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/__DEFINES/dcs/signals.dm

@@ -70,13 +70,29 @@
 	#define EXAMINE_POSITION_BEFORE (1<<1)
 	//End positions
 	#define COMPONENT_EXNAME_CHANGED (1<<0)
-///from base of atom/update_icon(): ()
+	///from base of [/atom/proc/update_appearance]: (updates)
+	#define COMSIG_ATOM_UPDATE_APPEARANCE "atom_update_appearance"
+	/// If returned from [COMSIG_ATOM_UPDATE_APPEARANCE] it prevents the atom from updating its name.
+	#define COMSIG_ATOM_NO_UPDATE_NAME UPDATE_NAME
+	/// If returned from [COMSIG_ATOM_UPDATE_APPEARANCE] it prevents the atom from updating its desc.
+	#define COMSIG_ATOM_NO_UPDATE_DESC UPDATE_DESC
+	/// If returned from [COMSIG_ATOM_UPDATE_APPEARANCE] it prevents the atom from updating its icon.
+	#define COMSIG_ATOM_NO_UPDATE_ICON UPDATE_ICON
+///from base of [/atom/proc/update_name]: (updates)
+#define COMSIG_ATOM_UPDATE_NAME "atom_update_name"
+///from base of [/atom/proc/update_desc]: (updates)
+#define COMSIG_ATOM_UPDATE_DESC "atom_update_desc"
+///from base of [/atom/update_icon]: ()
 #define COMSIG_ATOM_UPDATE_ICON "atom_update_icon"
-	#define COMSIG_ATOM_NO_UPDATE_ICON_STATE	(1<<0)
-	#define COMSIG_ATOM_NO_UPDATE_OVERLAYS		(1<<1)
-///from base of atom/update_overlays(): (list/new_overlays)
+	/// If returned from [COMSIG_ATOM_UPDATE_ICON] it prevents the atom from updating its icon state.
+	#define COMSIG_ATOM_NO_UPDATE_ICON_STATE UPDATE_ICON_STATE
+	/// If returned from [COMSIG_ATOM_UPDATE_ICON] it prevents the atom from updating its overlays.
+	#define COMSIG_ATOM_NO_UPDATE_OVERLAYS UPDATE_OVERLAYS
+///Sent after [atom/update_icon_state] is called by [/atom/update_icon]: ()
+#define COMSIG_ATOM_UPDATE_ICON_STATE "atom_update_icon_state"
+///Sent after [atom/update_overlays] is called by [/atom/update_icon]: (list/new_overlays)
 #define COMSIG_ATOM_UPDATE_OVERLAYS "atom_update_overlays"
-///from base of atom/update_icon(): (signalOut, did_anything)
+///from base of [/atom/update_icon]: (signalOut, did_anything)
 #define COMSIG_ATOM_UPDATED_ICON "atom_updated_icon"
 ///from base of atom/Entered(): (atom/movable/entering, /atom)
 #define COMSIG_ATOM_ENTERED "atom_entered"

code/__DEFINES/flags.dm

@@ -27,6 +27,17 @@
 ///Whether or not this atom shows screentips when hovered over
 #define NO_SCREENTIPS			32768
 
+// Update flags for [/atom/proc/update_appearance]
+/// Update the atom's name
+#define UPDATE_NAME (1<<0)
+/// Update the atom's desc
+#define UPDATE_DESC (1<<1)
+/// Update the atom's icon state
+#define UPDATE_ICON_STATE (1<<2)
+/// Update the atom's overlays
+#define UPDATE_OVERLAYS (1<<3)
+/// Update the atom's icon
+#define UPDATE_ICON (UPDATE_ICON_STATE|UPDATE_OVERLAYS)
 
 /* Secondary atom flags, for the flags_2 var, denoted with a _2 */
 

code/__HELPERS/unsorted.dm

@@ -855,7 +855,7 @@ Returns 1 if the chain up to the area contains the given typepath
 
 	if(perfectcopy)
 		if((O) && (original))
-			var/static/list/forbidden_vars = list("type","loc","locs","vars", "parent","parent_type", "verbs","ckey","key","power_supply","contents","reagents","stat","x","y","z","group")
+			var/static/list/forbidden_vars = list("type","loc","locs","vars", "parent","parent_type", "verbs","ckey","key","power_supply","contents","reagents","stat","x","y","z","group", "comp_lookup", "datum_components")
 
 			for(var/V in original.vars - forbidden_vars)
 				if(istype(original.vars[V],/list))
@@ -869,7 +869,7 @@ Returns 1 if the chain up to the area contains the given typepath
 		O.update_icon()
 	return O
 
-/area/proc/copy_contents_to(area/A , platingRequired = 0 )
+/area/proc/copy_contents_to(area/A , platingRequired = 0, perfect_copy = TRUE)
 	//Takes: Area. Optional: If it should copy to areas that don't have plating
 	//Returns: Nothing.
 	//Notes: Attempts to move the contents of one area to another area.
@@ -949,7 +949,7 @@ Returns 1 if the chain up to the area contains the given typepath
 
 
 					for(var/obj/O in objs)
-						newobjs += DuplicateObject(O , 1)
+						newobjs += DuplicateObject(O , perfect_copy)
 
 
 					for(var/obj/O in newobjs)

code/_onclick/hud/action_button.dm

@@ -88,7 +88,7 @@
 		name = "Show Buttons"
 	else
 		name = "Hide Buttons"
-	UpdateIcon()
+	update_icon(UPDATE_OVERLAYS)
 	usr.update_action_buttons()
 
 /obj/screen/movable/action_button/hide_toggle/AltClick(mob/user)
@@ -114,13 +114,13 @@
 	if(user.client)
 		alpha = user.client.prefs.UI_style_alpha
 		color = user.client.prefs.UI_style_color
-	UpdateIcon()
+	update_icon(UPDATE_OVERLAYS)
 
-/obj/screen/movable/action_button/hide_toggle/proc/UpdateIcon()
-	cut_overlays()
+/obj/screen/movable/action_button/hide_toggle/update_overlays()
+	. = ..()
 	var/image/img = image(initial(icon), src, hidden ? "show" : "hide")
 	img.appearance_flags = RESET_COLOR | RESET_ALPHA
-	overlays += img
+	. += img
 
 /obj/screen/movable/action_button/MouseEntered(location, control, params)
 	. = ..()

code/_onclick/hud/alien.dm

@@ -119,7 +119,8 @@
 
 	mymob.pullin = new /obj/screen/pull()
 	mymob.pullin.icon = 'icons/mob/screen_alien.dmi'
-	mymob.pullin.update_icon(mymob)
+	mymob.pullin.hud = src
+	mymob.pullin.update_icon(UPDATE_ICON_STATE)
 	mymob.pullin.screen_loc = ui_pull_resist
 	hotkeybuttons += mymob.pullin
 
@@ -127,7 +128,8 @@
 	infodisplay += alien_plasma_display
 
 	zone_select = new /obj/screen/zone_sel/alien()
-	zone_select.update_icon(mymob)
+	zone_select.hud = src
+	zone_select.update_icon(UPDATE_OVERLAYS)
 	static_inventory += zone_select
 
 	for(var/obj/screen/inventory/inv in (static_inventory + toggleable_inventory))

code/_onclick/hud/alien_larva.dm

@@ -26,7 +26,8 @@
 
 	mymob.pullin = new /obj/screen/pull()
 	mymob.pullin.icon = 'icons/mob/screen_alien.dmi'
-	mymob.pullin.update_icon(mymob)
+	mymob.pullin.hud = src
+	mymob.pullin.update_icon(UPDATE_ICON_STATE)
 	mymob.pullin.screen_loc = ui_pull_resist
 	hotkeybuttons += mymob.pullin
 
@@ -35,5 +36,6 @@
 	static_inventory += using
 
 	zone_select = new /obj/screen/zone_sel/alien()
-	zone_select.update_icon(mymob)
+	zone_select.hud = src
+	zone_select.update_icon(UPDATE_OVERLAYS)
 	static_inventory += zone_select

code/_onclick/hud/bot.dm

@@ -28,6 +28,7 @@
 
 	mymob.pullin = new /obj/screen/pull()
 	mymob.pullin.icon = 'icons/mob/screen_bot.dmi'
-	mymob.pullin.update_icon(mymob)
+	mymob.pullin.hud = src
+	mymob.pullin.update_icon(UPDATE_ICON_STATE)
 	mymob.pullin.screen_loc = ui_bot_pull
 	static_inventory += mymob.pullin

code/_onclick/hud/human.dm

@@ -333,7 +333,8 @@
 
 	mymob.pullin = new /obj/screen/pull()
 	mymob.pullin.icon = ui_style
-	mymob.pullin.update_icon(mymob)
+	mymob.pullin.hud = src
+	mymob.pullin.update_icon(UPDATE_ICON_STATE)
 	mymob.pullin.screen_loc = ui_pull_resist
 	static_inventory += mymob.pullin
 
@@ -347,7 +348,8 @@
 	zone_select.color = ui_color
 	zone_select.icon = ui_style
 	zone_select.alpha = ui_alpha
-	zone_select.update_icon(mymob)
+	zone_select.hud = src
+	zone_select.update_icon(UPDATE_OVERLAYS)
 	static_inventory += zone_select
 
 	inventory_shown = FALSE

code/_onclick/hud/other_mobs.dm

@@ -26,6 +26,7 @@
 
 	mymob.pullin = new /obj/screen/pull()
 	mymob.pullin.icon = 'icons/mob/screen_corgi.dmi'
-	mymob.pullin.update_icon(mymob)
+	mymob.pullin.hud = src
+	mymob.pullin.update_icon(UPDATE_ICON_STATE)
 	mymob.pullin.screen_loc = ui_construct_pull
 	static_inventory += mymob.pullin

code/_onclick/hud/robot.dm

@@ -157,12 +157,14 @@
 
 	mymob.pullin = new /obj/screen/pull()
 	mymob.pullin.icon = 'icons/mob/screen_robot.dmi'
-	mymob.pullin.update_icon(mymob)
+	mymob.pullin.hud = src
+	mymob.pullin.update_icon(UPDATE_ICON_STATE)
 	mymob.pullin.screen_loc = ui_borg_pull
 	hotkeybuttons += mymob.pullin
 
 	zone_select = new /obj/screen/zone_sel/robot()
-	zone_select.update_icon(mymob)
+	zone_select.hud = src
+	zone_select.update_icon(UPDATE_OVERLAYS)
 	static_inventory += zone_select
 
 //Headlamp

code/_onclick/hud/screen_objects.dm

@@ -22,6 +22,7 @@
 
 /obj/screen/Destroy()
 	master = null
+	hud = null
 	return ..()
 
 /obj/screen/proc/component_click(obj/screen/component_button/component, params)
@@ -120,10 +121,8 @@
 /obj/screen/pull/Click()
 	usr.stop_pulling()
 
-/obj/screen/pull/update_icon(mob/mymob)
-	if(!mymob)
-		return
-	if(mymob.pulling)
+/obj/screen/pull/update_icon_state()
+	if(hud?.mymob?.pulling)
 		icon_state = "pull"
 	else
 		icon_state = "pull0"
@@ -223,6 +222,7 @@
 	name = "damage zone"
 	icon_state = "zone_sel"
 	screen_loc = ui_zonesel
+	var/overlay_file = 'icons/mob/zone_sel.dmi'
 	var/selecting = "chest"
 	var/static/list/hover_overlays_cache = list()
 	var/hovering
@@ -323,32 +323,27 @@
 							return "eyes"
 				return "head"
 
-/obj/screen/zone_sel/proc/set_selected_zone(choice, mob/user)
-	if(isobserver(user))
+/obj/screen/zone_sel/proc/set_selected_zone(choice)
+	if(!hud)
+		return
+	if(isobserver(hud.mymob))
 		return
 
 	if(choice != selecting)
 		selecting = choice
-		update_icon(user)
+		update_icon(UPDATE_OVERLAYS)
 	return 1
 
-/obj/screen/zone_sel/update_icon(mob/user)
-	overlays.Cut()
-	var/image/human = image('icons/mob/zone_sel.dmi', "human")
-	human.appearance_flags = RESET_COLOR
-	overlays += human
-	var/image/sel = image('icons/mob/zone_sel.dmi', "[selecting]")
+/obj/screen/zone_sel/update_overlays()
+	. = ..()
+	var/image/sel = image(overlay_file, "[selecting]")
 	sel.appearance_flags = RESET_COLOR
-	overlays += sel
-	user.zone_selected = selecting
+	. += sel
+	hud.mymob.zone_selected = selecting
 
 /obj/screen/zone_sel/alien
 	icon = 'icons/mob/screen_alien.dmi'
-
-/obj/screen/zone_sel/alien/update_icon(mob/user)
-	overlays.Cut()
-	overlays += image('icons/mob/screen_alien.dmi', "[selecting]")
-	user.zone_selected = selecting
+	overlay_file = 'icons/mob/screen_alien.dmi'
 
 /obj/screen/zone_sel/robot
 	icon = 'icons/mob/screen_robot.dmi'
@@ -432,26 +427,24 @@
 	var/image/active_overlay
 	var/image/handcuff_overlay
 
-/obj/screen/inventory/hand/update_icon()
-	..()
+/obj/screen/inventory/hand/update_overlays()
+	. = ..()
 	if(!active_overlay)
 		active_overlay = image("icon"=icon, "icon_state"="hand_active")
 	if(!handcuff_overlay)
 		var/state = (slot_id == slot_r_hand) ? "markus" : "gabrielle"
 		handcuff_overlay = image("icon"='icons/mob/screen_gen.dmi', "icon_state"=state)
 
-	overlays.Cut()
-
 	if(hud && hud.mymob)
 		if(iscarbon(hud.mymob))
 			var/mob/living/carbon/C = hud.mymob
 			if(C.handcuffed)
-				overlays += handcuff_overlay
+				. += handcuff_overlay
 
 		if(slot_id == slot_l_hand && hud.mymob.hand)
-			overlays += active_overlay
+			. += active_overlay
 		else if(slot_id == slot_r_hand && !hud.mymob.hand)
-			overlays += active_overlay
+			. += active_overlay
 
 /obj/screen/inventory/hand/Click()
 	// At this point in client Click() code we have passed the 1/10 sec check and little else

code/_onclick/telekinesis.dm

@@ -68,6 +68,7 @@
 	layer = ABOVE_HUD_LAYER
 	plane = ABOVE_HUD_PLANE
 
+	blocks_emissive = FALSE
 	var/last_throw = 0
 	var/atom/movable/focus = null
 	var/mob/living/host = null
@@ -164,7 +165,7 @@
 		qdel(src)
 		return
 	focus = target
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 	apply_focus_overlay()
 	// Make it behave like other equipment
 	if(istype(target, /obj/item))
@@ -180,7 +181,7 @@
 		// Delete the key/value pair of item to TK grab
 		host.tkgrabbed_objects -= focus
 	focus = null
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/item/tk_grab/proc/apply_focus_overlay()
 	if(!focus)
@@ -193,9 +194,9 @@
 	focus_object(target, user)
 
 
-/obj/item/tk_grab/update_icon()
-	overlays.Cut()
+/obj/item/tk_grab/update_overlays()
+	. = ..()
 	if(focus && focus.icon && focus.icon_state)
-		overlays += icon(focus.icon,focus.icon_state)
+		. += icon(focus.icon,focus.icon_state)
 
 #undef TK_COOLDOWN

code/datums/components/ducttape.dm

@@ -8,7 +8,7 @@
 	if(!istype(I)) //Something went wrong
 		return
 	if(!hide_tape) //if TRUE this hides the tape overlay and added examine text
-		RegisterSignal(parent, COMSIG_OBJ_UPDATE_ICON, .proc/add_tape_overlay)
+		RegisterSignal(parent, COMSIG_ATOM_UPDATE_OVERLAYS, .proc/add_tape_overlay)
 		RegisterSignal(parent, COMSIG_PARENT_EXAMINE, .proc/add_tape_text)
 	x_offset = x
 	y_offset = y
@@ -27,7 +27,7 @@
 	tape_overlay = new('icons/obj/bureaucracy.dmi', "tape")
 	tape_overlay.Shift(EAST, x_offset - 2)
 	tape_overlay.Shift(NORTH, y_offset - 2)
-	O.overlays += tape_overlay
+	O.add_overlay(tape_overlay)
 
 /datum/component/ducttape/proc/remove_tape(obj/item/I, mob/user)
 	to_chat(user, "<span class='notice'>You tear the tape off [I]!</span>")
@@ -38,7 +38,7 @@
 	for(var/datum/action/item_action/remove_tape/RT in I.actions)
 		RT.Remove(user)
 		qdel(RT)
-	I.overlays.Cut(tape_overlay)
+	I.cut_overlay(tape_overlay)
 	user.transfer_fingerprints_to(I)
 	qdel(src)
 

code/datums/components/emissive_blocker.dm

@@ -0,0 +1,29 @@
+/datum/component/emissive_blocker
+	/// Stores either the mutable_appearance or a list of them
+	var/stored_blocker
+
+/datum/component/emissive_blocker/Initialize(_stored_blocker)
+	var/atom/movable/A = parent
+	stored_blocker = _stored_blocker
+	RegisterSignal(parent, COMSIG_ATOM_UPDATE_ICON_STATE, .proc/update_generic_block)
+	A.add_overlay(stored_blocker)
+
+/datum/component/emissive_blocker/Destroy()
+	stored_blocker = null
+	return ..()
+
+/// Updates the generic blocker when the icon_state is changed
+/datum/component/emissive_blocker/proc/update_generic_block(datum/source)
+	var/atom/movable/A = parent
+	if(!A.blocks_emissive && stored_blocker)
+		A.cut_overlay(stored_blocker)
+		stored_blocker = null
+		return
+	if(!A.blocks_emissive)
+		return
+	var/mutable_appearance/gen_emissive_blocker = emissive_blocker(A.icon, A.icon_state, alpha = A.alpha, appearance_flags = A.appearance_flags)
+	gen_emissive_blocker.dir = A.dir
+	if(gen_emissive_blocker != stored_blocker || !A.overlays)
+		A.cut_overlay(stored_blocker)
+		stored_blocker = gen_emissive_blocker
+		A.add_overlay(stored_blocker)

code/datums/components/persistent_overlay.dm

@@ -0,0 +1,35 @@
+/datum/component/persistent_overlay
+	var/image/persistent_overlay = null
+	var/atom/target = null
+
+/datum/component/persistent_overlay/Initialize(image_overlay, _target, timer)
+	persistent_overlay = image_overlay
+	target = _target
+	if(timer)
+		addtimer(CALLBACK(src, .proc/remove_persistent_overlay), timer)
+	if(target)
+		RegisterSignal(target, COMSIG_PARENT_QDELETING, .proc/remove_persistent_overlay)
+	RegisterSignal(parent, COMSIG_PARENT_QDELETING, .proc/remove_persistent_overlay)
+	add_persistent_overlay()
+
+/datum/component/persistent_overlay/Destroy()
+	persistent_overlay = null
+	target = null
+	return ..()
+
+/datum/component/persistent_overlay/proc/remove_persistent_overlay(datum/source)
+	var/atom/movable/A
+	if(target)
+		A = target
+	else
+		A = parent
+	A.cut_overlay(persistent_overlay, priority = TRUE)
+	qdel(src)
+
+/datum/component/persistent_overlay/proc/add_persistent_overlay(datum/source)
+	var/atom/movable/A
+	if(target)
+		A = target
+	else
+		A = parent
+	A.add_overlay(persistent_overlay, priority = TRUE)

code/datums/spells/wizard.dm

@@ -364,7 +364,7 @@
 	C.range = 20
 	return C
 
-/obj/effect/proc_holder/spell/fireball/update_icon()
+/obj/effect/proc_holder/spell/fireball/update_icon_state()
 	if(!action)
 		return
 	action.button_icon_state = "fireball[active]"

code/game/area/areas.dm

@@ -370,7 +370,7 @@
 		L.fire_mode = FALSE
 		L.update(TRUE, TRUE, FALSE)
 
