Burning and acid components fixes and improvements (#74803)

## About The Pull Request

Generally cleans up code on both components.
Moves burn proc back to /obj level, I'm not sure why I moved it to /atom
level, it was unnecessary.
Acid component generalized so it can be used on any atom that uses
atom_integrity.
Fixes a bug where objects that stopped burning didn't update their burn
overlay properly due to bad removal logic and leftover code.
Standardizes examine messages on burning items by just slapping an
examine signal registration on the component.
Adds fire particles to items thanks to Lemon's PR:
https://github.com/tgstation/tgstation/pull/74524

## Why It's Good For The Game

Particles look cool

![image](https://user-images.githubusercontent.com/82850673/232605615-6e3bc804-bc68-4f09-8615-5e5946acbc10.png)

![image](https://user-images.githubusercontent.com/82850673/232664951-e0474331-495f-4717-8b0f-a647aedc4d9f.png)

Bugfixes are good
Code improvements are good

## Changelog

🆑
add: Burning items now get (small) smoke particles. Sick.
fix: Burning objects now clear their burning overlay properly.
qol: Examining burning objects will always tell you that they are
burning.
/🆑

---------

Co-authored-by: san7890 <the@san7890.com>

code/__DEFINES/acid.dm

@@ -1,9 +1,9 @@
 /// The acid power required to destroy most closed turfs.
 #define ACID_POWER_MELT_TURF 200
 /// The maximum amount of damage (per second) acid can deal to an [/obj].
-#define OBJ_ACID_DAMAGE_MAX 300
+#define MOVABLE_ACID_DAMAGE_MAX 300
 /// Maximum acid volume that can be applied to an [/obj].
-#define OBJ_ACID_VOLUME_MAX 300
+#define MOVABLE_ACID_VOLUME_MAX 300
 /// Maximum acid volume that can be applied to a [/mob/living].
 #define MOB_ACID_VOLUME_MAX 1000
 /// Maximum acid volume that can be applied to a [/turf].
@@ -15,7 +15,5 @@
 /// The scaling factor for the acid decay rate.
 #define ACID_DECAY_SCALING 1
 
-/// The default icon state for the acid overlay. Not to be confused with the error icon state.
-#define ACID_OVERLAY_DEFAULT "default"
 /// The combined acid power and acid volume required to burn hands.
 #define ACID_LEVEL_HANDBURN 20

code/controllers/subsystem/processing/fire_burning.dm

@@ -1,6 +1,6 @@
 /// The subsystem used to tick [/datum/component/burning] instances.
-PROCESSING_SUBSYSTEM_DEF(fire_burning)
-	name = "Fire Burning"
+PROCESSING_SUBSYSTEM_DEF(burning)
+	name = "Burning"
 	priority = FIRE_PRIORITY_BURNING
 	flags = SS_NO_INIT|SS_BACKGROUND
 	runlevels = RUNLEVEL_GAME | RUNLEVEL_POSTGAME

code/datums/components/acid.dm

@@ -1,10 +1,11 @@
-GLOBAL_DATUM_INIT(acid_overlay, /mutable_appearance, mutable_appearance('icons/effects/effects.dmi', "acid"))
+GLOBAL_DATUM_INIT(acid_overlay, /mutable_appearance, mutable_appearance('icons/effects/acid.dmi', "default"))
 
-/** Component representing acid applied to an object.
- *
+/**
+ * Component representing acid applied to an object.
  * Must be attached to an atom.
  * Processes, repeatedly damaging whatever it is attached to.
  * If the parent atom is a turf it applies acid to the contents of the turf.
+ * If not being applied to a mob or turf, the atom must use the integrity system.
  */
 /datum/component/acid
 	dupe_mode = COMPONENT_DUPE_UNIQUE_PASSARGS
@@ -14,6 +15,8 @@ GLOBAL_DATUM_INIT(acid_overlay, /mutable_appearance, mutable_appearance('icons/e
 	var/acid_volume
 	/// The maximum volume of acid on the parent [/atom].
 	var/max_volume = INFINITY
+	/// Acid overlay appearance we apply
+	var/acid_overlay
 	/// The ambiant sound of acid eating away at the parent [/atom].
 	var/datum/looping_sound/acid/sizzle
 	/// Used exclusively for melting turfs. TODO: Move integrity to the atom level so that this can be dealt with there.
@@ -23,71 +26,80 @@ GLOBAL_DATUM_INIT(acid_overlay, /mutable_appearance, mutable_appearance('icons/e
 	/// The proc used to handle the parent [/atom] when processing. TODO: Unify damage and resistance flags so that this doesn't need to exist!
 	var/datum/callback/process_effect
 
