XNA 4.0 Game Development by Example Beginner's Guide（Visual Basic Edition）

上QQ阅读APP看书，第一时间看更新

Time for action – water in the pipes

Add a method to the GameBoard class to clear the water marker from all pieces:

Public Sub ResetWater()
  Dim x, y As Integer
  For x = 0 To GameBoardWidth
    For y = 0 To GameBoardHeight
      boardSquares(x, y).RemoveSufix("W")
    Next
  Next
End Sub

Add a method to the GameBoard class to fill an individual piece with water:

Public Sub FillPiece(x As Integer, y As Integer)
  boardSquares(x, y).AddSuffix("W")
End Sub

What just happened?

The ResetWater() method simply loops through each item in the boardSquares array and removes the W suffix from the GamePiece. Similarly, to fill a piece with water, the FillPiece() method adds the W suffix to the GamePiece. Recall that by having a W suffix, the GetSourceRect() method of GamePiece shifts the source rectangle one tile to the right on the sprite sheet, returning the image for a pipe filled with water, instead of an empty pipe.

Propagating water

Now that we can fill individual pipes with water, we can write the logic to determine which pipes should be filled depending on their orientation.