U_I Phase 2.7: Helmet lights, washing blood more

code/modules/clothing/clothing.dm

@@ -393,17 +393,17 @@
 	if(on)
 		// Generate object icon.
 		if(!light_overlay_cache["[light_overlay]_icon"])
-			light_overlay_cache["[light_overlay]_icon"] = image("icon" = 'icons/obj/light_overlays.dmi', "icon_state" = "[light_overlay]")
+			light_overlay_cache["[light_overlay]_icon"] = image(icon = 'icons/obj/light_overlays.dmi', icon_state = "[light_overlay]")
 		helmet_light = light_overlay_cache["[light_overlay]_icon"]
 		add_overlay(helmet_light)
 
 		// Generate and cache the on-mob icon, which is used in update_inv_head().
-		var/cache_key = "[light_overlay][H ? "_[H.species.get_bodytype(H)]" : ""]"
+		var/body_type = (H && H.species.get_bodytype(H))
+		var/cache_key = "[light_overlay][body_type && sprite_sheets[body_type] ? "_[body_type]" : ""]"
 		if(!light_overlay_cache[cache_key])
-			var/use_icon = 'icons/mob/light_overlays.dmi'
-			if(H && sprite_sheets[H.species.get_bodytype(H)])
-				use_icon = sprite_sheets[H.species.get_bodytype(H)]
-			light_overlay_cache[cache_key] = image("icon" = use_icon, "icon_state" = "[light_overlay]")
+			var/use_icon = LAZYACCESS(sprite_sheets,body_type) || 'icons/mob/light_overlays.dmi'
+			light_overlay_cache[cache_key] = image(icon = use_icon, icon_state = "[light_overlay]")
+	
 	else if(helmet_light)
 		cut_overlay(helmet_light)
 		helmet_light = null

code/modules/clothing/clothing_icons.dm

@@ -19,8 +19,8 @@
 //HELMET: May have a lighting overlay
 /obj/item/clothing/head/make_worn_icon(var/body_type,var/slot_name,var/inhands,var/default_icon,var/default_layer = 0)
 	var/image/standing = ..()
-	if(on)
-		var/cache_key = "[light_overlay]_[body_type]"
+	if(on && slot_name == slot_head_str)
+		var/cache_key = "[light_overlay][LAZYACCESS(sprite_sheets,body_type) ? "_[body_type]" : ""]"
 		if(standing && light_overlay_cache[cache_key])
 			standing.add_overlay(light_overlay_cache[cache_key])
 	return standing

code/modules/clothing/spacesuits/rig/rig.dm

@@ -339,7 +339,6 @@
 			piece.item_flags &= ~(STOPPRESSUREDAMAGE|AIRTIGHT)
 		else
 			piece.item_flags |=  (STOPPRESSUREDAMAGE|AIRTIGHT)
-	update_icon(1)
 
 /obj/item/weapon/rig/ui_action_click()
 	toggle_cooling(usr)

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

@@ -1018,30 +1018,27 @@
 
 /mob/living/carbon/human/clean_blood(var/washshoes)
 	. = ..()
+
 	gunshot_residue = null
+
 	//Always do hands (or whatever's on our hands)
 	if(gloves)
-		if(gloves.clean_blood())
-			update_inv_gloves()
-			. = 1
+		gloves.clean_blood()
+		update_inv_gloves()
 		gloves.germ_level = 0
 	else
-		if(bloody_hands)
-			. = 1
-			bloody_hands = 0
+		bloody_hands = 0
 		germ_level = 0
 	
-	//Sometimes do shoes if asked
+	//Sometimes do shoes if asked (or feet if no shoes)
 	if(washshoes && shoes)
-		if(shoes.clean_blood())
-			update_inv_shoes()
-			. = 1
+		shoes.clean_blood()
+		update_inv_shoes()
 		shoes.germ_level = 0
 	else if(washshoes && (feet_blood_color || LAZYLEN(feet_blood_DNA)))
-		feet_blood_color = null
 		LAZYCLEARLIST(feet_blood_DNA)
 		feet_blood_DNA = null
-		. = 1
+		feet_blood_color = null
 	
 	update_bloodied()
 

code/modules/mob/living/carbon/human/update_icons.dm

@@ -7,7 +7,44 @@ var/global/list/tail_icon_cache = list() //key is [species.race_key][r_skin][g_s
 var/global/list/light_overlay_cache = list() //see make_worn_icon() on helmets
 var/global/list/damage_icon_parts = list() //see UpdateDamageIcon()
 
-//Add an entry to overlays, assuming it existsup
+////////////////////////////////////////////////////////////////////////////////////////////////
+// # Human Icon Updating System
+//
+// This system takes care of the "icon" for human mobs.  Of course humans don't just have a single 
+// icon+icon_state, but a combination of dozens of little sprites including including the body, 
+// clothing, equipment, in-universe HUD images, etc.
+// 
+// # Basic Operation
+// Whenever you do something that should update the on-mob appearance of a worn or held item, You
+// will need to call the relevant update_inv_* proc. All of these are named after the variable they
+// update from. They are defined at the /mob level so you don't even need to cast to carbon/human.
+//
+// The new system leverages SSoverlays to actually add/remove the overlays from mob.overlays
+// Since SSoverlays already manages batching updates to reduce apperance churn etc, we don't need
+// to worry about that.  (In short, you can call add/cut overlay as many times as you want, it will
+// only get assigned to the mob once per tick.)
+// As a corrolary, this means users of this system do NOT need to tell the system when you're done
+// making changes.
+// 
+// There are also these special cases:
+//  update_icons_body()	//Handles updating your mob's icon to reflect their gender/race/complexion etc
+//  UpdateDamageIcon()	//Handles damage overlays for brute/burn damage //(will rename this when I geta round to it) ~Carn
+//  update_skin()		//Handles updating skin for species that have a skin overlay.
+//  update_bloodied()	//Handles adding/clearing the blood overlays for hands & feet.  Call when bloodied or cleaned.
+//  update_underwear()	//Handles updating the sprite for underwear.
+//  update_hair()		//Handles updating your hair and eyes overlay 
+//  update_mutations()	//Handles updating your appearance for certain mutations.  e.g TK head-glows
+//  update_fire()		//Handles overlay from being on fire.
+//  update_water()		//Handles overlay from being submerged.
+//  update_surgery()	//Handles overlays from open external organs.
+//
+// # History (i.e. I'm used to the old way, what is different?)
+// You used to have to call update_icons(FALSE) if you planned to make more changes, and call update_icons(TRUE)
+// on the final update.  All that is gone, just call update_inv_whatever() and it handles the rest.
+//
+////////////////////////////////////////////////////////////////////////////////////////////////
+
+//Add an entry to overlays, assuming it exists
 /mob/living/carbon/human/proc/apply_layer(cache_index)
 	if((. = overlays_standing[cache_index]))
 		add_overlay(.)