-/datum/component/acid/Initialize(_acid_power, _acid_volume, _max_volume=null)
-	if((_acid_power) <= 0 || (_acid_volume <= 0))
-		stack_trace("Acid component added with insufficient acid power ([_acid_power]) or acid volume ([_acid_power]).")
-		return COMPONENT_INCOMPATIBLE // Not enough acid or the acid's too weak, either one.
+/datum/component/acid/Initialize(acid_power = ACID_POWER_MELT_TURF, acid_volume = 50, acid_overlay = GLOB.acid_overlay)
 	if(!isatom(parent))
-		stack_trace("Acid component added to [parent] ([parent?.type]) which is not a /atom subtype.")
-		return COMPONENT_INCOMPATIBLE // Incompatible type. TODO: Rework take_damage to the atom level and move this there.
+		return COMPONENT_INCOMPATIBLE
+	//not incompatible, but pointless
+	var/atom/atom_parent = parent
+	if((acid_power) <= 0 || (acid_volume <= 0))
+		stack_trace("Acid component added to an atom ([atom_parent.type]) with insufficient acid power ([acid_power]) or acid volume ([acid_volume]).")
+		qdel(src)
+		return
 
-	if(isobj(parent))
-		var/obj/parent_object = parent
-		if(parent_object.resistance_flags & UNACIDABLE) // The parent object cannot have acid. Should never happen, will happen.
-			stack_trace("Acid component added to unacidable object [parent].")
-			return COMPONENT_INCOMPATIBLE
 
-		max_volume = OBJ_ACID_VOLUME_MAX
-		process_effect = CALLBACK(src, PROC_REF(process_obj), parent)
-	else if(isliving(parent))
+	if(isliving(parent))
 		max_volume = MOB_ACID_VOLUME_MAX
 		process_effect = CALLBACK(src, PROC_REF(process_mob), parent)
 	else if(isturf(parent))
 		max_volume = TURF_ACID_VOLUME_MAX
 		process_effect = CALLBACK(src, PROC_REF(process_turf), parent)
+	//if we failed all other checks, we must be an /atom/movable that uses integrity
+	else if(atom_parent.uses_integrity)
+		// The parent object cannot have acid. Not incompatible, but should not really happen.
+		if(atom_parent.resistance_flags & UNACIDABLE)
+			qdel(src)
+			return
 
-	acid_power = _acid_power
-	set_volume(_acid_volume)
+		max_volume = MOVABLE_ACID_VOLUME_MAX
+		process_effect = CALLBACK(src, PROC_REF(process_movable), parent)
+	//or not...
+	else
+		stack_trace("Tried to add /datum/component/acid to an atom ([atom_parent.type]) which does not use atom_integrity!")
+		return COMPONENT_INCOMPATIBLE
+
+	src.acid_power = acid_power
+	set_volume(acid_volume)
+	src.acid_overlay = acid_overlay
 
-	var/atom/parent_atom = parent
-	RegisterSignal(parent, COMSIG_ATOM_UPDATE_OVERLAYS, PROC_REF(on_update_overlays))
-	parent_atom.update_appearance()
 	sizzle = new(parent, TRUE)
 	START_PROCESSING(SSacid, src)
 
 /datum/component/acid/Destroy(force, silent)
 	STOP_PROCESSING(SSacid, src)
-	QDEL_NULL(sizzle)
+	if(sizzle)
+		QDEL_NULL(sizzle)
 	if(process_effect)
 		QDEL_NULL(process_effect)
-	UnregisterSignal(parent, COMSIG_ATOM_UPDATE_OVERLAYS)
-	if(parent && !QDELING(parent))
-		var/atom/parent_atom = parent
-		parent_atom.update_appearance()
 	return ..()
 
