}
}
+// TODO: for animation, moves should contains "moving" and "fading" maybe...
class Move
{
// o: {appear, vanish, [start,] [end,]}
/////////////////
// INITIALIZATION
- // fen = "position flags epSquare movesCount"
+ // fen == "position flags"
constructor(fen, moves)
{
this.moves = moves;
// Use fen string to initialize variables, flags and board
- this.initVariables(fen);
- this.flags = VariantRules.GetFlags(fen);
this.board = VariantRules.GetBoard(fen);
+ this.setFlags(fen);
+ this.initVariables(fen);
}
initVariables(fen)
const position = fenParts[0].split("/");
for (let i=0; i<position.length; i++)
{
- let j = 0;
- while (j < position[i].length)
+ let k = 0; //column index on board
+ for (let j=0; j<position[i].length; j++)
{
switch (position[i].charAt(j))
{
case 'k':
- this.kingPos['b'] = [i,j];
- this.INIT_COL_KING['b'] = j;
+ this.kingPos['b'] = [i,k];
+ this.INIT_COL_KING['b'] = k;
break;
case 'K':
- this.kingPos['w'] = [i,j];
- this.INIT_COL_KING['w'] = j;
+ this.kingPos['w'] = [i,k];
+ this.INIT_COL_KING['w'] = k;
break;
case 'r':
if (this.INIT_COL_ROOK['b'][0] < 0)
- this.INIT_COL_ROOK['b'][0] = j;
+ this.INIT_COL_ROOK['b'][0] = k;
else
- this.INIT_COL_ROOK['b'][1] = j;
+ this.INIT_COL_ROOK['b'][1] = k;
break;
case 'R':
if (this.INIT_COL_ROOK['w'][0] < 0)
- this.INIT_COL_ROOK['w'][0] = j;
+ this.INIT_COL_ROOK['w'][0] = k;
else
- this.INIT_COL_ROOK['w'][1] = j;
+ this.INIT_COL_ROOK['w'][1] = k;
break;
default:
let num = parseInt(position[i].charAt(j));
if (!isNaN(num))
- j += (num-1);
+ k += (num-1);
}
- j++;
+ k++;
}
}
- let epSq = undefined;
- if (fenParts[2] != "-")
- {
- const digits = fenParts[2].split(","); //3,2 ...
- epSq = { x:Number.parseInt(digits[0]), y:Number.parseInt(digits[1]) };
- }
+ const epSq = this.moves.length > 0 ? this.getEpSquare(this.lastMove) : undefined;
this.epSquares = [ epSq ];
- this.movesCount = Number.parseInt(fenParts[3]);
}
// Turn diagram fen into double array ["wb","wp","bk",...]
static GetBoard(fen)
{
let rows = fen.split(" ")[0].split("/");
- let [sizeX,sizeY] = VariantRules.size;
+ const [sizeX,sizeY] = VariantRules.size;
let board = doubleArray(sizeX, sizeY, "");
for (let i=0; i<rows.length; i++)
{
return board;
}
- // Overridable: flags can change a lot
- static GetFlags(fen)
+ // Extract (relevant) flags from fen
+ setFlags(fen)
{
// white a-castle, h-castle, black a-castle, h-castle
- let flags = {'w': new Array(2), 'b': new Array(2)};
- let fenFlags = fen.split(" ")[1]; //flags right after position
+ this.castleFlags = {'w': new Array(2), 'b': new Array(2)};
+ let flags = fen.split(" ")[1]; //flags right after position
for (let i=0; i<4; i++)
- flags[i < 2 ? 'w' : 'b'][i%2] = (fenFlags.charAt(i) == '1');
- return flags;
+ this.castleFlags[i < 2 ? 'w' : 'b'][i%2] = (flags.charAt(i) == '1');
}
///////////////////
// GETTERS, SETTERS
- // Simple useful getters
static get size() { return [8,8]; }
// Two next functions return 'undefined' if called on empty square
getColor(i,j) { return this.board[i][j].charAt(0); }
return L>0 ? this.moves[L-1] : null;
}
get turn() {
- return this.movesCount%2==0 ? 'w' : 'b';
+ return this.moves.length%2==0 ? 'w' : 'b';
}
// Pieces codes
'r': [ [-1,0],[1,0],[0,-1],[0,1] ],
'n': [ [-1,-2],[-1,2],[1,-2],[1,2],[-2,-1],[-2,1],[2,-1],[2,1] ],
'b': [ [-1,-1],[-1,1],[1,-1],[1,1] ],
- 'q': [ [-1,0],[1,0],[0,-1],[0,1],[-1,-1],[-1,1],[1,-1],[1,1] ]
};
}
+ // Aggregates flags into one object
+ get flags() {
+ return this.castleFlags;
+ }
+
+ // Reverse operation
+ parseFlags(flags)
+ {
+ this.castleFlags = flags;
+ }
+
// En-passant square, if any
getEpSquare(move)
{
return undefined; //default
}
- // can color1 take color2?
