Workshop › Tetris-style Blocks › Step 15 of 32

Wall kicks

What we are doing

A piece against a wall often cannot turn in place, and a game that says "no" feels bad. So we also try the turn nudged one or two cells sideways, and take the first place that fits.

```js
  const turned = rotate(piece.shape)
  // Wall kicks: if the turned piece does not fit, try nudging it sideways.
  for (const kick of [0, -1, 1, -2, 2]) {
    if (fits(turned, piece.x + kick, piece.y)) {
      piece.shape = turned
      piece.x += kick
      return true
    }
  }
  return false
}
```

What it means

• for (const kick of [0, -1, 1, -2, 2]) tries each offset in turn.
• The first offset where the turned shape fits wins: the piece takes the shape and moves by kick, and return true stops the search.
• If none fits, return false after the loop.

Your turn

In tryRotate, replace everything under const turned = ... with the lines shown.

Skills: Collision detection, Loops

← Turn with Up Falling by itself →

All steps

1. The well
2. The board as rows of numbers
3. Draw one cell
4. Draw the whole board
5. The number is the color
6. A piece is a small grid
7. A list of shapes
8. All seven pieces
9. Does it fit inside the well?
10. Blocks are in the way
11. Try, then move
12. Move with the arrows
13. Turn a matrix
14. Turn with Up
15. Wall kicks
16. Falling by itself
17. A random piece at the top
18. Land and lock
19. One function starts a game
20. When the pile reaches the top
21. Game Over on screen
22. Play again
23. Clear full rows
24. Points for lines
25. The side panel
26. Levels
27. Faster every level
28. A fair bag of pieces
29. The next piece
30. Drop it
31. The ghost piece
32. Build it yourself: hold a piece