feat: 添加敌人并且追踪player，同时避免敌人重叠

scenes/unit/enemy/enemy.gd

@@ -0,0 +1,57 @@
+extends Unit
+class_name Enemy
+
+@export var flock_push := 20.0
+
+@onready var vision_area: Area2D = $VisionArea
+
+var can_move := true
+
+
+# Called when the node enters the scene tree for the first time.
+func _ready() -> void:
+	pass # Replace with function body.
+
+
+# Called every frame. 'delta' is the elapsed time since the previous frame.
+func _process(delta: float) -> void:
+	if not can_move:
+		return
+	
+	if not can_move_forwards_player():
+		return
+	
+	position += get_move_direction() * stats.speed * delta
+	
+	update_rotate()
+		
+	
+func get_move_direction() -> Vector2:
+	
+	if not is_instance_valid(Global.player):
+		return Vector2.ZERO
+	
+	var direction := global_position.direction_to(Global.player.position)
+	
+	for area: Node2D in vision_area.get_overlapping_areas():
+		if area != self and area.is_inside_tree():
+			var vector := global_position - area.global_position
+			direction += flock_push * vector.normalized() / vector.length()
+	
+	return direction
+	
+func update_rotate() -> void:
+	if is_instance_valid(Global.player):
+		return 
+		
+	var player_pos := Global.player.position
+	
+	var moving_right := global_position.x < player_pos.x
+	visuals.scale = Vector2(-0.5,0.5) if moving_right else Vector2(0.5,0.5)
+	
+func can_move_forwards_player() -> bool:
+	return is_instance_valid(Global.player) and\
+	global_position.distance_to(Global.player.position) > 60
+	
+	
+