Makes using BYOND Filters easier.

code/_helpers/visual_filters.dm

@@ -0,0 +1,36 @@
+// These involve BYOND's built in filters that do visual effects, and not stuff that distinguishes between things.
+
+// All of this ported from TG.
+/atom/movable
+	var/list/filter_data // For handling persistent filters
+
+/proc/cmp_filter_data_priority(list/A, list/B)
+	return A["priority"] - B["priority"]
+
+/atom/movable/proc/add_filter(filter_name, priority, list/params)
+	LAZYINITLIST(filter_data)
+	var/list/p = params.Copy()
+	p["priority"] = priority
+	filter_data[filter_name] = p
+	update_filters()
+
+/atom/movable/proc/update_filters()
+	filters = null
+	filter_data = sortTim(filter_data, /proc/cmp_filter_data_priority, TRUE)
+	for(var/f in filter_data)
+		var/list/data = filter_data[f]
+		var/list/arguments = data.Copy()
+		arguments -= "priority"
+		filters += filter(arglist(arguments))
+
+/atom/movable/proc/get_filter(filter_name)
+	if(filter_data && filter_data[filter_name])
+		return filters[filter_data.Find(filter_name)]
+
+// Polaris Extensions
+/atom/movable/proc/remove_filter(filter_name)
+	var/thing = get_filter(filter_name)
+	if(thing)
+		LAZYREMOVE(filter_data, filter_name)
+		filters -= thing
+		update_filters()