Merge pull request #505 from ArchieBeepBoop/zlevel

Ports Citadel Multi-Z Level fixes

code/modules/mob/dead/observer/observer.dm

@@ -17,6 +17,7 @@ GLOBAL_VAR_INIT(observer_default_invisibility, INVISIBILITY_OBSERVER)
 	see_in_dark = 100
 	invisibility = INVISIBILITY_OBSERVER
 	hud_type = /datum/hud/ghost
+	movement_type = GROUND | FLYING
 	var/can_reenter_corpse
 	var/can_reenter_round = TRUE
 	var/datum/hud/living/carbon/hud = null // hud

code/modules/mob/dead/observer/observer_movement.dm

@@ -0,0 +1,2 @@
+/mob/dead/observer/canZMove(direction, turf/target)
+	return TRUE

code/modules/mob/living/living.dm

@@ -48,6 +48,15 @@
 	var/obj/item/clothing/head/mob_holder/holder = new(get_turf(src), src, (istext(can_be_held) ? can_be_held : ""), 'icons/mob/animals_held.dmi', 'icons/mob/animals_held_lh.dmi', 'icons/mob/animals_held_rh.dmi')
 	return holder
 
+/mob/living/onZImpact(turf/T, levels)
+	if(!isgroundlessturf(T))
+		ZImpactDamage(T, levels)
+	return ..()
+
+/mob/living/proc/ZImpactDamage(turf/T, levels)
+	visible_message("<span class='danger'>[src] crashes into [T] with a sickening noise!</span>")
+	adjustBruteLoss((levels * 5) ** 1.5)
+	Knockdown(levels * 50)
 
 /mob/living/proc/OpenCraftingMenu()
 	return

code/modules/mob/living/living_defines.dm

@@ -117,3 +117,5 @@
 	//List of active diseases
 	var/list/diseases = list() // list of all diseases in a mob
 	var/list/disease_resistances = list()
+
+	var/drag_slowdown = TRUE //Whether the mob is slowed down when dragging another prone mob

code/modules/mob/living/living_movement.dm

@@ -30,3 +30,14 @@
 		add_movespeed_modifier(MOVESPEED_ID_LIVING_TURF_SPEEDMOD, TRUE, 100, override = TRUE, multiplicative_slowdown = T.slowdown)
 	else
 		remove_movespeed_modifier(MOVESPEED_ID_LIVING_TURF_SPEEDMOD)
+
+/mob/living/proc/update_pull_movespeed()
+	if(pulling && isliving(pulling))
+		var/mob/living/L = pulling
+		if(drag_slowdown && L.lying && !L.buckled && grab_state < GRAB_AGGRESSIVE)
+			add_movespeed_modifier(MOVESPEED_ID_PRONE_DRAGGING, multiplicative_slowdown = PULL_PRONE_SLOWDOWN)
+			return
+	remove_movespeed_modifier(MOVESPEED_ID_PRONE_DRAGGING)
+
+/mob/living/canZMove(dir, turf/target)
+	return can_zTravel(target, dir) && (movement_type & FLYING)

code/modules/mob/mob_movement.dm

@@ -372,3 +372,35 @@
 	if(hud_used && hud_used.static_inventory)
 		for(var/obj/screen/mov_intent/selector in hud_used.static_inventory)
 			selector.update_icon(src)
+			
+/mob/verb/up()
+	set name = "Move Upwards"
+	set category = "IC"
+
+	if(zMove(UP, TRUE))
+		to_chat(src, "<span class='notice'>You move upwards.</span>")
+
+/mob/verb/down()
+	set name = "Move Down"
+	set category = "IC"
+
+	if(zMove(DOWN, TRUE))
+		to_chat(src, "<span class='notice'>You move down.</span>")
+
+/mob/proc/zMove(dir, feedback = FALSE)
+	if(dir != UP && dir != DOWN)
+		return FALSE
+	var/turf/target = get_step_multiz(src, dir)
+	if(!target)
+		if(feedback)
+			to_chat(src, "<span class='warning'>There's nothing in that direction!</span>")
+		return FALSE
+	if(!canZMove(dir, target))
+		if(feedback)
+			to_chat(src, "<span class='warning'>You couldn't move there!</span>")
+		return FALSE
+	forceMove(target)
+	return TRUE
+
+/mob/proc/canZMove(direction, turf/target)
+	return FALSE