 /datum/component/acid/RegisterWithParent()
 	RegisterSignal(parent, COMSIG_PARENT_EXAMINE, PROC_REF(on_examine))
+	RegisterSignal(parent, COMSIG_ATOM_UPDATE_OVERLAYS, PROC_REF(on_update_overlays))
 	RegisterSignal(parent, COMSIG_COMPONENT_CLEAN_ACT, PROC_REF(on_clean))
 	RegisterSignal(parent, COMSIG_ATOM_ATTACK_HAND, PROC_REF(on_attack_hand))
 	RegisterSignal(parent, COMSIG_ATOM_EXPOSE_REAGENT, PROC_REF(on_expose_reagent))
 	if(isturf(parent))
 		RegisterSignal(parent, COMSIG_ATOM_ENTERED, PROC_REF(on_entered))
+	var/atom/atom_parent = parent
+	atom_parent.update_appearance()
 
 /datum/component/acid/UnregisterFromParent()
 	UnregisterSignal(parent, list(
 		COMSIG_PARENT_EXAMINE,
+		COMSIG_ATOM_UPDATE_OVERLAYS,
 		COMSIG_COMPONENT_CLEAN_ACT,
 		COMSIG_ATOM_ATTACK_HAND,
 		COMSIG_ATOM_EXPOSE_REAGENT))
-
 	if(isturf(parent))
 		UnregisterSignal(parent, COMSIG_ATOM_ENTERED)
+	var/atom/atom_parent = parent
+	if(!QDELETED(atom_parent))
+		atom_parent.update_appearance()
 
 /// Averages corrosive power and sums volume.
-/datum/component/acid/InheritComponent(datum/component/C, i_am_original, _acid_power, _acid_volume)
-	acid_power = ((acid_power * acid_volume) + (_acid_power * _acid_volume)) / (acid_volume + _acid_volume)
-	set_volume(acid_volume + _acid_volume)
+/datum/component/acid/InheritComponent(datum/component/new_comp, i_am_original, acid_power, acid_volume)
+	acid_power = ((src.acid_power * src.acid_volume) + (acid_power * acid_volume)) / (src.acid_volume + acid_volume)
+	set_volume(src.acid_volume + acid_volume)
 
 /// Sets the acid volume to a new value. Limits the acid volume by the amount allowed to exist on the parent atom.
 /datum/component/acid/proc/set_volume(new_volume)
@@ -95,7 +107,6 @@ GLOBAL_DATUM_INIT(acid_overlay, /mutable_appearance, mutable_appearance('icons/e
 	if(!acid_volume)
 		qdel(src)
 
-
 /// Handles the slow corrosion of the parent [/atom].
 /datum/component/acid/process(seconds_per_tick)
 	process_effect?.InvokeAsync(seconds_per_tick)
@@ -103,11 +114,11 @@ GLOBAL_DATUM_INIT(acid_overlay, /mutable_appearance, mutable_appearance('icons/e
 		return
 	set_volume(acid_volume - (ACID_DECAY_BASE + (ACID_DECAY_SCALING*round(sqrt(acid_volume)))) * seconds_per_tick)
 
-/// Handles processing on a [/obj].
-/datum/component/acid/proc/process_obj(obj/target, seconds_per_tick)
+/// Handles processing on an [/atom/movable] (that uses atom_integrity).
+/datum/component/acid/proc/process_movable(atom/movable/target, seconds_per_tick)
 	if(target.resistance_flags & ACID_PROOF)
 		return
-	target.take_damage(min(1 + round(sqrt(acid_power * acid_volume)*0.3), OBJ_ACID_DAMAGE_MAX) * seconds_per_tick, BURN, ACID, 0)
+	target.take_damage(min(1 + round(sqrt(acid_power * acid_volume)*0.3), MOVABLE_ACID_DAMAGE_MAX) * seconds_per_tick, BURN, ACID, 0)
 
