Time for action – falling pieces

1. Add a new class to the Flood Control project called "FallingPiece".

2. Add using Microsoft.Xna.Framework; to the using area at the top of the class.

3. Update the declaration of the class to read class FallingPiece : GamePiece

4. Add the following declarations to the FallingPiece class:

   public int VerticalOffset;
   public static int fallRate = 5;

5. Add a constructor for the FallingPiece class:

   public FallingPiece(string pieceType, int verticalOffset)
       : base(pieceType)
   {
       VerticalOffset = verticalOffset;
   }

6. Add a method to update the piece:

   public void UpdatePiece()
   {
       VerticalOffset = (int)MathHelper.Max(
           0, 
           VerticalOffset - fallRate);
   }

What just happened?

Simpler than a RotatingPiece, a FallingPiece is also a child of the GamePiece class. A falling piece has an offset (how high above its final destination it is currently located) and a falling speed (the number of pixels it will move per update).

As with a RotatingPiece, the constructor passes the pieceType...