Port TG updating appearances (#17943)

* Get pants that match or else you gonna look silly yo

* Posters

* Fix other hud elements

* Rereviewed

* Update shotglass.dm

* Fix for new merged PRs

* Typo

* Coming across other stuff

* Update theblob.dm

* No takebacksies

* smh i forget to leave a comment

* Updated for the detgun and cards

* Should have rerun langserver again

* No longer plastic, more in scope

* Damn you bluespace

* Reverting turret logic, out of scope at this point

* Tweak that part

* Went over energy guns again, and fixed UI White's sprite sheet

* Welding masks, glasses, and JUSTICE

* Update portable_atmospherics.dm

* Cleaning up, clearing things up

* Review and suggestions

* Update valve.dm

* More tweaks

* Missing character

* Not distinct lightmasks, so they can be overlays

* Update generator.dm

* Add parameter so holodeck doesn't try to make a perfect copy

* Update unsorted.dm

* Spiders

* Better fix for spiders, fix vamps too

* Ghosts

* Update telekinesis.dm

* Cleaning up old procs

* It's set up to not copy datums... Unless they're in a list

* Donuts, duct tape, and detgun. D3VR coming to Early Access

* Update procs that interact with doors so they call update_state instead

* Forgot one spot, and actually might as well just force lock

* Cleaning up other things... Sigh, and kitty ears

* oops

* Getting used to how it works

* blinds

* Going back to the suit obscuring thing, so it doesn't update all the time

* Missed that from merging master

* I made this PR and forgot about it

* Fix runtimes in cards

* Make things a bit more unified

* Update update_icons.dm

* yarn, really?

* Update library_equipment.dm

* Update shieldgen.dm

* Every time Charlie merges something, I go back and see if I can improve things further

* what's this? more?

* Update misc_special.dm

* wow, paper

* Review

* More reviews

* To be sure, seems like being broken messed something sometimes

* Brought airlocks closer to how TG works to iron out some stuff

* Pizza and morgue

* Doesn't seem to hurt, tried with holodeck

* Revert "Doesn't seem to hurt, tried with holodeck"

This reverts commit 158529302b.

* Icon conflict

* Fix organ damage

* Don't ask how. Why. It's like that on prod too.

* Cutting down on things and updating from TG.

* More flexible. Just in case the thing you stuck it on didn't destroy.

* Hydro was one the things I touched earlier on, better rework it

* Reviews

* Cleaning up further, also bri'ish

* Undo a change I did, and switch over to a more recent implementation

* Update biogenerator.dm

* Rolling back to old airlocks, but with new duct taped note

* Functionally the same. I'd just rather not have the smoothing happen there

* Went over APCs again

* Fix welding helmet names in species files

* Update airlock.dm

* Update persistent_overlay.dm

* Oh, topic

code/modules/power/apc.dm

@@ -322,8 +322,6 @@
 		status_overlays_environ[3] = image(icon, "apco2-2")
 		status_overlays_environ[4] = image(icon, "apco2-3")
 
-
-
 	var/update = check_updates() 		//returns 0 if no need to update icons.
 						// 1 if we need to update the icon_state
 						// 2 if we need to update the overlays
@@ -331,53 +329,54 @@
 		return
 
 	if(force_update || update & 1) // Updating the icon state
-		if(update_state & UPSTATE_ALLGOOD)
-			icon_state = "apc0"
-		else if(update_state & (UPSTATE_OPENED1|UPSTATE_OPENED2))
-			var/basestate = "apc[ cell ? "2" : "1" ]"
-			if(update_state & UPSTATE_OPENED1)
-				if(update_state & (UPSTATE_MAINT|UPSTATE_BROKE))
-					icon_state = "apcmaint" //disabled APC cannot hold cell
-				else
-					icon_state = basestate
-			else if(update_state & UPSTATE_OPENED2)
-				icon_state = "[basestate]-nocover"
-		else if(update_state & UPSTATE_BROKE)
-			icon_state = "apc-b"
-		else if(update_state & UPSTATE_BLUESCREEN)
-			icon_state = "apcemag"
-		else if(update_state & UPSTATE_WIREEXP)
-			icon_state = "apcewires"
-
-
-
+		..(UPDATE_ICON_STATE)
+	
 	if(!(update_state & UPSTATE_ALLGOOD))
-		if(overlays.len)
-			overlays = 0
-			return
-
-
+		if(managed_overlays)
+			..(UPDATE_OVERLAYS)
+		return
 
 	if(force_update || update & 2)
+		..(UPDATE_OVERLAYS)
 