 /// Handles processing on a [/mob/living].
 /datum/component/acid/proc/process_mob(mob/living/target, seconds_per_tick)
@@ -117,8 +128,7 @@ GLOBAL_DATUM_INIT(acid_overlay, /mutable_appearance, mutable_appearance('icons/e
 /datum/component/acid/proc/process_turf(turf/target_turf, seconds_per_tick)
 	var/acid_used = min(acid_volume * 0.05, 20) * seconds_per_tick
 	var/applied_targets = 0
-	for(var/am in target_turf)
-		var/atom/movable/target_movable = am
+	for(var/atom/movable/target_movable as anything in target_turf)
 		if(target_movable.acid_act(acid_power, acid_used))
 			applied_targets++
 
@@ -150,16 +160,17 @@ GLOBAL_DATUM_INIT(acid_overlay, /mutable_appearance, mutable_appearance('icons/e
 /datum/component/acid/proc/on_update_overlays(atom/parent_atom, list/overlays)
 	SIGNAL_HANDLER
 
-	overlays += mutable_appearance('icons/effects/acid.dmi', parent_atom.custom_acid_overlay || ACID_OVERLAY_DEFAULT)
+	if(acid_overlay)
+		overlays += acid_overlay
 
 /// Alerts any examiners to the acid on the parent atom.
-/datum/component/acid/proc/on_examine(atom/A, mob/user, list/examine_list)
+/datum/component/acid/proc/on_examine(atom/source, mob/user, list/examine_list)
 	SIGNAL_HANDLER
 
-	examine_list += span_danger("[A.p_theyre()] covered in corrosive liquid!")
+	examine_list += span_danger("[source.p_theyre(TRUE)] covered in a corrosive liquid!")
 
 /// Makes it possible to clean acid off of objects.
-/datum/component/acid/proc/on_clean(atom/A, clean_types)
+/datum/component/acid/proc/on_clean(atom/source, clean_types)
 	SIGNAL_HANDLER
 
 	if(!(clean_types & CLEAN_TYPE_ACID))
@@ -178,7 +189,6 @@ GLOBAL_DATUM_INIT(acid_overlay, /mutable_appearance, mutable_appearance('icons/e
 	set_volume(acid_volume + reac_volume)
 	return NONE
 
-
 /// Handles searing the hand of anyone who tries to touch this without protection.
 /datum/component/acid/proc/on_attack_hand(atom/parent_atom, mob/living/carbon/user)
 	SIGNAL_HANDLER
@@ -201,7 +211,6 @@ GLOBAL_DATUM_INIT(acid_overlay, /mutable_appearance, mutable_appearance('icons/e
 	user.update_damage_overlays()
 	return COMPONENT_CANCEL_ATTACK_CHAIN
 
-
 /// Handles searing the feet of whoever walks over this without protection. Only active if the parent is a turf.
 /datum/component/acid/proc/on_entered(datum/source, atom/movable/arrived, atom/old_loc, list/atom/old_locs)
 	SIGNAL_HANDLER

code/datums/components/burning.dm

@@ -2,7 +2,8 @@ GLOBAL_DATUM_INIT(fire_overlay, /mutable_appearance, mutable_appearance('icons/e
 
 /**
  * Component representing an atom being on fire.
- * Should not be used on mobs, they use the fire stacks system.
+ * Should not be used on mobs, they use the fire stacks status effects.
+ * Can only be used on atoms that use the integrity system.
  */
 /datum/component/burning
 	/// Fire overlay appearance we apply
@@ -10,12 +11,12 @@ GLOBAL_DATUM_INIT(fire_overlay, /mutable_appearance, mutable_appearance('icons/e
 	/// Particle holder for fire particles, if any
 	var/obj/effect/abstract/particle_holder/particle_effect
 
