Pong - Step 3


In this tutorial we are going to take our pong game from step 2 and finish it up by adding ball spin and some sounds. At the end you’ll have a fully working Pong clone.

Ball Spin

You may have noticed when you ran the last tutorial that it is actually pretty boring. You can bounce the ball back, but you can’t really affect it in any way to make it harder on your opponent. In real ping pong, you can aim your shots and put spin on them, so we want to add something like that to our little pong game. One way to do this is to simply transfer some of the paddle’s velocity to the ball when they hit. If the paddle is going in the same direction as the ball it will start bouncing faster, if not it will slow it down. By adding this one line we can add a huge amount of depth to the gameplay. Figuring out how you can improve your game with little changes like this will be the difference between a boring game and a fun one. Add this at the end of the manageBall function.

# give a little of the paddle's velocity to the ball
self.ball.vely += hitpaddle.velocity/3.0</pre>


At this point the game is fun, but where are the characteristic ping and pong sounds? Let’s add them now. I’m going to preload the sounds in the game.init function, then call them inside game.manageBall. Note the above line numbers are going to change as we put code above it and push that code down.

Changes to Game.init

Here we create two sounds by loading them with pygame.mixer and storing them as self.pingsound and self.pongsound.

# create sounds
self.pingsound = pygame.mixer.Sound(os.path.join('sound', 'ping.wav'))
self.pongsound = pygame.mixer.Sound(os.path.join('sound', 'pong.wav'))

Changes to Game.manageBall

Now we need to tell the game to play the sounds we just added. We are going to play the pongsound when the ball hits a wall and the pingsound when the ball hits a paddle. It should make stereotypical (and highly annoying!) back and forth pong noises.

In the if block where we check if the ball hits the top wall, add this:

# play the pong sound

Similarly add this where we check if the ball hits the bottom wall:

# play the pong sound

Finally, add this to where we check if it hits a paddle:

# play the ping sound


It’s done! The game is not terribly entertaining but it is playable. It looks the same as before in a screenshot so run the code and notice the differences.