Adding SSpathfinding.

.gitignore

@@ -1,5 +1,6 @@
 # ignore misc BYOND files
 Thumbs.db
+Thumbs.db:encryptable
 *.log
 *.int
 *.rsc

code/__defines/ai.dm

@@ -6,6 +6,8 @@
 #define STANCE_ATTACKING         /decl/mob_controller_stance/attacking
 #define STANCE_TIRED             /decl/mob_controller_stance/tired
 #define STANCE_CONTAINED         /decl/mob_controller_stance/contained
+#define STANCE_BUSY              /decl/mob_controller_stance/busy
+
  //basically 'do nothing'
 #define STANCE_COMMANDED_STOP    /decl/mob_controller_stance/commanded/stop
 //follows a target

code/__defines/subsystem-priority.dm

@@ -39,6 +39,7 @@
 #define SS_PRIORITY_GHOST_IMAGES  10  // Updates ghost client images.
 #define SS_PRIORITY_ZCOPY         10  // Builds appearances for Z-Mimic.
 #define SS_PRIORITY_PROJECTILES   10  // Projectile processing!
+#define SS_PRIORITY_PATHFINDING   10  // Processing pathfinding requests
 
 // SS_BACKGROUND
 #define SS_PRIORITY_OBJECTS      100  // processing_objects processing.

code/controllers/subsystems/mob_ai/auto_movement.dm

@@ -51,5 +51,8 @@ SUBSYSTEM_DEF(automove)
 		if(controller.handle_mover(mover, moving_metadata[mover]) == PROCESS_KILL && !QDELETED(mover))
 			mover.stop_automove()
 		if(MC_TICK_CHECK)
-			processing_atoms.Cut(1, i+1)
+			if(i >= length(processing_atoms))
+				processing_atoms.Cut()
+			else
+				processing_atoms.Cut(1, i+1)
 			return

code/controllers/subsystems/pathfinding.dm

@@ -0,0 +1,123 @@
+SUBSYSTEM_DEF(pathfinding)
+	name       = "Pathfinding"
+	priority   = SS_PRIORITY_PATHFINDING
+	init_order = SS_INIT_MISC_LATE
+	wait       = 1
+
+	var/list/pending        = list()
+	var/list/processing     = list()
+	var/list/mover_metadata = list()
+
+	VAR_PRIVATE/static/_default_adjacency_call = TYPE_PROC_REF(/turf, CardinalTurfsWithAccess)
+	VAR_PRIVATE/static/_default_distance_call  = TYPE_PROC_REF(/turf, Distance)
+
+/atom/movable
+	var/waiting_for_path
+
+/atom/movable/proc/path_found(list/path)
+	SHOULD_CALL_PARENT(TRUE)
+	waiting_for_path = null
+
+/atom/movable/proc/path_not_found()
+	SHOULD_CALL_PARENT(TRUE)
+	waiting_for_path = null
+
+/datum/controller/subsystem/pathfinding/proc/dequeue_mover(atom/movable/mover, include_processing = TRUE)
+	if(!istype(mover))
+		return
+	mover.waiting_for_path = null
+	pending        -= mover
+	mover_metadata -= mover
+	if(include_processing)
+		processing -= mover
+
+// Hook to allow legacy use of AStar* to reuse the callback refs
+/datum/controller/subsystem/pathfinding/proc/find_path_immediate(start, end, max_nodes, max_node_depth = 30, min_target_dist = 0, min_node_dist, id, datum/exclude, check_tick = FALSE)
+	return find_path_astar(start, end, _default_adjacency_call, _default_distance_call, max_nodes, max_node_depth, min_target_dist, min_node_dist, id, exclude, check_tick)
+
+/datum/controller/subsystem/pathfinding/proc/enqueue_mover(atom/movable/mover, atom/target, datum/pathfinding_metadata/metadata)
+	if(!istype(mover) || mover.waiting_for_path)
+		return FALSE
+	if(!istype(target))
+		return FALSE
+	pending |= mover
+	pending[mover] = target
+	if(istype(metadata))
+		mover_metadata[mover] = metadata
+	mover.waiting_for_path = world.time
+	return TRUE
+
+/datum/controller/subsystem/pathfinding/stat_entry(msg)
+	. = ..("Q:[length(pending)] P:[length(processing)]")
+
+/datum/controller/subsystem/pathfinding/fire(resumed)
+
+	if(!resumed)
+		processing = pending?.Copy()
+
+	var/atom/movable/mover
+	var/atom/target
+	var/datum/pathfinding_metadata/metadata
+	var/i = 0
+
+	while(i < processing.len)
+
+		i++
+		mover  = processing[i]
+		target = processing[mover]
+		metadata = mover_metadata[mover]
+		dequeue_mover(mover, include_processing = FALSE)
+
+		if(!QDELETED(mover) && !QDELETED(target))
+			try_find_path(mover, target, metadata)
+
+		if (MC_TICK_CHECK)
+			processing.Cut(1, i+1)
+			return
+
+	processing.Cut()
+
+/datum/controller/subsystem/pathfinding/proc/try_find_path(atom/movable/mover, atom/target, datum/pathfinding_metadata/metadata, adjacency_call = _default_adjacency_call, distance_call = _default_distance_call)
+
+	var/started_pathing = world.time
+	mover.waiting_for_path = started_pathing
+
+	var/list/path = find_path_astar(
+		get_turf(mover),
+		target,
+		adjacency_call,
+		distance_call,
+		(metadata?.max_nodes || null),
+		(metadata?.max_node_depth || 250),
+		metadata?.min_target_dist,
+		metadata?.min_node_depth,
+		(metadata?.id || mover.GetIdCard()),
+		metadata?.obstacle,
+		check_tick = TRUE
+	)
+	if(mover.waiting_for_path == started_pathing)
+		if(length(path))
+			mover.path_found(path)
+		else
+			mover.path_not_found()
+
+/datum/pathfinding_metadata
+	var/max_nodes        = null
+	var/max_node_depth   = 250
+	var/atom/id          = null
+	var/min_target_dist  = null
+	var/min_node_depth   = null
+	var/obstacle         = null
+
+/datum/pathfinding_metadata/New(_max_nodes, _max_node_depth, _id, _min_target_dist, _min_node_depth, _obstacle)
+
+	id        = _id
+	obstacle  = _obstacle
+	max_nodes = _max_nodes
+
+	if(!isnull(_max_node_depth))
+		max_node_depth  = _max_node_depth
+	if(!isnull(_min_target_dist))
+		min_target_dist = _min_target_dist
+	if(!isnull(_min_node_depth))
+		min_node_depth  = _min_node_depth

