Standardizes greyscale belt overlays (tgstation#59362)

code/game/objects/items.dm

@@ -24,8 +24,10 @@ GLOBAL_DATUM_INIT(fire_overlay, /mutable_appearance, mutable_appearance('icons/e
 
 	///Icon file for mob worn overlays.
 	var/icon/worn_icon
-	///icon state for mob worn overlays, if null the normal icon_state will be used.
+	///Icon state for mob worn overlays, if null the normal icon_state will be used.
 	var/worn_icon_state
+	///Icon state for the belt overlay, if null the normal icon_state will be used.
+	var/belt_icon_state
 	///Forced mob worn layer instead of the standard preferred ssize.
 	var/alternate_worn_layer
 	///The config type to use for greyscaled worn sprites. Both this and greyscale_colors must be assigned to work.
@@ -34,6 +36,8 @@ GLOBAL_DATUM_INIT(fire_overlay, /mutable_appearance, mutable_appearance('icons/e
 	var/greyscale_config_inhand_left
 	///The config type to use for greyscaled right inhand sprites. Both this and greyscale_colors must be assigned to work.
 	var/greyscale_config_inhand_right
+	///The config type to use for greyscaled belt overlays. Both this and greyscale_colors must be assigned to work.
+	var/greyscale_config_belt
 
 	/* !!!!!!!!!!!!!!! IMPORTANT !!!!!!!!!!!!!!
 
@@ -713,8 +717,12 @@ GLOBAL_DATUM_INIT(fire_overlay, /mutable_appearance, mutable_appearance('icons/e
 		return SEND_SIGNAL(loc, COMSIG_TRY_STORAGE_TAKE, src, newLoc, TRUE)
 	return FALSE
 
-/obj/item/proc/get_belt_overlay() //Returns the icon used for overlaying the object on a belt
-	return mutable_appearance('icons/obj/clothing/belt_overlays.dmi', icon_state)
+/// Returns the icon used for overlaying the object on a belt
+/obj/item/proc/get_belt_overlay()
+	var/icon_state_to_use = belt_icon_state || icon_state
+	if(greyscale_config_belt && greyscale_colors)
+		return mutable_appearance(SSgreyscale.GetColoredIconByType(greyscale_config_belt, greyscale_colors), icon_state_to_use)
+	return mutable_appearance('icons/obj/clothing/belt_overlays.dmi', icon_state_to_use)
 
 /obj/item/proc/update_slot_icon()
 	if(!ismob(loc))

code/game/objects/items/tools/screwdriver.dm

@@ -5,6 +5,7 @@
 	icon_state = "screwdriver_map"
 	inhand_icon_state = "screwdriver"
 	worn_icon_state = "screwdriver"
+	belt_icon_state = "screwdriver"
 	lefthand_file = 'icons/mob/inhands/equipment/tools_lefthand.dmi'
 	righthand_file = 'icons/mob/inhands/equipment/tools_righthand.dmi'
 	flags_1 = CONDUCT_1
@@ -28,6 +29,7 @@
 	greyscale_config = /datum/greyscale_config/screwdriver
 	greyscale_config_inhand_left = /datum/greyscale_config/screwdriver_inhand_left
 	greyscale_config_inhand_right = /datum/greyscale_config/screwdriver_inhand_right
+	greyscale_config_belt = /datum/greyscale_config/screwdriver_belt
 	/// If the item should be assigned a random color
 	var/random_color = TRUE
 	/// List of possible random colors
@@ -40,8 +42,6 @@
 		"cyan" = "#18a2d5",
 		"yellow" = "#ffa500"
 	)
-	/// Colored belt appearance for adding it as a belt overlay
-	var/mutable_appearance/colored_belt_appearance
 
 /obj/item/screwdriver/suicide_act(mob/user)
 	user.visible_message("<span class='suicide'>[user] is stabbing [src] into [user.p_their()] [pick("temple", "heart")]! It looks like [user.p_theyre()] trying to commit suicide!</span>")
@@ -51,16 +51,9 @@
 	if(random_color)
 		var/our_color = pick(screwdriver_colors)
 		set_greyscale(colors=list(screwdriver_colors[our_color]))
-		colored_belt_appearance = mutable_appearance(SSgreyscale.GetColoredIconByType(/datum/greyscale_config/screwdriver_belt, greyscale_colors))
 	. = ..()
 	AddElement(/datum/element/eyestab)
 
-/obj/item/screwdriver/get_belt_overlay()
-	if(random_color)
-		return colored_belt_appearance
-	else
-		return mutable_appearance('icons/obj/clothing/belt_overlays.dmi', icon_state)
-
 /obj/item/screwdriver/abductor
 	name = "alien screwdriver"
 	desc = "An ultrasonic screwdriver."

code/modules/unit_tests/greyscale_config.dm

@@ -17,3 +17,8 @@
 		var/worn_icon_state = initial(item_path.worn_icon_state) || initial(item_path.icon_state)
 		if(worn && !worn.icon_states[worn_icon_state])
 			Fail("[worn.DebugName()] is missing a sprite for the worn overlay for [item_path]. Expected icon state: '[worn_icon_state]'")
+
+		var/datum/greyscale_config/belt = SSgreyscale.configurations["[initial(item_path.greyscale_config_belt)]"]
+		var/belt_icon_state = initial(item_path.belt_icon_state) || initial(item_path.icon_state)
+		if(belt && !belt.icon_states[belt_icon_state])
+			Fail("[belt.DebugName()] is missing a sprite for the belt overlay for [item_path]. Expected icon state: '[belt_icon_state]'")