Converts the crackable element to mutable appearances, saves 0.15 seconds of init (#73941)

## About The Pull Request

Instead of passing in an icon as a source to the alpha mask filter, we
can stick a mutable appearance in our overlays list with a render target
set, and use that render target to do our masking. Remember to use "*"
to avoid rendering the crack twice

## Why It's Good For The Game

CPU time

code/datums/components/cracked.dm

@@ -1,15 +1,15 @@
 /// Tracks damage to add or remove crack overlays, when none are needed this components is qdeleted
 /datum/component/cracked
 	dupe_mode = COMPONENT_DUPE_UNIQUE_PASSARGS
-	var/list/icon/crack_icons
+	var/list/mutable_appearance/crack_appearances
 	var/crack_integrity
 	var/list/applied_cracks = list()
 
-/datum/component/cracked/Initialize(list/crack_icons, crack_integrity)
+/datum/component/cracked/Initialize(list/crack_appearances, crack_integrity)
 	. = ..()
 	if(!isobj(parent))
 		return COMPONENT_INCOMPATIBLE
-	src.crack_icons = crack_icons
+	src.crack_appearances = crack_appearances
 	src.crack_integrity = crack_integrity
 
 /datum/component/cracked/Destroy(force, silent)
@@ -55,20 +55,24 @@
 	for(var/i in 1 to count)
 		var/rand_x = rand(0, 20) - 10
 		var/rand_y = rand(0, 20) - 10
-		var/icon/new_crack_icon = pick(crack_icons)
-		var/list/new_filter_data = alpha_mask_filter(icon=new_crack_icon, x=rand_x, y=rand_y, flags=MASK_INVERSE)
-		var/name
-		for(var/k in 1 to 100)
-			name = "crack[rand(0, 999)]"
-			if(!applied_cracks[name])
-				break
-		if(applied_cracks[name])
-			CRASH("No unique name could be found after 100 iterations.")
-		applied_cracks[name] = TRUE
-		source.add_filter(name, 1, new_filter_data)
+		var/mutable_appearance/new_crack_overlay = new(pick(crack_appearances))
+		// Now that we have our overlay, we need to give it a unique render source so we can use a filter against it
+		var/static/uuid = 0
+		uuid++
+		// * so it doesn't render on its own
+		new_crack_overlay.render_target = "*cracked_overlay_[uuid]"
+		var/render_source = new_crack_overlay.render_target
+
+		var/list/new_filter_data = alpha_mask_filter(render_source=render_source, x=rand_x, y=rand_y, flags=MASK_INVERSE)
+		applied_cracks[render_source] = new_crack_overlay
+
+		// We need to add it as an overlay so the render target from the filter knows what to point at
+		source.add_overlay(new_crack_overlay)
+		source.add_filter(render_source, 1, new_filter_data)
 
 /datum/component/cracked/proc/RemoveCracks(obj/source, count)
 	for(var/i in 1 to count)
 		var/removed_filter = pick(applied_cracks)
-		applied_cracks -= removed_filter
 		source.remove_filter(removed_filter)
+		source.cut_overlay(applied_cracks[removed_filter])
+		applied_cracks -= removed_filter

code/datums/elements/crackable.dm

@@ -2,7 +2,7 @@
 /datum/element/crackable
 	element_flags = ELEMENT_BESPOKE
 	argument_hash_start_idx = 2
-	var/list/icon/crack_icons
+	var/list/mutable_appearance/crack_appearances
 	/// The level at which the object starts showing cracks, 1 being at full health and 0.5 being at half health
 	var/crack_integrity = 1
 
@@ -11,17 +11,17 @@
 	if(!isobj(target))
 		return ELEMENT_INCOMPATIBLE
 	src.crack_integrity = crack_integrity || src.crack_integrity
-	if(!crack_icons) // This is the first attachment and we need to do first time setup
-		crack_icons = list()
+	if(!crack_appearances) // This is the first attachment and we need to do first time setup
+		crack_appearances = list()
 		for(var/state in crack_states)
-			for(var/i in 1 to 36)
-				var/icon/new_crack_icon = icon(crack_icon, state)
-				new_crack_icon.Turn(i * 10)
-				crack_icons += new_crack_icon
+			for(var/i in 1 to 35)
+				var/mutable_appearance/crack = mutable_appearance(crack_icon, state)
+				crack.transform.Turn(i * 10)
+				crack_appearances += crack
 	RegisterSignal(target, COMSIG_ATOM_INTEGRITY_CHANGED, PROC_REF(IntegrityChanged))
 
 /datum/element/crackable/proc/IntegrityChanged(obj/source, old_value, new_value)
 	SIGNAL_HANDLER
 	if(new_value >= source.max_integrity * crack_integrity)
 		return
-	source.AddComponent(/datum/component/cracked, crack_icons, crack_integrity)
+	source.AddComponent(/datum/component/cracked, crack_appearances, crack_integrity)