XNA 4.0 Game Development by Example Beginner's Guide

Time for action – generating new pieces

1. Add the GenerateNewPieces() method to the GameBoard class:

   public void GenerateNewPieces(bool dropSquares)
   {
   
       if (dropSquares)
       {
           for (int x = 0; x < GameBoard.GameBoardWidth; x++)
           {
               for (int y = GameBoard.GameBoardHeight - 1; y >= 0; y--)
               {
                   if (GetSquare(x, y) == "Empty")
                   {
                       FillFromAbove(x, y);
                   }
               }
           }
       }
   
       for (int y = 0; y < GameBoard.GameBoardHeight; y++)
           for (int x = 0; x < GameBoard.GameBoardWidth; x++)
           {
               if (GetSquare(x, y) == "Empty")
               {
                   RandomPiece(x, y);
               }
           }
   }

What just happened?

When GenerateNewPieces() is called with "true" passed as dropSquares, the looping logic processes one column at a time from the bottom up. When it finds an empty square it calls FillFromAbove() to pull a filled square from above ...