Question

I want to make a game where the playing pieces can move around. When I click on a playing piece it shows all available moves were I can go like this:

Red represents legal moves and dark gray represents a wall.

I have created a grid and buttons in it. When I click on a button, I subtract or add the available step count to the button index in the grid. For example if my piece can move 3 places, I subtract 3 from the index of the button and get the available position to the left of the piece. Then I do the same for all other directions. It looks something like this:

For each i as button in grid
 Select case grid.indexof(i)
  Case grid.getindex(currentPlayingPiece) - 3 'Left
   i.background = brushes.red
  Case grid.getindex(currentPlayingPiece) + 3 'Right
   i.background = brushes.red
  Case grid.getindex(currentPlayingPiece) - grid.columndefinitions.count 'Top
   i.background = brushes.red
  ...
Next

Using this method it is very slow and cumbersome to get all available moves and not intuitive to get top and bottom moves. Also if there is a wall in the way and behind there’s a available spot it shows that I can move to it. So my question is: is there a better method to accomplish this?

Answer 1

If you prefer not to use an “advanced” algorithm involving graphs or similar solutions, there are a couple of simpler things you might try.

Firstly, creating a variable instead of calling getIndex() a bunch of times might save a few cycles.

Secondly, I would try to use the absolute of each position to evaluate, and so calculate the distance without having to check once for each direction (+ or -); Maybe something like this:

dim currentButtonIndex as Integer = grid.getIndex(currentPlayingPiece)
For each i as button in grid
    dim indexToEvaluate as Integer = grid.indexOf(i)
    If (Math.Abs(indexToEvaluate - currentButtonIndex) = 3) Then
        i.background = brushes.red
    End If
Next