cache for appearance cache in SSskybox

code/controllers/subsystems/skybox.dm

@@ -6,6 +6,7 @@ SUBSYSTEM_DEF(skybox)
 	flags = SS_NO_FIRE
 	var/static/list/skybox_cache = list()
 
+	var/static/mutable_appearance/normal_space
 	var/static/list/dust_cache = list()
 	var/static/list/speedspace_cache = list()
 	var/static/list/mapedge_cache = list()
@@ -13,52 +14,75 @@ SUBSYSTEM_DEF(skybox)
 	var/static/list/phase_shift_by_y = list()
 
 /datum/controller/subsystem/skybox/PreInit()
+	//Shuffle some lists
+	phase_shift_by_x = get_cross_shift_list(15)
+	phase_shift_by_y = get_cross_shift_list(15)
+
+	//Create our 'normal' space appearance
+	normal_space = new()
+	normal_space.name = "\proper space"
+	normal_space.desc = "Space!"
+	normal_space.mouse_opacity = 2 //Always fully opaque. It's SPACE there can't be things BEHIND IT.
+	normal_space.appearance_flags = TILE_BOUND|PIXEL_SCALE|KEEP_TOGETHER
+	normal_space.plane = SPACE_PLANE
+	normal_space.layer = TURF_LAYER
+	normal_space.icon = 'icons/turf/space.dmi'
+	normal_space.icon_state = "white"
+	
 	//Static
 	for (var/i in 0 to 25)
+		var/mutable_appearance/MA = new(normal_space)
 		var/image/im = image('icons/turf/space_dust.dmi', "[i]")
 		im.plane = DUST_PLANE
 		im.alpha = 128 //80
 		im.blend_mode = BLEND_ADD
-		dust_cache["[i]"] = im
+		
+		MA.overlays = list(im)
+
+		dust_cache["[i]"] = MA
+	
 	//Moving
 	for (var/i in 0 to 14)
 		// NORTH/SOUTH
+		var/mutable_appearance/MA = new(normal_space)
 		var/image/im = image('icons/turf/space_dust_transit.dmi', "speedspace_ns_[i]")
 		im.plane = DUST_PLANE
 		im.blend_mode = BLEND_ADD
-		speedspace_cache["NS_[i]"] = im
+		MA.overlays = list(im)
+		speedspace_cache["NS_[i]"] = MA
 		// EAST/WEST
+		MA = new(normal_space)
 		im = image('icons/turf/space_dust_transit.dmi', "speedspace_ew_[i]")
 		im.plane = DUST_PLANE
 		im.blend_mode = BLEND_ADD
-		speedspace_cache["EW_[i]"] = im
+		
+		MA.overlays = list(im)
+		
+		speedspace_cache["EW_[i]"] = MA
+	
 	//Over-the-edge images
 	for (var/dir in alldirs)
-		var/image/I = image('icons/turf/space.dmi', "white")
+		var/mutable_appearance/MA = new(normal_space)
 		var/matrix/M = matrix()
 		var/horizontal = (dir & (WEST|EAST))
 		var/vertical = (dir & (NORTH|SOUTH))
 		M.Scale(horizontal ? 8 : 1, vertical ? 8 : 1)
-		I.transform = M
-		I.appearance_flags = KEEP_APART | TILE_BOUND
-		I.plane = SPACE_PLANE
-		I.layer = 0
+		MA.transform = M
+		MA.appearance_flags = KEEP_APART | TILE_BOUND
+		MA.plane = SPACE_PLANE
+		MA.layer = 0
 
 		if(dir & NORTH)
-			I.pixel_y = 112
+			MA.pixel_y = 112
 		else if(dir & SOUTH)
-			I.pixel_y = -112
+			MA.pixel_y = -112
 
 		if(dir & EAST)
-			I.pixel_x = 112
+			MA.pixel_x = 112
 		else if(dir & WEST)
-			I.pixel_x = -112
+			MA.pixel_x = -112
 
-		mapedge_cache["[dir]"] = I
-
-	//Shuffle some lists
-	phase_shift_by_x = get_cross_shift_list(15)
-	phase_shift_by_y = get_cross_shift_list(15)
+		mapedge_cache["[dir]"] = MA
 
 	. = ..()
 

code/game/turfs/space/space.dm

@@ -9,46 +9,20 @@
 	thermal_conductivity = OPEN_HEAT_TRANSFER_COEFFICIENT
 	can_build_into_floor = TRUE
 	var/keep_sprite = FALSE
-	var/edge = 0
+	var/edge = 0 //If we're an edge
+	var/forced_dirs = 0 //Force this one to pretend it's an overedge turf
 
 /turf/space/Initialize()
 	. = ..()
 
-	if(!keep_sprite)
-		icon_state = "white"
-
 	if(config.starlight)
 		update_starlight()
 
-	build_overedge() //Spread out over the edge of the map if we're an edge
-	toggle_transit() //Add static dust (not passing a dir)
+	//Sprite stuff only beyond here
+	if(keep_sprite)
+		return .
 