code/datums/ai/_ai.dm

@@ -62,6 +62,23 @@
 	/// Aggressive AI var; defined here for reference without casting.
 	var/try_destroy_surroundings = FALSE
 
+	/// Reference to the atom we are targetting.
+	var/weakref/target_ref
+
+	/// Current path for A* pathfinding.
+	var/list/executing_path
+	/// A counter for times we have failed to progress along our path.
+	var/path_frustration = 0
+	/// A list of any obstacles we should path around in future.
+	var/list/path_obstacles = null
+
+	/// Radius of target scan area when looking for valid targets. Set to 0 to disable target scanning.
+	var/target_scan_distance = 0
+	/// Time tracker for next target scan.
+	var/next_target_scan_time
+	/// How long minimum between scans.
+	var/target_scan_delay = 1 SECOND
+
 /datum/mob_controller/New(var/mob/living/target_body)
 	body = target_body
 	if(expected_type && !istype(body, expected_type))
@@ -71,6 +88,7 @@
 /datum/mob_controller/Destroy()
 	LAZYCLEARLIST(_friends)
 	LAZYCLEARLIST(_enemies)
+	set_target(null)
 	if(is_processing)
 		STOP_PROCESSING(SSmob_ai, src)
 	if(body)
@@ -79,12 +97,6 @@
 		body = null
 	. = ..()
 
-/datum/mob_controller/proc/get_automove_target(datum/automove_metadata/metadata)
-	return null
-
-/datum/mob_controller/proc/can_do_automated_move(variant_move_delay)
-	return body && !body.client
-
 /datum/mob_controller/proc/can_process()
 	if(!body || !body.loc || ((body.client || body.mind) && !(body.status_flags & ENABLE_AI)))
 		return FALSE
@@ -111,13 +123,13 @@
 // This is the place to actually do work in the AI.
 /datum/mob_controller/proc/do_process()
 	SHOULD_CALL_PARENT(TRUE)
-	if(!QDELETED(body) && !QDELETED(src))
+	if(get_stance() != STANCE_BUSY && !QDELETED(body) && !QDELETED(src))
 		if(!body.stat)
 			try_unbuckle()
 			try_wander()
 			try_bark()
 			// Recheck in case we walked into lava or something during wandering.
-			return !QDELETED(body) && !QDELETED(src)
+			return get_stance() != STANCE_BUSY && !QDELETED(body) && !QDELETED(src)
 		return TRUE
 	return FALSE
 
@@ -132,16 +144,6 @@
 		else if(prob(25))
 			body.visible_message(SPAN_WARNING("\The [body] struggles against \the [body.buckled]!"))
 