-/area/proc/updateicon()
+/area/update_icon_state()
 	var/weather_icon
 	for(var/V in SSweather.processing)
 		var/datum/weather/W = V
@@ -380,7 +380,7 @@
 	if(!weather_icon)
 		icon_state = null
 
-/area/space/updateicon()
+/area/space/update_icon_state()
 	icon_state = null
 
 /*
@@ -417,7 +417,7 @@
 	for(var/obj/machinery/M in src)	// for each machine in the area
 		M.power_change()			// reverify power status (to update icons etc.)
 	SEND_SIGNAL(src, COMSIG_AREA_POWER_CHANGE)
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 
 /area/proc/usage(chan)
 	var/used = 0

code/game/area/areas/depot-areas.dm

@@ -36,25 +36,33 @@
 	var/obj/machinery/computer/syndicate_depot/syndiecomms/comms_computer = null
 	var/obj/structure/fusionreactor/reactor
 
-/area/syndicate_depot/core/updateicon()
+/area/syndicate_depot/core/proc/update_state()
 	if(destroyed)
-		icon_state = null
 		invisibility = INVISIBILITY_MAXIMUM
 	else if(on_peaceful)
-		icon_state = "green"
 		invisibility = INVISIBILITY_LIGHTING
 	else if(used_self_destruct)
-		icon_state = "radiation"
 		invisibility = INVISIBILITY_LIGHTING
 	else if(called_backup)
-		icon_state = "red"
 		invisibility = INVISIBILITY_LIGHTING
 	else if(local_alarm)
-		icon_state = "bluenew"
 		invisibility = INVISIBILITY_LIGHTING
 	else
-		icon_state = null
 		invisibility = INVISIBILITY_MAXIMUM
+	update_icon(UPDATE_ICON_STATE)
+
+/area/syndicate_depot/core/update_icon_state()
+	if(invisibility == INVISIBILITY_MAXIMUM)
+		icon_state = null
+		return
+	else if(on_peaceful)
+		icon_state = "green"
+	else if(used_self_destruct)
+		icon_state = "radiation"
+	else if(called_backup)
+		icon_state = "red"
+	else if(local_alarm)
+		icon_state = "bluenew"
 
 /area/syndicate_depot/core/proc/reset_alert()
 
@@ -84,7 +92,7 @@
 	detected_pod = FALSE
 	detected_double_agent = FALSE
 	mine_trigger_count = 0
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 
 	if(!istype(reactor))
 		for(var/obj/structure/fusionreactor/R in src)
@@ -112,7 +120,7 @@
 		return
 	if(!used_self_destruct)
 		activate_self_destruct(reason, FALSE, null)
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 
 /area/syndicate_depot/core/proc/locker_looted()
 	if(!something_looted)
@@ -197,7 +205,7 @@
 				message_admins("- SYNDI DEPOT VISITOR: [ADMIN_FULLMONTY(M)]")
 				list_add(M, hostile_list)
 		peaceful_list = list()
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 
 /area/syndicate_depot/core/proc/local_alarm(reason, silent)
 	if(local_alarm)
@@ -219,7 +227,7 @@
 			var/mob/living/simple_animal/bot/ed209/syndicate/B = new /mob/living/simple_animal/bot/ed209/syndicate(get_turf(S))
 			list_add(B, guard_list)
 			B.depotarea = src
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 
 /area/syndicate_depot/core/proc/call_backup(reason, silent)
 	if(called_backup || used_self_destruct)
@@ -252,7 +260,7 @@
 						list_add(S, guard_list)
 	else if(!silent)
 		announce_here("Depot Communications Offline", "Comms computer is damaged, destroyed or depowered. Unable to call in backup from Syndicate HQ.")
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 
 /area/syndicate_depot/core/proc/activate_self_destruct(reason, containment_failure, mob/user)
 	if(used_self_destruct)
@@ -265,7 +273,7 @@
 	called_backup = TRUE
 	activate_lockdown(TRUE)
 	lockout_computers()
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 	despawn_guards()
 	if(containment_failure)
 		announce_here("Depot Code DELTA", reason)
@@ -287,7 +295,7 @@
 	else
 		log_debug("Depot: [src] called activate_self_destruct with no reactor.")
 		message_admins("<span class='adminnotice'>Syndicate Depot lacks reactor to initiate self-destruct. Must be destroyed manually.</span>")
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 
 /area/syndicate_depot/core/proc/activate_lockdown()
 	if(used_lockdown)
@@ -312,7 +320,7 @@
 		if(istype(A, /obj/machinery/door/airlock/hatch/syndicate/vault))
 			continue
 		A.emergency = !!openaccess
-		A.update_icon()
+		A.update_appearance()
 
 /area/syndicate_depot/core/proc/toggle_falsewalls()
 	for(var/obj/structure/falsewall/plastitanium/F in src)

code/game/atoms.dm

@@ -45,6 +45,8 @@
 	var/list/priority_overlays	//overlays that should remain on top and not normally removed when using cut_overlay functions, like c4.
 	var/list/remove_overlays // a very temporary list of overlays to remove
 	var/list/add_overlays // a very temporary list of overlays to add
+	///overlays managed by [update_overlays][/atom/proc/update_overlays] to prevent removing overlays that weren't added by the same proc. Single items are stored on their own, not in a list.
+	var/list/managed_overlays
 
 	var/list/atom_colours	 //used to store the different colors on an atom
 						//its inherent color, the colored paint applied on it, special color effect etc...
@@ -189,6 +191,8 @@
 	LAZYCLEARLIST(overlays)
 	LAZYCLEARLIST(priority_overlays)
 
+	managed_overlays = null
+
 	QDEL_NULL(light)
 
 	return ..()
@@ -391,6 +395,70 @@
 
 	SEND_SIGNAL(src, COMSIG_PARENT_EXAMINE, user, .)
 
+/**
+ * Updates the appearence of the icon
+ *
+ * Mostly delegates to update_name, update_desc, and update_icon
+ *
+ * Arguments:
+ * - updates: A set of bitflags dictating what should be updated. Defaults to [ALL]
+ */
+/atom/proc/update_appearance(updates=ALL)
+	SHOULD_NOT_SLEEP(TRUE)
+	SHOULD_CALL_PARENT(TRUE)
+
+	/// Signal sent should the appearance be updated. This is more broad if listening to a more specific signal doesn't cut it
+	updates &= ~SEND_SIGNAL(src, COMSIG_ATOM_UPDATE_APPEARANCE, updates)
+	if(updates & UPDATE_NAME)
+		update_name(updates)
+	if(updates & UPDATE_DESC)
+		update_desc(updates)
+	if(updates & UPDATE_ICON)
+		update_icon(updates)
+
+/// Updates the name of the atom
+/atom/proc/update_name(updates=ALL)
+	SHOULD_CALL_PARENT(TRUE)
+	return SEND_SIGNAL(src, COMSIG_ATOM_UPDATE_NAME, updates)
+
+/// Updates the description of the atom
+/atom/proc/update_desc(updates=ALL)
+	SHOULD_CALL_PARENT(TRUE)
+	return SEND_SIGNAL(src, COMSIG_ATOM_UPDATE_DESC, updates)
+
+/// Updates the icon of the atom
+/atom/proc/update_icon(updates=ALL)
+	SIGNAL_HANDLER
+	SHOULD_CALL_PARENT(TRUE)
+
+	updates &= ~SEND_SIGNAL(src, COMSIG_ATOM_UPDATE_ICON, updates)
+	if(updates & UPDATE_ICON_STATE)
+		update_icon_state()
+		SEND_SIGNAL(src, COMSIG_ATOM_UPDATE_ICON_STATE)
+
+	if(updates & UPDATE_OVERLAYS)
+		var/list/new_overlays = update_overlays(updates)
+		if(managed_overlays)
+			cut_overlay(managed_overlays)
+			managed_overlays = null
+		if(length(new_overlays))
+			if(length(new_overlays) == 1)
+				managed_overlays = new_overlays[1]
+			else
+				managed_overlays = new_overlays
+			add_overlay(new_overlays)
+		SEND_SIGNAL(src, COMSIG_ATOM_UPDATE_OVERLAYS)
+
+	SEND_SIGNAL(src, COMSIG_ATOM_UPDATED_ICON, updates)
+
+/// Updates the icon state of the atom
+/atom/proc/update_icon_state()
+	return
+
+/// Updates the overlays of the atom. It has to return a list of overlays if it can't call the parent to create one. The list can contain anything that would be valid for the add_overlay proc: Images, mutable appearances, icon states...
+/atom/proc/update_overlays()
+	return list()
+
 /atom/proc/relaymove()
 	return
 

code/game/atoms_movable.dm

@@ -51,24 +51,17 @@
 			gen_emissive_blocker.color = EM_BLOCK_COLOR
 			gen_emissive_blocker.dir = dir
 			gen_emissive_blocker.appearance_flags |= appearance_flags
-			add_overlay(list(gen_emissive_blocker))
+			AddComponent(/datum/component/emissive_blocker, gen_emissive_blocker)
 		if(EMISSIVE_BLOCK_UNIQUE)
 			render_target = ref(src)
 			em_block = new(src, render_target)
 			add_overlay(list(em_block))
 
 /atom/movable/proc/update_emissive_block()
-	if(!blocks_emissive)
-		return
-	else if (blocks_emissive == EMISSIVE_BLOCK_GENERIC)
-		var/mutable_appearance/gen_emissive_blocker = emissive_blocker(icon, icon_state, alpha = src.alpha, appearance_flags = src.appearance_flags)
-		gen_emissive_blocker.dir = dir
-		return gen_emissive_blocker
-	else if(blocks_emissive == EMISSIVE_BLOCK_UNIQUE)
-		if(!em_block && !QDELETED(src))
-			render_target = ref(src)
-			em_block = new(src, render_target)
-		add_overlay(list(em_block))
+	if(!em_block && !QDELETED(src))
+		render_target = ref(src)
+		em_block = new(src, render_target)
+	add_overlay(list(em_block))
 
 /atom/movable/Destroy()
 	unbuckle_all_mobs(force = TRUE)

code/game/data_huds.dm

@@ -20,11 +20,11 @@
 /datum/atom_hud/data/human/medical/basic
 
 /datum/atom_hud/data/human/medical/basic/proc/check_sensors(mob/living/carbon/human/H)
-	if(!istype(H)) return 0
+	if(!istype(H)) return
 	var/obj/item/clothing/under/U = H.w_uniform
-	if(!istype(U)) return 0
-	if(U.sensor_mode <= 2) return 0
-	return 1
+	if(!istype(U)) return
+	if(U.sensor_mode <= SENSOR_VITALS) return
+	return TRUE
 
 /datum/atom_hud/data/human/medical/basic/add_to_single_hud(mob/M, mob/living/carbon/H)
 	if(check_sensors(H) || istype(M,/mob/dead/observer) )

code/game/dna/dna_modifier.dm

@@ -168,6 +168,12 @@
 	add_fingerprint(usr)
 	SStgui.update_uis(src)
 
+/obj/machinery/dna_scannernew/update_icon_state()
+	if(occupant)
+		icon_state = "scanner_occupied"
+	else
+		icon_state = "scanner_open"
+
 /obj/machinery/dna_scannernew/MouseDrop_T(atom/movable/O, mob/user)
 	if(!istype(O))
 		return
@@ -266,7 +272,7 @@
 /obj/machinery/dna_scannernew/proc/put_in(mob/M)
 	M.forceMove(src)
 	occupant = M
-	icon_state = "scanner_occupied"
+	update_icon(UPDATE_ICON_STATE)
 	SStgui.update_uis(src)
 
 	// search for ghosts, if the corpse is empty and the scanner is connected to a cloner
@@ -288,7 +294,7 @@
 		return
 	occupant.forceMove(loc)
 	occupant = null
-	icon_state = "scanner_open"
+	update_icon(UPDATE_ICON_STATE)
 	SStgui.update_uis(src)
 
 /obj/machinery/dna_scannernew/force_eject_occupant(mob/target)
@@ -304,7 +310,7 @@
 	if(A == occupant)
 		occupant = null
 		updateUsrDialog()
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 		SStgui.update_uis(src)
 
 // Checks if occupants can be irradiated/mutated - prevents exploits where wearing full rad protection would still let you gain mutations

code/game/dna/mutations/powers.dm

@@ -394,7 +394,7 @@
 	var/can_eat = TRUE
 	if(iscarbon(user))
 		var/mob/living/carbon/C = user
-		if((C.head && (C.head.flags_cover & HEADCOVERSMOUTH)) || (C.wear_mask && (C.wear_mask.flags_cover & MASKCOVERSMOUTH) && !C.wear_mask.mask_adjusted))
+		if((C.head && (C.head.flags_cover & HEADCOVERSMOUTH)) || (C.wear_mask && (C.wear_mask.flags_cover & MASKCOVERSMOUTH) && !C.wear_mask.up))
 			if(show_message)
 				to_chat(C, "<span class='warning'>Your mouth is covered, preventing you from eating!</span>")
 			can_eat = FALSE

code/game/gamemodes/blob/blobs/captured_nuke.dm

@@ -11,12 +11,11 @@
 	START_PROCESSING(SSobj, src)
 	N?.forceMove(src)
 
-/obj/structure/blob/captured_nuke/update_icon()
-	..()
-	cut_overlays()
+/obj/structure/blob/captured_nuke/update_overlays()
+	. = ..()
 	var/image/nuke_overlay = image('icons/mob/blob.dmi', "blob_nuke_overlay")
 	nuke_overlay.appearance_flags = RESET_COLOR
-	add_overlay(nuke_overlay)
+	. += nuke_overlay
 
 /obj/structure/blob/captured_nuke/Destroy()
 	for(var/obj/machinery/nuclearbomb/O in contents)

code/game/gamemodes/blob/blobs/shield.dm

@@ -12,20 +12,43 @@
 /obj/structure/blob/shield/core
 	point_return = 0
 
-/obj/structure/blob/shield/update_icon()
-	..()
+/obj/structure/blob/shield/check_integrity()
+	var/old_compromised_integrity = compromised_integrity
 	if(obj_integrity < max_integrity * 0.5)
-		icon_state = "[initial(icon_state)]_damaged"
-		name = "weakened [initial(name)]"
-		desc = "A wall of twitching tendrils."
+		compromised_integrity = TRUE
+	else
+		compromised_integrity = FALSE
+	if(old_compromised_integrity != compromised_integrity)
+		update_state()
+		update_appearance(UPDATE_NAME|UPDATE_DESC|UPDATE_ICON_STATE)
+
+/obj/structure/blob/shield/update_state()
+	if(compromised_integrity)
 		atmosblock = FALSE
 	else
-		icon_state = initial(icon_state)
-		name = initial(name)
-		desc = initial(desc)
 		atmosblock = TRUE
 	air_update_turf(1)
 
+/obj/structure/blob/shield/update_name()
+	. = ..()
+	if(compromised_integrity)
+		name = "weakened [initial(name)]"
+	else
+		name = initial(name)
+
+/obj/structure/blob/shield/update_desc()
+	. = ..()
+	if(compromised_integrity)
+		desc = "A wall of twitching tendrils."
+	else
+		desc = initial(desc)
+
+/obj/structure/blob/shield/update_icon_state()
+	if(compromised_integrity)
+		icon_state = "[initial(icon_state)]_damaged"
+	else
+		icon_state = initial(icon_state)
+
 /obj/structure/blob/shield/CanPass(atom/movable/mover, turf/target, height=0)
 	if(istype(mover) && mover.checkpass(PASSBLOB))	return 1
 	return 0

code/game/gamemodes/blob/theblob.dm

@@ -14,13 +14,15 @@
 	var/brute_resist = 0.5 //multiplies brute damage by this
 	var/fire_resist = 1 //multiplies burn damage by this
 	var/atmosblock = FALSE //if the blob blocks atmos and heat spread
+	/// If a threshold is reached, resulting in shifting variables
+	var/compromised_integrity = FALSE
 	var/mob/camera/blob/overmind
 
 /obj/structure/blob/Initialize(mapload)
 	. = ..()
 	GLOB.blobs += src
 	setDir(pick(GLOB.cardinal))
-	update_icon()
+	check_integrity()
 	if(atmosblock)
 		air_update_turf(TRUE)
 	ConsumeTile()
@@ -63,13 +65,19 @@
 /obj/structure/blob/proc/Life()
 	return
 
+/obj/structure/blob/proc/check_integrity()
+	return
+
+/obj/structure/blob/proc/update_state()
+	return
+
 /obj/structure/blob/proc/RegenHealth()
 	// All blobs heal over time when pulsed, but it has a cool down
 	if(health_timestamp > world.time)
 		return 0
 	if(obj_integrity < max_integrity)
 		obj_integrity = min(max_integrity, obj_integrity + 1)
-		update_icon()
+		check_integrity()
 		health_timestamp = world.time + 10 // 1 seconds
 
