feat: 添加spawner生成器，生成敌人

scenes/arena/spawner.gd

@@ -0,0 +1,65 @@
+extends Node2D
+class_name Spawner
+
+@export var spawn_area_size := Vector2(1000, 500)
+@export var waves_data: Array[WaveData]
+@export var enemy_collection: Array[UnitStats]
+
+@onready var spawn_timer: Timer = $SpawnTimer
+@onready var wave_timer: Timer = $WaveTimer
+
+var wave_index := 1
+var current_wave_data: WaveData
+var spawned_enemiese: Array[Enemy] = []
+
+
+# Called when the node enters the scene tree for the first time.
+func _ready() -> void:
+	start_wave()
+
+
+func find_wave_data() -> WaveData:
+	for wave in waves_data:
+		if wave and wave.is_vaild_index(wave_index):
+			return wave
+	return null
+	
+
+func start_wave() -> void:
+	current_wave_data = find_wave_data()
+	if not current_wave_data :
+		printerr("No valid wave.")
+		spawn_timer.stop()
+		wave_timer.stop()
+		return
+		
+	wave_timer.wait_time = current_wave_data.wave_time
+	wave_timer.start()
+	
+	set_spawn_timer()
+	
+func set_spawn_timer() -> void:
+	match current_wave_data.spawn_type:
+		WaveData.SpawnType.FIXED:
+			spawn_timer.wait_time = current_wave_data.fixed_spawn_time
+		WaveData.SpawnType.RANDOM:
+			var min_t := current_wave_data.min_spawn_time
+			var max_t := current_wave_data.max_spawn_time
+			spawn_timer.wait_time = randf_range(min_t, max_t)
+	
+	if spawn_timer.is_stopped():
+		spawn_timer.start()
+	
+func spawn_enemy() -> void:
+	var enemy_scene := current_wave_data.get_randon_unit_scene() as PackedScene		
+	if enemy_scene:
+		var enemy_instance := enemy_scene.instantiate() as Enemy
+		enemy_instance.global_position = Vector2.ZERO
+		get_parent().add_child(enemy_instance)
+		spawned_enemiese.append(enemy_instance)
+	
+	set_spawn_timer()
+	
+
+func _on_spawn_timer_timeout() -> void:
+	spawn_enemy()