- canTake(color1, color2)
+ // Can thing on square1 take thing on square2
+ canTake([x1,y1], [x2,y2])
{
- return color1 != color2;
+ return this.getColor(x1,y1) != this.getColor(x2,y2);
}
///////////////////
// All possible moves from selected square (assumption: color is OK)
getPotentialMovesFrom([x,y])
{
- let c = this.getColor(x,y);
- // Fill possible moves according to piece type
switch (this.getPiece(x,y))
{
case VariantRules.PAWN:
- return this.getPotentialPawnMoves(x,y,c);
+ return this.getPotentialPawnMoves([x,y]);
case VariantRules.ROOK:
- return this.getPotentialRookMoves(x,y,c);
+ return this.getPotentialRookMoves([x,y]);
case VariantRules.KNIGHT:
- return this.getPotentialKnightMoves(x,y,c);
+ return this.getPotentialKnightMoves([x,y]);
case VariantRules.BISHOP:
- return this.getPotentialBishopMoves(x,y,c);
+ return this.getPotentialBishopMoves([x,y]);
case VariantRules.QUEEN:
- return this.getPotentialQueenMoves(x,y,c);
+ return this.getPotentialQueenMoves([x,y]);
case VariantRules.KING:
- return this.getPotentialKingMoves(x,y,c);
+ return this.getPotentialKingMoves([x,y]);
}
}
// Build a regular move from its initial and destination squares; tr: transformation
- getBasicMove(sx, sy, ex, ey, tr)
+ getBasicMove([sx,sy], [ex,ey], tr)
{
- var mv = new Move({
+ let mv = new Move({
appear: [
new PiPo({
x: ex,
y: ey,
- c: this.getColor(sx,sy),
- p: !!tr ? tr : this.getPiece(sx,sy)
+ c: !!tr ? tr.c : this.getColor(sx,sy),
+ p: !!tr ? tr.p : this.getPiece(sx,sy)
})
],
vanish: [
}
// Generic method to find possible moves of non-pawn pieces ("sliding or jumping")
- getSlideNJumpMoves(x, y, color, steps, oneStep)
+ getSlideNJumpMoves([x,y], steps, oneStep)
{
- var moves = [];
- let [sizeX,sizeY] = VariantRules.size;
+ const color = this.getColor(x,y);
+ let moves = [];
+ const [sizeX,sizeY] = VariantRules.size;
outerLoop:
for (let step of steps)
{
- var i = x + step[0];
- var j = y + step[1];
+ let i = x + step[0];
+ let j = y + step[1];
while (i>=0 && i<sizeX && j>=0 && j<sizeY
&& this.board[i][j] == VariantRules.EMPTY)
{
- moves.push(this.getBasicMove(x, y, i, j));
+ moves.push(this.getBasicMove([x,y], [i,j]));
if (oneStep !== undefined)
continue outerLoop;
i += step[0];
j += step[1];
}
- if (i>=0 && i<8 && j>=0 && j<8 && this.canTake(color, this.getColor(i,j)))
- moves.push(this.getBasicMove(x, y, i, j));
+ if (i>=0 && i<sizeX && j>=0 && j<sizeY && this.canTake([x,y], [i,j]))
+ moves.push(this.getBasicMove([x,y], [i,j]));
}
return moves;
}
- // What are the pawn moves from square x,y considering color "color" ?
