# Minesweeper Bomb Generation And Tile Revealing | tait.tech
Author: Tait Hoyem

# Minesweeper Bomb Generation And Tile Revealing

Saturday, September 12 2020

When I was creating a little Minesweeper game, I got confused at some points. My bomb generation didn’t look quite right, and I for sure didn’t quite get the whole cascading tile reveal thing. With a bit of internet research, I found what I was looking for. I’ll explain it all in one place for my own research purposes.

## Bomb Generation

When I started this project I attempted to use a random bomb generator. By this I mean on each square, before it gets generated, give it a one in 15 change of being a bomb. Personally, I’m not sure why this never looked right. Something about the layout of the bombs did not mimic the classic Minesweeper game.

After looking at some open source Minesweeper examples, I started to get the idea. I wrote some mathematical statements describing the generation of bombs and how to get their x,y position from an appropriate number. For those non-mathy people, don’t leave just yet; there will be code equivalents to the math.

W and H are the width and height of the board respectively.

0≤r≤W×H \it 0 \leq r \leq \text W \times \text H 0≤r≤W×H x=r mod W \it x = r \bmod \text W x=rmodW y=⌊r H⌋ \it y = \left\lfloor\frac{r}{\text H}\right\rfloor y=⌊Hr​⌋

The code equivalent to this in Python is below:

    import random
    # r <= 0 <= W*H
    r = random.randint(1, W*H)-1

    # x = r mod W
    x = r % W

    # y = floor(r/H); note the special syntax python has for this operation
    y = r // H

So that’s that, we can put this in a big ‘ol for loop and generate an arbitrary n number of bombs given a width and height of a Minesweeper board.

## Cascading Tile Revealing

This one is hard to describe; I am adapting this from leetcode.com. Whenever a player clicks a tile, the following logic should be used:

1. If a mine is revealed, the game is over. (obviously)
2. If a tile with no adjacent mines is revealed, recursively reveal all eight adjacent tiles.
3. If a tile with one or more adjacent mines is revealed, display the number of mines next to it.

Here is the code in Python for this algorithm.

    def reveal_square(x, y, board, alread_revealed):
      # if already checked
      if (x, y) in already_revealed:
        return
      # if it's a bomb
      if board[x][y] == 'B':
        you_lose()
        return
      # if the bomb number is more than 0
      already_revealed.append((nx, ny))

      # from -1 to 1
      for xd in range(-1, 2):
        for yd in range(-1, 2):
          # skip if it is this the center tile
          if x+xd == x and y+yd == y:
            continue
          # recursively check the adjacent square
          reveal(x+xd, y+yd, board, already_revealed)
      return already_revealed

This has no checks for valid squares, but it’s the general idea. This function returns an array of tile coordinates which should be revealed.

## Conclusion

I wrote this because in the first place because I was writing my own Minesweeper game. I hope that this helps you with getting the general idea of a Minesweeper game. The completed version of this game is available on my lamegames site. Let me know what you think!

Happy hacking!