Workshop › Pac-Man-style Maze Chase › Step 2 of 42

The game loop

What we are doing

Everything will move, so the picture is drawn again before every screen refresh (about 60 times a second). draw paints the dark background; loop draws and asks for the next frame with requestAnimationFrame.

```js
function draw() {
  ctx.fillStyle = '#0b1020'
  ctx.fillRect(0, 0, canvas.width, canvas.height)
}

function loop() {
  draw()
  requestAnimationFrame(loop)
}

requestAnimationFrame(loop)
```

What it means

• fillStyle picks the color, fillRect(x, y, w, h) fills a rectangle; (0, 0) is the top-left corner.
• requestAnimationFrame(loop) asks the browser to run loop before the next screen refresh; loop asks again each time, so it never stops. The last line starts it.

Your turn

Under COLS, leave an empty line and write draw, loop and the start line.

Skills: The game loop, Drawing on a canvas

← The maze as text Draw the walls →

All steps

1. The maze as text
2. The game loop
3. Draw the walls
4. A set of pellets
5. Draw the pellets
6. The player
7. Where can you walk?
8. What a mover remembers
9. One frame of movement
10. Move every frame
11. Turns you can press early
12. Glide between tiles
13. Turn back at once
14. Swipes on a phone
15. Eat the pellets
16. Show the score
17. Clear the maze
18. A red ghost
19. A ghost never turns back
20. The ghost walks
21. The ghost hunts you
22. Four ghosts in the house
23. One by one out of the house
24. Scatter or chase?
25. Every ghost to its corner
26. Pink cuts you off
27. Orange is shy
28. Cyan works with red
29. Wait for the first key
30. Tell the player to start
31. Three lives
32. Caught!
33. Game over
34. Play again
35. Frighten the ghosts
36. Power pellets work
37. Scared ghosts wander slowly
38. Eat a scared ghost
39. Blue, then flashing
40. Harder levels
41. A best score that lasts
42. Build it yourself: the slow tunnel