Workshop › Flappy-style Bird › Step 4 of 30

A function that draws

What we are doing

A game redraws its picture many times a second. We put the drawing lines in a function named draw, so one word repaints everything.

```js
function draw() {
  ctx.fillStyle = '#70c5ce'
  ctx.fillRect(0, 0, canvas.width, canvas.height)

  ctx.fillStyle = 'gold'
  ctx.beginPath()
  ctx.arc(bird.x, bird.y, bird.r, 0, Math.PI * 2)
  ctx.fill()
}

draw()
```

What it means

• function draw() { ... } defines the recipe; it does not run yet.
• The body is indented by two spaces.
• draw() with parentheses runs it. It paints the sky first, which wipes the old picture.

Your turn

Wrap the six drawing lines in function draw() { ... } (indent them by two spaces) and call draw() after it.

Skills: Functions

← Draw the bird A function that moves →

All steps

1. Get the canvas and the pen
2. Paint the sky
3. Draw the bird
4. A function that draws
5. A function that moves
6. The game loop
7. Gravity
8. A flap
9. Space, Up arrow or a tap
10. Wait for the first flap
11. The ground and the sky
12. Tell the player
13. A pipe as data
14. Draw the pipes
15. The world moves, not the bird
16. A new pipe at a random height
17. A pipe every 90 frames
18. Remove the pipes you passed
19. Is the bird level with a pipe?
20. Through the opening
21. Score each pipe once
22. Show the score
23. A function for a fresh start
24. Try again
25. One place where the game ends
26. Remember the best score
27. Show the best score
28. The same speed on every screen
29. No catching up after a pause
30. Build it yourself: a medal