Fixes SaturnX (#69765)

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

@@ -401,6 +401,8 @@
 	. += "-[body_zone]"
 	if(should_draw_greyscale && draw_color)
 		. += "-[draw_color]"
+	if(is_invisible)
+		. += "-invisible"
 	for(var/obj/item/organ/external/external_organ as anything in external_organs)
 		if(!external_organ.can_draw_on_bodypart(owner))
 			continue

code/modules/reagents/chemistry/reagents/drug_reagents.dm

@@ -674,13 +674,14 @@
 		animate(size = 0, time = 6 SECONDS, easing = CIRCULAR_EASING|EASE_IN)
 
 ///This proc turns the living mob passed as the arg "invisible_man"s invisible by giving him the invisible man trait and updating his body, this changes the sprite of all his organic limbs to a 1 alpha version.
-/datum/reagent/drug/saturnx/proc/turn_man_invisible(mob/living/carbon/invisible_man)
-	if(!invisible_man.getorganslot(ORGAN_SLOT_LIVER))
-		return
-	if(invisible_man.undergoing_liver_failure())
-		return
-	if(HAS_TRAIT(invisible_man, TRAIT_NOMETABOLISM))
-		return
+/datum/reagent/drug/saturnx/proc/turn_man_invisible(mob/living/carbon/invisible_man, requires_liver = TRUE)
+	if(requires_liver)
+		if(!invisible_man.getorganslot(ORGAN_SLOT_LIVER))
+			return
+		if(invisible_man.undergoing_liver_failure())
+			return
+		if(HAS_TRAIT(invisible_man, TRAIT_NOMETABOLISM))
+			return
 	if(invisible_man.has_status_effect(/datum/status_effect/grouped/stasis))
 		return
 
@@ -695,7 +696,7 @@
 	invisible_man.remove_from_all_data_huds()
 	invisible_man.sound_environment_override = SOUND_ENVIROMENT_PHASED
 
-/datum/reagent/drug/saturnx/on_mob_end_metabolize(mob/living/invisible_man)
+/datum/reagent/drug/saturnx/on_mob_end_metabolize(mob/living/carbon/invisible_man)
 	. = ..()
 	if(HAS_TRAIT(invisible_man, TRAIT_INVISIBLE_MAN))
 		invisible_man.add_to_all_human_data_huds() //Is this safe, what do you think, Floyd?

code/modules/surgery/bodyparts/_bodyparts.dm

@@ -12,6 +12,8 @@
 	VAR_PROTECTED/icon_static = 'icons/mob/species/human/bodyparts.dmi'
 	///The icon for husked limbs
 	VAR_PROTECTED/icon_husk = 'icons/mob/species/human/bodyparts.dmi'
+	///The icon for invisible limbs
+	VAR_PROTECTED/icon_invisible = 'icons/mob/species/human/bodyparts.dmi'
 	///The type of husk for building an iconstate
 	var/husk_type = "humanoid"
 	layer = BELOW_MOB_LAYER //so it isn't hidden behind objects when on the floor
@@ -25,7 +27,10 @@
 	///Defines when a bodypart should not be changed. Example: BP_BLOCK_CHANGE_SPECIES prevents the limb from being overwritten on species gain
 	var/change_exempt_flags
 
+	///Whether the bodypart (and the owner) is husked.
 	var/is_husked = FALSE
+	///Whether the bodypart (and the owner) is invisible through invisibleman trait.
+	var/is_invisible = FALSE
 	///The ID of a species used to generate the icon. Needs to match the icon_state portion in the limbs file!
 	var/limb_id = SPECIES_HUMAN
 	//Defines what sprite the limb should use if it is also sexually dimorphic.
@@ -624,12 +629,17 @@
 /obj/item/bodypart/proc/update_limb(dropping_limb = FALSE, is_creating = FALSE)
 	SHOULD_CALL_PARENT(TRUE)
 
