Visual Basic.NET How to Program (PDF)

726 Graphics and Multimedia Chapter 16
Fig. 16.26 Chess-game code (part 7 of 9).
The FrmChessSurface Load event (lines 33–45) loads each tile image into
mChessTile. It then calls method ResetBoard to refresh the Form and begin the
game. Method ResetBoard (lines 48–136) assigns mChessPieces to a new Array-
List, loading images for both the black and white chess-piece sets, and creates Bitmap
selected to define the currently selected Bitmap set. Lines 72–134 loop through 64
positions on the chess board, setting the tile color and piece for each tile. Lines 75–77 cause
the currently selected image to switch to the blackPieces after the fifth row. If the row
counter is on the first or last row, lines 83–109 add a new piece to mChessPieces. The
type of the piece is based on the current column we are initializing. Pieces in chess are positioned
in the following order, from left to right: Rook, knight, bishop, queen, king, bishop,
knight and rook. Lines 112–117 add a new pawn at the current location if the current row
is second or seventh.
A chess board is defined by alternating light and dark tiles across a row in a pattern
where the color that starts each row is equal to the color of the last tile of the previous row.
Lines 122–128 assign the current board-tile color as an index in the mBoard array. Based
on the alternating value of Boolean variable light and the results of the random operation
on line 120, 0 and 1 are light tiles, whereas 2 and 3 are dark tiles. Line 133 inverts
the value of light at the end of each row to maintain the staggered effect of a chess board.