More complicated but hopefully better target acquisition (#34)

code/__DEFINES/xeno_ai.dm

@@ -15,10 +15,6 @@
 #define WALL_PENALTY 50
 #define FIRE_PENALTY 25
 
-// Xeno AI flags
-#define XENO_AI_NO_DESPAWN (1<<0)
-#define XENO_AI_CHOOSE_RANDOM_STRAIN (1<<1)
-
 /*
 PROBABILITY CALCULATIONS ARE HERE
 */
@@ -86,41 +82,6 @@ PROBABILITY CALCULATIONS ARE HERE
 #define PRAETORIAN_SPIT 80
 #define PRAETORIAN_SPRAY 80
 
-/*
-	GAME DIRECTOR AI
-*/
-
-/datum/config_entry/number/ai_director
-	abstract_type = /datum/config_entry/number/ai_director
-
-#define IDEAL_T2_PERCENT 0.5
-#define IDEAL_T3_PERCENT 0.25
-
-/// The maximum amount of xenomorphs that can spawn, scaled up by population.
-/datum/config_entry/number/ai_director/max_xeno_per_player
-	config_entry_value = 1
-
-// Xenos spawn
-/datum/config_entry/number/ai_director/t2_spawn_at_percentage
-	config_entry_value = 0.25
-
-/datum/config_entry/number/ai_director/t3_spawn_at_percentage
-	config_entry_value = 0.5
-
-/// The minimum range at which a xeno can be spawned from a human
-#define MIN_RANGE_TO_SPAWN_XENO 10
-/// The maximum range at which a xeno can be spawned from a human
-#define MAX_RANGE_TO_SPAWN_XENO 25
-
-/// When a xeno gets despawned if there is no human within a specific range.
-#define RANGE_TO_DESPAWN_XENO 25
-/// When a xeno gets despawned if they can't find a target within a specific amount of time.
-#define XENO_DESPAWN_NO_TARGET_PERIOD 200 SECONDS
-
-// Director flags
-#define XENO_SPAWN_T1 (1<<0)
-#define XENO_SPAWN_T2 (1<<1)
-#define XENO_SPAWN_T3 (1<<2)
 
 /// Special blockers for pathfinding or obstacle handling
 #define XENO_AI_SPECIAL_BLOCKERS list(/obj/flamer_fire, /obj/vehicle/multitile)

code/_globalvars/lists/object_lists.dm

@@ -28,7 +28,7 @@ GLOBAL_LIST_EMPTY_TYPED(hijack_deletable_windows, /obj/structure/machinery/door/
 GLOBAL_LIST_EMPTY_TYPED(hijack_bustable_ladders, /obj/structure/ladder/fragile_almayer)
 
 GLOBAL_LIST_EMPTY_TYPED(all_multi_vehicles, /obj/vehicle/multitile)
-GLOBAL_LIST_EMPTY_TYPED(all_defenses, /obj/structure/machinery/defenses)
+GLOBAL_LIST_EMPTY_TYPED(all_active_defenses, /obj/structure/machinery/defenses)
 
 GLOBAL_LIST_EMPTY_TYPED(lifeboat_almayer_docks, /obj/docking_port/stationary/lifeboat_dock)
 GLOBAL_LIST_EMPTY_TYPED(lifeboat_doors, /obj/structure/machinery/door/airlock/multi_tile/almayer/dropshiprear/lifeboat/blastdoor)

code/modules/defenses/defenses.dm

@@ -101,14 +101,14 @@
 	power_on_action()
 	update_icon()
 
-	GLOB.all_defenses += src
+	GLOB.all_active_defenses += src
 
 /obj/structure/machinery/defenses/proc/power_off()
 	turned_on = FALSE
 	power_off_action()
 	update_icon()
 
-	GLOB.all_defenses -= src
+	GLOB.all_active_defenses -= src
 
 /**
  * Update state category for this structure.
@@ -472,7 +472,7 @@
 	return
 
 /obj/structure/machinery/defenses/Destroy()
-	GLOB.all_defenses -= src
+	GLOB.all_active_defenses -= src
 
 	if(owner_mob)
 		owner_mob = null

code/modules/mob/living/carbon/xenomorph/ai/xeno_ai.dm

@@ -1,6 +1,5 @@
 /mob/living/carbon/xenomorph
 	// AI stuff
-	var/flags_ai = XENO_AI_NO_DESPAWN
 	var/atom/movable/current_target
 
 	var/next_path_generation = 0
@@ -206,61 +205,103 @@ GLOBAL_LIST_INIT(ai_target_limbs, list(
 
 	return TRUE
 
+#define EXTRA_CHECK_DISTANCE_MULTIPLIER 0.20
+
 /mob/living/carbon/xenomorph/proc/get_target(range)
-	var/list/viable_humans = list()
-	var/list/viable_vehicles = list()
-	var/list/viable_defenses = list()
+	var/list/viable_targets = list()
+	var/atom/movable/closest_target
 	var/smallest_distance = INFINITY
-	for(var/mob/living/carbon/human/alive_human as anything in GLOB.alive_human_list)
-		if(alive_human.species.flags & IS_SYNTHETIC)
+	for(var/mob/living/carbon/human/potential_alive_human_target as anything in GLOB.alive_human_list)
+		if(z != potential_alive_human_target.z)
 			continue
 
