Workshop › Tower Defense › Step 39 of 42

A second tower: the cannon

What we are doing

A second kind of tower: the cannon. It costs more, shoots slower and not as far, but hits harder, and later its shots will hit everything around the target (splash). Keys 1 and 2 choose which kind to build.

```js
arrow: { cost: 50, range: 2.5, damage: 4, reload: 24, splash: 0, color: '#38bdf8' },
cannon: { cost: 70, range: 2, damage: 8, reload: 60, splash: 1.2, color: '#f97316' },

if (event.key === '1') selected = 'arrow'
if (event.key === '2') selected = 'cannon'
```

What it means

• Every kind of tower is one entry in TOWERS, so building, range circles and shooting already work for the cannon.
• splash is a distance in tiles: 0 for arrows, 1.2 for cannons.
• Keys '1' and '2' set selected, the kind the next click builds.

Your turn

1. In TOWERS, add splash: 0, to arrow (before color) and write the cannon line under it.
2. At the top of the keydown listener, write the two key lines.

Skills: Game states, Keyboard and mouse input

← Click to start Tower buttons →

All steps

1. Measure the map
2. A map of tiles
3. Draw it every frame
4. The road as corners
5. Fill in the road
6. Draw the road
7. Walking by distance
8. Enemies on the road
9. Walk
10. Off the end of the road
11. Here they come
12. Towers
13. From a click to a tile
14. Click to build
15. Where can you build?
16. Show the gold
17. Show before you click
18. Show the range
19. Pick a target
20. Fire!
21. A hit hurts
22. Homing bullets
23. Fizzle out
24. Gold for every kill
25. Lives
26. Health bars
27. Build, then defend
28. Space starts a wave
29. The wave is over
30. Stronger every wave
31. Closer together
32. Out of lives
33. No building after the end
34. The most waves survived
35. The game over screen
36. Play again
37. The bottom bar
38. Click to start
39. A second tower: the cannon
40. Tower buttons
41. Splash damage
42. Build it yourself: sell a tower