- getPotentialPawnMoves(x, y, color)
+ // What are the pawn moves from square x,y ?
+ getPotentialPawnMoves([x,y])
{
- var moves = [];
- var V = VariantRules;
- let [sizeX,sizeY] = VariantRules.size;
- let shift = (color == "w" ? -1 : 1);
- let startRank = (color == "w" ? sizeY-2 : 1);
- let lastRank = (color == "w" ? 0 : sizeY-1);
+ const color = this.turn;
+ let moves = [];
+ const V = VariantRules;
+ const [sizeX,sizeY] = V.size;
+ const shift = (color == "w" ? -1 : 1);
+ const firstRank = (color == 'w' ? sizeX-1 : 0);
+ const startRank = (color == "w" ? sizeX-2 : 1);
+ const lastRank = (color == "w" ? 0 : sizeX-1);
if (x+shift >= 0 && x+shift < sizeX && x+shift != lastRank)
{
// Normal moves
if (this.board[x+shift][y] == V.EMPTY)
{
- moves.push(this.getBasicMove(x, y, x+shift, y));
- if (x==startRank && this.board[x+2*shift][y] == V.EMPTY)
+ moves.push(this.getBasicMove([x,y], [x+shift,y]));
+ // Next condition because variants with pawns on 1st rank allow them to jump
+ if ([startRank,firstRank].includes(x) && this.board[x+2*shift][y] == V.EMPTY)
{
// Two squares jump
- moves.push(this.getBasicMove(x, y, x+2*shift, y));
+ moves.push(this.getBasicMove([x,y], [x+2*shift,y]));
}
}
// Captures
- if (y>0 && this.canTake(this.getColor(x,y), this.getColor(x+shift,y-1))
+ if (y>0 && this.canTake([x,y], [x+shift,y-1])
&& this.board[x+shift][y-1] != V.EMPTY)
{
- moves.push(this.getBasicMove(x, y, x+shift, y-1));
+ moves.push(this.getBasicMove([x,y], [x+shift,y-1]));
}
- if (y<sizeY-1 && this.canTake(this.getColor(x,y), this.getColor(x+shift,y+1))
+ if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1])
&& this.board[x+shift][y+1] != V.EMPTY)
{
- moves.push(this.getBasicMove(x, y, x+shift, y+1));
+ moves.push(this.getBasicMove([x,y], [x+shift,y+1]));
}
}
if (x+shift == lastRank)
{
// Promotion
+ const pawnColor = this.getColor(x,y); //can be different for checkered
let promotionPieces = [V.ROOK,V.KNIGHT,V.BISHOP,V.QUEEN];
promotionPieces.forEach(p => {
// Normal move
if (this.board[x+shift][y] == V.EMPTY)
- moves.push(this.getBasicMove(x, y, x+shift, y, p));
+ moves.push(this.getBasicMove([x,y], [x+shift,y], {c:pawnColor,p:p}));
// Captures
- if (y>0 && this.canTake(this.getColor(x,y), this.getColor(x+shift,y-1))
+ if (y>0 && this.canTake([x,y], [x+shift,y-1])
&& this.board[x+shift][y-1] != V.EMPTY)
{
- moves.push(this.getBasicMove(x, y, x+shift, y-1, p));
+ moves.push(this.getBasicMove([x,y], [x+shift,y-1], {c:pawnColor,p:p}));
}
- if (y<sizeY-1 && this.canTake(this.getColor(x,y), this.getColor(x+shift,y+1))
+ if (y<sizeY-1 && this.canTake([x,y], [x+shift,y+1])
&& this.board[x+shift][y+1] != V.EMPTY)
{
- moves.push(this.getBasicMove(x, y, x+shift, y+1, p));
+ moves.push(this.getBasicMove([x,y], [x+shift,y+1], {c:pawnColor,p:p}));
}
});
}
if (!!epSquare && epSquare.x == x+shift && Math.abs(epSquare.y - y) == 1)
{
let epStep = epSquare.y - y;
- var enpassantMove = this.getBasicMove(x, y, x+shift, y+epStep);
+ var enpassantMove = this.getBasicMove([x,y], [x+shift,y+epStep]);
enpassantMove.vanish.push({
x: x,
y: y+epStep,
}
// What are the rook moves from square x,y ?