-		if(overlays.len)
-			overlays.len = 0
+/obj/machinery/power/apc/update_icon_state()
+	if(update_state & UPSTATE_ALLGOOD)
+		icon_state = "apc0"
+	else if(update_state & (UPSTATE_OPENED1|UPSTATE_OPENED2))
+		var/basestate = "apc[ cell ? "2" : "1" ]"
+		if(update_state & UPSTATE_OPENED1)
+			if(update_state & (UPSTATE_MAINT|UPSTATE_BROKE))
+				icon_state = "apcmaint" //disabled APC cannot hold cell
+			else
+				icon_state = basestate
+		else if(update_state & UPSTATE_OPENED2)
+			icon_state = "[basestate]-nocover"
+	else if(update_state & UPSTATE_BROKE)
+		icon_state = "apc-b"
+	else if(update_state & UPSTATE_BLUESCREEN)
+		icon_state = "apcemag"
+	else if(update_state & UPSTATE_WIREEXP)
+		icon_state = "apcewires"
 
-		if(!(stat & (BROKEN|MAINT)) && update_state & UPSTATE_ALLGOOD)
-			overlays += status_overlays_lock[locked+1]
-			overlays += status_overlays_charging[charging+1]
-			if(operating)
-				overlays += status_overlays_equipment[equipment+1]
-				overlays += status_overlays_lighting[lighting+1]
-				overlays += status_overlays_environ[environ+1]
+/obj/machinery/power/apc/update_overlays()
+	. = ..()
+	if(!(update_state & UPSTATE_ALLGOOD))
+		return
 
+	if(!(stat & (BROKEN|MAINT)) && update_state & UPSTATE_ALLGOOD)
+		. += status_overlays_lock[locked+1]
+		. += status_overlays_charging[charging+1]
+		if(operating)
+			. += status_overlays_equipment[equipment+1]
+			. += status_overlays_lighting[lighting+1]
+			. += status_overlays_environ[environ+1]
 
 /obj/machinery/power/apc/proc/check_updates()
 
 	var/last_update_state = update_state
 	var/last_update_overlay = update_overlay
-	update_state = 0
-	update_overlay = 0
+	update_state = NONE
+	update_overlay = NONE
 
 	if(cell)
 		update_state |= UPSTATE_CELL_IN
@@ -456,6 +455,7 @@
 	if(!second_pass) //The first time, we just cut overlays
 		addtimer(CALLBACK(src, /obj/machinery/power/apc/proc.flicker, TRUE), 1)
 		cut_overlays()
+		managed_overlays = null
 		// APC power distruptions have a chance to propogate to other machines on its network
 		for(var/obj/machinery/M in area)
 			// Please don't cascade, thanks
@@ -763,7 +763,7 @@
 			user.visible_message("<span class='warning'>[user.name] removes [cell] from [src]!", "<span class='notice'>You remove [cell].</span>")
 			user.put_in_hands(cell)
 			cell.add_fingerprint(user)
-			cell.update_icon()
+			cell.update_icon(UPDATE_OVERLAYS)
 			cell = null
 			charging = APC_NOT_CHARGING
 			update_icon()

code/modules/power/cable.dm

@@ -107,15 +107,14 @@ By design, d1 is the smallest direction and d2 is the highest
 
 	if(level == 1 && isturf(loc))
 		invisibility = i ? INVISIBILITY_MAXIMUM : 0
-	updateicon()
+	update_icon()
 
-/obj/structure/cable/proc/updateicon()
+/obj/structure/cable/update_icon_state()
 	if(invisibility)
 		icon_state = "[d1]-[d2]-f"
 	else
 		icon_state = "[d1]-[d2]"
 
-
 ////////////////////////////////////////////
 // Power related
 ///////////////////////////////////////////
@@ -587,19 +586,22 @@ GLOBAL_LIST_INIT(cable_coil_recipes, list (new/datum/stack_recipe/cable_restrain
 	C.color = color
 	return C
 