 
@@ -186,7 +194,7 @@
 /obj/structure/blob/take_damage(damage_amount, damage_type = BRUTE, damage_flag = 0, sound_effect = 1, attack_dir)
 	. = ..()
 	if(. && obj_integrity > 0)
-		update_icon()
+		check_integrity()
 
 /obj/structure/blob/proc/change_to(type)
 	if(!ispath(type))
@@ -219,6 +227,7 @@
 		if(lowertext(B.blob_reagent_datum.color) == lowertext(src.color)) // Goddamit why we use strings for these
 			return B.blob_reagent_datum.description
 	return "something unknown"
+
 /obj/structure/blob/normal
 	icon_state = "blob"
 	light_range = 0
@@ -226,20 +235,38 @@
 	max_integrity = 25
 	brute_resist = 0.25
 
-/obj/structure/blob/normal/update_icon()
-	..()
+/obj/structure/blob/normal/check_integrity()
+	var/old_compromised_integrity = compromised_integrity
 	if(obj_integrity <= 15)
-		icon_state = "blob_damaged"
-		name = "fragile blob"
-		desc = "A thin lattice of slightly twitching tendrils."
+		compromised_integrity = TRUE
+	else
+		compromised_integrity = FALSE
+	if(old_compromised_integrity != compromised_integrity)
+		update_state()
+		update_appearance(UPDATE_NAME|UPDATE_DESC|UPDATE_ICON_STATE)
+
+/obj/structure/blob/normal/update_state()
+	if(compromised_integrity)
 		brute_resist = 0.5
-	else if(overmind)
-		icon_state = "blob"
-		name = "blob"
-		desc = "A thick wall of writhing tendrils."
+	else
 		brute_resist = 0.25
+
+/obj/structure/blob/normal/update_name()
+	. = ..()
+	if(compromised_integrity)
+		name = "fragile blob"
+	else
+		name = "[overmind ? "blob" : "dead blob"]"
+
+/obj/structure/blob/normal/update_desc()
+	. = ..()
+	if(compromised_integrity)
+		desc = "A thin lattice of slightly twitching tendrils."
+	else
+		desc = "A thick wall of [overmind ? "writhing" : "lifeless"] tendrils."
+
+/obj/structure/blob/normal/update_icon_state()
+	if(compromised_integrity)
+		icon_state = "blob_damaged"
 	else
 		icon_state = "blob"
-		name = "dead blob"
-		desc = "A thick wall of lifeless tendrils."
-		brute_resist = 0.25

code/game/gamemodes/cult/cult_items.dm

@@ -249,7 +249,7 @@
 	prefix = "darkened"
 	claw_damage_increase = 4
 
-/obj/item/whetstone/cult/update_icon()
+/obj/item/whetstone/cult/update_icon_state()
 	icon_state = "cult_sharpener[used ? "_used" : ""]"
 
 /obj/item/whetstone/cult/attackby(obj/item/I, mob/user, params)
@@ -571,7 +571,7 @@
 		qdel(spear_act)
 	..()
 
-/obj/item/twohanded/cult_spear/update_icon()
+/obj/item/twohanded/cult_spear/update_icon_state()
 	icon_state = "bloodspear[wielded]"
 
 /obj/item/twohanded/cult_spear/throw_impact(atom/hit_atom, datum/thrownthing/throwingdatum)

code/game/gamemodes/miniantags/abduction/abduction_gear.dm

@@ -384,7 +384,7 @@
 <br>
 Congratulations! You are now trained for invasive xenobiology research!"}
 
-/obj/item/paper/abductor/update_icon()
+/obj/item/paper/abductor/update_icon_state()
 	return
 
 /obj/item/paper/abductor/AltClick()
@@ -422,12 +422,12 @@ Congratulations! You are now trained for invasive xenobiology research!"}
 			txt = "probing"
 
 	to_chat(usr, "<span class='notice'>You switch the baton to [txt] mode.</span>")
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	for(var/X in actions)
 		var/datum/action/A = X
 		A.UpdateButtonIcon()
 
-/obj/item/abductor_baton/update_icon()
+/obj/item/abductor_baton/update_icon_state()
 	switch(mode)
 		if(BATON_STUN)
 			icon_state = "wonderprodStun"

code/game/gamemodes/miniantags/abduction/gland.dm

@@ -19,7 +19,7 @@
 	var/mind_control_duration = 1800
 	var/active_mind_control = FALSE
 
-/obj/item/organ/internal/heart/gland/update_icon()
+/obj/item/organ/internal/heart/gland/update_icon_state()
 	return
 
 /obj/item/organ/internal/heart/gland/proc/ownerCheck()

code/game/gamemodes/miniantags/abduction/machinery/experiment.dm

@@ -17,6 +17,12 @@
 	eject_abductee()
 	return ..()
 
+/obj/machinery/abductor/experiment/update_icon_state()
+	if(occupant)
+		icon_state = "experiment"
+	else
+		icon_state = "experiment-open"
+
 /obj/machinery/abductor/experiment/MouseDrop_T(mob/living/carbon/human/target, mob/user)
 	if(user.stat || HAS_TRAIT(user, TRAIT_UI_BLOCKED) || !Adjacent(user) || !target.Adjacent(user) || !ishuman(target))
 		return
@@ -34,7 +40,7 @@
 
 	target.forceMove(src)
 	occupant = target
-	icon_state = "experiment"
+	update_icon(UPDATE_ICON_STATE)
 	add_fingerprint(user)
 
 /obj/machinery/abductor/experiment/attack_hand(mob/user)
@@ -196,7 +202,7 @@
 		var/mob/living/carbon/human/H = grabbed.affecting
 		H.forceMove(src)
 		occupant = H
-		icon_state = "experiment"
+		update_icon(UPDATE_ICON_STATE)
 		add_fingerprint(user)
 		qdel(G)
 		return
@@ -212,11 +218,11 @@
 	if(A == occupant)
 		occupant = null
 		updateUsrDialog()
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/abductor/experiment/proc/eject_abductee()
 	if(!occupant)
 		return
 	occupant.forceMove(get_turf(src))
 	occupant = null
-	icon_state = "experiment-open"
+	update_icon(UPDATE_ICON_STATE)

code/game/gamemodes/miniantags/guardian/guardian.dm

@@ -465,10 +465,9 @@
  <b>Protector</b>: You will become leashed to your holoparasite instead of them to you. Has two modes, a medium attack/defense mode and a protection mode which greatly reduces incoming damage to the holoparasite.
 "}
 
-/obj/item/paper/guardian/update_icon()
+/obj/item/paper/guardian/update_icon_state()
 	return
 
-
 /obj/item/storage/box/syndie_kit/guardian
 	name = "holoparasite injector kit"
 

code/game/gamemodes/miniantags/slaughter/slaughter.dm

@@ -248,7 +248,7 @@
 	icon_state = "demon_heart"
 	origin_tech = "combat=5;biotech=7"
 
-/obj/item/organ/internal/heart/demon/update_icon()
+/obj/item/organ/internal/heart/demon/update_icon_state()
 	return //always beating visually
 
 /obj/item/organ/internal/heart/demon/prepare_eat()

code/game/gamemodes/nuclear/nuclearbomb.dm

@@ -73,6 +73,11 @@ GLOBAL_VAR(bomb_set)
 			INVOKE_ASYNC(src, .proc/explode)
 	return
 
+/obj/machinery/nuclearbomb/update_overlays()
+	. = ..()
+	if(panel_open)
+		. += "npanel_open"
+
 /obj/machinery/nuclearbomb/attackby(obj/item/O as obj, mob/user as mob, params)
 	if(istype(O, /obj/item/disk/nuclear))
 		if(extended)
@@ -184,13 +189,11 @@ GLOBAL_VAR(bomb_set)
 	if(auth || (istype(I, /obj/item/screwdriver/nuke)))
 		if(!panel_open)
 			panel_open = TRUE
-			overlays += image(icon, "npanel_open")
 			to_chat(user, "You unscrew the control panel of [src].")
 			anchor_stage = removal_stage
 			removal_stage = core_stage
 		else
 			panel_open = FALSE
-			overlays -= image(icon, "npanel_open")
 			to_chat(user, "You screw the control panel of [src] back on.")
 			core_stage = removal_stage
 			removal_stage = anchor_stage
@@ -199,11 +202,11 @@ GLOBAL_VAR(bomb_set)
 			to_chat(user, "[src] emits a buzzing noise, the panel staying locked in.")
 		if(panel_open == TRUE)
 			panel_open = FALSE
-			overlays -= image(icon, "npanel_open")
 			to_chat(user, "You screw the control panel of [src] back on.")
 			core_stage = removal_stage
 			removal_stage = anchor_stage
 		flick("nuclearbombc", src)
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/machinery/nuclearbomb/wirecutter_act(mob/user, obj/item/I)
 	if(!panel_open)

code/game/machinery/Beacon.dm

@@ -43,10 +43,10 @@
 
 /obj/machinery/bluespace_beacon/hide(intact)
 	invisibility = intact ? INVISIBILITY_MAXIMUM : 0
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 // update the icon_state
-/obj/machinery/bluespace_beacon/update_icon()
+/obj/machinery/bluespace_beacon/update_icon_state()
 	var/state="floor_beacon"
 	if(invisibility)
 		icon_state = "[state]f"
@@ -60,11 +60,11 @@
 				Beacon.loc = loc
 		else
 			create_beacon()
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 	else
 		if(Beacon)
 			destroy_beacon()
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 
 
 /obj/machinery/bluespace_beacon/syndicate

code/game/machinery/PDApainter.dm

@@ -9,23 +9,21 @@
 	var/obj/item/pda/storedpda = null
 	var/list/colorlist = list()
 
-
-/obj/machinery/pdapainter/update_icon()
-	cut_overlays()
-
+/obj/machinery/pdapainter/update_icon_state()
 	if(stat & BROKEN)
 		icon_state = "[initial(icon_state)]-broken"
 		return
-
-	if(storedpda)
-		add_overlay("[initial(icon_state)]-closed")
-
 	if(powered())
 		icon_state = initial(icon_state)
 	else
 		icon_state = "[initial(icon_state)]-off"
 
-	return
+/obj/machinery/pdapainter/update_overlays()
+	. = ..()
+	if(stat & BROKEN)
+		return
+	if(storedpda)
+		. += "[initial(icon_state)]-closed"
 
 /obj/machinery/pdapainter/Initialize(mapload)
 	. = ..()

code/game/machinery/Sleeper.dm

@@ -50,6 +50,12 @@
 	else
 		set_light(0)
 
+/obj/machinery/sleeper/update_icon_state()
+	if(occupant)
+		icon_state = base_icon
+	else
+		icon_state = "[base_icon]-open"
+
 /obj/machinery/sleeper/Initialize(mapload)
 	. = ..()
 	component_parts = list()
@@ -346,7 +352,7 @@
 			var/mob/M = G.affecting
 			M.forceMove(src)
 			occupant = M
-			icon_state = "[base_icon]"
+			update_icon(UPDATE_ICON_STATE)
 			to_chat(M, "<span class='boldnotice'>You feel cool air surround you. You go numb as your senses turn inward.</span>")
 			add_fingerprint(user)
 			qdel(G)
@@ -396,7 +402,7 @@
 	if(A == occupant)
 		occupant = null
 		updateUsrDialog()
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 		SStgui.update_uis(src)
 	if(A == beaker)
 		beaker = null
@@ -431,7 +437,7 @@
 		return
 	occupant.forceMove(loc)
 	occupant = null
-	icon_state = "[base_icon]-open"
+	update_icon(UPDATE_ICON_STATE)
 	// eject trash the occupant dropped
 	for(var/atom/movable/A in contents - component_parts - list(beaker))
 		A.forceMove(loc)
@@ -468,7 +474,6 @@
 	if(usr.incapacitated()) //are you cuffed, dying, lying, stunned or other
 		return
 
-	icon_state = "[base_icon]-open"
 	go_out()
 	add_fingerprint(usr)
 	return
@@ -504,7 +509,7 @@
 			return
 		L.forceMove(src)
 		occupant = L
-		icon_state = "[base_icon]"
+		update_icon(UPDATE_ICON_STATE)
 		to_chat(L, "<span class='boldnotice'>You feel cool air surround you. You go numb as your senses turn inward.</span>")
 		add_fingerprint(user)
 		if(user.pulling == L)
@@ -575,7 +580,7 @@
 		usr.stop_pulling()
 		usr.forceMove(src)
 		occupant = usr
-		icon_state = "[base_icon]"
+		update_icon(UPDATE_ICON_STATE)
 
 		for(var/obj/O in src)
 			qdel(O)

code/game/machinery/adv_med.dm

@@ -48,6 +48,12 @@
 	component_parts += new /obj/item/stack/cable_coil(null, 2)
 	RefreshParts()
 
+/obj/machinery/bodyscanner/update_icon_state()
+	if(occupant)
+		icon_state = "bodyscanner"
+	else
+		icon_state = "bodyscanner-open"
+
 /obj/machinery/bodyscanner/attackby(obj/item/I, mob/user)
 	if(exchange_parts(user, I))
 		return
@@ -71,7 +77,7 @@
 			return
 		M.forceMove(src)
 		occupant = M
-		icon_state = "bodyscanner"
+		update_icon(UPDATE_ICON_STATE)
 		add_fingerprint(user)
 		qdel(TYPECAST_YOUR_SHIT)
 		SStgui.update_uis(src)
@@ -135,7 +141,7 @@
 
 	H.forceMove(src)
 	occupant = H
-	icon_state = "bodyscanner"
+	update_icon(UPDATE_ICON_STATE)
 	add_fingerprint(user)
 	SStgui.update_uis(src)
 
@@ -178,7 +184,7 @@
 		return
 	occupant.forceMove(loc)
 	occupant = null
-	icon_state = "bodyscanner-open"
+	update_icon(UPDATE_ICON_STATE)
 	// eject trash the occupant dropped
 	for(var/atom/movable/A in contents - component_parts)
 		A.forceMove(loc)
@@ -197,7 +203,7 @@
 	if(A == occupant)
 		occupant = null
 		updateUsrDialog()
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/bodyscanner/narsie_act()
 	go_out()

code/game/machinery/ai_slipper.dm

@@ -21,7 +21,7 @@
 		stat &= ~NOPOWER
 	else
 		stat |= NOPOWER
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/ai_slipper/attack_ai(mob/user)
 	add_hiddenprint(user)
@@ -56,7 +56,7 @@
 		power_change()
 		addtimer(CALLBACK(src, .proc/recharge), cooldown_time)
 
-/obj/machinery/ai_slipper/update_icon()
+/obj/machinery/ai_slipper/update_icon_state()
 	if(stat & (NOPOWER|BROKEN) || cooldown_on || !uses)
 		icon_state = "liquid_dispenser"
 	else

code/game/machinery/camera/camera.dm

@@ -74,21 +74,21 @@
 		return
 	if(!isEmpProof())
 		if(prob(150/severity))
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 			var/list/previous_network = network
 			network = list()
 			GLOB.cameranet.removeCamera(src)
 			stat |= EMPED
 			set_light(0)
 			emped = emped+1  //Increase the number of consecutive EMP's
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 			var/thisemp = emped //Take note of which EMP this proc is for
 			spawn(900)
 				if(!QDELETED(src))
 					if(emped == thisemp) //Only fix it if the camera hasn't been EMP'd again
 						network = previous_network
 						stat &= ~EMPED
-						update_icon()
+						update_icon(UPDATE_ICON_STATE)
 						if(can_use())
 							GLOB.cameranet.addCamera(src)
 						emped = 0 //Resets the consecutive EMP count
@@ -243,7 +243,7 @@
 			new /obj/item/stack/cable_coil(loc, 2)
 	qdel(src)
 
-/obj/machinery/camera/update_icon()
+/obj/machinery/camera/update_icon_state()
 	if(!status)
 		icon_state = "[initial(icon_state)]1"
 	else if(stat & EMPED)
@@ -277,7 +277,7 @@
 			visible_message("<span class='danger'>\The [src] [change_msg]!</span>")
 
 		playsound(loc, toggle_sound, 100, 1)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 	// now disconnect anyone using the camera
 	//Apparently, this will disconnect anyone even if the camera was re-activated.

code/game/machinery/camera/camera_assembly.dm

@@ -127,12 +127,12 @@
 		WRENCH_ANCHOR_TO_WALL_MESSAGE
 		anchored = TRUE
 		state = ASSEMBLY_WRENCHED
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 		auto_turn()
 	else if(state == ASSEMBLY_WRENCHED)
 		WRENCH_UNANCHOR_WALL_MESSAGE
 		anchored = FALSE
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 		state = ASSEMBLY_UNBUILT
 	else
 		to_chat(user, "<span class='warning'>[src] can't fit here!</span>")
@@ -155,7 +155,7 @@
 		to_chat(user, "<span class='notice'>You unweld [src] from its place.</span>")
 		state = ASSEMBLY_WRENCHED
 
-/obj/item/camera_assembly/update_icon()
+/obj/item/camera_assembly/update_icon_state()
 	if(anchored)
 		icon_state = "camera1"
 	else

code/game/machinery/cell_charger.dm

@@ -21,20 +21,13 @@
 	QDEL_NULL(charging)
 	return ..()
 
-/obj/machinery/cell_charger/proc/updateicon()
+/obj/machinery/cell_charger/update_icon_state()
 	icon_state = "ccharger[charging ? 1 : 0]"
 
+/obj/machinery/cell_charger/update_overlays()
+	. = ..()
 	if(charging && !(stat & (BROKEN|NOPOWER)))
-		var/newlevel = 	round(charging.percent() * 4 / 100)
-
-		if(chargelevel != newlevel)
-			chargelevel = newlevel
-
-			overlays.Cut()
-			overlays += "ccharger-o[newlevel]"
-
-	else
-		overlays.Cut()
+		. += "ccharger-o[chargelevel]"
 
 /obj/machinery/cell_charger/examine(mob/user)
 	. = ..()
@@ -66,8 +59,8 @@
 			I.forceMove(src)
 			charging = I
 			user.visible_message("[user] inserts a cell into the charger.", "<span class='notice'>You insert a cell into the charger.</span>")
-			chargelevel = -1
-			updateicon()
+			check_level()
+			update_icon()
 	else
 		return ..()
 
@@ -89,7 +82,7 @@
 	charging.update_icon()
 	charging = null
 	chargelevel = -1
-	updateicon()
+	update_icon()
 
 /obj/machinery/cell_charger/attack_hand(mob/user)
 	if(!charging)
@@ -134,4 +127,11 @@
 	use_power(200)		//this used to use CELLRATE, but CELLRATE is fucking awful. feel free to fix this properly!
 	charging.give(175)	//inefficiency.
 