- getPotentialRookMoves(x, y, color)
+ getPotentialRookMoves(sq)
{
- return this.getSlideNJumpMoves(
- x, y, color, VariantRules.steps[VariantRules.ROOK]);
+ return this.getSlideNJumpMoves(sq, VariantRules.steps[VariantRules.ROOK]);
}
// What are the knight moves from square x,y ?
- getPotentialKnightMoves(x, y, color)
+ getPotentialKnightMoves(sq)
{
- return this.getSlideNJumpMoves(
- x, y, color, VariantRules.steps[VariantRules.KNIGHT], "oneStep");
+ return this.getSlideNJumpMoves(sq, VariantRules.steps[VariantRules.KNIGHT], "oneStep");
}
// What are the bishop moves from square x,y ?
- getPotentialBishopMoves(x, y, color)
+ getPotentialBishopMoves(sq)
{
- return this.getSlideNJumpMoves(
- x, y, color, VariantRules.steps[VariantRules.BISHOP]);
+ return this.getSlideNJumpMoves(sq, VariantRules.steps[VariantRules.BISHOP]);
}
// What are the queen moves from square x,y ?
- getPotentialQueenMoves(x, y, color)
+ getPotentialQueenMoves(sq)
{
- return this.getSlideNJumpMoves(
- x, y, color, VariantRules.steps[VariantRules.QUEEN]);
+ const V = VariantRules;
+ return this.getSlideNJumpMoves(sq, V.steps[V.ROOK].concat(V.steps[V.BISHOP]));
}
// What are the king moves from square x,y ?
- getPotentialKingMoves(x, y, c)
+ getPotentialKingMoves(sq)
{
+ const V = VariantRules;
// Initialize with normal moves
- var moves = this.getSlideNJumpMoves(x, y, c,
- VariantRules.steps[VariantRules.QUEEN], "oneStep");
-
- return moves.concat(this.getCastleMoves(x,y,c));
+ let moves = this.getSlideNJumpMoves(sq,
+ V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
+ return moves.concat(this.getCastleMoves(sq));
}
- getCastleMoves(x,y,c)
+ getCastleMoves([x,y])
{
- if (x != (c=="w" ? 7 : 0) || y != this.INIT_COL_KING[c])
+ const c = this.getColor(x,y);
+ const [sizeX,sizeY] = VariantRules.size;
+ if (x != (c=="w" ? sizeX-1 : 0) || y != this.INIT_COL_KING[c])
return []; //x isn't first rank, or king has moved (shortcut)
const V = VariantRules;
const oppCol = this.getOppCol(c);
let moves = [];
let i = 0;
- const finalSquares = [ [2,3], [6,5] ]; //king, then rook
+ const finalSquares = [ [2,3], [sizeY-2,sizeY-3] ]; //king, then rook
castlingCheck:
for (let castleSide=0; castleSide < 2; castleSide++) //large, then small
{
- if (!this.flags[c][castleSide])
+ if (!this.castleFlags[c][castleSide])
continue;
// If this code is reached, rooks and king are on initial position
let step = finalSquares[castleSide][0] < y ? -1 : 1;
for (i=y; i!=finalSquares[castleSide][0]; i+=step)
{
- if (this.isAttacked([x,i], oppCol) || (this.board[x][i] != V.EMPTY &&
+ if (this.isAttacked([x,i], [oppCol]) || (this.board[x][i] != V.EMPTY &&
// NOTE: next check is enough, because of chessboard constraints
(this.getColor(x,i) != c || ![V.KING,V.ROOK].includes(this.getPiece(x,i)))))
{
///////////////////
// MOVES VALIDATION
- canIplay(color, sq)
+ canIplay(side, [x,y])
{
- return ((color=='w' && this.movesCount%2==0)
- || (color=='b' && this.movesCount%2==1))
- && this.getColor(sq[0], sq[1]) == color;
+ return ((side=='w' && this.moves.length%2==0) || (side=='b' && this.moves.length%2==1))
+ && this.getColor(x,y) == side;
}
getPossibleMovesFrom(sq)
{
if (moves.length == 0)
return [];
