cosmetic parts addition

hyperstation/code/modules/mob/dead/new_player/cosmetic_parts.dm

@@ -0,0 +1,29 @@
+/*
+COSMETIC PARTS
+
+this system allows you to change the _base_ appearance of a limb independent
+of species or markings. this, for example, allows us to create "hybrids" like a
+mammal with avian legs.
+
+keep in mind that this does not change the species of a leg! in the above example,
+the mammal's bird-legs are still mammal legs. this matters in some places, like
+body part transplants; mis-matched species will cause extra damage if the surgery
+fails and the part is rejected. so you can't attach mammal-bird legs to avians
+safely.
+*/
+
+/datum/cosmetic_part
+	var/name
+	var/icon = 'hyperstation/icons/mob/char_parts.dmi'
+	var/icon_state
+	var/support_digitigrade = TRUE
+
+/datum/cosmetic_part/head
+/datum/cosmetic_part/chest
+/datum/cosmetic_part/arms
+/datum/cosmetic_part/legs
+
+/datum/cosmetic_part/legs/avian
+	name = "avian"
+	icon = 'modular_citadel/icons/mob/mutant_bodyparts.dmi'
+	icon_state = "avian"

hyperstation/code/modules/mob/living/carbon/human/cosmetic_part_handler.dm

@@ -0,0 +1,18 @@
+/obj/item/bodypart/proc/apply_cosmetic(datum/cosmetic_part/part)
+	if(!is_organic_limb() || animal_origin || !part)
+		return
+	cosmetic_icon = part.icon_state
+	icon = part.icon
+
+/mob/living/carbon/human/proc/handle_cosmetic_parts()
+	var/features = src.dna.features
+	var/list/body_zones = list(BODY_ZONE_HEAD, BODY_ZONE_CHEST, BODY_ZONE_L_ARM, BODY_ZONE_R_ARM, BODY_ZONE_L_LEG, BODY_ZONE_R_LEG)
+	for(var/I in body_zones)
+		var/zone = body_zones[I]
+		var/cosmetic_pref = features["cosmetic_" + zone]
+		if(!istype(cosmetic_pref, /datum/cosmetic_part))
+			continue
+		var/datum/cosmetic_part/part = cosmetic_pref
+		var/obj/item/bodypart/body_part = get_bodypart(zone)
+		if(body_part && part)
+			body_part.apply_cosmetic(part)