-	updateicon()
+	if(check_level())
+		update_icon(UPDATE_OVERLAYS)
+
+/obj/machinery/cell_charger/proc/check_level()
+	var/newlevel = 	round(charging.percent() * 4 / 100)
+	if(chargelevel != newlevel)
+		chargelevel = newlevel
+		return TRUE

code/game/machinery/cloning.dm

@@ -523,13 +523,7 @@ GLOBAL_LIST_INIT(cloner_biomass_items, list(\
 	mess = TRUE
 	update_icon()
 
-/obj/machinery/clonepod/update_icon()
-	..()
-	cut_overlays()
-
-	if(panel_open)
-		add_overlay("panel_open")
-
+/obj/machinery/clonepod/update_icon_state()
 	if(occupant && !(stat & NOPOWER))
 		icon_state = "pod_cloning"
 	else if(mess)
@@ -537,6 +531,11 @@ GLOBAL_LIST_INIT(cloner_biomass_items, list(\
 	else
 		icon_state = "pod_idle"
 
+/obj/machinery/clonepod/update_overlays()
+	. = ..()
+	if(panel_open)
+		. += "panel_open"
+
 /obj/machinery/clonepod/relaymove(mob/user)
 	if(user.stat == CONSCIOUS)
 		go_out()

code/game/machinery/computer/HolodeckControl.dm

@@ -289,7 +289,7 @@
 	for(var/mob/living/simple_animal/hostile/carp/C in linkedholodeck)
 		qdel(C)
 
-	holographic_items = A.copy_contents_to(linkedholodeck , 1)
+	holographic_items = A.copy_contents_to(linkedholodeck , 1, perfect_copy = FALSE)
 
 	if(emagged)
 		for(var/obj/item/holo/H in linkedholodeck)
@@ -343,9 +343,9 @@
 
 /turf/simulated/floor/holofloor/carpet/Initialize(mapload)
 	. = ..()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
-/turf/simulated/floor/holofloor/carpet/update_icon()
+/turf/simulated/floor/holofloor/carpet/update_icon_state()
 	if(!..())
 		return 0
 	if(smoothing_flags & (SMOOTH_CORNERS|SMOOTH_BITMASK))
@@ -594,7 +594,7 @@
 
 	ready = !ready
 
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 	var/numbuttons = 0
 	var/numready = 0
@@ -606,7 +606,7 @@
 	if(numbuttons == numready)
 		begin_event()
 
-/obj/machinery/readybutton/update_icon()
+/obj/machinery/readybutton/update_icon_state()
 	if(ready)
 		icon_state = "auth_on"
 	else

code/game/machinery/computer/ai_core.dm

@@ -24,7 +24,7 @@
 					return
 				playsound(loc, P.usesound, 50, 1)
 				to_chat(user, "<span class='notice'>You place the circuit board inside the frame.</span>")
-				update_icon()
+				update_icon(UPDATE_ICON_STATE)
 				state = CIRCUIT_CORE
 				P.forceMove(src)
 				circuit = P
@@ -38,7 +38,7 @@
 					if(do_after(user, 20, target = src) && state == SCREWED_CORE && C.use(5))
 						to_chat(user, "<span class='notice'>You add cables to the frame.</span>")
 						state = CABLED_CORE
-						update_icon()
+						update_icon(UPDATE_ICON_STATE)
 				else
 					to_chat(user, "<span class='warning'>You need five lengths of cable to wire the AI core!</span>")
 				return
@@ -51,7 +51,7 @@
 					if(do_after(user, 20, target = src) && state == CABLED_CORE && G.use(2))
 						to_chat(user, "<span class='notice'>You put in the glass panel.</span>")
 						state = GLASS_CORE
-						update_icon()
+						update_icon(UPDATE_ICON_STATE)
 				else
 					to_chat(user, "<span class='warning'>You need two sheets of reinforced glass to insert them into the AI core!</span>")
 				return
@@ -119,7 +119,7 @@
 				M.forceMove(src)
 				brain = M
 				to_chat(user, "<span class='notice'>You add [M.name] to the frame.</span>")
-				update_icon()
+				update_icon(UPDATE_ICON_STATE)
 				return
 
 	return ..()
@@ -147,7 +147,7 @@
 				to_chat(user, "<span class='notice'>You remove the brain.</span>")
 				brain.forceMove(loc)
 				brain = null
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/structure/AIcore/screwdriver_act(mob/living/user, obj/item/I)
 	if(!(state in list(SCREWED_CORE, CIRCUIT_CORE, GLASS_CORE, AI_READY_CORE)))
@@ -185,7 +185,7 @@
 		if(AI_READY_CORE)
 			to_chat(user, "<span class='notice'>You disconnect the monitor.</span>")
 			state = GLASS_CORE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 
 /obj/structure/AIcore/wirecutter_act(mob/living/user, obj/item/I)
@@ -199,7 +199,7 @@
 	else
 		to_chat(user, "<span class='notice'>You remove the cables.</span>")
 		state = SCREWED_CORE
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 		var/obj/item/stack/cable_coil/A = new /obj/item/stack/cable_coil( loc )
 		A.amount = 5
 
@@ -209,7 +209,7 @@
 		return
 	default_unfasten_wrench(user, I, 20)
 
-/obj/structure/AIcore/update_icon()
+/obj/structure/AIcore/update_icon_state()
 	switch(state)
 		if(EMPTY_CORE)
 			icon_state = "0"

code/game/machinery/computer/aifixer.dm

@@ -74,7 +74,7 @@
 		if("radio")
 			occupant.aiRadio.disabledAi = !occupant.aiRadio.disabledAi
 
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 	return TRUE
 
 /obj/machinery/computer/aifixer/proc/fix_ai() // Can we fix it? Probrably.
@@ -86,26 +86,22 @@
 		occupant.updatehealth()
 		if(occupant.health >= 0 && occupant.stat == DEAD)
 			occupant.update_revive()
-			update_icon()
+			update_icon(UPDATE_OVERLAYS)
 		sleep(10)
 	active = FALSE
 
-/obj/machinery/computer/aifixer/update_icon()
-	..()
-	if(stat & (NOPOWER|BROKEN))
-		return
+/obj/machinery/computer/aifixer/update_overlays()
+	. = ..()
+	if(active)
+		. += "ai-fixer-on"
+	if(occupant)
+		switch(occupant.stat)
+			if(0)
+				. += "ai-fixer-full"
+			if(2)
+				. += "ai-fixer-404"
 	else
-		var/overlay_layer = LIGHTING_LAYER+0.2 // +0.1 from the default computer overlays
-		if(active)
-			overlays += image(icon,"ai-fixer-on",overlay_layer)
-		if(occupant)
-			switch(occupant.stat)
-				if(0)
-					overlays += image(icon,"ai-fixer-full",overlay_layer)
-				if(2)
-					overlays += image(icon,"ai-fixer-404",overlay_layer)
-		else
-			overlays += image(icon,"ai-fixer-empty",overlay_layer)
+		. += "ai-fixer-empty"
 
 /obj/machinery/computer/aifixer/transfer_ai(interaction, mob/user, mob/living/silicon/ai/AI, obj/item/aicard/card)
 	if(!..())
@@ -121,7 +117,7 @@
 		AI.aiRadio.disabledAi = TRUE
 		to_chat(AI, "You have been uploaded to a stationary terminal. Sadly, there is no remote access from here.")
 		to_chat(user, "<span class='boldnotice'>Transfer successful</span>: [AI.name] ([rand(1000,9999)].exe) installed and executed successfully. Local copy has been removed.")
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 
 	else //Uploading AI from terminal to card
 		if(occupant && !active)
@@ -129,7 +125,7 @@
 			to_chat(user, "<span class='boldnotice'>Transfer successful</span>: [occupant.name] ([rand(1000,9999)].exe) removed from host terminal and stored within local memory.")
 			occupant.forceMove(card)
 			occupant = null
-			update_icon()
+			update_icon(UPDATE_OVERLAYS)
 		else if(active)
 			to_chat(user, "<span class='boldannounce'>ERROR</span>: Reconstruction in progress.")
 		else if(!occupant)

code/game/machinery/computer/atmos_alert.dm

@@ -79,7 +79,7 @@
 		minor_alarms += zone
 	update_icon()
 
-/obj/machinery/computer/atmos_alert/update_icon()
+/obj/machinery/computer/atmos_alert/update_icon_state()
 	if(length(priority_alarms))
 		icon_screen = "alert:2"
 	else if(length(minor_alarms))

code/game/machinery/computer/atmos_control.dm

@@ -25,7 +25,7 @@
 	// 16 for nitrogen concentration
 	// 32 for carbon dioxide concentration
 
-/obj/machinery/air_sensor/update_icon()
+/obj/machinery/air_sensor/update_icon_state()
 	icon_state = "gsensor[on]"
 
 /obj/machinery/air_sensor/multitool_menu(mob/user, obj/item/multitool/P)

code/game/machinery/computer/buildandrepair.dm

@@ -457,8 +457,7 @@
 	if(state == STATE_GLASS)
 		new /obj/item/stack/sheet/glass(location, 2)
 
-/obj/structure/computerframe/update_icon()
-	. = ..()
+/obj/structure/computerframe/update_icon_state()
 	icon_state = "comp_frame_[state]"
 
 /obj/structure/computerframe/welder_act(mob/user, obj/item/I)

code/game/machinery/computer/computer.dm

@@ -67,24 +67,24 @@
 	update_icon()
 	flickering = FALSE
 
-/obj/machinery/computer/update_icon()
-	cut_overlays()
+/obj/machinery/computer/update_overlays()
+	. = ..()
 	underlays.Cut()
 	if((stat & NOPOWER) || force_no_power_icon_state)
 		if(icon_keyboard)
-			add_overlay("[icon_keyboard]_off")
+			. += "[icon_keyboard]_off"
 		return
 
 	// This whole block lets screens and keyboards ignore lighting and be visible even in the darkest room
 	var/overlay_state = icon_screen
 	if(stat & BROKEN)
 		overlay_state = "[icon_state]_broken"
-	add_overlay("[overlay_state]")
+	. += "[overlay_state]"
 	if(!(stat & BROKEN) && light)
 		underlays += emissive_appearance(icon, "[icon_state]_lightmask")
 
 	if(icon_keyboard)
-		add_overlay("[icon_keyboard]")
+		. += "[icon_keyboard]"
 		underlays += emissive_appearance(icon, "[icon_keyboard]_lightmask")
 
 /obj/machinery/computer/power_change()

code/game/machinery/computer/message.dm

@@ -81,14 +81,12 @@
 		else
 			to_chat(user, "<span class='notice'>A no server error appears on the screen.</span>")
 
-/obj/machinery/computer/message_monitor/update_icon()
+/obj/machinery/computer/message_monitor/update_icon_state()
 	if(emag || hacking)
 		icon_screen = hack_icon
 	else
 		icon_screen = normal_icon
 
-	..()
-
 /obj/machinery/computer/message_monitor/attack_hand(mob/user as mob)
 	if(..())
 		return

code/game/machinery/computer/station_alert.dm

@@ -72,7 +72,7 @@
 		return
 	update_icon()
 
-/obj/machinery/computer/station_alert/update_icon()
+/obj/machinery/computer/station_alert/update_icon_state()
 	var/active_alarms = FALSE
 	var/list/list/temp_alarm_list = SSalarm.alarms.Copy()
 	for(var/cat in temp_alarm_list)
@@ -92,5 +92,3 @@
 		icon_screen = "alert:2"
 	else
 		icon_screen = "alert:0"
-
-	..()

code/game/machinery/dance_machine.dm

@@ -70,13 +70,11 @@
 		WRENCH_UNANCHOR_MESSAGE
 	playsound(src, 'sound/items/deconstruct.ogg', 50, 1)
 
-/obj/machinery/disco/update_icon()
+/obj/machinery/disco/update_icon_state()
 	if(active)
 		icon_state = "disco1"
 	else
 		icon_state = "disco0"
-	..()
-
 
 /obj/machinery/disco/attack_hand(mob/user)
 	if(..())
@@ -127,7 +125,7 @@
 					playsound(src, 'sound/misc/compiler-failure.ogg', 50, 1)
 					return
 				active = TRUE
-				update_icon()
+				update_icon(UPDATE_ICON_STATE)
 				dance_setup()
 				START_PROCESSING(SSobj, src)
 				lights_spin()

code/game/machinery/defib_mount.dm

@@ -37,7 +37,7 @@
 /obj/machinery/defibrillator_mount/loaded/Initialize(mapload) //loaded subtype for mapping use
 	. = ..()
 	defib = new/obj/item/defibrillator/loaded(src)
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/machinery/defibrillator_mount/Destroy()
 	QDEL_NULL(defib)
@@ -58,19 +58,19 @@
 	if(defib && defib.cell && defib.cell.charge < defib.cell.maxcharge && is_operational())
 		use_power(200)
 		defib.cell.give(180) //90% efficiency, slightly better than the cell charger's 87.5%
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 
-/obj/machinery/defibrillator_mount/update_icon()
-	cut_overlays()
+/obj/machinery/defibrillator_mount/update_overlays()
+	. = ..()
 	if(defib)
-		add_overlay("defib")
+		. += "defib"
 		if(defib.powered)
-			add_overlay(defib.safety ? "online" : "emagged")
+			. += "[defib.safety ? "online" : "emagged"]"
 			var/ratio = defib.cell.charge / defib.cell.maxcharge
 			ratio = CEILING(ratio * 4, 1) * 25
-			add_overlay("charge[ratio]")
+			. += "charge[ratio]"
 		if(clamps_locked)
-			add_overlay("clamps")
+			. += "clamps"
 
 //defib interaction
 /obj/machinery/defibrillator_mount/attack_hand(mob/living/user)
@@ -95,7 +95,7 @@
 		"<span class='notice'>You press [I] into the mount, and it clicks into place.</span>")
 		playsound(src, 'sound/machines/click.ogg', 50, TRUE)
 		defib = I
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 		return
 	else if(defib && I == defib.paddles)
 		user.drop_item()
@@ -108,7 +108,7 @@
 				return
 			clamps_locked = !clamps_locked
 			to_chat(user, "<span class='notice'>Clamps [clamps_locked ? "" : "dis"]engaged.</span>")
-			update_icon()
+			update_icon(UPDATE_OVERLAYS)
 		else
 			to_chat(user, "<span class='warning'>Insufficient access.</span>")
 		return
@@ -143,7 +143,7 @@
 	"<span class='notice'>You slide out [defib] from [src] and unhook the charging cables.</span>")
 	playsound(src, 'sound/items/deconstruct.ogg', 50, TRUE)
 	defib = null
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 //wallframe, for attaching the mounts easily
 /obj/item/mounted/frame/defib_mount

code/game/machinery/doors/airlock.dm

@@ -330,8 +330,14 @@ GLOBAL_LIST_EMPTY(airlock_overlays)
 		if(AIRLOCK_OPEN, AIRLOCK_CLOSED)
 		if(AIRLOCK_DENY, AIRLOCK_OPENING, AIRLOCK_CLOSING, AIRLOCK_EMAG)
 			icon_state = "nonexistenticonstate" //MADNESS
+
+	. = ..(UPDATE_ICON_STATE) // Sent after the icon_state is changed
+
 	set_airlock_overlays(state)
 
+/obj/machinery/door/airlock/update_icon_state()
+	return
+
 /obj/machinery/door/airlock/proc/set_airlock_overlays(state)
 	var/image/frame_overlay
 	var/image/filling_overlay
@@ -1380,9 +1386,13 @@ GLOBAL_LIST_EMPTY(airlock_overlays)
 /obj/machinery/door/airlock/proc/note_type() //Returns a string representing the type of note pinned to this airlock
 	if(!note)
 		return
-	else if(istype(note, /obj/item/paper))
-		return "note"
-	else if(istype(note, /obj/item/photo))
+	if(istype(note, /obj/item/paper))
+		var/obj/item/paper/pinned_paper = note
+		if(pinned_paper.info)
+			return "note_words"
+		else
+			return "note"
+	if(istype(note, /obj/item/photo))
 		return "photo"
 
 //Removes the current note on the door if any. Returns if a note is removed

code/game/machinery/doors/airlock_control.dm

@@ -155,7 +155,7 @@
 	var/alert = 0
 	var/previousPressure
 
-/obj/machinery/airlock_sensor/update_icon()
+/obj/machinery/airlock_sensor/update_icon_state()
 	if(on)
 		if(alert)
 			icon_state = "airlock_sensor_alert"
@@ -191,7 +191,7 @@
 
 			alert = (pressure < ONE_ATMOSPHERE*0.8)
 
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/airlock_sensor/set_frequency(new_frequency)
 	SSradio.remove_object(src, frequency)
@@ -226,7 +226,7 @@
 	var/command = "cycle"
 	var/on = TRUE
 
-/obj/machinery/access_button/update_icon()
+/obj/machinery/access_button/update_icon_state()
 	if(on)
 		icon_state = "access_button_standby"
 	else

code/game/machinery/doors/brigdoors.dm

@@ -142,9 +142,9 @@
 		if(T.id == id)
 			targets += T
 
-	if(targets.len==0)
+	if(!length(targets))
 		stat |= BROKEN
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/door_timer/Destroy()
 	QDEL_NULL(Radio)
@@ -165,7 +165,7 @@
 			timer_end() // open doors, reset timer, clear status screen
 			timing = FALSE
 			. = PROCESS_KILL
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 	else
 		timer_end()
 		return PROCESS_KILL
@@ -173,7 +173,7 @@
 // has the door power situation changed, if so update icon.
 /obj/machinery/door_timer/power_change()
 	..()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 
 // open/closedoor checks if door_timer has power, if so it checks if the
@@ -358,7 +358,7 @@
 			prisoner_time = null
 			timing = TRUE
 			timer_start()
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 		if("restart_timer")
 			if(timing)
 				var/reset_reason = sanitize(copytext(input(usr, "Reason for resetting timer:", name, "") as text|null, 1, MAX_MESSAGE_LEN))
@@ -395,7 +395,7 @@
 // if NOPOWER, display blank
 // if BROKEN, display blue screen of death icon AI uses
 // if timing=true, run update display function
-/obj/machinery/door_timer/update_icon()
+/obj/machinery/door_timer/update_icon_state()
 	if(stat & (NOPOWER))
 		icon_state = "frame"
 		return

code/game/machinery/doors/door.dm

@@ -149,26 +149,34 @@
 				var/mob/living/simple_animal/bot/B = user
 				B.door_opened(src)
 		else
+			if(pry_open_check(user))
+				return
 			do_animate("deny")
-			if(HAS_TRAIT(user, TRAIT_FORCE_DOORS))
-				var/datum/antagonist/vampire/V = user.mind.has_antag_datum(/datum/antagonist/vampire)
 
