Workshop › Candy Crush-style Match 3 › Step 18 of 29

Cascades

What we are doing

Fallen and new gems can line up by themselves: a cascade. After a collapse the game is 'falling'; then it looks for new matches and clears again, each round of the chain worth more: 10, 20, 30 points a gem.

```js
let chain // how many clears in a row this move has caused
let phase // 'idle', 'clearing' (matched gems flash) or 'falling'

function trySwap(a, b) {
  // ...
  chain = 0
  startClearing()
  return true
}

function startClearing() {
  matched = findMatches()
  chain += 1
  score += matched.size * 10 * chain // cascades are worth more and more
  // ...
}

function collapse() {
  // ...
  phase = 'falling'
}

function update() {
  // ...
  if (phase === 'falling') {
    // Landed: new matches make a cascade; otherwise the move is over.
    if (findMatches().size > 0) startClearing()
    else phase = 'idle'
  }
}
```

What it means

• Each move starts a chain at 0; each clear adds 1 and multiplies the points by it.
• collapse ends in 'falling'. On the next frame update checks the board: new matches start another clear, otherwise the move is over.

Your turn

1. Above let phase write let chain, and add 'falling' to the comment of let phase.
2. In trySwap, write chain = 0 above startClearing().
3. In startClearing, count the chain and multiply the points.
4. At the end of collapse, change 'idle' to 'falling'.
5. In update, under the 'clearing' block, write the 'falling' block.

Skills: Game states

← Flash, and hands off Where a gem came from →

All steps

1. A place for the board
2. A checkered grid
3. The game loop
4. A board of random gems
5. Draw the gems
6. Start without matches
7. Click a gem
8. Show the selection
9. Swap two neighbours
10. Find every match
11. No match, no swap
12. A score and a fresh start
13. Clear the match
14. Let the gems fall
15. Two halves of a clear
16. Wait before clearing
17. Flash, and hands off
18. Cascades
19. Where a gem came from
20. Slide down
21. Out from under the top
22. Is there any move?
23. Never stuck
24. A hint after five seconds
25. Show the hint
26. Twenty moves
27. The end of a game
28. Remember the best score
29. Build it yourself: swipe to swap