- let color = this.getColor( moves[0].start.x, moves[0].start.y );
- return moves.filter(m => {
- return !this.underCheck(m, color);
- });
+ return moves.filter(m => { return !this.underCheck(m); });
}
// Search for all valid moves considering current turn (for engine and game end)
- getAllValidMoves(color)
+ getAllValidMoves()
{
+ const color = this.turn;
const oppCol = this.getOppCol(color);
- var potentialMoves = [];
- let [sizeX,sizeY] = VariantRules.size;
- for (var i=0; i<sizeX; i++)
+ let potentialMoves = [];
+ const [sizeX,sizeY] = VariantRules.size;
+ for (let i=0; i<sizeX; i++)
{
- for (var j=0; j<sizeY; j++)
+ for (let j=0; j<sizeY; j++)
{
// Next condition ... != oppCol is a little HACK to work with checkered variant
if (this.board[i][j] != VariantRules.EMPTY && this.getColor(i,j) != oppCol)
// No: if happen on last 1/2 move, could lead to forbidden moves, wrong evals
return this.filterValid(potentialMoves);
}
-
+
// Stop at the first move found
- atLeastOneMove(color)
+ atLeastOneMove()
{
+ const color = this.turn;
const oppCol = this.getOppCol(color);
- let [sizeX,sizeY] = VariantRules.size;
- for (var i=0; i<sizeX; i++)
+ const [sizeX,sizeY] = VariantRules.size;
+ for (let i=0; i<sizeX; i++)
{
- for (var j=0; j<sizeY; j++)
+ for (let j=0; j<sizeY; j++)
{
if (this.board[i][j] != VariantRules.EMPTY && this.getColor(i,j) != oppCol)
{
const moves = this.getPotentialMovesFrom([i,j]);
if (moves.length > 0)
{
- for (let i=0; i<moves.length; i++)
+ for (let k=0; k<moves.length; k++)
{
- if (this.filterValid([moves[i]]).length > 0)
+ if (this.filterValid([moves[k]]).length > 0)
return true;
}
}
return false;
}
- // Check if pieces of color 'color' are attacking square x,y
- isAttacked(sq, color)
+ // Check if pieces of color in array 'colors' are attacking square x,y
+ isAttacked(sq, colors)
{
- return (this.isAttackedByPawn(sq, color)
- || this.isAttackedByRook(sq, color)
- || this.isAttackedByKnight(sq, color)
- || this.isAttackedByBishop(sq, color)
- || this.isAttackedByQueen(sq, color)
- || this.isAttackedByKing(sq, color));
+ return (this.isAttackedByPawn(sq, colors)
+ || this.isAttackedByRook(sq, colors)
+ || this.isAttackedByKnight(sq, colors)
+ || this.isAttackedByBishop(sq, colors)
+ || this.isAttackedByQueen(sq, colors)
+ || this.isAttackedByKing(sq, colors));
}
- // Is square x,y attacked by pawns of color c ?
- isAttackedByPawn([x,y], c)
+ // Is square x,y attacked by 'colors' pawns ?
+ isAttackedByPawn([x,y], colors)
{
- let pawnShift = (c=="w" ? 1 : -1);
- if (x+pawnShift>=0 && x+pawnShift<8)
+ const [sizeX,sizeY] = VariantRules.size;
+ for (let c of colors)
{
- for (let i of [-1,1])
+ let pawnShift = (c=="w" ? 1 : -1);
+ if (x+pawnShift>=0 && x+pawnShift<sizeX)
{
- if (y+i>=0 && y+i<8 && this.getPiece(x+pawnShift,y+i)==VariantRules.PAWN
- && this.getColor(x+pawnShift,y+i)==c)
+ for (let i of [-1,1])
{
- return true;
+ if (y+i>=0 && y+i<sizeY && this.getPiece(x+pawnShift,y+i)==VariantRules.PAWN
+ && this.getColor(x+pawnShift,y+i)==c)
+ {
+ return true;
+ }
}
}
}
return false;
}
- // Is square x,y attacked by rooks of color c ?
- isAttackedByRook(sq, color)
+ // Is square x,y attacked by 'colors' rooks ?
