Proximity sensing refactor (#425)

code/game/objects/effects/effects.dm

@@ -23,6 +23,12 @@
 /obj/effect/blob_act()
 	return
 
+/obj/effect/attack_hulk(mob/living/carbon/human/user, does_attack_animation = 0)
+	return 0
+
+/obj/effect/experience_pressure_difference()
+	return
+
 /obj/effect/ex_act(severity, target)
 	if(target == src)
 		qdel(src)
@@ -37,12 +43,15 @@
 				if(prob(25))
 					qdel(src)
 
-/obj/effect/attack_hulk(mob/living/carbon/human/user, does_attack_animation = 0)
-	return 0
-
-/obj/effect/experience_pressure_difference()
-	return
-
 /obj/effect/singularity_act()
 	qdel(src)
-	return 0
+	return 0
+
+/obj/effect/abstract/ex_act(severity, target)
+	return
+
+/obj/effect/abstract/singularity_pull()
+	return
+
+/obj/effect/abstract/singularity_act()
+	return

code/game/objects/effects/proximity.dm

@@ -0,0 +1,97 @@
+/datum/proximity_monitor
+	var/atom/host	//the atom we are tracking
+	var/atom/last_host_loc
+	var/list/checkers //list of /obj/effect/abstract/proximity_checkers
+	var/current_range
+	var/ignore_if_not_on_turf	//don't check turfs in range if the host's loc isn't a turf
+
+/datum/proximity_monitor/New(atom/_host, range, _ignore_if_not_on_turf = TRUE)
+	host = _host
+	last_host_loc = _host.loc
+	ignore_if_not_on_turf = _ignore_if_not_on_turf
+	SetRange(range)
+
+/datum/proximity_monitor/Destroy()
+	host = null
+	QDEL_LIST(checkers)
+	return ..()
+
+/datum/proximity_monitor/proc/HandleMove()
+	var/atom/_host = host
+	var/atom/new_host_loc = _host.loc
+	if(last_host_loc != new_host_loc)
+		last_host_loc = new_host_loc	//hopefully this won't cause GC issues with containers
+		var/curr_range = current_range
+		SetRange(curr_range, TRUE)
+		if(curr_range)
+			testing("HasProx: [host] -> [host]")
+			_host.HasProximity(host)	//if we are processing, we're guaranteed to be a movable
+
+/datum/proximity_monitor/proc/SetRange(range, force_rebuild = FALSE)
+	if(!force_rebuild && range == current_range)
+		return FALSE
+	. = TRUE
+	
+	current_range = range
+
+	var/list/old_checkers = checkers
+	var/old_checkers_len = LAZYLEN(old_checkers)
+
+	var/atom/host_loc = host.loc
+
+	var/atom/loc_to_use = ignore_if_not_on_turf ? host_loc : get_turf(host)
+	if(!isturf(loc_to_use))	//only check the host's loc
+		if(range)
+			var/obj/effect/abstract/proximity_checker/pc
+			if(old_checkers_len)
+				pc = old_checkers[old_checkers_len]
+				--old_checkers.len
+			else
+				pc = new(host_loc, src)
+
+			checkers = list(pc)	//only check the host's loc
+		return
+
+	var/list/turfs = RANGE_TURFS(range, loc_to_use)
+	var/old_checkers_used = min(turfs.len, old_checkers_len)
+
+	//reuse what we can
+	for(var/I in 1 to old_checkers_len)
+		if(I <= old_checkers_used)
+			var/obj/effect/abstract/proximity_checker/pc = old_checkers[I]
+			pc.loc = turfs[I]
+		else
+			qdel(old_checkers[I])	//delete the leftovers
+
+	LAZYCLEARLIST(old_checkers)
+
+	//create what we lack
+	var/list/checkers_local = list()
+	for(var/I in (old_checkers_used + 1) to turfs.len)
+		checkers_local += new /obj/effect/abstract/proximity_checker(turfs[I], src)
+	
+	checkers = checkers_local
+
+/obj/effect/abstract/proximity_checker
+	var/datum/proximity_monitor/monitor
+
+/obj/effect/abstract/proximity_checker/Initialize(mapload, datum/proximity_monitor/_monitor)
+	. = ..()
+	if(_monitor)
+		monitor = _monitor
+	else
+		stack_trace("proximity_checker created without proximity_monitor")
+		qdel(src)
+
+/obj/effect/abstract/proximity_checker/Destroy()
+	monitor = null
+	return ..()
+
+/obj/effect/abstract/proximity_checker/Crossed(atom/movable/AM)
+	set waitfor = FALSE
+	var/datum/proximity_monitor/M = monitor
+	if(!M.current_range)
+		return
+	var/atom/H = M.host
+	testing("HasProx: [H] -> [AM]")
+	H.HasProximity(AM)

code/game/objects/structures/aliens.dm

@@ -227,7 +227,6 @@
 	layer = MOB_LAYER
 	var/obj/item/clothing/mask/facehugger/child
 
-
 /obj/structure/alien/egg/Initialize(mapload)
 	..()
 	update_icon()
@@ -235,15 +234,10 @@
 		child = new(src)
 	if(status == GROWING)
 		addtimer(CALLBACK(src, .proc/Grow), rand(MIN_GROWTH_TIME, MAX_GROWTH_TIME))
-	if(status == GROWN)
-		add_to_proximity_list(src, 1)
+	proximity_monitor = new(src, status == GROWN ? 1 : 0)
 	if(status == BURST)
 		obj_integrity = integrity_failure
 
-/obj/structure/alien/egg/Destroy()
-	remove_from_proximity_list(src, 1)
-	. = ..()
-
 /obj/structure/alien/egg/update_icon()
 	..()
 	switch(status)
@@ -283,12 +277,12 @@
 /obj/structure/alien/egg/proc/Grow()
 	status = GROWN
 	update_icon()
-	add_to_proximity_list(src, 1)
+	proximity_monitor.SetRange(1)
 
 //drops and kills the hugger if any is remaining
 /obj/structure/alien/egg/proc/Burst(kill = TRUE)
 	if(status == GROWN || status == GROWING)
-		remove_from_proximity_list(src, 1)
+		proximity_monitor.SetRange(0)
 		status = BURST
 		update_icon()
 		flick("egg_opening", src)
@@ -307,12 +301,6 @@
 						child.Attach(M)
 						break
 
-/obj/structure/alien/egg/Moved(oldloc)
-	remove_from_proximity_list(oldloc, 1)
-	if(status == GROWN)
-		add_to_proximity_list(src, 1)
-	return ..()
-
 /obj/structure/alien/egg/obj_break(damage_flag)
 	if(!(flags & NODECONSTRUCT))
 		if(status != BURST)