-				if(V && HAS_TRAIT_FROM(user, TRAIT_FORCE_DOORS, VAMPIRE_TRAIT))
-					if(!V.bloodusable)
-						REMOVE_TRAIT(user, TRAIT_FORCE_DOORS, VAMPIRE_TRAIT)
-						return
-				if(welded)
-					to_chat(user, "<span class='warning'>The door is welded.</span>")
-					return
-				if(locked)
-					to_chat(user, "<span class='warning'>The door is bolted.</span>")
-					return
-				if(density)
-					visible_message("<span class='danger'>[user] forces the door open!</span>")
-					playsound(loc, "sparks", 100, TRUE, SHORT_RANGE_SOUND_EXTRARANGE)
-					open(TRUE)
-				if(V && HAS_TRAIT_FROM(user, TRAIT_FORCE_DOORS, VAMPIRE_TRAIT))
-					V.bloodusable = max(V.bloodusable - 5, 0)
+/obj/machinery/door/proc/pry_open_check(mob/user)
+	. = TRUE
+	if(isterrorspider(user))
+		return
+
+	if(!HAS_TRAIT(user, TRAIT_FORCE_DOORS))
+		return FALSE
+	var/datum/antagonist/vampire/V = user.mind?.has_antag_datum(/datum/antagonist/vampire)
+	if(V && HAS_TRAIT_FROM(user, TRAIT_FORCE_DOORS, VAMPIRE_TRAIT))
+		if(!V.bloodusable)
+			REMOVE_TRAIT(user, TRAIT_FORCE_DOORS, VAMPIRE_TRAIT)
+			return FALSE
+	if(welded)
+		to_chat(user, "<span class='warning'>The door is welded.</span>")
+		return FALSE
+	if(locked)
+		to_chat(user, "<span class='warning'>The door is bolted.</span>")
+		return FALSE
+	if(density)
+		visible_message("<span class='danger'>[user] forces the door open!</span>")
+		playsound(loc, "sparks", 100, TRUE, SHORT_RANGE_SOUND_EXTRARANGE)
+		open(TRUE)
+	if(V && HAS_TRAIT_FROM(user, TRAIT_FORCE_DOORS, VAMPIRE_TRAIT))
+		V.bloodusable = max(V.bloodusable - 5, 0)
 
 /obj/machinery/door/attack_ai(mob/user)
 	return attack_hand(user)
@@ -194,7 +202,7 @@
 			open()
 		else
 			close()
-		return
+		return TRUE
 	if(density)
 		do_animate("deny")
 
@@ -259,11 +267,8 @@
 		emagged = TRUE
 		return TRUE
 
-/obj/machinery/door/update_icon()
-	if(density)
-		icon_state = "door1"
-	else
-		icon_state = "door0"
+/obj/machinery/door/update_icon_state()
+	icon_state = "door[density]"
 
 /obj/machinery/door/proc/do_animate(animation)
 	switch(animation)

code/game/machinery/doors/firedoor.dm

@@ -200,18 +200,21 @@
 			flick("door_closing", src)
 			playsound(src, 'sound/machines/airlock_ext_close.ogg', 30, 1)
 
-/obj/machinery/door/firedoor/update_icon()
-	overlays.Cut()
-	if(active_alarm && hasPower())
-		overlays += image('icons/obj/doors/doorfire.dmi', "alarmlights")
+/obj/machinery/door/firedoor/update_icon_state()
 	if(density)
 		icon_state = "door_closed"
-		if(welded)
-			overlays += "welded"
 	else
 		icon_state = "door_open"
-		if(welded)
-			overlays += "welded_open"
+
+/obj/machinery/door/firedoor/update_overlays()
+	. = ..()
+	if(active_alarm && hasPower())
+		. += image('icons/obj/doors/doorfire.dmi', "alarmlights")
+	if(density && welded)
+		. += "welded"
+		return
+	if(welded)
+		. += "welded_open"
 
 /obj/machinery/door/firedoor/proc/activate_alarm()
 	active_alarm = TRUE
@@ -344,8 +347,7 @@
 		if(CONSTRUCTION_NOCIRCUIT)
 			. += "<span class='notice'>There are no <i>firelock electronics</i> in the frame. The frame could be <b>cut</b> apart.</span>"
 
-/obj/structure/firelock_frame/update_icon()
-	..()
+/obj/structure/firelock_frame/update_icon_state()
 	icon_state = "frame[constructionStep]"
 
 /obj/structure/firelock_frame/attackby(obj/item/C, mob/user)

code/game/machinery/doors/poddoor.dm

@@ -50,7 +50,7 @@
 			flick("closing", src)
 			playsound(src, 'sound/machines/blastdoor.ogg', 30, 1)
 
-/obj/machinery/door/poddoor/update_icon()
+/obj/machinery/door/poddoor/update_icon_state()
 	if(density)
 		icon_state = "closed"
 	else

code/game/machinery/doors/windowdoor.dm

@@ -28,7 +28,6 @@
 /obj/machinery/door/window/Initialize(mapload)
 	. = ..()
 	if(req_access && req_access.len)
-		icon_state = "[icon_state]"
 		base_state = icon_state
 
 /obj/machinery/door/window/Destroy()
@@ -38,7 +37,7 @@
 	QDEL_NULL(electronics)
 	return ..()
 
-/obj/machinery/door/window/update_icon()
+/obj/machinery/door/window/update_icon_state()
 	if(density)
 		icon_state = base_state
 	else

code/game/machinery/dye_generator.dm

@@ -24,19 +24,19 @@
 	else
 		stat |= NOPOWER
 		set_light(0)
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/machinery/dye_generator/extinguish_light()
 	set_light(0)
 	underlays.Cut()
 
-/obj/machinery/dye_generator/update_icon()
-	cut_overlays()
+/obj/machinery/dye_generator/update_overlays()
+	. = ..()
 	underlays.Cut()
 	if(stat & (BROKEN|NOPOWER))
-		add_overlay("barbervend_off")
+		. += "barbervend_off"
 		if(stat & BROKEN)
-			add_overlay("barbervend_broken")
+			. += "barbervend_broken"
 	if(light)
 		underlays += emissive_appearance(icon, "barbervend_lightmask")
 
@@ -58,14 +58,14 @@
 		var/obj/item/hair_dye_bottle/HD = I
 		user.visible_message("<span class='notice'>[user] fills [HD] up with some dye.</span>","<span class='notice'>You fill [HD] up with some hair dye.</span>")
 		HD.dye_color = dye_color
-		HD.update_dye_overlay()
+		HD.update_icon()
 		return
 	return ..()
 
 /obj/machinery/dye_generator/obj_break(damage_flag)
 	if(!(stat & BROKEN))
 		stat |= BROKEN
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 
 //Hair Dye Bottle
 
@@ -83,13 +83,13 @@
 
 /obj/item/hair_dye_bottle/New()
 	..()
-	update_dye_overlay()
+	update_icon(UPDATE_OVERLAYS)
 
-/obj/item/hair_dye_bottle/proc/update_dye_overlay()
-	overlays.Cut()
+/obj/item/hair_dye_bottle/update_overlays()
+	. = ..()
 	var/image/I = new('icons/obj/items.dmi', "hairdyebottle-overlay")
 	I.color = dye_color
-	overlays += I
+	. += I
 
 /obj/item/hair_dye_bottle/attack(mob/living/carbon/M, mob/user)
 	if(user.a_intent != INTENT_HELP)

code/game/machinery/embedded_controller/airlock_controllers.dm

@@ -75,7 +75,7 @@
 	name = "Access Controller"
 	tag_secure = 1
 
-/obj/machinery/embedded_controller/radio/airlock/access_controller/update_icon()
+/obj/machinery/embedded_controller/radio/airlock/access_controller/update_icon_state()
 	if(on && program)
 		if(program.memory["processing"])
 			icon_state = "access_control_process"

code/game/machinery/embedded_controller/embedded_controller_base.dm

@@ -10,7 +10,7 @@
 	var/on = TRUE
 
 /obj/machinery/embedded_controller/proc/post_signal(datum/signal/signal, comm_line)
-	return 0
+	return FALSE
 
 /obj/machinery/embedded_controller/receive_signal(datum/signal/signal, receive_method, receive_param)
 	if(!signal || signal.encryption) return
@@ -23,7 +23,7 @@
 	if(program)
 		program.process()
 
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	src.updateDialog()
 
 /obj/machinery/embedded_controller/attack_ghost(mob/user as mob)
@@ -60,7 +60,7 @@
 	radio_connection = null
 	return ..()
 
-/obj/machinery/embedded_controller/radio/update_icon()
+/obj/machinery/embedded_controller/radio/update_icon_state()
 	if(on && program)
 		if(program.memory["processing"])
 			icon_state = "airlock_control_process"

code/game/machinery/firealarm.dm

@@ -44,13 +44,7 @@ FIRE ALARM
 	report_fire_alarms = FALSE
 	show_alert_level = FALSE
 
-/obj/machinery/firealarm/update_icon()
-	underlays.Cut()
-	if(light)
-		if(overlays)
-			underlays += emissive_appearance(icon, "firealarm_overlay_lightmask")
-		if(!wiresexposed)
-			underlays += emissive_appearance(icon, "firealarm_lightmask")
+/obj/machinery/firealarm/update_icon_state()
 	if(wiresexposed)
 		icon_state = "firealarm_b[buildstage]"
 		return
@@ -63,6 +57,17 @@ FIRE ALARM
 	else
 		icon_state = "firealarm_on"
 
+/obj/machinery/firealarm/update_overlays()
+	. = ..()
+	underlays.Cut()
+	if(is_station_contact(z) && show_alert_level)
+		if(GLOB.security_level)
+			. += "overlay_[get_security_level()]"
+		if(light)
+			underlays += emissive_appearance(icon, "firealarm_overlay_lightmask")
+	if(light && !wiresexposed)
+		underlays += emissive_appearance(icon, "firealarm_lightmask")
+
 /obj/machinery/firealarm/emag_act(mob/user)
 	if(!emagged)
 		emagged = TRUE
@@ -271,12 +276,6 @@ FIRE ALARM
 		setDir(direction)
 		set_pixel_offsets_from_dir(26, -26, 26, -26)
 
-	if(is_station_contact(z) && show_alert_level)
-		if(GLOB.security_level)
-			overlays += image('icons/obj/monitors.dmi', "overlay_[get_security_level()]")
-		else
-			overlays += image('icons/obj/monitors.dmi', "overlay_green")
-
 	myArea = get_area(src)
 	LAZYADD(myArea.firealarms, src)
 

code/game/machinery/floodlight.dm

@@ -26,20 +26,21 @@
 	QDEL_NULL(cell)
 	return ..()
 
-/obj/machinery/floodlight/proc/updateicon()
+/obj/machinery/floodlight/update_icon_state()
 	icon_state = "flood[open ? "o" : ""][open && cell ? "b" : ""]0[on]"
 
 /obj/machinery/floodlight/process()
 	if(!cell && on)
 		on = FALSE
 		visible_message("<span class='warning'>[src] shuts down due to lack of power!</span>")
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 		set_light(0)
+		return
 	if(on)
 		cell.charge -= use
 		if(cell.charge <= 0)
 			on = FALSE
-			updateicon()
+			update_icon(UPDATE_ICON_STATE)
 			set_light(0)
 			visible_message("<span class='warning'>[src] shuts down due to lack of power!</span>")
 
@@ -55,7 +56,7 @@
 			cell.loc = loc
 
 		cell.add_fingerprint(user)
-		cell.update_icon()
+		cell.update_icon(UPDATE_ICON_STATE)
 
 		cell = null
 		to_chat(user, "You remove the power cell.")
@@ -63,7 +64,7 @@
 			on = FALSE
 			visible_message("<span class='warning'>[src] shuts down due to lack of power!</span>")
 			set_light(0)
-		updateicon()
+		update_icon(UPDATE_ICON_STATE)
 		return
 
 	if(on)
@@ -79,7 +80,7 @@
 		to_chat(user, "<span class='notice'>You turn on the light.</span>")
 		set_light(brightness_on)
 
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/floodlight/proc/mapVarInit()
 	if(on)
@@ -88,7 +89,7 @@
 		if(cell.charge <= 0)
 			return
 		set_light(brightness_on)
-		updateicon()
+		update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/floodlight/attackby(obj/item/W as obj, mob/user as mob, params)
 	if(istype(W, /obj/item/wrench))
@@ -106,7 +107,7 @@
 				"<span class='notice'> You have loosened \the [src]'s casters.</span>", \
 				"You hear ratchet.")
 			anchored = FALSE
-		updateicon()
+		update_icon(UPDATE_ICON_STATE)
 		return
 	if(istype(W, /obj/item/screwdriver))
 		if(!open)
@@ -116,19 +117,18 @@
 			else
 				unlocked = TRUE
 				to_chat(user, "You unscrew the battery panel.")
-		updateicon()
+		update_icon(UPDATE_ICON_STATE)
 		return
 	if(istype(W, /obj/item/crowbar))
 		if(unlocked)
 			if(open)
 				open = FALSE
-				overlays = null
 				to_chat(user, "You crowbar the battery panel in place.")
 			else
 				if(unlocked)
 					open = TRUE
 					to_chat(user, "You remove the battery panel.")
-		updateicon()
+		update_icon(UPDATE_ICON_STATE)
 		return
 	if(istype(W, /obj/item/stock_parts/cell))
 		if(open)
@@ -139,11 +139,11 @@
 				W.loc = src
 				cell = W
 				to_chat(user, "You insert the power cell.")
-		updateicon()
+		update_icon(UPDATE_ICON_STATE)
 		return
 	return ..()
 
 /obj/machinery/floodlight/extinguish_light()
 	on = FALSE
 	set_light(0)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)

code/game/machinery/gameboard.dm

@@ -20,13 +20,13 @@
 
 /obj/machinery/gameboard/power_change()
 	. = ..()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	if(stat & NOPOWER)
 		set_light(0)
 	else
 		set_light(3, 3)
 
-/obj/machinery/gameboard/update_icon()
+/obj/machinery/gameboard/update_icon_state()
 	if(stat & NOPOWER)
 		icon_state = "gboard_off"
 	else

code/game/machinery/hologram.dm

@@ -290,7 +290,7 @@ GLOBAL_LIST_EMPTY(holopads)
 				playsound(src, 'sound/machines/twobeep.ogg', 100)	//bring, bring!
 				ringing = TRUE
 
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 
 //Try to transfer hologram to another pad that can project on T
@@ -405,13 +405,11 @@ For the other part of the code, check silicon say.dm. Particularly robot talk.*/
 	active_power_usage = HOLOPAD_PASSIVE_POWER_USAGE + (HOLOGRAM_POWER_USAGE * total_users)
 	if(total_users)
 		set_light(2)
-		icon_state = "holopad1"
 	else
 		set_light(0)
-		icon_state = "holopad0"
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
-/obj/machinery/hologram/holopad/update_icon()
+/obj/machinery/hologram/holopad/update_icon_state()
 	var/total_users = LAZYLEN(masters) + LAZYLEN(holo_calls)
 	if(icon_state == "holopad_open")
 		return

code/game/machinery/holosign.dm

@@ -14,9 +14,9 @@
 	if(stat & (BROKEN|NOPOWER))
 		return
 	lit = !lit
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
-/obj/machinery/holosign/update_icon()
+/obj/machinery/holosign/update_icon_state()
 	if(!lit)
 		icon_state = "sign_off"
 	else
@@ -25,7 +25,7 @@
 /obj/machinery/holosign/power_change()
 	if(stat & NOPOWER)
 		lit = FALSE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/holosign/surgery
 	name = "surgery holosign"

code/game/machinery/iv_drip.dm

@@ -11,19 +11,18 @@
 
 /obj/machinery/iv_drip/process()
 	if(istype(bag) && bag.injection_target)
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 		return
 	return PROCESS_KILL
 
-/obj/machinery/iv_drip/update_icon()
-	cut_overlays()
-
+/obj/machinery/iv_drip/update_overlays()
+	. = ..()
 	if(bag)
-		add_overlay("hangingbag")
+		. += "hangingbag"
 		if(bag.reagents.total_volume)
 			var/image/filling = image('icons/goonstation/objects/iv.dmi', src, "hangingbag-fluid")
 			filling.icon += mix_color_from_reagents(bag.reagents.reagent_list)
-			add_overlay(filling)
+			. += filling
 
 /obj/machinery/iv_drip/MouseDrop(mob/living/target)
 	if(usr.incapacitated())
@@ -39,9 +38,9 @@
 /obj/machinery/iv_drip/attack_hand(mob/user)
 	if(bag)
 		user.put_in_hands(bag)
-		bag.update_icon()
+		bag.update_icon(UPDATE_OVERLAYS)
 		bag = null
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 
 /obj/machinery/iv_drip/attackby(obj/item/I, mob/user, params)
 	if(istype(I, /obj/item/reagent_containers/iv_bag))
@@ -54,12 +53,12 @@
 		I.forceMove(src)
 		bag = I
 		to_chat(user, "<span class='notice'>You attach [I] to [src].</span>")
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 		START_PROCESSING(SSmachines, src)
 	else if (bag && istype(I, /obj/item/reagent_containers))
 		bag.attackby(I)
 		I.afterattack(bag, usr, TRUE)
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 	else
 		return ..()
 

code/game/machinery/lightswitch.dm

@@ -44,7 +44,7 @@
 			name = "light switch([area.name])"
 
 		src.on = src.area.lightswitch
-		updateicon()
+		update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/light_switch/Initialize()
 	..()
@@ -63,18 +63,15 @@
 	radio_connection = null
 	return ..()
 
-/obj/machinery/light_switch/proc/updateicon()
+/obj/machinery/light_switch/update_icon_state()
 	if(stat & NOPOWER)
 		icon_state = "light-p"
-	else
-		if(on)
-			icon_state = "light1"
-		else
-			icon_state = "light0"
+		return
+	icon_state = "light[on]"
 
 /obj/machinery/light_switch/examine(mob/user)
 	. = ..()
-	. += "A light switch. It is [on? "on" : "off"]."
+	. += "A light switch. It is [on ? "on" : "off"]."
 