-
-/datum/mob_controller/proc/get_activity()
-	return current_activity
-
-/datum/mob_controller/proc/set_activity(new_activity)
-	if(current_activity != new_activity)
-		current_activity = new_activity
-		return TRUE
-	return FALSE
-
 // The mob will periodically sit up or step 1 tile in a random direction.
 /datum/mob_controller/proc/try_wander()
 	//Movement
@@ -185,133 +187,17 @@
 		else if(ispath(do_emote, /decl/emote))
 			body.emote(do_emote)
 
-/datum/mob_controller/proc/get_target()
-	return null
-
-/datum/mob_controller/proc/set_target(atom/new_target)
-	return
-
-/datum/mob_controller/proc/find_target()
-	return
-
-/datum/mob_controller/proc/valid_target(var/atom/A)
-	return
-
-/datum/mob_controller/proc/move_to_target(var/move_only = FALSE)
-	return
-
-/datum/mob_controller/proc/stop_wandering()
-	stop_wander = TRUE
-
-/datum/mob_controller/proc/resume_wandering()
-	stop_wander = FALSE
-
-/datum/mob_controller/proc/set_stance(new_stance)
-	if(stance != new_stance)
-		stance = new_stance
-		return TRUE
-	return FALSE
-
-/datum/mob_controller/proc/get_stance()
-	return stance
-
-/datum/mob_controller/proc/list_targets(var/dist = 7)
-	return
-
-/datum/mob_controller/proc/open_fire()
-	return
-
-/datum/mob_controller/proc/startle()
-	if(QDELETED(body) || body.stat != UNCONSCIOUS)
-		return
-	body.set_stat(CONSCIOUS)
-	if(body.current_posture?.prone)
-		body.set_posture(/decl/posture/standing)
-
-/datum/mob_controller/proc/retaliate(atom/source)
-	SHOULD_CALL_PARENT(TRUE)
-	if(!istype(body) || body.stat == DEAD)
-		return FALSE
-	startle()
-	if(isliving(source))
-		remove_friend(source)
-	return TRUE
-
 /datum/mob_controller/proc/destroy_surroundings()
 	return
 
-/datum/mob_controller/proc/lose_target()
-	return
-
-/datum/mob_controller/proc/lost_target()
-	return
-
 /datum/mob_controller/proc/handle_death(gibbed)
 	return
 
-/datum/mob_controller/proc/pacify(mob/user)
-	lose_target()
-	add_friend(user)
-
-// General-purpose memorise proc, used by /commanded
-/datum/mob_controller/proc/memorise(mob/speaker, message)
-	return
-
-// General-purpose memory checking proc, used by /faithful_hound
-/datum/mob_controller/proc/check_memory(mob/speaker, message)
-	return FALSE
-
 /// General-purpose scooping reaction proc, used by /passive.
 /// Returns TRUE if the scoop should proceed, FALSE if it should be canceled.
 /datum/mob_controller/proc/scooped_by(mob/initiator)
 	return TRUE
 
-// Enemy tracking - used on /aggressive
-/datum/mob_controller/proc/get_enemies()
-	return _enemies
-
-/datum/mob_controller/proc/add_enemy(mob/enemy)
-	if(istype(enemy))
-		LAZYDISTINCTADD(_enemies, weakref(enemy))
-
-/datum/mob_controller/proc/add_enemies(list/enemies)
-	for(var/thing in enemies)
-		if(ismob(thing))
-			add_friend(thing)
-		else if(istype(thing, /weakref))
-			LAZYDISTINCTADD(_enemies, thing)
-
-/datum/mob_controller/proc/remove_enemy(mob/enemy)
-	LAZYREMOVE(_enemies, weakref(enemy))
-
-/datum/mob_controller/proc/set_enemies(list/new_enemies)
-	_enemies = new_enemies
-
-/datum/mob_controller/proc/is_enemy(mob/enemy)
-	. = istype(enemy) && LAZYLEN(_enemies) && (weakref(enemy) in _enemies)
-
-/datum/mob_controller/proc/clear_enemies()
-	LAZYCLEARLIST(_enemies)
-
-// Friend tracking - used on /aggressive.
-/datum/mob_controller/proc/get_friends()
-	return _friends
-
-/datum/mob_controller/proc/add_friend(mob/friend)
-	if(istype(friend))
-		LAZYDISTINCTADD(_friends, weakref(friend))
-		return TRUE
-	return FALSE
-
-/datum/mob_controller/proc/remove_friend(mob/friend)
-	LAZYREMOVE(_friends, weakref(friend))
-
-/datum/mob_controller/proc/set_friends(list/new_friends)
-	_friends = new_friends
-
-/datum/mob_controller/proc/is_friend(mob/friend)
-	. = istype(friend) && LAZYLEN(_friends) && (weakref(friend) in _friends)
-
 // By default, randomize the target area a bit to make armor/combat
 // a bit more dynamic (and avoid constant organ damage to the chest)
 /datum/mob_controller/proc/update_target_zone()