Make blood generation less garbage

code/game/objects/items.dm

@@ -602,19 +602,24 @@ var/list/global/slot_flags_enumeration = list(
 		blood_DNA[M.dna.unique_enzymes] = M.dna.b_type
 	return 1 //we applied blood to the item
 
-
+GLOBAL_LIST_EMPTY(blood_overlays_by_type)
 /obj/item/proc/generate_blood_overlay()
+	// Already got one
 	if(blood_overlay)
 		return
+	
+	// Already cached
+	if(GLOB.blood_overlays_by_type[type])
+		blood_overlay = GLOB.blood_overlays_by_type[type]
+		return
 
-	var/icon/I = new /icon(icon, icon_state)
-	I.Blend(new /icon('icons/effects/blood.dmi', rgb(255,255,255)),ICON_ADD) //fills the icon_state with white (except where it's transparent)
-	I.Blend(new /icon('icons/effects/blood.dmi', "itemblood"),ICON_MULTIPLY) //adds blood and the remaining white areas become transparant
-
-	//not sure if this is worth it. It attaches the blood_overlay to every item of the same type if they don't have one already made.
-	for(var/obj/item/A in world)
-		if(A.type == type && !A.blood_overlay)
-			A.blood_overlay = image(I)
+	// Firsties!
+	var/image/blood = image(icon = 'icons/effects/blood.dmi', icon_state = "itemblood") // Needs to be a new one each time since we're slicing it up with filters.
+	blood.filters += filter(type = "alpha", icon = icon(icon, icon_state)) // Same, this filter is unique for each blood overlay per type
+	GLOB.blood_overlays_by_type[type] = blood
+	
+	// And finally
+	blood_overlay = blood
 
 /obj/item/proc/showoff(mob/user)
 	for (var/mob/M in view(user))