gamedev-the-steward/world/creatures/creature_visual.gd

class_name CreatureVisual
extends Node3D

signal position_changed(creature_id: StringName, active_position: Vector3)
signal arrived_at_sim_position(creature_id: StringName)

const ARRIVAL_DISTANCE := 0.5
const PATH_RETARGET_DISTANCE := 0.8
const PATH_RETRY_BASE_SECONDS := 0.5
const PATH_RETRY_MAX_SECONDS := 4.0

@export_range(0.5, 12.0, 0.1) var move_speed := 3.5
@export_range(0.05, 1.0, 0.05) var waypoint_reached_distance := 0.3
@export_range(1.0, 20.0, 0.5) var rotation_speed := 8.0

var creature_id: StringName
var sim_position := Vector3.INF
var is_dead_visual := false

var current_path := PackedVector3Array()
var path_index := 0
var path_target := Vector3.INF
var path_request_id := 0
var path_pending := false
var path_query_count := 0
var path_retry_remaining := 0.0
var path_retry_delay := PATH_RETRY_BASE_SECONDS


func _physics_process(delta: float) -> void:
	if is_dead_visual:
		return
	if not sim_position.is_finite():
		return
	if _horizontal_distance_to(sim_position) <= ARRIVAL_DISTANCE:
		_stop_moving()
		return
	if path_retry_remaining > 0.0:
		path_retry_remaining = maxf(path_retry_remaining - delta, 0.0)
		if path_retry_remaining > 0.0:
			return
	_ensure_path()
	if path_pending:
		return
	if current_path.is_empty() or path_index >= current_path.size():
		_request_path()
		return
	var next_position := current_path[path_index]
	var offset := next_position - global_position
	if offset.length() <= waypoint_reached_distance:
		path_index += 1
		return
	var direction := offset.normalized()
	global_position = global_position.move_toward(next_position, move_speed * delta)
	position_changed.emit(creature_id, global_position)
	var target_angle := atan2(direction.x, direction.z)
	rotation.y = lerp_angle(rotation.y, target_angle, rotation_speed * delta)


func set_sim_position(position: Vector3) -> void:
	if not position.is_finite():
		return
	var target_changed := (
		not sim_position.is_finite()
		or _horizontal_distance_to_position(sim_position, position) > PATH_RETARGET_DISTANCE
	)
	sim_position = position
	if target_changed and not is_dead_visual:
		path_retry_remaining = 0.0
		path_retry_delay = PATH_RETRY_BASE_SECONDS
		if _horizontal_distance_to(sim_position) <= ARRIVAL_DISTANCE:
			_stop_moving()
			return
		_request_path()


func play_death() -> void:
	is_dead_visual = true
	_stop_moving()
	var tween := create_tween()
	tween.set_trans(Tween.TRANS_QUAD).set_ease(Tween.EASE_IN)
	tween.tween_property(self, "scale", Vector3(0.001, 0.001, 0.001), 0.45)
	tween.tween_callback(queue_free)


func build_visual() -> void:
	pass


func _ensure_path() -> void:
	if (
		path_pending
		or (
			path_target.is_finite()
			and (
				_horizontal_distance_to_position(path_target, sim_position)
				<= PATH_RETARGET_DISTANCE
			)
		)
	):
		return
	_request_path()


func _request_path() -> void:
	path_request_id += 1
	var request_id := path_request_id
	path_target = sim_position
	current_path = PackedVector3Array()
	path_index = 0
	path_pending = true
	await get_tree().physics_frame
	if request_id != path_request_id or is_dead_visual:
		return
	if _horizontal_distance_to(sim_position) <= ARRIVAL_DISTANCE:
		path_pending = false
		return
	current_path = NavigationServer3D.map_get_path(
		get_world_3d().navigation_map, global_position, sim_position, true
	)
	path_query_count += 1
	path_pending = false
	if current_path.is_empty():
		_schedule_path_retry()
		return
	path_retry_remaining = 0.0
	path_retry_delay = PATH_RETRY_BASE_SECONDS


func _schedule_path_retry() -> void:
	current_path = PackedVector3Array()
	path_index = 0
	path_pending = false
	path_target = sim_position
	path_retry_remaining = path_retry_delay
	path_retry_delay = minf(path_retry_delay * 2.0, PATH_RETRY_MAX_SECONDS)


func _stop_moving() -> void:
	if (
		current_path.is_empty()
		and not path_pending
		and path_retry_remaining <= 0.0
		and path_target.is_finite()
		and sim_position.is_finite()
		and _horizontal_distance_to_position(path_target, sim_position) <= PATH_RETARGET_DISTANCE
	):
		return
	path_request_id += 1
	current_path = PackedVector3Array()
	path_index = 0
	path_pending = false
	path_target = sim_position
	path_retry_remaining = 0.0
	path_retry_delay = PATH_RETRY_BASE_SECONDS


func _horizontal_distance_to(target_position: Vector3) -> float:
	return _horizontal_distance_to_position(global_position, target_position)


static func _horizontal_distance_to_position(from_position: Vector3, to_position: Vector3) -> float:
	return Vector2(from_position.x, from_position.z).distance_to(
		Vector2(to_position.x, to_position.z)
	)