first work

scenes/playground/Playground.gd

@@ -0,0 +1,47 @@
+extends Node2D
+
+var Ball = preload("res://scenes/playground/ball/Ball.tscn")
+
+var left_point = 0
+var right_point = 0
+
+func start():
+	var ball = Ball.instantiate()
+	add_child(ball)
+
+func set_score():
+	get_node("Score").text = "{right} - {left}".format({
+		"left": left_point,
+		"right": right_point
+	})
+
+func new_round(ball):
+	remove_child(ball)
+	set_score()
+	start()
+
+func _ready():
+	start()
+
+func _process(delta):
+	pass
+
+func _on_goal_area_left_body_entered(body):
+	if body.name == "Ball":	
+		left_point += 1
+		new_round(body)
+
+func _on_goal_area_right_body_entered(body):
+	if body.name == "Ball":
+		right_point += 1
+		new_round(body)
+
+
+func _on_racket_left_body_entered(body):
+	if body.name == "Ball":
+		body.linear_velocity = body.linear_velocity * -1
+
+
+func _on_racket_right_body_entered(body):
+	if body.name == "Ball":
+		body.linear_velocity = body.linear_velocity * -1