-/obj/item/stack/cable_coil/update_icon()
+/obj/item/stack/cable_coil/update_name()
+	. = ..()
+	if(amount > 2)
+		name = "cable coil"
+	else
+		name = "cable piece"
+
+/obj/item/stack/cable_coil/update_icon_state()
 	if(!color)
 		color = pick(COLOR_RED, COLOR_BLUE, COLOR_GREEN, COLOR_ORANGE, COLOR_WHITE, COLOR_PINK, COLOR_YELLOW, COLOR_CYAN)
 	if(amount == 1)
 		icon_state = "coil1"
-		name = "cable piece"
 	else if(amount == 2)
 		icon_state = "coil2"
-		name = "cable piece"
 	else
 		icon_state = "coil"
-		name = "cable coil"
-	..()
 
 /obj/item/stack/cable_coil/proc/update_wclass()
 	if(amount == 1)
@@ -686,7 +688,7 @@ GLOBAL_LIST_INIT(cable_coil_recipes, list (new/datum/stack_recipe/cable_restrain
 	C.d1 = 0 //it's a O-X node cable
 	C.d2 = dirn
 	C.add_fingerprint(user)
-	C.updateicon()
+	C.update_icon()
 
 	//create a new powernet with the cable, if needed it will be merged later
 	var/datum/powernet/PN = new()
@@ -796,7 +798,7 @@ GLOBAL_LIST_INIT(cable_coil_recipes, list (new/datum/stack_recipe/cable_restrain
 		C.d2 = nd2
 
 		C.add_fingerprint()
-		C.updateicon()
+		C.update_icon()
 
 
 		C.mergeConnectedNetworks(C.d1) //merge the powernets...
@@ -831,7 +833,7 @@ GLOBAL_LIST_INIT(cable_coil_recipes, list (new/datum/stack_recipe/cable_restrain
 	src.amount = rand(1,2)
 	pixel_x = rand(-2,2)
 	pixel_y = rand(-2,2)
-	update_icon()
+	update_appearance(UPDATE_NAME|UPDATE_ICON_STATE)
 	update_wclass()
 
 /obj/item/stack/cable_coil/yellow
@@ -877,7 +879,7 @@ GLOBAL_LIST_INIT(cable_coil_recipes, list (new/datum/stack_recipe/cable_restrain
 	energy_type = /datum/robot_energy_storage/cable
 	is_cyborg = TRUE
 
-/obj/item/stack/cable_coil/cyborg/update_icon()
+/obj/item/stack/cable_coil/cyborg/update_icon_state()
 	return // icon_state should always be a full cable
 
 /obj/item/stack/cable_coil/cyborg/attack_self(mob/user)

code/modules/power/cell.dm

@@ -28,7 +28,7 @@
 	charge = maxcharge
 	if(ratingdesc)
 		desc += " This one has a power rating of [DisplayPower(maxcharge)], and you should not swallow it."
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/item/stock_parts/cell/Destroy()
 	STOP_PROCESSING(SSobj, src)
@@ -49,16 +49,16 @@
 	else
 		return PROCESS_KILL
 
-/obj/item/stock_parts/cell/update_icon()
-	overlays.Cut()
+/obj/item/stock_parts/cell/update_overlays()
+	. = ..()
 	if(grown_battery)
-		overlays += image('icons/obj/power.dmi', "grown_wires")
+		. += image('icons/obj/power.dmi', "grown_wires")
 	if(charge < 0.01)
 		return
 	else if(charge/maxcharge >=0.995)
-		overlays += "cell-o2"
+		. += "cell-o2"
 	else
-		overlays += "cell-o1"
+		. += "cell-o1"
 
 /obj/item/stock_parts/cell/proc/percent()		// return % charge of cell
 	return 100 * charge / maxcharge
@@ -179,7 +179,7 @@
 /obj/item/stock_parts/cell/crap/empty/New()
 	..()
 	charge = 0
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/item/stock_parts/cell/upgraded
 	name = "upgraded power cell"
@@ -204,7 +204,7 @@
 /obj/item/stock_parts/cell/secborg/empty/New()
 	..()
 	charge = 0
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/item/stock_parts/cell/hos_gun
 	name = "\improper X-01 multiphase energy gun power cell"
@@ -243,7 +243,7 @@
 /obj/item/stock_parts/cell/high/empty/New()
 	..()
 	charge = 0
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/item/stock_parts/cell/super
 	name = "super-capacity power cell"
@@ -257,7 +257,7 @@
 /obj/item/stock_parts/cell/super/empty/New()
 	..()
 	charge = 0
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/item/stock_parts/cell/hyper
 	name = "hyper-capacity power cell"
@@ -271,7 +271,7 @@
 /obj/item/stock_parts/cell/hyper/empty/New()
 	..()
 	charge = 0
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/item/stock_parts/cell/bluespace
 	name = "bluespace power cell"
@@ -286,7 +286,7 @@
 /obj/item/stock_parts/cell/bluespace/empty/New()
 	..()
 	charge = 0
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/item/stock_parts/cell/bluespace/charging
 	name = "self-charging bluespace power cell"
@@ -315,9 +315,8 @@
 	rating = 12
 	ratingdesc = FALSE
 
