Layers are now defines (#17949)

* Layers are now defines

* this looks better

* GAS_phil_LAYER

* no message

* remove the three unneeded defines

* no message

code/modules/atmospherics/environmental/LINDA_fire.dm

@@ -49,7 +49,7 @@
 	unacidable = 1//So you can't melt fire with acid.
 	icon = 'icons/effects/fire.dmi'
 	icon_state = "1"
-	layer = TURF_LAYER
+	layer = ABOVE_OPEN_TURF_LAYER
 	luminosity = 3
 
 	var/volume = 125

code/modules/atmospherics/gasmixtures/gas_types.dm

@@ -76,7 +76,7 @@ var/list/hardcoded_gases = list("o2","n2","co2","plasma") //the main four gases,
 /obj/effect/overlay/gas/
 	icon = 'icons/effects/tile_effects.dmi'
 	mouse_opacity = 0
-	layer = 5
+	layer = FLY_LAYER
 	appearance_flags = RESET_COLOR|TILE_BOUND
 
 /obj/effect/overlay/gas/New(state)

code/modules/atmospherics/machinery/atmosmachinery.dm

@@ -15,6 +15,7 @@ Pipelines + Other Objects -> Pipe network
 	active_power_usage = 0
 	power_channel = ENVIRON
 	on_blueprints = TRUE
+	layer = GAS_PIPE_LAYER //under wires
 	var/nodealert = 0
 	var/can_unwrench = 0
 	var/initialize_directions = 0

code/modules/atmospherics/machinery/components/unary_devices/unary_devices.dm

@@ -2,7 +2,6 @@
 	icon = 'icons/obj/atmospherics/components/unary_devices.dmi'
 	dir = SOUTH
 	initialize_directions = SOUTH
-	layer = TURF_LAYER+0.1
 	device_type = UNARY
 
 /obj/machinery/atmospherics/components/unary/SetInitDirections()

code/modules/atmospherics/machinery/components/unary_devices/vent_pump.dm

@@ -259,7 +259,7 @@
 					user.visible_message("[user] unwelds the vent.", "<span class='notice'>You unweld the vent.</span>", "<span class='italics'>You hear welding.</span>")
 					welded = 0
 				update_icon()
-				pipe_vision_img = image(src, loc, layer = 20, dir = dir)
+				pipe_vision_img = image(src, loc, layer = ABOVE_HUD_LAYER, dir = dir)
 			return 0
 	else
 		return ..()
@@ -289,7 +289,7 @@
 	user.visible_message("[user] furiously claws at [src]!", "You manage to clear away the stuff blocking the vent", "You hear loud scraping noises.")
 	welded = 0
 	update_icon()
-	pipe_vision_img = image(src, loc, layer = 20, dir = dir)
+	pipe_vision_img = image(src, loc, layer = ABOVE_HUD_LAYER, dir = dir)
 	playsound(loc, 'sound/weapons/bladeslice.ogg', 100, 1)
 
 

code/modules/atmospherics/machinery/components/unary_devices/vent_scrubber.dm

@@ -308,7 +308,7 @@
 					user.visible_message("[user] unwelds the scrubber.", "You unweld the scrubber.", "You hear welding.")
 					welded = 0
 				update_icon()
-				pipe_vision_img = image(src, loc, layer = 20, dir = dir)
+				pipe_vision_img = image(src, loc, layer = ABOVE_HUD_LAYER, dir = dir)
 			return 0
 	else
 		return ..()
@@ -329,7 +329,7 @@
 	user.visible_message("[user] furiously claws at [src]!", "You manage to clear away the stuff blocking the scrubber.", "You hear loud scraping noises.")
 	welded = 0
 	update_icon()
-	pipe_vision_img = image(src, loc, layer = 20, dir = dir)
+	pipe_vision_img = image(src, loc, layer = ABOVE_HUD_LAYER, dir = dir)
 	playsound(loc, 'sound/weapons/bladeslice.ogg', 100, 1)
 
 

code/modules/atmospherics/machinery/pipes/pipes.dm

@@ -3,7 +3,6 @@
 	var/volume = 0
 
 	level = 1
-	layer = 2.4 //under wires with their 2.44
 
 	use_power = 0
 	can_unwrench = 1