-		if(z != alive_human.z)
+		if(!check_mob_target(potential_alive_human_target))
 			continue
 
-		if(FACTION_XENOMORPH in alive_human.faction_group)
+		var/distance = get_dist(src, potential_alive_human_target)
+
+		if(distance > ai_range)
 			continue
 
-		var/distance = get_dist(src, alive_human)
+		viable_targets += potential_alive_human_target
+
+		if(smallest_distance <= distance)
+			continue
 
-		if(distance < ai_range && alive_human.stat == CONSCIOUS)
-			viable_humans += alive_human
-		smallest_distance = min(distance, smallest_distance)
+		closest_target = potential_alive_human_target
+		smallest_distance = distance
 
-	for(var/l in GLOB.all_multi_vehicles)
-		var/obj/vehicle/multitile/V = l
-		if(z != V.z)
+	for(var/obj/vehicle/multitile/potential_vehicle_target as anything in GLOB.all_multi_vehicles)
+		if(z != potential_vehicle_target.z)
 			continue
-		var/distance = get_dist(src, V)
 
-		if(distance < ai_range)
-			viable_vehicles += V
-		smallest_distance = min(distance, smallest_distance)
+		var/distance = get_dist(src, potential_vehicle_target)
 
-	for(var/l in GLOB.all_defenses)
-		var/obj/structure/machinery/defenses/S = l
-		if(z != S.z)
+		if(distance > ai_range)
 			continue
-		var/distance = get_dist(src, S)
 
-		if(distance < ai_range)
-			viable_defenses += S
-		smallest_distance = min(distance, smallest_distance)
+		if(potential_vehicle_target.health <= 0)
+			var/skip_vehicle = TRUE
 
+			var/list/interior_living_mobs = potential_vehicle_target.interior.get_passengers()
+			for(var/mob/living/carbon/human/human_mob in interior_living_mobs)
+				if(!check_mob_target(human_mob))
+					continue
 
-	if(smallest_distance > RANGE_TO_DESPAWN_XENO && !(XENO_AI_NO_DESPAWN & flags_ai))
-		remove_ai()
-		qdel(src)
-		return
+				skip_vehicle = FALSE
+
+			if(skip_vehicle)
+				continue
+
+		viable_targets += potential_vehicle_target
+
+		if(smallest_distance <= distance)
+			continue
+
+		closest_target = potential_vehicle_target
+		smallest_distance = distance
+
+	for(var/obj/structure/machinery/defenses/potential_defense_target as anything in GLOB.all_active_defenses)
+		if(z != potential_defense_target.z)
+			continue
+
+		var/distance = get_dist(src, potential_defense_target)
+
+		if(distance > ai_range)
+			continue
 
-	if(length(viable_humans))
-		return pick(viable_humans)
+		viable_targets += potential_defense_target
 
-	if(length(viable_vehicles))
-		return pick(viable_vehicles)
+		if(smallest_distance <= distance)
+			continue
+
+		closest_target = potential_defense_target
+		smallest_distance = distance
+
+	var/extra_check_distance = round(smallest_distance * EXTRA_CHECK_DISTANCE_MULTIPLIER)
+
+	if(extra_check_distance < 1)
+		return closest_target
+
+	var/list/extra_checked = orange(extra_check_distance, closest_target)
+
+	var/list/final_targets = extra_checked & viable_targets
+
+	return length(final_targets) ? pick(final_targets) : closest_target
+
+#undef EXTRA_CHECK_DISTANCE_MULTIPLIER
 
-	if(length(viable_defenses))
-		return pick(viable_defenses)
+/mob/living/carbon/xenomorph/proc/check_mob_target(mob/living/carbon/human/checked_human)
+	if(checked_human.species.flags & IS_SYNTHETIC)
+		return FALSE
+
+	if(FACTION_XENOMORPH in checked_human.faction_group)
+		return FALSE
+
+	if(checked_human.stat != CONSCIOUS)
+		return FALSE
+
+	return TRUE
 
 /mob/living/carbon/xenomorph/proc/make_ai()
 	SHOULD_CALL_PARENT(TRUE)