My first kivy game--pong ball

 ##### pong.kv file#####

<pongBall>:
	size:100,100
	canvas:
		Ellipse:
			pos:self.pos
			size:self.size
			
<pongPaddle>:
	size:50,300
	canvas:
		Rectangle:
			pos:self.pos
			size:self.size
					
<pongGame>:
	ball:pong_ball
	player1:playerLeft
	player2:playerRight
	
	canvas:
		Rectangle:
			pos :self.center_x -5 ,0
			size:10,self.height

	Label:
		font_size:70
		center_x:root.width/4
		top: root.top-50
		text:str(root.player2.score)
		
	Label:
		font_size:70
		center_x:root.width*3/4
		top: root.top-50
		text:str(root.player1.score)
		
	pongBall:
		id:pong_ball
		center:self.parent.center
	
	pongPaddle:
		id:playerLeft
		x:root.x
		center_y:root.center_y
		
	pongPaddle:
		id:playerRight
		x:root.width-self.width
		center_y:root.center_y
	

#main.py file

from kivy.app import App

from kivy.uix.widget import Widget

from kivy.properties import NumericProperty , ReferenceListProperty,ObjectProperty  

from kivy.vector import Vector

from kivy.clock import Clock

from random import randint,choice

class pongPaddle(Widget):

 score=NumericProperty(0)

 def bounceball(self,ball):

  if self.collide_widget(ball):

   if ball.velocity_x >= -25 and ball.velocity_x <= 25: 

    ball.velocity_x*=-1.1

    print(ball.velocity_y)

   else:

    ball.velocity_x*=-1

    ball.velocity_y=-4

    

   

class pongBall(Widget):

 velocity_x=NumericProperty(0)

 velocity_y=NumericProperty(0)

 velocity=ReferenceListProperty(velocity_x,velocity_y)

 def move(self):

  self.pos= Vector(*self.velocity)+self.pos

  

  

class pongGame(Widget):

 ball=ObjectProperty(None)

 player1=ObjectProperty(None)

 player2=ObjectProperty(None)

 def serve_ball(self):

  self.ball.velocity=Vector(6,0).rotate(randint(0,360))

  

 def update(self,dt):

  self.ball.move()

###bounce of top and bottom

  if self.ball.y <0:

   self.ball.velocity_y*=-1

  if self.ball.y >self.height-100:

   self.ball.velocity_y*=-1

###Incresing score

###bounce off left  

  if self.ball.x <0:

   self.ball.velocity_x*=-1

   self.player1.score+=1

###bounce off left   

  if self.ball.x>self.width-100:

   self.ball.velocity_x*=-1

   self.player2.score+=1

   

  self.player1.bounceball(self.ball)

  self.player2.bounceball(self.ball)

  

 def on_touch_move(self,touch):

   if touch.x< self.width *1/4:

     self.player1.center_y=touch.y

   if touch.x>self.width *3/4:

      self.player2.center_y=touch.y

      

     

class pongApp(App):

 def build(self):

  game=pongGame()

  game.serve_ball()

  Clock.schedule_interval(game.update,1.0/60.0)

  return game

pongApp().run()