Workshop › Pong › Step 12 of 26

The ball moves

What we are doing

The ball gets a velocity: vx pixels to the right and vy pixels down every frame. update adds them to its position.

```js
let ball = { x: 295, y: 195, vx: 4, vy: 3 }

  ball.x += ball.vx
  ball.y += ball.vy
```

What it means

• vx and vy are the ball's speed in pixels per frame. A negative vx would go left, a negative vy up.
• Each frame the position grows by the speed.

Your turn

1. Add vx: 4, vy: 3 to ball.
2. At the end of update, leave an empty line and write the two ball lines.

Skills: Velocity and gravity

← The ball Bounce off the top and bottom →

All steps

1. Get the canvas and the pen
2. A black court
3. One dash of the net
4. The whole net
5. Two paddles
6. A function that draws
7. The game loop
8. Remember held keys
9. Move the paddles
10. Stay on the court
11. The ball
12. The ball moves
13. Bounce off the top and bottom
14. Does the ball touch a paddle?
15. The paddles hit back
16. Serve again
17. Keep the score
18. Show the score
19. First to five
20. Who won?
21. Play again
22. Aim with the paddle
23. Faster every hit
24. A computer opponent
25. One player or two
26. Build it yourself: a serve pause