-/obj/item/stock_parts/cell/infinite/abductor/update_icon()
-	return
-
+/obj/item/stock_parts/cell/infinite/abductor/update_overlays()
+	return list()
 
 /obj/item/stock_parts/cell/potato
 	name = "potato battery"
@@ -351,7 +350,7 @@
 /obj/item/stock_parts/cell/emproof/empty/New()
 	..()
 	charge = 0
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/item/stock_parts/cell/emproof/emp_act(severity)
 	return

code/modules/power/generator.dm

@@ -21,10 +21,11 @@
 
 /obj/machinery/power/generator/Initialize(mapload)
 	. = ..()
-	update_desc()
+	update_appearance(UPDATE_DESC)
 	connect()
 
-/obj/machinery/power/generator/proc/update_desc()
+/obj/machinery/power/generator/update_desc()
+	. = ..()
 	desc = initial(desc) + " Its cold circulator is located on the [dir2text(cold_dir)] side, and its heat circulator is located on the [dir2text(hot_dir)] side."
 
 /obj/machinery/power/generator/Destroy()
@@ -74,22 +75,21 @@
 		set_light(0)
 	else
 		set_light(light_range_on, light_power_on)
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
-
-/obj/machinery/power/generator/update_icon()
+/obj/machinery/power/generator/update_overlays()
+	. = ..()
 	if(stat & (NOPOWER|BROKEN))
-		cut_overlays()
-		underlays.Cut()
 		return
-	else
-		cut_overlays()
-		if(lastgenlev != 0)
-			add_overlay(mutable_appearance('icons/obj/power.dmi', "teg-op[lastgenlev]"))
-			underlays += emissive_appearance(icon, "teg-op[lastgenlev]")
 
-		add_overlay(mutable_appearance('icons/obj/power.dmi', "teg-oc[lastcirc]"))
-		underlays += emissive_appearance(icon, "teg-oc[lastcirc]")
+	if(lastgenlev != 0)
+		. += "teg-op[lastgenlev]"
+		if(light)
+			. += emissive_appearance(icon, "teg-op[lastgenlev]")
+
+	. += "teg-oc[lastcirc]"
+	if(light)
+		. += emissive_appearance(icon, "teg-oc[lastcirc]")
 
 /obj/machinery/power/generator/process()
 	if(stat & (NOPOWER|BROKEN))
@@ -152,7 +152,7 @@
 	if((genlev != lastgenlev) || (circ != lastcirc))
 		lastgenlev = genlev
 		lastcirc = circ
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 
 	updateDialog()
 
@@ -188,7 +188,7 @@
 		hot_dir = SOUTH
 	connect()
 	to_chat(user, "<span class='notice'>You reverse the generator's circulator settings. The cold circulator is now on the [dir2text(cold_dir)] side, and the heat circulator is now on the [dir2text(hot_dir)] side.</span>")
-	update_desc()
+	update_appearance(UPDATE_DESC)
 
 /obj/machinery/power/generator/wrench_act(mob/user, obj/item/I)
 	. = TRUE

code/modules/power/gravitygenerator.dm

@@ -250,15 +250,14 @@ GLOBAL_LIST_EMPTY(gravity_generators)
 	else
 		return "off"
 
-/obj/machinery/gravity_generator/main/update_icon()
-	..()
-	cut_overlays()
+/obj/machinery/gravity_generator/main/update_overlays()
+	. = ..()
 	if(get_status() != "generator_welding" && get_status() != "generator_plasteel")
-		add_overlay("generator_part")
+		. += "generator_part"
 	if(get_status() == "off")
 		return
-	add_overlay("[get_status()]")
-	add_overlay("[overlay_state]")
+	. += "[get_status()]"
+	. += "[overlay_state]"
 
 /**
   * Set the charging state based on external power and the breaker state.

code/modules/power/lighting.dm

@@ -279,8 +279,7 @@
 //		A.update_lights()
 	return ..()
 
