improve and update ai

core/ai/agents/base/ai_base.gd

@@ -4,6 +4,7 @@ class_name AIBase
 
 @export_group("Settings")
 @export var speed: float = 4.0
+@export_flags_3d_navigation var navigation_layers: int = 1
 var _enable_state_machine: bool = true
 @export var enable_state_machine: bool: 
 	set(value):
@@ -26,6 +27,8 @@ enum EntityType { HUMANOID, ANIMAL }
 
 func _ready() -> void:
 	randomize()
+	if nav_agent:
+		nav_agent.navigation_layers = navigation_layers
 	toggle_enable_state_machine()
 
 func toggle_enable_state_machine() -> void:
@@ -52,7 +55,7 @@ func _physics_process(delta: float) -> void:
 		var look_dir = Vector3(velocity.x, 0, velocity.z)
 		var target_transform = global_transform.looking_at(global_position - look_dir, Vector3.UP)
 		global_transform = global_transform.interpolate_with(target_transform, delta * 10.0)
-	 
+
 	move_and_slide()
 
 func navigate_to_random_point() -> void:
@@ -67,4 +70,6 @@ func navigate_to_random_point() -> void:
 		if nav_agent.is_target_reachable():
 			return
 			
-	nav_agent.target_position = global_position
+	# Fallback: if we can't find a reachable point (e.g. we drifted slightly off navmesh),
+	# try to navigate to the closest navmesh point to our CURRENT position to get unstuck.
+	nav_agent.target_position = NavigationServer3D.map_get_closest_point(nav_map_rid, global_position)