 /obj/machinery/light_switch/attack_ghost(mob/user)
 	if(user.can_advanced_admin_interact())
@@ -83,11 +80,11 @@
 /obj/machinery/light_switch/attack_hand(mob/user)
 	on = !on
 	playsound(src, 'sound/machines/lightswitch.ogg', 10, TRUE)
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 
 	if(light_connect)
 		area.lightswitch = on
-		area.updateicon()
+		area.update_icon(UPDATE_ICON_STATE)
 
 	if(logic_connect && powered(LIGHT))		//Don't bother sending a signal if we aren't set to send them or we have no power to send with.
 		handle_output()
@@ -95,7 +92,7 @@
 	if(light_connect)
 		for(var/obj/machinery/light_switch/L in area)
 			L.on = on
-			L.updateicon()
+			L.update_icon(UPDATE_ICON_STATE)
 
 		area.power_change()
 
@@ -135,7 +132,7 @@
 		else
 			stat |= NOPOWER
 
-		updateicon()
+		update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/light_switch/emp_act(severity)
 	if(stat & (BROKEN|NOPOWER))

code/game/machinery/magnet.dm

@@ -44,20 +44,11 @@
 	// update the invisibility and icon
 /obj/machinery/magnetic_module/hide(intact)
 	invisibility = intact ? INVISIBILITY_MAXIMUM : 0
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 
-	// update the icon_state
-/obj/machinery/magnetic_module/proc/updateicon()
-	var/state="floor_magnet"
-	var/onstate=""
-	if(!on)
-		onstate="0"
-
-	if(invisibility)
-		icon_state = "[state][onstate]-f"	// if invisible, set icon to faded version
+/obj/machinery/magnetic_module/update_icon_state()
+	icon_state = "floor_magnet[on ? "" : "0"][invisibility ? "-f" : ""]"	// if invisible, set icon to faded version
 											// in case of being revealed by T-scanner
-	else
-		icon_state = "[state][onstate]"
 
 /obj/machinery/magnetic_module/receive_signal(datum/signal/signal)
 	var/command = signal.data["command"]
@@ -149,7 +140,7 @@
 		active_power_usage = electricity_level*15
 	else
 		use_power = 0
-		updateicon()
+		update_icon(UPDATE_ICON_STATE)
 
 
 /obj/machinery/magnetic_module/proc/magnetic_process() // proc that actually does the pulling

code/game/machinery/navbeacon.dm

@@ -76,17 +76,11 @@
 // hide the object if turf is intact
 /obj/machinery/navbeacon/hide(intact)
 	invisibility = intact ? INVISIBILITY_MAXIMUM : 0
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)
 
-// update the icon_state
-/obj/machinery/navbeacon/proc/updateicon()
-	var/state="navbeacon[open]"
-
-	if(invisibility)
-		icon_state = "[state]-f"	// if invisible, set icon to faded version
-									// in case revealed by T-scanner
-	else
-		icon_state = "[state]"
+/obj/machinery/navbeacon/update_icon_state()
+	icon_state = "navbeacon[open][invisibility ? "-f" : ""]"	// if invisible, set icon to faded version
+																// in case revealed by T-scanner
 
 /obj/machinery/navbeacon/attackby(obj/item/I, mob/user, params)
 	var/turf/T = loc
@@ -98,7 +92,7 @@
 
 		user.visible_message("[user] [open ? "opens" : "closes"] the beacon's cover.", "<span class='notice'>You [open ? "open" : "close"] the beacon's cover.</span>")
 
-		updateicon()
+		update_icon(UPDATE_ICON_STATE)
 
 	else if(istype(I, /obj/item/card/id) || istype(I, /obj/item/pda))
 		if(open)
@@ -221,4 +215,4 @@ Transponder Codes:<UL>"}
 
 /obj/machinery/navbeacon/invisible/hide(intact)
 	invisibility = INVISIBILITY_MAXIMUM
-	updateicon()
+	update_icon(UPDATE_ICON_STATE)

code/game/machinery/portable_tag_turret.dm

@@ -37,7 +37,7 @@
 	)
 	return data
 
-/obj/machinery/porta_turret/tag/update_icon()
+/obj/machinery/porta_turret/tag/update_icon_state()
 	if(!anchored)
 		icon_state = "turretCover"
 		return

code/game/machinery/portable_turret.dm

@@ -147,7 +147,7 @@
 			eshot_sound = 'sound/weapons/pulse.ogg'
 
 GLOBAL_LIST_EMPTY(turret_icons)
-/obj/machinery/porta_turret/update_icon()
+/obj/machinery/porta_turret/update_icon_state()
 	if(!GLOB.turret_icons)
 		GLOB.turret_icons = list()
 		GLOB.turret_icons["open"] = image(icon, "openTurretCover")
@@ -321,7 +321,7 @@ GLOBAL_LIST_EMPTY(turret_icons)
 		stat &= ~NOPOWER
 	else
 		stat |= NOPOWER
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 
 /obj/machinery/porta_turret/attackby(obj/item/I, mob/user)
@@ -364,16 +364,10 @@ GLOBAL_LIST_EMPTY(turret_icons)
 		wrenching = TRUE
 		if(do_after(user, 50 * I.toolspeed, target = src))
 			//This code handles moving the turret around. After all, it's a portable turret!
-			if(!anchored)
-				playsound(loc, I.usesound, 100, 1)
-				anchored = TRUE
-				update_icon()
-				to_chat(user, "<span class='notice'>You secure the exterior bolts on the turret.</span>")
-			else if(anchored)
-				playsound(loc, I.usesound, 100, 1)
-				anchored = FALSE
-				to_chat(user, "<span class='notice'>You unsecure the exterior bolts on the turret.</span>")
-				update_icon()
+			playsound(loc, I.usesound, 100, 1)
+			anchored = !anchored
+			update_icon(UPDATE_ICON_STATE)
+			to_chat(user, "<span class='notice'>You [anchored ? "" : "un"]secure the exterior bolts on the turret.</span>")
 		wrenching = FALSE
 
 	else if(istype(I, /obj/item/card/id) || istype(I, /obj/item/pda))
@@ -499,7 +493,7 @@ GLOBAL_LIST_EMPTY(turret_icons)
 	stat |= BROKEN	//enables the BROKEN bit
 	if(spark_system)
 		spark_system.start()	//creates some sparks because they look cool
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/porta_turret/process()
 	//the main machinery process
@@ -651,7 +645,7 @@ GLOBAL_LIST_EMPTY(turret_icons)
 /obj/machinery/porta_turret/proc/pop_up()	//pops the turret up
 	set_raised_raising(raised, TRUE)
 	playsound(get_turf(src), 'sound/effects/turret/open.wav', 60, 1)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 	var/atom/flick_holder = new /atom/movable/porta_turret_cover(loc)
 	flick_holder.layer = layer + 0.1
@@ -660,7 +654,7 @@ GLOBAL_LIST_EMPTY(turret_icons)
 	qdel(flick_holder)
 
 	set_raised_raising(TRUE, FALSE)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/porta_turret/proc/pop_down()	//pops the turret down
 	last_target = null
@@ -672,7 +666,7 @@ GLOBAL_LIST_EMPTY(turret_icons)
 		return
 	set_raised_raising(raised, TRUE)
 	playsound(get_turf(src), 'sound/effects/turret/open.wav', 60, 1)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 	var/atom/flick_holder = new /atom/movable/porta_turret_cover(loc)
 	flick_holder.layer = layer + 0.1
@@ -682,7 +676,7 @@ GLOBAL_LIST_EMPTY(turret_icons)
 
 	set_raised_raising(FALSE, FALSE)
 	set_angle(0)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/porta_turret/on_assess_perp(mob/living/carbon/human/perp)
 	if((check_access || attacked) && !allowed(perp))
@@ -722,7 +716,7 @@ GLOBAL_LIST_EMPTY(turret_icons)
 	if(!istype(T) || !istype(U))
 		return
 
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	var/obj/item/projectile/A
 	if(emagged || lethal)
 		if(eprojectile)
@@ -1059,7 +1053,7 @@ GLOBAL_LIST_EMPTY(turret_icons)
 	req_access = list(ACCESS_SYNDICATE)
 	one_access = FALSE
 
-/obj/machinery/porta_turret/syndicate/update_icon()
+/obj/machinery/porta_turret/syndicate/update_icon_state()
 	if(stat & BROKEN)
 		icon_state = icon_state_destroyed
 	else if(enabled)

code/game/machinery/recharger.dm

@@ -59,7 +59,7 @@
 			charging = G
 			use_power = ACTIVE_POWER_USE
 			using_power = check_cell_needs_recharging(get_cell_from(G))
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 		else
 			to_chat(user, "<span class='notice'>[src] isn't connected to anything!</span>")
 		return TRUE
@@ -97,7 +97,7 @@
 		user.put_in_hands(charging)
 		charging = null
 		use_power = IDLE_POWER_USE
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/recharger/attack_tk(mob/user)
 	if(charging)
@@ -105,14 +105,14 @@
 		charging.forceMove(loc)
 		charging = null
 		use_power = IDLE_POWER_USE
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/recharger/process()
 	if(stat & (NOPOWER|BROKEN) || !anchored)
 		return
 
 	using_power = try_recharging_if_possible()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/recharger/emp_act(severity)
 	if(stat & (NOPOWER|BROKEN) || !anchored)
@@ -132,9 +132,9 @@
 
 /obj/machinery/recharger/power_change()
 	..()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
-/obj/machinery/recharger/update_icon()	//we have an update_icon() in addition to the stuff in process to make it feel a tiny bit snappier.
+/obj/machinery/recharger/update_icon_state()
 	if(stat & (NOPOWER|BROKEN) || !anchored)
 		icon_state = icon_state_off
 		return

code/game/machinery/rechargestation.dm

@@ -33,7 +33,7 @@
 	component_parts += new /obj/item/stock_parts/manipulator(null)
 	component_parts += new /obj/item/stock_parts/cell/high(null)
 	RefreshParts()
-	build_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/recharge_station/upgraded/Initialize(mapload)
 	. = ..()
@@ -87,7 +87,7 @@
 	if(A == occupant)
 		occupant = null
 		updateUsrDialog()
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/recharge_station/narsie_act()
 	go_out()
@@ -116,9 +116,9 @@
 		go_out()
 	..(severity)
 
-/obj/machinery/recharge_station/proc/build_icon()
+/obj/machinery/recharge_station/update_icon_state()
 	if(NOPOWER|BROKEN)
-		if(src.occupant)
+		if(occupant)
 			icon_state = "borgcharger1"
 		else
 			icon_state = "borgcharger0"
@@ -164,7 +164,7 @@
 		return
 	occupant.forceMove(loc)
 	occupant = null
-	build_icon()
+	update_icon(UPDATE_ICON_STATE)
 	use_power = IDLE_POWER_USE
 	return
 
@@ -234,6 +234,6 @@
 	occupant = user
 
 	add_fingerprint(user)
-	build_icon()
+	update_icon(UPDATE_ICON_STATE)
 	update_use_power(1)
 	return

code/game/machinery/recycler.dm

@@ -27,7 +27,7 @@
 	component_parts += new /obj/item/stock_parts/matter_bin(null)
 	component_parts += new /obj/item/stock_parts/manipulator(null)
 	RefreshParts()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/recycler/ComponentInitialize()
 	..()
@@ -53,7 +53,7 @@
 
 /obj/machinery/recycler/power_change()
 	..()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/recycler/attackby(obj/item/I, mob/user, params)
 	add_fingerprint(user)
@@ -80,15 +80,14 @@
 		emagged = TRUE
 		if(emergency_mode)
 			emergency_mode = FALSE
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 		playsound(src, "sparks", 75, TRUE, SHORT_RANGE_SOUND_EXTRARANGE)
 		to_chat(user, "<span class='notice'>You use the cryptographic sequencer on [src].</span>")
 
-/obj/machinery/recycler/update_icon()
-	..()
+/obj/machinery/recycler/update_icon_state()
 	var/is_powered = !(stat & (BROKEN|NOPOWER))
 	if(emergency_mode)
-		is_powered = 0
+		is_powered = FALSE
 	icon_state = icon_name + "[is_powered]" + "[(blood ? "bld" : "")]" // add the blood tag at the end
 
 // This is purely for admin possession !FUN!.
@@ -151,14 +150,14 @@
 /obj/machinery/recycler/proc/emergency_stop(mob/living/L)
 	playsound(loc, 'sound/machines/buzz-sigh.ogg', 50, 0)
 	emergency_mode = TRUE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	L.loc = loc
 	addtimer(CALLBACK(src, .proc/reboot), SAFETY_COOLDOWN)
 
 /obj/machinery/recycler/proc/reboot()
 	playsound(loc, 'sound/machines/ping.ogg', 50, 0)
 	emergency_mode = FALSE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/recycler/proc/crush_living(mob/living/L)
 
@@ -169,17 +168,17 @@
 	else
 		playsound(loc, 'sound/effects/splat.ogg', 50, 1)
 
-	var/gib = 1
+	var/gib = TRUE
 	// By default, the emagged recycler will gib all non-carbons. (human simple animal mobs don't count)
 	if(iscarbon(L))
-		gib = 0
+		gib = FALSE
 		if(L.stat == CONSCIOUS)
 			L.say("ARRRRRRRRRRRGH!!!")
 		add_mob_blood(L)
 
 	if(!blood && !issilicon(L))
 		blood = TRUE
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 
 	// Remove and recycle the equipped items
 	if(eat_victim_items)

code/game/machinery/requests_console.dm

@@ -73,9 +73,9 @@ GLOBAL_LIST_EMPTY(allRequestConsoles)
 
 /obj/machinery/requests_console/power_change()
 	..()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
-/obj/machinery/requests_console/update_icon()
+/obj/machinery/requests_console/update_icon_state()
 	if(stat & NOPOWER)
 		if(icon_state != "req_comp_off")
 			icon_state = "req_comp_off"
@@ -336,7 +336,7 @@ GLOBAL_LIST_EMPTY(allRequestConsoles)
 	capitalize(title)
 	if(newmessagepriority < priority)
 		newmessagepriority = priority
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 	if(!silent)
 		playsound(loc, 'sound/machines/twobeep.ogg', 50, TRUE)
 		atom_say(title)

code/game/machinery/shieldgen.dm

@@ -152,7 +152,7 @@
 		return //If it's already turned on, how did this get called?
 
 	active = TRUE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	anchored = TRUE
 
 	for(var/turf/target_tile in range(2, src))
@@ -170,7 +170,7 @@
 		return //If it's already off, how did this get called?
 
 	active = FALSE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 	QDEL_LIST(deployed_shields)
 
@@ -184,7 +184,7 @@
 		malfunction = TRUE
 	if(health <= 0)
 		qdel(src)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	return
 
 /obj/machinery/shieldgen/ex_act(severity)
@@ -239,7 +239,7 @@
 /obj/machinery/shieldgen/attackby(obj/item/I as obj, mob/user as mob, params)
 	if(istype(I, /obj/item/card/emag))
 		malfunction = TRUE
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 
 	else if(istype(I, /obj/item/stack/cable_coil) && malfunction && is_open)
 		var/obj/item/stack/cable_coil/coil = I
@@ -249,10 +249,10 @@
 				return
 			coil.use(1)
 			health = max_health
-			malfunction = TRUE
+			malfunction = FALSE
 			playsound(loc, coil.usesound, 50, 1)
 			to_chat(user, "<span class='notice'>You repair [src]!</span>")
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 
 	else if(istype(I, /obj/item/card/id) || istype(I, /obj/item/pda))
 		if(allowed(user))
@@ -286,48 +286,41 @@
 		if(active)
 			visible_message("<span class='warning'>[src] shuts off!</span>")
 			shields_down()
-		anchored = FALSE
 	else
 		if(istype(get_turf(src), /turf/space))
 			return //No wrenching these in space!
 		WRENCH_ANCHOR_MESSAGE
-		anchored = TRUE
-
-/obj/machinery/shieldgen/update_icon()
-	if(active)
-		icon_state = malfunction ? "shieldonbr":"shieldon"
-	else
-		icon_state = malfunction ? "shieldoffbr":"shieldoff"
-	return
+	anchored = !anchored
 
+/obj/machinery/shieldgen/update_icon_state()
+	icon_state = "shield[active ? "on" : "off"][malfunction ? "br" : ""]"
 
 ////FIELD GEN START //shameless copypasta from fieldgen, powersink, and grille
 #define maxstoredpower 500
 /obj/machinery/shieldwallgen
-		name = "Shield Generator"
-		desc = "A shield generator."
-		icon = 'icons/obj/stationobjs.dmi'
-		icon_state = "Shield_Gen"
-		anchored = FALSE
-		density = TRUE
-		req_access = list(ACCESS_TELEPORTER)
-		var/active = 0
-		var/power = 0
-		var/state = 0
-		var/steps = 0
-		var/last_check = 0
-		var/check_delay = 10
-		var/locked = TRUE
-		var/directwired = 1
-		var/obj/structure/cable/attached		// the attached cable
-		var/storedpower = 0
-		flags = CONDUCT
-		use_power = NO_POWER_USE
+	name = "Shield Generator"
+	desc = "A shield generator."
+	icon = 'icons/obj/stationobjs.dmi'
+	icon_state = "Shield_Gen"
+	anchored = FALSE
+	density = TRUE
+	req_access = list(ACCESS_TELEPORTER)
+	var/active = FALSE
+	var/power = FALSE
+	var/state = FALSE
+	var/steps = 0
+	var/locked = TRUE
+	var/storedpower = 0
+	flags = CONDUCT
+	use_power = NO_POWER_USE
+
+/obj/machinery/shieldwallgen/update_icon_state()
+	icon_state = "Shield_Gen[active ? " +a" : ""]"
 