-/obj/machinery/light/update_icon()
-
+/obj/machinery/light/update_icon_state()
 	switch(status)		// set icon_states
 		if(LIGHT_OK)
 			if(emergency_mode)
@@ -296,7 +295,6 @@
 		if(LIGHT_BROKEN)
 			icon_state = "[base_state]-broken"
 			on = FALSE
-	return
 
 /**
   * Updates the light's 'on' state and power consumption based on [/obj/machinery/light/var/on].

code/modules/power/port_gen.dm

@@ -30,7 +30,7 @@
 /obj/machinery/power/port_gen/proc/handleInactive()
 	return
 
-/obj/machinery/power/port_gen/update_icon()
+/obj/machinery/power/port_gen/update_icon_state()
 	icon_state = "[base_icon]_[active]"
 
 /obj/machinery/power/port_gen/process()

code/modules/power/singularity/emitter.dm

@@ -97,13 +97,12 @@
 	QDEL_NULL(sparks)
 	return ..()
 
-/obj/machinery/power/emitter/update_icon()
+/obj/machinery/power/emitter/update_icon_state()
 	if(active && powernet && avail(active_power_usage))
 		icon_state = "emitter_+a"
 	else
 		icon_state = "emitter"
 
-
 /obj/machinery/power/emitter/emag_act(mob/living/user)
 	if(!emagged)
 		locked = FALSE

code/modules/power/singularity/field_generator.dm

@@ -40,15 +40,14 @@ field_generator power level display
 	var/list/obj/machinery/field/generator/connected_gens
 	var/clean_up = FALSE
 
-/obj/machinery/field/generator/update_icon()
-	overlays.Cut()
+/obj/machinery/field/generator/update_overlays()
+	. = ..()
 	if(warming_up)
-		overlays += "+a[warming_up]"
+		. += "+a[warming_up]"
 	if(fields.len)
-		overlays += "+on"
+		. += "+on"
 	if(power_level)
-		overlays += "+p[power_level]"
-
+		. += "+p[power_level]"
 
 /obj/machinery/field/generator/Initialize(mapload)
 	. = ..()

code/modules/power/singularity/particle_accelerator/particle_accelerator.dm

@@ -87,11 +87,6 @@ So, hopefully this is helpful if any more icons are to be added/changed/wonderin
 	icon_state = "end_cap"
 	reference = "end_cap"
 
-/obj/structure/particle_accelerator/update_icon()
-	..()
-	return
-
-
 /obj/structure/particle_accelerator/verb/rotate()
 	set name = "Rotate Clockwise"
 	set category = "Object"
@@ -155,7 +150,7 @@ So, hopefully this is helpful if any more icons are to be added/changed/wonderin
 	if(prob(50))
 		qdel(src)
 
-/obj/structure/particle_accelerator/update_icon()
+/obj/structure/particle_accelerator/update_icon_state()
 	switch(construction_state)
 		if(0,1)
 			icon_state="[reference]"
@@ -166,7 +161,6 @@ So, hopefully this is helpful if any more icons are to be added/changed/wonderin
 				icon_state="[reference]p[strength]"
 			else
 				icon_state="[reference]c"
-	return
 
 /obj/structure/particle_accelerator/proc/update_state()
 	if(master)
@@ -292,9 +286,6 @@ So, hopefully this is helpful if any more icons are to be added/changed/wonderin
 	dir = turn(dir, 90)
 	return 1
 
-/obj/machinery/particle_accelerator/update_icon()
-	return
-
 /obj/machinery/particle_accelerator/attackby(obj/item/W, mob/user, params)
 	if(!iscoil(W))
 		return ..()

code/modules/power/singularity/particle_accelerator/particle_chamber.dm

@@ -4,7 +4,3 @@
 	icon = 'icons/obj/machines/particle_accelerator.dmi'
 	icon_state = "fuel_chamber"
 	reference = "fuel_chamber"
-
-/obj/structure/particle_accelerator/fuel_chamber/update_icon()
-	..()
-	return

code/modules/power/singularity/particle_accelerator/particle_control.dm

@@ -64,7 +64,7 @@
 
 	return
 
-/obj/machinery/particle_accelerator/control_box/update_icon()
+/obj/machinery/particle_accelerator/control_box/update_icon_state()
 	if(active)
 		icon_state = "[reference]p[strength]"
 	else
@@ -83,7 +83,6 @@
 					icon_state = "[reference]w"
 				else
 					icon_state = "[reference]c"
-	return
 
