game: add weapon base and sword

scenes/weapons/weapon_base.gd

@@ -0,0 +1,42 @@
+class_name WeaponBase
+extends Node2D
+
+@export var attack_cd: float
+@export var attack_damage: float
+@export var attack_aoe: float
+@export var attack_duration: float
+@export var attack_range: float
+
+
+func _on_attack_cd_timer_timeout() -> void:
+	do_attack()
+
+
+func do_attack() -> void:
+	push_error("%s does not implement do_attack" % self)
+
+
+func find_target_in_radius() -> EnemyBase:
+	var space_state: PhysicsDirectSpaceState2D = get_world_2d().direct_space_state
+	var shape := CircleShape2D.new()
+	shape.radius = attack_range
+
+	var query := PhysicsShapeQueryParameters2D.new()
+	query.shape = shape
+	query.transform = Transform2D(0, global_position)
+	query.collision_mask = 2
+	query.collide_with_bodies = true
+	var results := space_state.intersect_shape(query)
+	if len(results) < 1:
+		return null
+	var closest: PhysicsBody2D = results[0]["collider"]
+	for r in results:
+		var c: PhysicsBody2D = r["collider"]
+		if not c.is_in_group(GlobalConst.GROUP_ENEMY):
+			continue
+		if (
+			c.global_position.distance_to(global_position)
+			< closest.global_position.distance_to(global_position)
+		):
+			closest = c
+	return closest