Add is_plating feature to flooring

code/game/turfs/flooring/flooring.dm

@@ -45,6 +45,7 @@ var/list/flooring_types
 	var/can_paint
 	var/list/footstep_sounds = list() // key=species name, value = list of sounds, 
 									  // For instance, footstep_sounds = list("key" = list(sound.ogg))
+	var/is_plating = FALSE
 
 /decl/flooring/grass
 	name = "grass"

code/game/turfs/simulated/floor.dm

@@ -33,7 +33,9 @@
 	var/lava = 0
 
 /turf/simulated/floor/is_plating()
-	return !flooring
+	if(!flooring || flooring.is_plating)
+		return TRUE
+	return FALSE
 
 /turf/simulated/floor/Initialize(mapload, floortype)
 	. = ..()
@@ -95,8 +97,9 @@
 		update_icon(1)
 
 /turf/simulated/floor/levelupdate()
+	var/floored_over = !is_plating()
 	for(var/obj/O in src)
-		O.hide(O.hides_under_flooring() && src.flooring)
+		O.hide(O.hides_under_flooring() && floored_over)
 
 /turf/simulated/floor/rcd_values(mob/living/user, obj/item/weapon/rcd/the_rcd, passed_mode)
 	switch(passed_mode)

code/game/turfs/simulated/floor_types_eris.dm

@@ -872,11 +872,11 @@
 	flags = TURF_REMOVE_WRENCH | TURF_HAS_CORNERS | TURF_HAS_EDGES | TURF_CAN_BURN | TURF_CAN_BREAK
 	can_paint = 1
 	has_base_range = 18
+	is_plating = TRUE
 	//build_type = /obj/item/stack/material/steel
 	
 	/* Eris features we lack on flooring decls
 	plating_type = /decl/flooring/reinforced/plating/under
-	is_plating = TRUE
 	footstep_sound = "plating"
 	space_smooth = FALSE
 	removal_time = 150
@@ -908,12 +908,12 @@
 	icon_base = "under"
 	flags = TURF_HAS_CORNERS | TURF_HAS_EDGES | TURF_CAN_BURN | TURF_CAN_BREAK
 	has_base_range = 0
+	is_plating = TRUE
 
 	//build_type = /obj/item/stack/material/underplating
 	
 	/* Eris features we lack on flooring decls
 	plating_type = /decl/flooring/reinforced/plating/hull
-	is_plating = TRUE
 	removal_time = 250
 	health = 200
 	resistance = RESISTANCE_ARMOURED
@@ -941,11 +941,11 @@
 	flags = TURF_HAS_EDGES | TURF_HAS_CORNERS | TURF_REMOVE_WRENCH | TURF_CAN_BURN | TURF_CAN_BREAK
 	build_type = /obj/item/stack/material/plasteel
 	has_base_range = 35
+	is_plating = FALSE
 	
 	/* Eris features we lack on flooring decls
 	try_update_icon = 0
 	plating_type = null
-	is_plating = TRUE
 	health = 350
 	resistance = RESISTANCE_HEAVILY_ARMOURED
 	removal_time = 1 MINUTES //Cutting through the hull is very slow work