 /obj/machinery/shieldwallgen/proc/power()
 	if(!anchored)
-		power = 0
-		return 0
+		power = FALSE
+		return
 	var/turf/T = loc
 
 	var/obj/structure/cable/C = T.get_cable_node()
@@ -336,16 +329,16 @@
 		PN = C.powernet		// find the powernet of the connected cable
 
 	if(!PN)
-		power = 0
-		return 0
+		power = FALSE
+		return
 
 	var/surplus = max(PN.avail-PN.load, 0)
 	var/shieldload = min(rand(50,200), surplus)
-	if(shieldload==0 && !storedpower)		// no cable or no power, and no power stored
-		power = 0
-		return 0
+	if(shieldload == 0 && !storedpower)		// no cable or no power, and no power stored
+		power = FALSE
+		return
 	else
-		power = 1	// IVE GOT THE POWER!
+		power = TRUE	// IVE GOT THE POWER!
 		if(PN) //runtime errors fixer. They were caused by PN.load trying to access missing network in case of working on stored power.
 			storedpower += shieldload
 			PN.load += shieldload //uses powernet power.
@@ -355,29 +348,22 @@
 /obj/machinery/shieldwallgen/attack_hand(mob/user)
 	if(state != 1)
 		to_chat(user, "<span class='warning'>The shield generator needs to be firmly secured to the floor first.</span>")
-		return 1
+		return TRUE
 	if(locked && !issilicon(user))
 		to_chat(user, "<span class='warning'>The controls are locked!</span>")
-		return 1
-	if(power != 1)
+		return TRUE
+	if(!power)
 		to_chat(user, "<span class='warning'>The shield generator needs to be powered by wire underneath.</span>")
-		return 1
+		return TRUE
 
-	if(active >= 1)
-		active = 0
-		icon_state = "Shield_Gen"
-
-		user.visible_message("[user] turned the shield generator off.", \
-			"You turn off the shield generator.", \
-			"You hear heavy droning fade out.")
+	active = !active
+	user.visible_message("[user] turned the shield generator [active ? "on" : "off"].", \
+	"You turn [active ? "on" : "off"] the shield generator.", \
+	"You hear heavy droning [active ? "" : "fade out"].")
+	if(active)
 		for(var/dir in list(NORTH, SOUTH, EAST, WEST))
 			cleanup(dir)
-	else
-		active = 1
-		icon_state = "Shield_Gen +a"
-		user.visible_message("[user] turned the shield generator on.", \
-			"You turn on the shield generator.", \
-			"You hear heavy droning.")
+	update_icon(UPDATE_ICON_STATE)
 	add_fingerprint(user)
 
 /obj/machinery/shieldwallgen/process()
@@ -390,9 +376,9 @@
 	if(storedpower <= 0)
 		storedpower = 0
 
-	if(active == 1)
-		if(!state == 1)
-			active = 0
+	if(active)
+		if(state)
+			active = FALSE
 			return
 		spawn(1)
 			setup_field(1)
@@ -402,15 +388,14 @@
 			setup_field(4)
 		spawn(4)
 			setup_field(8)
-		active = 2
-	if(active >= 1)
-		if(power == 0)
+	if(active)
+		if(!power)
 			visible_message("<span class='warning'>[name] shuts down due to lack of power!</span>", \
 				"You hear heavy droning fade out")
-			icon_state = "Shield_Gen"
-			active = 0
+			active = FALSE
 			for(var/dir in list(NORTH, SOUTH, EAST, WEST))
 				cleanup(dir)
+			update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/shieldwallgen/proc/setup_field(NSEW = 0)
 	var/turf/T = loc
@@ -458,25 +443,6 @@
 
 
 /obj/machinery/shieldwallgen/attackby(obj/item/I, mob/user, params)
-	if(istype(I, /obj/item/wrench))
-		if(active)
-			to_chat(user, "Turn off the field generator first.")
-			return
-
-		else if(state == 0)
-			state = 1
-			playsound(loc, I.usesound, 75, 1)
-			to_chat(user, "You secure the external reinforcing bolts to the floor.")
-			anchored = TRUE
-			return
-
-		else if(state == 1)
-			state = 0
-			playsound(loc, I.usesound, 75, 1)
-			to_chat(user, "You undo the external reinforcing bolts.")
-			anchored = FALSE
-			return
-
 	if(istype(I, /obj/item/card/id)||istype(I, /obj/item/pda))
 		if(allowed(user))
 			locked = !locked
@@ -488,6 +454,17 @@
 		add_fingerprint(user)
 		..()
 
+/obj/machinery/shieldwallgen/wrench_act(mob/user, obj/item/I)
+	. = TRUE
+	if(active)
+		to_chat(user, "Turn off the field generator first.")
+		return
+	if(!I.use_tool(src, user, 0, volume = I.tool_volume))
+		return
+	state = !state
+	anchored = !anchored
+	to_chat(user, anchored ? "You secure the external reinforcing bolts to the floor." : "You undo the external reinforcing bolts.")
+
 /obj/machinery/shieldwallgen/proc/cleanup(NSEW)
 	var/obj/machinery/shieldwall/F
 	var/obj/machinery/shieldwallgen/G
@@ -522,29 +499,26 @@
 
 ////////////// Containment Field START
 /obj/machinery/shieldwall
-		name = "Shield"
-		desc = "An energy shield."
-		icon = 'icons/effects/effects.dmi'
-		icon_state = "shieldwall"
-		anchored = TRUE
-		density = TRUE
-		move_resist = INFINITY
-		resistance_flags = INDESTRUCTIBLE | LAVA_PROOF | FIRE_PROOF | UNACIDABLE | ACID_PROOF
-		light_range = 3
-		var/needs_power = 0
-		var/active = TRUE
-		var/delay = 5
-		var/last_active
-		var/mob/U
-		var/obj/machinery/shieldwallgen/gen_primary
-		var/obj/machinery/shieldwallgen/gen_secondary
+	name = "Shield"
+	desc = "An energy shield."
+	icon = 'icons/effects/effects.dmi'
+	icon_state = "shieldwall"
+	anchored = TRUE
+	density = TRUE
+	move_resist = INFINITY
+	resistance_flags = INDESTRUCTIBLE | LAVA_PROOF | FIRE_PROOF | UNACIDABLE | ACID_PROOF
+	light_range = 3
+	var/needs_power = FALSE
+	var/active = TRUE
+	var/obj/machinery/shieldwallgen/gen_primary
+	var/obj/machinery/shieldwallgen/gen_secondary
 
 /obj/machinery/shieldwall/New(obj/machinery/shieldwallgen/A, obj/machinery/shieldwallgen/B)
 	..()
 	gen_primary = A
 	gen_secondary = B
 	if(A && B)
-		needs_power = 1
+		needs_power = TRUE
 
 /obj/machinery/shieldwall/attack_hand(mob/user)
 	return
@@ -629,16 +603,16 @@
 	if(isliving(mover))
 		var/mob/living/M = mover
 		if("syndicate" in M.faction)
-			return 1
+			return TRUE
 	if(istype(mover, /obj/item/projectile))
-		return 0
+		return FALSE
 	return ..(mover, target, height)
 
 /obj/machinery/shieldwall/syndicate/CanAStarPass(ID, to_dir, caller)
 	if(isliving(caller))
 		var/mob/living/M = caller
 		if("syndicate" in M.faction)
-			return 1
+			return TRUE
 	return ..(ID, to_dir, caller)
 
 /obj/machinery/shieldwall/syndicate/proc/phaseout()

code/game/machinery/snow_machine.dm

@@ -87,10 +87,9 @@
 	..()
 	if(!powered())
 		turn_on_or_off(FALSE, TRUE)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
-/obj/machinery/snow_machine/update_icon()
-	..()
+/obj/machinery/snow_machine/update_icon_state()
 	if(panel_open)
 		icon_state = "snow_machine_openpanel"
 	else
@@ -131,5 +130,5 @@
 	if(!active && give_message)
 		visible_message("<span class='warning'>[src] switches off!</span>")
 		playsound(loc, 'sound/machines/buzz-sigh.ogg', 50, FALSE)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	return TRUE

code/game/machinery/spaceheater.dm

@@ -26,12 +26,13 @@
 	QDEL_NULL(cell)
 	return ..()
 
-/obj/machinery/space_heater/update_icon()
-	overlays.Cut()
+/obj/machinery/space_heater/update_icon_state()
 	icon_state = "sheater[on]"
+
+/obj/machinery/space_heater/update_overlays()
+	. = ..()
 	if(open)
-		overlays  += "sheater-open"
-	return
+		. += "sheater-open"
 
 /obj/machinery/space_heater/examine(mob/user)
 	. = ..()

code/game/machinery/suit_storage_unit.dm

@@ -289,7 +289,7 @@
 		boots = new boots_type(src)
 	if(storage_type)
 		storage = new storage_type(src)
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 	//move this into machinery eventually...
 	if(occupant_typecache)
@@ -300,32 +300,32 @@
 	QDEL_NULL(wires)
 	return ..()
 
-/obj/machinery/suit_storage_unit/update_icon()
-	cut_overlays()
+/obj/machinery/suit_storage_unit/update_overlays()
+	. = ..()
 	if(panel_open)
-		add_overlay("[base_icon_state]_panel")
+		. += "[base_icon_state]_panel"
 
 	if(uv)
 		if(uv_super)
-			add_overlay("[base_icon_state]_super")
-			add_overlay("[base_icon_state]_[occupant ? "body" : "uvstrong"]")
+			. += "[base_icon_state]_super"
+			. += "[base_icon_state]_[occupant ? "body" : "uvstrong"]"
 		else
-			add_overlay("[base_icon_state]_[occupant ? "body" : "uv"]")
-		add_overlay("[base_icon_state]_lights_red")
+			. += "[base_icon_state]_[occupant ? "body" : "uv"]"
+		. += "[base_icon_state]_lights_red"
 		return
 
 	if(state_open)
-		add_overlay("[base_icon_state]_open")
+		. += "[base_icon_state]_open"
 		if(suit)
-			add_overlay("[base_icon_state]_suit")
+			. += "[base_icon_state]_suit"
 		if(helmet)
-			add_overlay("[base_icon_state]_helm")
+			. += "[base_icon_state]_helm"
 		if(storage)
-			add_overlay("[base_icon_state]_storage")
+			. += "[base_icon_state]_storage"
 	else
-		add_overlay("[base_icon_state]_lights_closed")
+		. += "[base_icon_state]_lights_closed"
 
-	add_overlay("[base_icon_state]_[occupant ? "body" : "ready"]")
+	. += "[base_icon_state]_[occupant ? "body" : "ready"]"
 
 /obj/machinery/suit_storage_unit/attackby(obj/item/I, mob/user, params)
 	if(shocked)
@@ -344,7 +344,7 @@
 		return
 	if(state_open)
 		if(store_item(I, user))
-			update_icon()
+			update_icon(UPDATE_OVERLAYS)
 			SStgui.update_uis(src)
 			to_chat(user, "<span class='notice'>You load [I] into the storage compartment.</span>")
 		else
@@ -360,7 +360,7 @@
 		if(shock(user, 100))
 			return
 	if(default_deconstruction_screwdriver(user, "[base_icon_state]", "[base_icon_state]", I))
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 
 /**
   * Tries to store the item into whatever slot it can go, returns true if the item is stored successfully.
@@ -405,7 +405,7 @@
 	if(!is_operational() && state_open)
 		open_machine()
 		dump_contents()
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 
 /obj/machinery/suit_storage_unit/proc/dump_contents()
@@ -498,7 +498,7 @@
 			playsound(src, 'sound/machines/airlock_close.ogg', 25, 1)
 		if(occupant)
 			dump_contents()
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 		SStgui.update_uis(src)
 
 /obj/machinery/suit_storage_unit/relaymove(mob/user)
@@ -547,7 +547,7 @@
 	state_open = TRUE
 	if(drop)
 		dropContents()
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 	SStgui.update_uis(src)
 
 /obj/machinery/suit_storage_unit/dropContents()
@@ -576,7 +576,7 @@
 		occupant = target
 		target.forceMove(src)
 	SStgui.update_uis(src)
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 
 ////////
@@ -649,7 +649,7 @@
 			cook()
 		if("eject_occupant")
 			eject_occupant(usr)
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/machinery/suit_storage_unit/proc/toggleUV()
 	if(!panel_open)
@@ -731,7 +731,7 @@
 	occupant = null
 	if(!state_open)
 		state_open = 1
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 	return
 
 /obj/machinery/suit_storage_unit/force_eject_occupant(mob/target)
@@ -747,7 +747,7 @@
 	eject_occupant(usr)
 	add_fingerprint(usr)
 	SStgui.update_uis(src)
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 	return
 
 /obj/machinery/suit_storage_unit/verb/move_inside()
@@ -774,7 +774,7 @@
 		usr.forceMove(src)
 		occupant = usr
 		state_open = FALSE //Close the thing after the guy gets inside
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 
 		add_fingerprint(usr)
 		SStgui.update_uis(src)

code/game/machinery/syndicatebomb.dm

@@ -74,7 +74,7 @@
 	if(active && !defused && ((detonation_timer <= world.time) || explode_now))
 		active = FALSE
 		timer_set = initial(timer_set)
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 		try_detonate(TRUE)
 	//Counter terrorists win
 	else if(defused)
@@ -87,7 +87,7 @@
 	wires = new(src)
 	if(payload)
 		payload = new payload(src)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	countdown = new(src)
 
 /obj/machinery/syndicatebomb/Destroy()
@@ -101,7 +101,7 @@
 	. = ..()
 	. += "A digital display on it reads \"[seconds_remaining()]\"."
 
-/obj/machinery/syndicatebomb/update_icon()
+/obj/machinery/syndicatebomb/update_icon_state()
 	icon_state = "[initial(icon_state)][active ? "-active" : "-inactive"][open_panel ? "-wires" : ""]"
 
 /obj/machinery/syndicatebomb/proc/seconds_remaining()
@@ -152,7 +152,7 @@
 	if(!I.use_tool(src, user, 0, volume = I.tool_volume))
 		return
 	open_panel = !open_panel
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	to_chat(user, "<span class='notice'>You [open_panel ? "open" : "close"] the wire panel.</span>")
 
 /obj/machinery/syndicatebomb/wirecutter_act(mob/user, obj/item/I)
@@ -254,7 +254,7 @@
 		else
 			loc.visible_message("<span class='danger'>[bicon(src)] [timer_set] seconds until detonation, please clear the area.</span>")
 			activate()
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 			add_fingerprint(user)
 
 			var/turf/bombturf = get_turf(src)
@@ -362,7 +362,7 @@
 		holder.delayedbig = FALSE
 		holder.delayedlittle = FALSE
 		holder.explode_now = FALSE
-		holder.update_icon()
+		holder.update_icon(UPDATE_ICON_STATE)
 		holder.updateDialog()
 
 /obj/item/bombcore/training/detonate()

code/game/machinery/tcomms/_base.dm

@@ -51,7 +51,7 @@ GLOBAL_LIST_EMPTY(tcomms_machines)
 /obj/machinery/tcomms/Initialize(mapload)
 	. = ..()
 	GLOB.tcomms_machines += src
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	if((!mapload) && (usr))
 		// To the person who asks "Hey affected, why are you using this massive operator when you can use AREACOORD?" Well, ill tell you
 		// get_area_name is fucking broken and uses a for(x in world) search
@@ -82,8 +82,7 @@ GLOBAL_LIST_EMPTY(tcomms_machines)
   *
   * Ensures that the icon updates properly based on if the machine is active or not. This removes the need for this check in many other places.
   */
-/obj/machinery/tcomms/update_icon()
-	. = ..()
+/obj/machinery/tcomms/update_icon_state()
 	// Show the off sprite if were inactive, ion'd or unpowered
 	var/functioning = (active && !(stat & NOPOWER) && !ion)
 	icon_state = "[initial(icon_state)][panel_open ? "_o" : null][functioning ? null : "_off"]"
@@ -114,7 +113,7 @@ GLOBAL_LIST_EMPTY(tcomms_machines)
   */
 /obj/machinery/tcomms/proc/start_ion()
 	ion = TRUE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /**
   * End of Ion Anomaly Event
@@ -123,7 +122,7 @@ GLOBAL_LIST_EMPTY(tcomms_machines)
   */
 /obj/machinery/tcomms/proc/end_ion()
 	ion = FALSE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /**
   * Z-Level transit change helper
@@ -136,7 +135,7 @@ GLOBAL_LIST_EMPTY(tcomms_machines)
 		active = FALSE
 		// This needs a timer because otherwise its on the shuttle Z and the message is missed
 		addtimer(CALLBACK(src, /atom.proc/visible_message, "<span class='warning'>Radio equipment on [src] has been overloaded by heavy bluespace interference. Please restart the machine.</span>"), 5)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 
 /**
@@ -160,7 +159,7 @@ GLOBAL_LIST_EMPTY(tcomms_machines)
   */
 /obj/machinery/tcomms/power_change()
 	..()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /**
   * # Telecommunications Message
@@ -448,7 +447,7 @@ GLOBAL_LIST_EMPTY(tcomms_machines)
 		if(C.network_id == "STATION-CORE")
 			info = "<center><h2>Telecommunications Key</h2></center>\n\t<br>The station core linkage password is '[C.link_password]'.<br>Should this paper be misplaced or destroyed, fear not, as the password is visible under the core linkage section. Should you wish to modify this password, it can be modified from the core."
 			info_links = info
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 			// Save time, even though there should only be one STATION-CORE in the world
 			break
 	return ..()

code/game/machinery/teleporter.dm

@@ -155,7 +155,7 @@
 	power_station.engaged = FALSE
 	if(power_station.teleporter_hub.accurate < 3)
 		power_station.teleporter_hub.calibrated = FALSE
-	power_station.teleporter_hub.update_icon()
+	power_station.teleporter_hub.update_icon(UPDATE_ICON_STATE)
 
 /**
 *	Calibrates the hub. Helper function of ui_act
@@ -288,7 +288,7 @@
 	trg.stat &= ~NOPOWER
 	if(trg.teleporter_hub)
 		trg.teleporter_hub.stat &= ~NOPOWER
-		trg.teleporter_hub.update_icon()
+		trg.teleporter_hub.update_icon(UPDATE_ICON_STATE)
 	if(trg.teleporter_console)
 		trg.teleporter_console.stat &= ~NOPOWER
 		trg.teleporter_console.update_icon()
@@ -405,7 +405,7 @@
 		if(accurate < 3)
 			calibrated = FALSE
 
-/obj/machinery/teleport/hub/update_icon()
+/obj/machinery/teleport/hub/update_icon_state()
 	if(panel_open)
 		icon_state = "tele-o"
 	else if(power_station && power_station.engaged)
@@ -432,7 +432,7 @@
 	for(var/obj/item/stock_parts/matter_bin/M in component_parts)
 		A -= M.rating * 10
 	tele_delay = max(A, 0)
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /**
 	Internal helper function
@@ -464,18 +464,18 @@
 		use_power(5000)
 		if(tele_delay)
 			recalibrating = TRUE
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 			addtimer(CALLBACK(src, .proc/BumpedCallback), tele_delay)
 
