Workshop › Pinball › Step 25 of 42

Where is the tip?

What we are doing

The pivot is fixed; the tip is FLIPPER_LENGTH away in the direction of the angle. Cosine and sine turn an angle into a horizontal and a vertical part. Then each flipper is drawn as a thick blue line from pivot to tip.

```js
const tip = (f) => ({ x: f.x + Math.cos(f.angle) * FLIPPER_LENGTH, y: f.y + Math.sin(f.angle) * FLIPPER_LENGTH })

  ctx.strokeStyle = '#38bdf8'
  ctx.lineWidth = 10
  for (const f of flippers) {
    const t = tip(f)
    ctx.beginPath()
    ctx.moveTo(f.x, f.y)
    ctx.lineTo(t.x, t.y)
    ctx.stroke()
  }
```

What it means

• For an angle a, Math.cos(a) is how far right and Math.sin(a) how far down a one-pixel step in that direction goes. Multiplying by the length gives the tip's offset from the pivot.
• tip is written as an arrow function stored in a constant; it returns an object { x, y }.
• The drawing loop goes from each pivot to its tip, 10 pixels thick.

Your turn

1. Above the // Push the ball out of a segment... comment write tip, with an empty line after it.
2. In draw, under the bumpers' forEach block, write the flipper drawing.

Skills: Drawing on a canvas, Functions

← Two flippers Flippers stop the ball →

All steps

1. Paint the table
2. Draw one wall
3. A list of walls
4. The game loop
5. A ball in the lane
6. Draw the ball
7. Move by the velocity
8. Launch with Space
9. Gravity
10. Does the ball touch a wall?
11. Push the ball out
12. Bounce off the wall
13. Small steps and a speed limit
14. Ready or playing
15. The next ball
16. Three bumpers
17. The ball meets a bumper
18. A bumper kicks
19. A score and a fresh start
20. Points for every hit
21. Remember which bumper was hit
22. Light it up
23. Lit for a moment, points once
24. Two flippers
25. Where is the tip?
26. Flippers stop the ball
27. Which keys are held?
28. Which way to turn
29. Flip!
30. A moving wall
31. The flipper throws
32. Three balls
33. Balls left and game over
34. Play again
35. Remember the best score
36. Launch on letting go
37. Pull the spring
38. Show the spring
39. Two thumbs
40. Pull with a finger
41. Tap to play again
42. Build it yourself: slingshots