-/turf/space/proc/toggle_transit(var/direction)
-	cut_overlays()
-
-	if(!direction)
-		add_overlay(SSskybox.dust_cache["[((x + y) ^ ~(x * y) + z) % 25]"])
-		return
-
-	if(direction & (NORTH|SOUTH))
-		var/x_shift = SSskybox.phase_shift_by_x[src.x % (SSskybox.phase_shift_by_x.len - 1) + 1]
-		var/transit_state = ((direction & SOUTH ? world.maxy - src.y : src.y) + x_shift)%15
-		add_overlay(SSskybox.speedspace_cache["NS_[transit_state]"])
-	else if(direction & (EAST|WEST))
-		var/y_shift = SSskybox.phase_shift_by_y[src.y % (SSskybox.phase_shift_by_y.len - 1) + 1]
-		var/transit_state = ((direction & WEST ? world.maxx - src.x : src.x) + y_shift)%15
-		add_overlay(SSskybox.speedspace_cache["EW_[transit_state]"])
-
-	for(var/atom/movable/AM in src)
-		if (!AM.simulated)
-			continue
-
-		if(!AM.anchored)
-			AM.throw_at(get_step(src,reverse_direction(direction)), 5, 1)
-		else if (istype(AM, /obj/effect/decal))
-			qdel(AM) //No more space blood coming with the shuttle
-
-/turf/space/proc/build_overedge(var/forced_dirs)
+	//We might be an edge
 	if(y == world.maxy || forced_dirs & NORTH)
 		edge |= NORTH
 	else if(y == 1 || forced_dirs & SOUTH)
@@ -59,10 +33,34 @@
 	else if(x == world.maxx || forced_dirs & EAST)
 		edge |= EAST
 
-	if(!edge)
+	if(edge) //Magic edges
+		appearance = SSskybox.mapedge_cache["[edge]"]
+	else //Dust
+		appearance = SSskybox.dust_cache["[((x + y) ^ ~(x * y) + z) % 25]"]
+
+/turf/space/proc/toggle_transit(var/direction)
+	if(edge) //Not a great way to do this yet. Maybe we'll come up with one. We could pre-make sprites... or tile the overlay over it?
 		return
 	
-	add_overlay(SSskybox.mapedge_cache["[edge]"], TRUE)
+	if(!direction) //Stopping our transit
+		appearance = SSskybox.dust_cache["[((x + y) ^ ~(x * y) + z) % 25]"]
+	else if(direction & (NORTH|SOUTH)) //Starting transit vertically
+		var/x_shift = SSskybox.phase_shift_by_x[src.x % (SSskybox.phase_shift_by_x.len - 1) + 1]
+		var/transit_state = ((direction & SOUTH ? world.maxy - src.y : src.y) + x_shift)%15
+		appearance = SSskybox.speedspace_cache["NS_[transit_state]"]
+	else if(direction & (EAST|WEST)) //Starting transit horizontally
+		var/y_shift = SSskybox.phase_shift_by_y[src.y % (SSskybox.phase_shift_by_y.len - 1) + 1]
+		var/transit_state = ((direction & WEST ? world.maxx - src.x : src.x) + y_shift)%15
+		appearance = SSskybox.speedspace_cache["EW_[transit_state]"]
+
+	for(var/atom/movable/AM in src)
+		if (!AM.simulated)
+			continue
+
+		if(!AM.anchored)
+			AM.throw_at(get_step(src,reverse_direction(direction)), 5, 1)
+		else if (istype(AM, /obj/effect/decal))
+			qdel(AM) //No more space blood coming with the shuttle
 
 /turf/space/is_space()
 	return 1

maps/submaps/_helpers.dm

@@ -5,26 +5,30 @@
 	opacity = 1
 	blocks_air = TRUE
 
-/turf/space/internal_edge/Initialize()
-	. = ..()
-	build_overedge(dir)
-
 /turf/space/internal_edge/top
 	dir = NORTH
+	forced_dirs = NORTH
 /turf/space/internal_edge/bottom
 	dir = SOUTH
+	forced_dirs = SOUTH
 /turf/space/internal_edge/left
 	dir = WEST
+	forced_dirs = WEST
 /turf/space/internal_edge/right
 	dir = EAST
+	forced_dirs = EAST
 /turf/space/internal_edge/topleft
 	dir = NORTHWEST
+	forced_dirs = NORTHWEST
 /turf/space/internal_edge/topright
 	dir = NORTHEAST
+	forced_dirs = NORTHEAST
 /turf/space/internal_edge/bottomleft
 	dir = SOUTHWEST
+	forced_dirs = SOUTHWEST
 /turf/space/internal_edge/bottomright
 	dir = SOUTHEAST
+	forced_dirs = SOUTHEAST
 
 //These are fake stairs, that when you try to go up them, they shove you to
 //  their 'connected' friend! Try to use the appropriate top/bottom ones for good looks.