-/datum/component/burning/Initialize(fire_overlay, fire_particles)
+/datum/component/burning/Initialize(fire_overlay = GLOB.fire_overlay, fire_particles = /particles/smoke/burning)
 	if(!isatom(parent))
 		return COMPONENT_INCOMPATIBLE
 	var/atom/atom_parent = parent
 	if(!atom_parent.uses_integrity)
-		stack_trace("Tried to add /datum/component/burning to an atom ([atom_parent]) that does not use atom_integrity!")
+		stack_trace("Tried to add /datum/component/burning to an atom ([atom_parent.type]) that does not use atom_integrity!")
 		return COMPONENT_INCOMPATIBLE
 	// only flammable atoms should have this component, but it's not really an error if we try to apply this to a non flammable one
 	if(!(atom_parent.resistance_flags & FLAMMABLE) || (atom_parent.resistance_flags & FIRE_PROOF))
@@ -23,30 +24,30 @@ GLOBAL_DATUM_INIT(fire_overlay, /mutable_appearance, mutable_appearance('icons/e
 		return
 	src.fire_overlay = fire_overlay
 	if(fire_particles)
-		particle_effect = new(atom_parent, fire_particles)
-	atom_parent.resistance_flags |= ON_FIRE
-	START_PROCESSING(SSfire_burning, src)
+		// burning particles look pretty bad when they stack on mobs, so that behavior is not wanted for items
+		particle_effect = new(atom_parent, fire_particles, isitem(atom_parent) ? NONE : PARTICLE_ATTACH_MOB)
+	START_PROCESSING(SSburning, src)
+
+/datum/component/burning/Destroy(force, silent)
+	STOP_PROCESSING(SSburning, src)
+	if(particle_effect)
+		QDEL_NULL(particle_effect)
+	return ..()
 
 /datum/component/burning/RegisterWithParent()
-	. = ..()
+	RegisterSignal(parent, COMSIG_PARENT_EXAMINE, PROC_REF(on_examine))
 	RegisterSignal(parent, COMSIG_ATOM_UPDATE_OVERLAYS, PROC_REF(on_update_overlays))
 	RegisterSignal(parent, COMSIG_ATOM_EXTINGUISH, PROC_REF(on_extinguish))
 	var/atom/atom_parent = parent
-	atom_parent.update_appearance(UPDATE_ICON)
+	atom_parent.resistance_flags |= ON_FIRE
+	atom_parent.update_appearance()
 
 /datum/component/burning/UnregisterFromParent()
-	. = ..()
-	UnregisterSignal(parent, list(COMSIG_ATOM_UPDATE_OVERLAYS, COMSIG_ATOM_EXTINGUISH))
-
-/datum/component/burning/Destroy(force, silent)
-	STOP_PROCESSING(SSfire_burning, src)
-	if(particle_effect)
-		QDEL_NULL(particle_effect)
+	UnregisterSignal(parent, list(COMSIG_PARENT_EXAMINE, COMSIG_ATOM_UPDATE_OVERLAYS, COMSIG_ATOM_EXTINGUISH))
 	var/atom/atom_parent = parent
-	if(!QDELING(atom_parent) && (atom_parent.resistance_flags & ON_FIRE))
+	if(!QDELETED(atom_parent))
 		atom_parent.resistance_flags &= ~ON_FIRE
-		atom_parent.update_appearance(UPDATE_ICON)
-	return ..()
+		atom_parent.update_appearance()
 
 /datum/component/burning/process(seconds_per_tick)
 	var/atom/atom_parent = parent
@@ -56,10 +57,20 @@ GLOBAL_DATUM_INIT(fire_overlay, /mutable_appearance, mutable_appearance('icons/e
 		return
 	atom_parent.take_damage(10 * seconds_per_tick, BURN, FIRE, FALSE)
 
+/// Alerts any examiners that the parent is on fire (even though it should be rather obvious)
+/datum/component/burning/proc/on_examine(atom/source, mob/user, list/examine_list)
+	SIGNAL_HANDLER
+
+	examine_list += span_danger("[source.p_theyre(TRUE)] burning!")
+
 /// Maintains the burning overlay on the parent atom
 /datum/component/burning/proc/on_update_overlays(atom/source, list/overlays)
 	SIGNAL_HANDLER
 