-	if(HAS_TRAIT(owner, TRAIT_HUSK) && IS_ORGANIC_LIMB(src))
-		dmg_overlay_type = "" //no damage overlay shown when husked
-		is_husked = TRUE
-	else
-		dmg_overlay_type = initial(dmg_overlay_type)
-		is_husked = FALSE
+	if(IS_ORGANIC_LIMB(src))
+		if(HAS_TRAIT(owner, TRAIT_HUSK))
+			dmg_overlay_type = "" //no damage overlay shown when husked
+			is_husked = TRUE
+		else if(HAS_TRAIT(owner, TRAIT_INVISIBLE_MAN))
+			dmg_overlay_type = "" //no damage overlay shown when invisible since the wounds themselves are invisible.
+			is_invisible = TRUE
+		else
+			dmg_overlay_type = initial(dmg_overlay_type)
+			is_husked = FALSE
+			is_invisible = FALSE
 
 	if(!dropping_limb && owner.dna?.check_mutation(/datum/mutation/human/hulk))
 		mutation_color = "#00aa00"
@@ -723,7 +733,7 @@
 				limb.icon = 'icons/mob/species/monkey/bodyparts.dmi'
 			else
 				limb.icon = 'icons/mob/species/alien/bodyparts.dmi'
-			
+
 			if(limb_id == "husk")
 				limb.icon_state = "[animal_origin]_husk_[body_zone]"
 			else
@@ -750,6 +760,12 @@
 			. += aux
 		return .
 	//END HUSK SHIIIIT
+	//invisibility
+	if(is_invisible)
+		limb.icon = icon_invisible
+		limb.icon_state = "invisible_[body_zone]"
+		. += limb
+		return .
 
 	////This is the MEAT of limb icon code
 	limb.icon = icon_greyscale

code/modules/surgery/bodyparts/hair.dm

@@ -25,6 +25,7 @@
 		if(mask.flags_inv & HIDEFACIALHAIR)
 			facial_hair_hidden = TRUE
 	///FACIAL HAIR CHECKS END
+
 	///HAIR CHECKS START
 	hair_hidden = FALSE
 	if(human_head_owner.head)
@@ -42,6 +43,10 @@
 		if(mask.flags_inv & HIDEHAIR)
 			hair_hidden = TRUE
 	///HAIR CHECKS END
+	//invisibility stuff
+	if(HAS_TRAIT(human_head_owner, TRAIT_INVISIBLE_MAN))
+		hair_hidden = TRUE
+		facial_hair_hidden = TRUE
 
 	if(!hair_hidden && !owner.getorganslot(ORGAN_SLOT_BRAIN) && !(NOBLOOD in species_flags_list))
 		show_debrained = TRUE

code/modules/unit_tests/_unit_tests.dm

@@ -143,6 +143,7 @@
 #include "screenshot_antag_icons.dm"
 #include "screenshot_basic.dm"
 #include "screenshot_humanoids.dm"
+#include "screenshot_saturnx.dm"
 #include "security_officer_distribution.dm"
 #include "security_levels.dm"
 #include "serving_tray.dm"

code/modules/unit_tests/screenshot_saturnx.dm

@@ -0,0 +1,23 @@
+/// A screenshot test for making sure invisible limbs function, keeping them clothed so we know they're there.
+/datum/unit_test/screenshot_saturnx
+
+/datum/unit_test/screenshot_saturnx/Run()
+	var/mob/living/carbon/human/human = allocate(/mob/living/carbon/human/dummy/consistent) //we don't use a dummy as they have no organs
+	human.equipOutfit(/datum/outfit/job/assistant/consistent, visualsOnly = TRUE)
+
+	var/datum/reagent/drug/saturnx/saturnx_reagent = new()
+
+	saturnx_reagent.expose_atom(human, 15)
+	saturnx_reagent.turn_man_invisible(human, requires_liver = FALSE) //immediately turn us invisible
+
+	test_screenshot("invisibility", get_flat_icon_for_all_directions(human))
+
+/datum/unit_test/screenshot_saturnx/proc/get_flat_icon_for_all_directions(atom/thing)
+	var/icon/output = icon('icons/effects/effects.dmi', "nothing")
+	COMPILE_OVERLAYS(thing)
+
+	for (var/direction in GLOB.cardinals)
+		var/icon/partial = getFlatIcon(thing, defdir = direction)
+		output.Insert(partial, dir = direction)
+
+	return output