SLU CHESS

By: James Cofield

Dustin Dotson

Travis Larkins

Forest Marie

Accidental Productions 2002

Introduction

• Who are we?

• About our chess program.

Documentation

--Presented by James Cofield

Graphics—A Larkian approach

Please wait while processing….

Chess logic and math

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A B C D E F G H

Setting up the board

char pieceIdentifiers[ 66 ];

strcpy( pieceIdentifiers, “_rnbqkbnrpppppppp ……. PPPPPPPPRNBKQBNR”);

for ( int walker = 1; walker <= 64; i++ )

DrawPieceToBoard( walker, pieceIdentifiers[ walker ] );

X-Y Position

struct Square { int squarePosition; };

int xPosition ( Square & square ) { return ( 1 + ( ( square – 1 ) % 8 ); }

Why not square % 8?

Consider the positions of 8n, where 1 <= n <= 8.

int yPosition( Square & square ) { return 8 – (( square – 1 ) / 8 ); }

Legal Move—Pawnsint moveDifference = abs(xPosition( prevSquarePosition ) ) - abs(xPosition(currSquarePosition)); LegalPawnMove() {if ( yPosition( prevSquarePosition ) == yPosition( currSquarePosition )+ 1 ){ if ( !moveDifference ) // if not zero { if ( pieceIdentifiers[ currSquarePosition ] == ‘ ‘ ) return true; } else if ( moveDifference == 1 ) //Possible capture! if ( ( PieceColor( currSquare ) == Black ) return true; } else if ( ( yPosition( prevSquare == 2 ) && ( yPosition( currSquare == 4 ) ) if ( !moveDifference && pieceIdentifer[ currSquarePosition ] == ‘ ‘ && pieceIdentifier[ prevSquarePosition +currSquarePosition / 2 ] == ‘ ‘ ) return true; else return false; }

Legal Move—Knights int moveDifferenceX = abs(( xPosition( prevSquarePosition ) – xPosition( currSquarePosition ) ); int moveDifferenceY = abs(( yPosition( prevSquarePosition ) – yPosition( currSquarePosition );

if ( moveDifferenceX == 2 && moveDifferenceY == 1 ) if ( PieceColor( currSquarePosition ) == White || pieceIdentifier[ currSquarePosition ] == ‘ ‘ ) return true; else if ( moveDifferenceX == 1 && moveDifferenceY == 2 ) if( PieceColor( currSquarePosition ) == White || pieceIdentifier[ currSquarePosition ] == ‘ ‘ ) return true; else return false;

Legal Move—Bishops int xCoordinate = xPosition( prevSquare ); int yCoordinate = yPosition( prevSquare ); Square boardRunner; int pieceColor = PieceColor( prevSquare );

for ( int x = -1; x <= 1; x+= 2 ) for ( int y = -1; y <= 1; y+= 2 ) for ( int z = 1; z <= 7; z++ ) { boardRunner = MouseToSquare( xCoordinate + x * z, yCoordinate + y * z ); //if the next squre is blank or the opposit= color of *this, test to see if the //drop location equals boardRunner if ( PieceColor( boardRunner ) == BLANK || ( PieceColor( boardRunner ) != pieceColor ) if ( boardRunner == currSquare ) //the location tested equals the dropped location. return true; else if ( PieceColor( boardRunner ) != ‘ ‘ ) break; } return false; //FALSE OTHERWISE

Legal Move—Rook int xCoordinate = xPosition( prevSquare );

int yCoordinate = yPosition( currSquare );

Square boardRunner;

int pieceColor = PieceColor( prevSquare );

//Run up X side.

for ( int x = -1; x <=1; x+= 2 )

for ( int r = -1; r <= 7; r++ )

{

boardRunner = MouseToSquare( xCoordinate + x * r, yCoordinate );

if ( PieceColor( boardRunner ) == BLANK || PieceColor( boardRunner ) != pieceColor )

if ( v == currSquare )

return true;

else if ( PieceColor( boardRunner ) != ‘ ‘ ) break;

}

//Run up Y side.

for ( int y = -1; y <=1; y+= 2 )

for ( int r = 1; r <=7; r++ )

…….

Legal Move—Queens

bool legalQueenMove = legalBishopMove( prevSquarePosition, currSquarePosition );

return ( legalQueenMove == true ) ? legalQueenMove : legalRookMove( prevSquarePosition,

currSquarePosition );

Legal Move—Kings int xCoordinate = xPosition( currSquarePosition );

int yCoordinate = yPosition( currSquarePosition );

int xDifference = abs( ( xPosition( prevSquarePosition ) – xPosition( currSquarePosition ) );

int yDifference = abs( ( yPosition( prevSquarePosition ) – yPosition( currSquarePosition ) );

if ( xDifference <=1 && yDifference <=1 && !whiteInCheck( currSquarePosition )

return true;

if( SquarePositionLiteral(oldSquarePosition ) == E1&& SquarePositionLiteral( currSquarePosition ) == G1&& CastlingAllowed( WhiteKingSide ) && !whiteInCheck( currSquarePosition ) )

return true;

else

if ( SquarePositionLiteral( oldSquarePosition ) == E1 && SquarePositionLiteral( currSquarePosition ) == C1 && CastlingAllowed( WhiteQueenSide ) && !whiteInCheck( currSquarePosition ) )

return true;