+	//most likely means the component is being removed
+	if(!(source.resistance_flags & ON_FIRE))
+		return
+
 	if(fire_overlay)
 		overlays += fire_overlay
 

code/game/atom_defense.dm

@@ -135,19 +135,3 @@
 /// A cut-out proc for [/atom/proc/bullet_act] so living mobs can have their own armor behavior checks without causing issues with needing their own on_hit call
 /atom/proc/check_projectile_armor(def_zone, obj/projectile/impacting_projectile, is_silent)
 	return 0
-
-/**
- * Should be called when the atom is destroyed by fire
- * This proc is terrible. I do not know why it exists.
- * Please remove it at some point.
- */
-/atom/proc/burn()
-	return
-
-/**
- * Sends COMSIG_ATOM_EXTINGUISH signal which properly removes burning component.
- * Can be hooked onto for extra behavior.
- */
-/atom/proc/extinguish()
-	SHOULD_CALL_PARENT(TRUE)
-	return SEND_SIGNAL(src, COMSIG_ATOM_EXTINGUISH)

code/game/atoms.dm

@@ -930,9 +930,23 @@
 		return FALSE
 	return TRUE
 
+/**
+ * Respond to fire being used on our atom
+ *
+ * Default behaviour is to send [COMSIG_ATOM_FIRE_ACT] and return
+ */
 /atom/proc/fire_act(exposed_temperature, exposed_volume)
 	SEND_SIGNAL(src, COMSIG_ATOM_FIRE_ACT, exposed_temperature, exposed_volume)
-	return
+	return FALSE
+
+/**
+ * Sends [COMSIG_ATOM_EXTINGUISH] signal, which properly removes burning component if it is present.
+ *
+ * Default behaviour is to send [COMSIG_ATOM_ACID_ACT] and return
+ */
+/atom/proc/extinguish()
+	SHOULD_CALL_PARENT(TRUE)
+	return SEND_SIGNAL(src, COMSIG_ATOM_EXTINGUISH)
 
 /**
  * React to being hit by a thrown object
@@ -1879,6 +1893,7 @@
  * Override this if you want custom behaviour in whatever gets hit by the rust
  */
 /atom/proc/rust_heretic_act()
+	return
 
 /**
  * Used to set something as 'open' if it's being used as a supplypod

code/game/machinery/_machinery.dm

@@ -1118,8 +1118,6 @@
 	if(machine_stat & BROKEN)
 		. += span_notice("It looks broken and non-functional.")
 	if(!(resistance_flags & INDESTRUCTIBLE))
-		if(resistance_flags & ON_FIRE)
-			. += span_warning("It's on fire!")
 		var/healthpercent = (atom_integrity/max_integrity) * 100
 		switch(healthpercent)
 			if(50 to 99)

code/game/objects/effects/particles/smoke.dm

@@ -18,6 +18,11 @@
 /particles/smoke/burning
 	position = list(0, 0, 0)
 
+/particles/smoke/burning/small
+	spawning = 1
+	scale = list(0.8, 0.8)
+	velocity = list(0, 0.4, 0)
+
 /particles/smoke/steam
 	icon_state = list("steam_1" = 1, "steam_2" = 1, "steam_3" = 2)
 	fade = 1.5 SECONDS

code/game/objects/items.dm

@@ -3,6 +3,7 @@
 	name = "item"
 	icon = 'icons/obj/objects.dmi'
 	blocks_emissive = EMISSIVE_BLOCK_GENERIC
+	burning_particles = /particles/smoke/burning/small
 	pass_flags_self = PASSITEM
 
 	/* !!!!!!!!!!!!!!! IMPORTANT !!!!!!!!!!!!!!

code/game/objects/obj_defense.dm

@@ -99,10 +99,10 @@
 ///the obj's reaction when touched by acid
 /obj/acid_act(acidpwr, acid_volume)
 	. = ..()
-	if((resistance_flags & UNACIDABLE) || (acid_volume <= 0) || acidpwr <= 0)
+	if((resistance_flags & UNACIDABLE) || (acid_volume <= 0) || (acidpwr <= 0))
 		return FALSE
 
-	AddComponent(/datum/component/acid, acidpwr, acid_volume)
+	AddComponent(/datum/component/acid, acidpwr, acid_volume, custom_acid_overlay || GLOB.acid_overlay)
 	return TRUE
 