 /obj/machinery/particle_accelerator/control_box/Topic(href, href_list)
 	if(..(href, href_list))

code/modules/power/singularity/particle_accelerator/particle_emitter.dm

@@ -18,10 +18,6 @@
 	icon_state = "emitter_right"
 	reference = "emitter_right"
 
-/obj/structure/particle_accelerator/particle_emitter/update_icon()
-	..()
-	return
-
 /obj/structure/particle_accelerator/particle_emitter/proc/set_delay(delay)
 	if(delay && delay >= 0)
 		fire_delay = delay

code/modules/power/smes.dm

@@ -83,17 +83,17 @@
 		C += PC.maxcharge
 	capacity = C / (15000) * 1e6
 
-/obj/machinery/power/smes/update_icon()
-	cut_overlays()
+/obj/machinery/power/smes/update_overlays()
+	. = ..()
 	if(stat & BROKEN)
 		return
 
-	add_overlay("smes-op[outputting ? 1 : 0]")
-	add_overlay("smes-oc[inputting ? 1 : 0]")
+	. += "smes-op[outputting ? 1 : 0]"
+	. += "smes-oc[inputting ? 1 : 0]"
 
-	var/clevel = chargedisplay()
-	if(clevel > 0)
-		add_overlay("smes-og[clevel]")
+	var/charge_level = chargedisplay()
+	if(charge_level > 0)
+		. += "smes-og[charge_level]"
 
 /obj/machinery/power/smes/attackby(obj/item/I, mob/user, params)
 	//opening using screwdriver

code/modules/power/solar.dm

@@ -93,15 +93,13 @@
 			new /obj/item/shard(src.loc)
 	qdel(src)
 
-/obj/machinery/power/solar/update_icon()
-	..()
-	overlays.Cut()
+/obj/machinery/power/solar/update_overlays()
+	. = ..()
 	if(stat & BROKEN)
-		overlays += image('icons/goonstation/objects/power.dmi', icon_state = "solar_panel-b", layer = FLY_LAYER)
+		. += image('icons/goonstation/objects/power.dmi', icon_state = "solar_panel-b", layer = FLY_LAYER)
 	else
-		overlays += image('icons/goonstation/objects/power.dmi', icon_state = "solar_panel", layer = FLY_LAYER)
+		. += image('icons/goonstation/objects/power.dmi', icon_state = "solar_panel", layer = FLY_LAYER)
 		set_angle(adir)
-	return
 
 //calculates the fraction of the sunlight that the panel recieves
 /obj/machinery/power/solar/proc/update_solar_exposure()
@@ -340,16 +338,16 @@
 		set_panels(cdir)
 	updateDialog()
 
-/obj/machinery/power/solar_control/update_icon()
-	overlays.Cut()
+/obj/machinery/power/solar_control/update_overlays()
+	. = ..()
 	if(stat & NOPOWER)
-		overlays += "[icon_keyboard]_off"
+		. += "[icon_keyboard]_off"
 		return
-	overlays += icon_keyboard
+	. += icon_keyboard
 	if(stat & BROKEN)
-		overlays += "[icon_state]_broken"
+		. += "[icon_state]_broken"
 	else
-		overlays += icon_screen
+		. += icon_screen
 
 /obj/machinery/power/solar_control/attack_ai(mob/user as mob)
 	add_hiddenprint(user)

code/modules/power/treadmill.dm

@@ -22,7 +22,7 @@
 	if(anchored)
 		connect_to_network()
 
-/obj/machinery/power/treadmill/update_icon()
+/obj/machinery/power/treadmill/update_icon_state()
 	icon_state = speed ? "conveyor-1" : "conveyor0"
 
 /obj/machinery/power/treadmill/Crossed(mob/living/M, oldloc)
@@ -171,13 +171,13 @@
 	. = ..()
 	. += "The display reads:<div style='text-align: center'>[line1]<br>[line2]</div>"
 
-/obj/machinery/treadmill_monitor/update_icon()
-	overlays.Cut()
+/obj/machinery/treadmill_monitor/update_overlays()
+	. = ..()
 	if(stat & NOPOWER || !total_joules || !on)
 		line1 = ""
 		line2 = ""
 	else if(stat & BROKEN)
-		overlays += image('icons/obj/status_display.dmi', icon_state = "ai_bsod")
+		. += image('icons/obj/status_display.dmi', icon_state = "ai_bsod")
 		line1 = "A@#$A"
 		line2 = "729%!"
 	else