 /obj/machinery/teleport/perma/proc/BumpedCallback()
 	recalibrating = FALSE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/teleport/perma/power_change()
 	..()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
-/obj/machinery/teleport/perma/update_icon()
+/obj/machinery/teleport/perma/update_icon_state()
 	if(panel_open)
 		icon_state = "tele-o"
 	else if(target && !recalibrating && !(stat & (BROKEN|NOPOWER)))
@@ -543,7 +543,7 @@
 /obj/machinery/teleport/station/Destroy()
 	if(teleporter_hub)
 		teleporter_hub.power_station = null
-		teleporter_hub.update_icon()
+		teleporter_hub.update_icon(UPDATE_ICON_STATE)
 		teleporter_hub = null
 	if(teleporter_console)
 		teleporter_console.power_station = null
@@ -584,7 +584,7 @@
 
 /obj/machinery/teleport/station/screwdriver_act(mob/user, obj/item/I)
 	if(default_deconstruction_screwdriver(user, "controller-o", "controller", I))
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 		return TRUE
 
 /obj/machinery/teleport/station/wirecutter_act(mob/user, obj/item/I)
@@ -618,17 +618,17 @@
 	else
 		visible_message("<span class='alert'>No target detected.</span>")
 		engaged = FALSE
-	teleporter_hub.update_icon()
+	teleporter_hub.update_icon(UPDATE_ICON_STATE)
 	if(istype(user))
 		add_fingerprint(user)
 
 /obj/machinery/teleport/station/power_change()
 	..()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	if(teleporter_hub)
-		teleporter_hub.update_icon()
+		teleporter_hub.update_icon(UPDATE_ICON_STATE)
 
-/obj/machinery/teleport/station/update_icon()
+/obj/machinery/teleport/station/update_icon_state()
 	if(panel_open)
 		icon_state = "controller-o"
 	else if(stat & NOPOWER)

code/game/machinery/transformer.dm

@@ -48,10 +48,9 @@
 
 /obj/machinery/transformer/power_change()
 	..()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
-/obj/machinery/transformer/update_icon()
-	..()
+/obj/machinery/transformer/update_icon_state()
 	if(is_on_cooldown || stat & (BROKEN|NOPOWER))
 		icon_state = "separator-AO0"
 	else
@@ -66,7 +65,7 @@
 /// Resets `is_on_cooldown` to `FALSE` and updates our icon. Used in a callback after the transformer does a transformation.
 /obj/machinery/transformer/proc/reset_cooldown()
 	is_on_cooldown = FALSE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/transformer/Bumped(atom/movable/AM)
 	// They have to be human to be transformed.
@@ -94,7 +93,7 @@
 
 	// Activate the cooldown
 	is_on_cooldown = TRUE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	addtimer(CALLBACK(src, .proc/reset_cooldown), cooldown_duration)
 	addtimer(CALLBACK(null, .proc/playsound, loc, 'sound/machines/ping.ogg', 50, 0), 3 SECONDS)
 
@@ -141,7 +140,7 @@
 
 	// Activate the cooldown
 	is_on_cooldown = TRUE
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	addtimer(CALLBACK(src, .proc/reset_cooldown), cooldown_duration)
 
 /obj/machinery/transformer/xray
@@ -167,10 +166,9 @@
 
 /obj/machinery/transformer/xray/power_change()
 	..()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
-/obj/machinery/transformer/xray/update_icon()
-	..()
+/obj/machinery/transformer/xray/update_icon_state()
 	if(stat & (BROKEN|NOPOWER))
 		icon_state = "separator-AO0"
 	else

code/game/machinery/turret_control.dm

@@ -215,15 +215,14 @@
 			if(faction == aTurret.faction)
 				aTurret.setState(TC)
 
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/turretid/power_change()
 	..()
 	updateTurrets()
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
-/obj/machinery/turretid/update_icon()
-	..()
+/obj/machinery/turretid/update_icon_state()
 	if(stat & NOPOWER)
 		icon_state = "control_off"
 		set_light(0)

code/game/machinery/vending.dm

@@ -164,17 +164,17 @@
 	for(var/obj/item/vending_refill/VR in component_parts)
 		restock(VR)
 
-/obj/machinery/vending/update_icon()
-	cut_overlays()
+/obj/machinery/vending/update_overlays()
+	. = ..()
 	underlays.Cut()
 	if(panel_open)
-		add_overlay("[icon_panel ? "[icon_panel]_panel" : "[icon_state]_panel"]")
+		. += "[icon_panel ? "[icon_panel]_panel" : "[icon_state]_panel"]"
 	if(icon_addon)
-		add_overlay("[icon_addon]")
+		. += "[icon_addon]"
 	if((stat & (BROKEN|NOPOWER)) || force_no_power_icon_state)
-		add_overlay("[icon_off ? "[icon_off]_off" : "[icon_state]_off"]")
+		. += "[icon_off ? "[icon_off]_off" : "[icon_state]_off"]"
 		if(stat & BROKEN)
-			add_overlay("[icon_broken ? "[icon_broken]_broken" : "[icon_state]_broken"]")
+			. += "[icon_broken ? "[icon_broken]_broken" : "[icon_state]_broken"]"
 		return
 	if(light)
 		underlays += emissive_appearance(icon, "[icon_lightmask ? "[icon_lightmask]_lightmask" : "[icon_state]_off"]")
@@ -203,14 +203,14 @@
 	for(var/i in 1 to amount)
 		force_no_power_icon_state = TRUE
 		set_light(0)
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 		sleep(rand(1, 3))
 
 		force_no_power_icon_state = FALSE
 		set_light(light_range_on, light_power_on)
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 		sleep(rand(1, 10))
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 	flickering = FALSE
 
 /**
@@ -363,7 +363,7 @@
 	if(anchored)
 		panel_open = !panel_open
 		panel_open ? SCREWDRIVER_OPEN_PANEL_MESSAGE : SCREWDRIVER_CLOSE_PANEL_MESSAGE
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 		SStgui.update_uis(src)
 
 /obj/machinery/vending/wirecutter_act(mob/user, obj/item/I)
@@ -840,13 +840,13 @@
 		set_light(0)
 	else
 		set_light(light_range_on, light_power_on)
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/machinery/vending/obj_break(damage_flag)
 	if(!(stat & BROKEN))
 		stat |= BROKEN
 		set_light(0)
-		update_icon()
+		update_icon(UPDATE_OVERLAYS)
 
 		var/dump_amount = 0
 		var/found_anything = TRUE

code/game/machinery/washing_machine.dm

@@ -37,7 +37,7 @@
 		state = 8
 	else
 		state = 5
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 	sleep(200)
 	for(var/atom/A in contents)
 		A.clean_blood()
@@ -188,7 +188,7 @@
 		gibs_ready = 1
 	else
 		state = 4
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/washing_machine/verb/climb_out()
 	set name = "Climb out"
@@ -200,7 +200,7 @@
 		usr.loc = src.loc
 
 
-/obj/machinery/washing_machine/update_icon()
+/obj/machinery/washing_machine/update_icon_state()
 	icon_state = "wm_[state][panel]"
 
 /obj/machinery/washing_machine/attackby(obj/item/W as obj, mob/user as mob, params)
@@ -216,7 +216,7 @@
 				user.drop_item()
 				crayon = W
 				crayon.loc = src
-				update_icon()
+				update_icon(UPDATE_ICON_STATE)
 			else
 				return ..()
 		else
@@ -228,7 +228,7 @@
 				G.affecting.loc = src
 				qdel(G)
 				state = 3
-			update_icon()
+			update_icon(UPDATE_ICON_STATE)
 		else
 			return ..()
 	else if(istype(W,/obj/item/stack/sheet/hairlesshide) || \
@@ -296,7 +296,7 @@
 				to_chat(user, "<span class='notice'>You can't put the item in right now.</span>")
 		else
 			to_chat(user, "<span class='notice'>The washing machine is full.</span>")
-		update_icon()
+		update_icon(UPDATE_ICON_STATE)
 	else
 		return ..()
 
@@ -332,7 +332,7 @@
 			state = 1
 
 
-	update_icon()
+	update_icon(UPDATE_ICON_STATE)
 
 /obj/machinery/washing_machine/deconstruct(disassembled = TRUE)
 	new /obj/item/stack/sheet/metal(drop_location(), 2)

code/game/mecha/equipment/tools/work_tools.dm

@@ -438,13 +438,13 @@
 	NC.cable_color("red")
 	NC.d1 = 0
 	NC.d2 = fdirn
-	NC.updateicon()
+	NC.update_icon()
 
 	var/datum/powernet/PN
 	if(last_piece && last_piece.d2 != Dir)
 		last_piece.d1 = min(last_piece.d2, Dir)
 		last_piece.d2 = max(last_piece.d2, Dir)
-		last_piece.updateicon()
+		last_piece.update_icon()
 		PN = last_piece.powernet
 
 	if(!PN)

code/game/mecha/mech_bay.dm

@@ -122,7 +122,7 @@
 	var/obj/machinery/mech_bay_recharge_port/recharge_port
 
 
-/obj/machinery/computer/mech_bay_power_console/update_icon()
+/obj/machinery/computer/mech_bay_power_console/update_overlays()
 	if(!recharge_port || !recharge_port.recharging_mecha || !recharge_port.recharging_mecha.cell || !(recharge_port.recharging_mecha.cell.charge < recharge_port.recharging_mecha.cell.maxcharge) || stat & (NOPOWER|BROKEN))
 		icon_screen = "recharge_comp"
 	else

code/game/mecha/working/ripley.dm

@@ -42,24 +42,34 @@
 
 /obj/mecha/working/ripley/go_out()
 	..()
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/mecha/working/ripley/moved_inside(mob/living/carbon/human/H)
 	..()
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
 /obj/mecha/working/ripley/mmi_moved_inside(obj/item/mmi/mmi_as_oc, mob/user)
 	..()
-	update_icon()
+	update_icon(UPDATE_OVERLAYS)
 
-/obj/mecha/working/ripley/update_icon()
-	..()
-	if(hides)
-		cut_overlays()
-		if(hides < 3)
-			add_overlay(occupant ? "ripley-g" : "ripley-g-open")
-		else
-			add_overlay(occupant ? "ripley-g-full" : "ripley-g-full-open")
+/obj/mecha/working/ripley/update_desc()
+	. = ..()
+	if(!hides) // Just in case if hides are somehow removed
+		desc = initial(desc)
+		return
+	if(hides == 3)
+		desc = "Autonomous Power Loader Unit. It's wearing a fearsome carapace entirely composed of goliath hide plates - its pilot must be an experienced monster hunter."
+	else
+		desc = "Autonomous Power Loader Unit. Its armour is enhanced with some goliath hide plates."
+
+/obj/mecha/working/ripley/update_overlays()
+	. = ..()
+	if(!hides)
+		return
+	if(hides == 3)
+		. += occupant ? "ripley-g-full" : "ripley-g-full-open"
+	else
+		. += occupant ? "ripley-g" : "ripley-g-open"
 
 /obj/mecha/working/ripley/firefighter
 	desc = "A standard APLU chassis that was refitted with additional thermal protection and a cistern."

code/game/objects/effects/decals/Cleanable/aliens.dm

@@ -19,6 +19,7 @@
 
 /obj/effect/decal/cleanable/blood/gibs/xeno/update_icon()
 	color = "#FFFFFF"
+	. = ..()
 
 /obj/effect/decal/cleanable/blood/gibs/xeno/up
 	random_icon_states = list("xgib1", "xgib2", "xgib3", "xgib4", "xgib5", "xgib6", "xgibup1", "xgibup1", "xgibup1")

code/game/objects/effects/decals/Cleanable/humans.dm

@@ -50,6 +50,7 @@ GLOBAL_LIST_EMPTY(splatter_cache)
 	if(basecolor == "rainbow")
 		basecolor = "#[pick(list("FF0000","FF7F00","FFFF00","00FF00","0000FF","4B0082","8F00FF"))]"
 	color = basecolor
+	..()
 
 /obj/effect/decal/cleanable/blood/proc/dry()
 	name = dryname
@@ -142,21 +143,26 @@ GLOBAL_LIST_EMPTY(splatter_cache)
 	random_icon_states = list("gib1", "gib2", "gib3", "gib4", "gib5", "gib6")
 	no_clear = TRUE
 	mergeable_decal = FALSE
-
+	var/image/giblets
 	var/fleshcolor = "#FFFFFF"
 
+/obj/effect/decal/cleanable/blood/gibs/Destroy()
+	giblets = null
+	return ..()
+
 /obj/effect/decal/cleanable/blood/gibs/update_icon()
-	var/image/giblets = new(base_icon, "[icon_state]_flesh", dir)
+	giblets = new(base_icon, "[icon_state]_flesh", dir)
 	if(!fleshcolor || fleshcolor == "rainbow")
 		fleshcolor = "#[pick(list("FF0000","FF7F00","FFFF00","00FF00","0000FF","4B0082","8F00FF"))]"
 	giblets.color = fleshcolor
 	var/icon/blood = new(base_icon,"[icon_state]",dir)
-
 	icon = blood
-	overlays.Cut()
-	overlays += giblets
 	. = ..()
 
+/obj/effect/decal/cleanable/blood/gibs/update_overlays()
+	. = ..()
+	. += giblets
+
 /obj/effect/decal/cleanable/blood/gibs/ex_act(severity)
 	return
 

code/game/objects/effects/decals/Cleanable/robots.dm

@@ -13,6 +13,7 @@
 
 /obj/effect/decal/cleanable/blood/gibs/robot/update_icon()
 	color = "#FFFFFF"
+	. = ..()
 
 /obj/effect/decal/cleanable/blood/gibs/robot/dry()	//pieces of robots do not dry up like
 	return

code/game/objects/effects/decals/Cleanable/tracks.dm

@@ -87,8 +87,8 @@ GLOBAL_LIST_EMPTY(fluidtrack_cache)
 				update_icon()
 
 
-/obj/effect/decal/cleanable/blood/footprints/update_icon()
-	overlays.Cut()
+/obj/effect/decal/cleanable/blood/footprints/update_overlays()
+	. = ..()
 
 	for(var/Ddir in GLOB.cardinal)
 		if(entered_dirs & Ddir)
@@ -100,7 +100,7 @@ GLOBAL_LIST_EMPTY(fluidtrack_cache)
 				GLOB.fluidtrack_cache["entered-[blood_state]-[Ddir]"] = I
 			if(I)
 				I.color = basecolor
-				overlays += I
+				. += I
 		if(exited_dirs & Ddir)
 			var/image/I
 			if(GLOB.fluidtrack_cache["exited-[blood_state]-[Ddir]"])
@@ -110,7 +110,7 @@ GLOBAL_LIST_EMPTY(fluidtrack_cache)
 				GLOB.fluidtrack_cache["exited-[blood_state]-[Ddir]"] = I
 			if(I)
 				I.color = basecolor
-				overlays += I
+				. += I
 
 	alpha = base_alpha + bloodiness
 

code/game/objects/effects/decals/contraband.dm

@@ -62,9 +62,9 @@
 	var/poster_item_icon_state = "rolled_poster"
 
 /obj/structure/sign/poster/Initialize(mapload)
-	. = ..()
 	if(random_basetype)
 		randomise(random_basetype)
+	. = ..()
 	if(!ruined)
 		original_name = name
 		name = "poster - [name]"

code/game/objects/effects/effect_system/effects_foam.dm

@@ -36,7 +36,7 @@
 
 			var/obj/structure/foamedmetal/M = new(src.loc)
 			M.metal = metal
-			M.updateicon()
+			M.update_state()
 
 		flick("[icon_state]-disolve", src)
 		sleep(5)
@@ -193,15 +193,20 @@
 /obj/structure/foamedmetal/play_attack_sound(damage_amount, damage_type = BRUTE, damage_flag = 0)
 	playsound(src.loc, 'sound/weapons/tap.ogg', 100, TRUE)
 
-/obj/structure/foamedmetal/proc/updateicon()
+/obj/structure/foamedmetal/proc/update_state()
 	if(metal == MFOAM_ALUMINUM)
-		icon_state = "metalfoam"
 		max_integrity = 20
 		obj_integrity = max_integrity
 	else
-		icon_state = "ironfoam"
 		max_integrity = 50
 		obj_integrity = max_integrity
+	update_icon(UPDATE_ICON_STATE)
+
+/obj/structure/foamedmetal/update_icon_state()
+	if(metal == MFOAM_ALUMINUM)
+		icon_state = "metalfoam"
+	else
+		icon_state = "ironfoam"
 
 /obj/structure/foamedmetal/attack_hand(mob/user)
 	user.changeNext_move(CLICK_CD_MELEE)

code/game/objects/items/ashtray.dm

@@ -30,19 +30,25 @@
 
 		visible_message("[user] places [I] in [src].")
 		add_fingerprint(user)
-		update_icon()
+		update_appearance(UPDATE_DESC|UPDATE_ICON_STATE)
 	else
 		return ..()
 
-/obj/item/ashtray/update_icon()
+/obj/item/ashtray/update_icon_state()
 	if(contents.len == max_butts)
 		icon_state = icon_full
-		desc = initial(desc) + " It's stuffed full."
 	else if(contents.len > max_butts * 0.5)
 		icon_state = icon_half
-		desc = initial(desc) + " It's half-filled."
 	else
 		icon_state = initial(icon_state)
+
+/obj/item/ashtray/update_desc()
+	. = ..()
+	if(contents.len == max_butts)
+		desc = initial(desc) + " It's stuffed full."
+	else if(contents.len > max_butts * 0.5)
+		desc = initial(desc) + " It's half-filled."
+	else
 		desc = initial(desc)
 
 /obj/item/ashtray/deconstruct()
@@ -52,7 +58,7 @@
 /obj/item/ashtray/proc/empty_tray()
 	for(var/obj/item/I in contents)
 		I.forceMove(loc)
-	update_icon()
+	update_appearance(UPDATE_DESC|UPDATE_ICON_STATE)
 
 /obj/item/ashtray/throw_impact(atom/hit_atom)
 	if(contents.len)

code/game/objects/items/bodybag.dm

@@ -56,7 +56,7 @@
 /obj/structure/closet/body_bag/update_overlays()
 	..()
 	if(name != initial(name))
-		add_overlay("bodybag_label")
+		. += "bodybag_label"
 
 /obj/structure/closet/body_bag/MouseDrop(over_object, src_location, over_location)
 	. = ..()