 ///called when the obj is destroyed by acid.
@@ -114,8 +114,8 @@
 ///Called when the obj is exposed to fire.
 /obj/fire_act(exposed_temperature, exposed_volume)
 	if(isturf(loc))
-		var/turf/T = loc
-		if(T.underfloor_accessibility < UNDERFLOOR_INTERACTABLE && HAS_TRAIT(src, TRAIT_T_RAY_VISIBLE))
+		var/turf/our_turf = loc
+		if(our_turf.underfloor_accessibility < UNDERFLOOR_INTERACTABLE && HAS_TRAIT(src, TRAIT_T_RAY_VISIBLE))
 			return
 	if(exposed_temperature && !(resistance_flags & FIRE_PROOF))
 		take_damage(clamp(0.02 * exposed_temperature, 0, 20), BURN, FIRE, 0)
@@ -124,9 +124,8 @@
 		return TRUE
 	return ..()
 
-///called when the obj is destroyed by fire
-/obj/burn()
-	. = ..()
+/// Should be called when the atom is destroyed by fire, comparable to acid_melt() proc
+/obj/proc/burn()
 	deconstruct(FALSE)
 
 ///Called when the obj is hit by a tesla bolt.

code/game/objects/objs.dm

@@ -338,11 +338,6 @@ GLOBAL_LIST_EMPTY(objects_by_id_tag)
 	if(. && receive_ricochet_damage_coeff)
 		take_damage(P.damage * receive_ricochet_damage_coeff, P.damage_type, P.armor_flag, 0, turn(P.dir, 180), P.armour_penetration) // pass along receive_ricochet_damage_coeff damage to the structure for the ricochet
 
-/obj/update_overlays()
-	. = ..()
-	if(resistance_flags & ON_FIRE)
-		. += custom_fire_overlay ? custom_fire_overlay : GLOB.fire_overlay
-
 /// Handles exposing an object to reagents.
 /obj/expose_reagents(list/reagents, datum/reagents/source, methods=TOUCH, volume_modifier=1, show_message=TRUE)
 	. = ..()

code/game/objects/structures/bonfire.dm

@@ -146,13 +146,13 @@
 			var/mob/living/burn_victim = burn_target
 			burn_victim.adjust_fire_stacks(BONFIRE_FIRE_STACK_STRENGTH * 0.5 * seconds_per_tick)
 			burn_victim.ignite_mob()
-		else if(isobj(burn_target))
-			var/obj/burned_object = burn_target
-			if(grill && isitem(burned_object))
-				var/obj/item/grilled_item = burned_object
+		else
+			var/atom/movable/burned_movable = burn_target
+			if(grill && isitem(burned_movable))
+				var/obj/item/grilled_item = burned_movable
 				SEND_SIGNAL(grilled_item, COMSIG_ITEM_GRILL_PROCESS, src, seconds_per_tick) //Not a big fan, maybe make this use fire_act() in the future.
 				continue
-			burned_object.fire_act(1000, 250 * seconds_per_tick)
+			burned_movable.fire_act(1000, 250 * seconds_per_tick)
 
 /obj/structure/bonfire/process(seconds_per_tick)
 	if(!check_oxygen())

code/game/turfs/turf.dm

@@ -597,12 +597,12 @@ GLOBAL_LIST_EMPTY(station_turfs)
 	if((acidpwr <= 0) || (acid_volume <= 0))
 		return FALSE
 
-	AddComponent(/datum/component/acid, acidpwr, acid_volume)
-	for(var/obj/O in src)
-		if(underfloor_accessibility < UNDERFLOOR_INTERACTABLE && HAS_TRAIT(O, TRAIT_T_RAY_VISIBLE))
+	AddComponent(/datum/component/acid, acidpwr, acid_volume, GLOB.acid_overlay)
+	for(var/atom/movable/movable_atom as anything in src)
+		if(underfloor_accessibility < UNDERFLOOR_INTERACTABLE && HAS_TRAIT(movable_atom, TRAIT_T_RAY_VISIBLE))
 			continue
 
-		O.acid_act(acidpwr, acid_volume)
+		movable_atom.acid_act(acidpwr, acid_volume)
 
 	return . || TRUE
 

code/modules/vehicles/_vehicle.dm

@@ -64,8 +64,6 @@
 
 /obj/vehicle/examine(mob/user)
 	. = ..()
-	if(resistance_flags & ON_FIRE)
-		. += span_warning("It's on fire!")
 	. += generate_integrity_message()
 
 /// Returns a readable string of the vehicle's health for examining. Overridden by subtypes who want to be more verbose with their health messages.