hides ugly finger prints behind the Forensic Spray:tm: (#8060)

title

gif

![47sjvfYo61Kfv1zo](https://github.com/user-attachments/assets/02634a55-a1f6-4ace-a201-30c742b43c23)


:cl:
add: fingerprints must now be revealed by forensic spray. they disappear
after a minute
/:cl:

code/game/machinery/vending/vending_types.dm

@@ -241,6 +241,7 @@
 		/obj/item/explosive/grenade/flashbang = 4,
 		/obj/item/weapon/gun/energy/taser = 4,
 		/obj/item/reagent_container/spray/pepper = 4,
+		/obj/item/reagent_container/spray/investigation = 4,
 		/obj/item/weapon/baton = 4,
 		/obj/item/device/flashlight = 4,
 		/obj/item/storage/belt/security/MP = 4,

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

@@ -3,6 +3,8 @@
 	gender = PLURAL
 	icon = 'icons/effects/fingerprints.dmi'
 	icon_state = "prints"
+	alpha = 0
+	mouse_opacity = MOUSE_OPACITY_TRANSPARENT
 	anchored = TRUE
 	unacidable = TRUE
 
@@ -79,6 +81,16 @@
 
 	return information
 
+/// Toggles between the prints being hidden and shown, including in the context menu
+/obj/effect/decal/prints/proc/set_visiblity(visible = FALSE)
+	if(!visible)
+		animate(src, time = 2 SECONDS, alpha = 0)
+		mouse_opacity = MOUSE_OPACITY_TRANSPARENT
+		return
+
+	animate(src, time = 2 SECONDS, alpha = 255)
+	mouse_opacity = MOUSE_OPACITY_OPAQUE
+
 /obj/effect/decal/prints/Destroy()
 	SSclues.prints_list -= src
 

code/game/objects/items/reagent_containers/spray.dm

@@ -245,3 +245,12 @@
 /obj/item/reagent_container/spray/hydro/Initialize()
 	. = ..()
 	reagents.add_reagent("ammonia", src.volume)
+
+/obj/item/reagent_container/spray/investigation
+	name = "forensic spray"
+	desc = /datum/reagent/forensic_spray::description
+
+/obj/item/reagent_container/spray/investigation/Initialize()
+	. = ..()
+
+	reagents.add_reagent(/datum/reagent/forensic_spray::id, volume)

code/modules/reagents/chemistry_reagents/other.dm

@@ -1069,3 +1069,20 @@
 	chemclass = CHEM_CLASS_SPECIAL
 	properties = list(PROPERTY_TRANSFORMATIVE = 4, PROPERTY_NUTRITIOUS = 3, PROPERTY_HEMOGENIC = 1)
 	flags = REAGENT_SCANNABLE
+
+/datum/reagent/forensic_spray
+	name = "Forensic Spray"
+	id = "forensic_spray"
+	description = "A dye-containing spray that binds to the skin oils left behind by fingerprints."
+	reagent_state = LIQUID
+	color = "#79847a"
+	chemclass = CHEM_CLASS_RARE
+
+/datum/reagent/forensic_spray/reaction_obj(obj/reacting_on, volume)
+	if(!istype(reacting_on, /obj/effect/decal/prints))
+		return
+
+	var/obj/effect/decal/prints/reacting_prints = reacting_on
+	reacting_prints.set_visiblity(TRUE)
+
+	addtimer(CALLBACK(reacting_prints, TYPE_PROC_REF(/obj/effect/decal/prints, set_visiblity), FALSE), 1 MINUTES, TIMER_UNIQUE|TIMER_OVERRIDE)