More interactions for small mobs (#6764)

Small mobs such as rats can now bite cables.
Small mobs that can ventcrawl now interact with atmospheric machines that contain pumps
Small mobs can no longer block airlocks by standing in them.

code/modules/ventcrawl/ventcrawl_atmospherics.dm

@@ -23,6 +23,78 @@
 		L.ventcrawl_layer = layer
 	. = ..()
 
+/obj/machinery/atmospherics/binary/pump/Entered(atom/movable/AM)
+	. = ..()
+	Blend(AM, network2)
+
+/obj/machinery/atmospherics/unary/vent_scrubber/Entered(atom/movable/AM)
+	. = ..()
+	Blend(AM, null)
+
+/obj/machinery/atmospherics/unary/outlet_injector/Entered(atom/movable/AM)
+	. = ..()
+	Blend(AM, null)
+
+//Blends a mob AM and outputs the contents via vents in pipe_network N
+//  If the network is not set, creates a local cloud
+/obj/machinery/atmospherics/proc/Blend(atom/movable/AM, var/datum/pipe_network/N)
+	//If its not small or the device isnt enabled, it wont blend
+	if(!issmall(AM) || !use_power)
+		return FALSE
+	
+	//Get the things we need to create the "output"
+	var/mob/living/L = AM
+
+	var/blood_color = "#A10808"
+	if(L.blood_color)
+		blood_color = L.blood_color
+	
+	if(iscarbon(AM))
+		var/mob/living/carbon/C = AM
+		blood_color = C.species.blood_color
+
+	var/reagent_amount = L.mob_size * 2
+
+	//Blend the Mob
+	to_chat(AM, span("danger","\The [src] blends you to a fine dust."))
+	L.death()
+	qdel(L)	
+
+	//Output what´s left through the connected vents
+	if(N)
+		var/count = 0
+		for(var/V in N.normal_members)
+			CHECK_TICK
+			if(count > reagent_amount)
+				return TRUE
+			var/obj/machinery/atmospherics/unary/vent_pump/vent = V
+			if(istype(V, /obj/machinery/atmospherics/unary/vent_pump) && vent.loc && !vent.is_welded())
+				var/datum/reagents/R = new/datum/reagents(reagent_amount)
+				R.my_atom = vent
+				R.add_reagent("blood", reagent_amount, list("blood_colour" = blood_color))
+
+				var/datum/effect/effect/system/smoke_spread/chem/smoke = new
+				smoke.show_log = 0 // This displays a log on creation
+				smoke.show_touch_log = 1 // This displays a log when a player is chemically affected
+				smoke.set_up(R, 3, 0, vent, 20)
+				playsound(vent.loc, 'sound/effects/smoke.ogg', 50, 1, -3)
+				smoke.start()
+				qdel(R)
+				count++
+	else
+		var/datum/reagents/R = new/datum/reagents(reagent_amount)
+		R.my_atom = src
+		R.add_reagent("blood", reagent_amount, list("blood_colour" = blood_color))
+
+		var/datum/effect/effect/system/smoke_spread/chem/smoke = new
+		smoke.show_log = 0 // This displays a log on creation
+		smoke.show_touch_log = 1 // This displays a log when a player is chemically affected
+		smoke.set_up(R, 3, 0, src, 20)
+		playsound(src.loc, 'sound/effects/smoke.ogg', 50, 1, -3)
+		smoke.start()
+		qdel(R)
+		return TRUE
+
 /obj/machinery/atmospherics/relaymove(mob/living/user, direction)
 	if(user.loc != src || !(direction & initialize_directions)) //can't go in a way we aren't connecting to
 		return
@@ -44,6 +116,8 @@
 				user.remove_ventcrawl()
 				user.add_ventcrawl(target_move)
 			user.forceMove(target_move)
+			if(!user || !user.client)
+				return
 			user.client.eye = target_move //if we don't do this, Byond only updates the eye every tick - required for smooth movement
 			if(world.time > user.next_play_vent)
 				user.next_play_vent = world.time+30
@@ -115,4 +189,4 @@ obj/machinery/atmospherics/trinary/isConnectable(var/obj/machinery/atmospherics/
 	if(!do_after(L, 100, needhand = 0, act_target = get_turf(src)) || !can_z_crawl(L, direction))
 		to_chat(L, span("danger", "You gave up on climbing [travel_direction_name] the pipe."))
 		return FALSE
-	return ventcrawl_to(L, node2, null)
+	return ventcrawl_to(L, node2, null)