Time for action – generating falling pieces

1. Modify the FillFromAbove() method of the GameBoard class by adding a call to generate falling pieces right before the rowLookup = -1 line (inside the If block):

   AddFallingPiece(x, y, GetSquare(x, y),
       GamePiece.PieceHeight * (y - rowLookup))

2. Update the GenerateNewPieces() method by adding the following call, right after the RandomPiece(x,y) line as follows:

   AddFallingPiece(x, y, GetSquare(x, y),
       GamePiece.PieceHeight * (GameBoardHeight + 1))

What just happened?

When FillFromAbove() moves a piece downward, we now create an entry in the FallingPieces dictionary that is equivalent to the newly moved piece. The vertical offset is set to the height of a piece (40 pixels) times the number of board squares the piece was moved. For example, if the empty space was at location 5, 5 on the board, and the piece above it (5, 4) is being moved down one block, the animated piece is created at 5, 5 with an offset of 40 pixels (5-4 = 1, times 40).

When new pieces...