+ isAttackedByRook(sq, colors)
{
- return this.isAttackedBySlideNJump(sq, color,
+ return this.isAttackedBySlideNJump(sq, colors,
VariantRules.ROOK, VariantRules.steps[VariantRules.ROOK]);
}
- // Is square x,y attacked by knights of color c ?
- isAttackedByKnight(sq, color)
+ // Is square x,y attacked by 'colors' knights ?
+ isAttackedByKnight(sq, colors)
{
- return this.isAttackedBySlideNJump(sq, color,
+ return this.isAttackedBySlideNJump(sq, colors,
VariantRules.KNIGHT, VariantRules.steps[VariantRules.KNIGHT], "oneStep");
}
- // Is square x,y attacked by bishops of color c ?
- isAttackedByBishop(sq, color)
+ // Is square x,y attacked by 'colors' bishops ?
+ isAttackedByBishop(sq, colors)
{
- return this.isAttackedBySlideNJump(sq, color,
+ return this.isAttackedBySlideNJump(sq, colors,
VariantRules.BISHOP, VariantRules.steps[VariantRules.BISHOP]);
}
- // Is square x,y attacked by queens of color c ?
- isAttackedByQueen(sq, color)
+ // Is square x,y attacked by 'colors' queens ?
+ isAttackedByQueen(sq, colors)
{
- return this.isAttackedBySlideNJump(sq, color,
- VariantRules.QUEEN, VariantRules.steps[VariantRules.QUEEN]);
+ const V = VariantRules;
+ return this.isAttackedBySlideNJump(sq, colors, V.QUEEN,
+ V.steps[V.ROOK].concat(V.steps[V.BISHOP]));
}
- // Is square x,y attacked by king of color c ?
- isAttackedByKing(sq, color)
+ // Is square x,y attacked by 'colors' king(s) ?
+ isAttackedByKing(sq, colors)
{
- return this.isAttackedBySlideNJump(sq, color,
- VariantRules.KING, VariantRules.steps[VariantRules.QUEEN], "oneStep");
+ const V = VariantRules;
+ return this.isAttackedBySlideNJump(sq, colors, V.KING,
+ V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
}
- // Generic method for non-pawn pieces ("sliding or jumping"): is x,y attacked by piece != color ?
- isAttackedBySlideNJump([x,y], c,piece,steps,oneStep)
+ // Generic method for non-pawn pieces ("sliding or jumping"):
+ // is x,y attacked by a piece of color in array 'colors' ?
+ isAttackedBySlideNJump([x,y], colors, piece, steps, oneStep)
{
+ const [sizeX,sizeY] = VariantRules.size;
for (let step of steps)
{
let rx = x+step[0], ry = y+step[1];
- while (rx>=0 && rx<8 && ry>=0 && ry<8 && this.board[rx][ry] == VariantRules.EMPTY
- && !oneStep)
+ while (rx>=0 && rx<sizeX && ry>=0 && ry<sizeY
+ && this.board[rx][ry] == VariantRules.EMPTY && !oneStep)
{
rx += step[0];
ry += step[1];
}
- if (rx>=0 && rx<8 && ry>=0 && ry<8 && this.board[rx][ry] != VariantRules.EMPTY
- && this.getPiece(rx,ry) == piece && this.getColor(rx,ry) == c)
+ if (rx>=0 && rx<sizeX && ry>=0 && ry<sizeY
+ && this.board[rx][ry] != VariantRules.EMPTY
+ && this.getPiece(rx,ry) == piece && colors.includes(this.getColor(rx,ry)))
{
return true;
}
return false;
}
- // Is color c under check after move ?
- underCheck(move, c)
+ // Is current player under check after his move ?
+ underCheck(move)
{
+ const color = this.turn;
this.play(move);
- let res = this.isAttacked(this.kingPos[c], this.getOppCol(c));
+ let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)]);
this.undo(move);
return res;
}
- // On which squares is color c under check (after move) ?
- getCheckSquares(move, c)
+ // On which squares is opponent under check after our move ?
+ getCheckSquares(move)
{
this.play(move);
- let res = this.isAttacked(this.kingPos[c], this.getOppCol(c))
- ? [ JSON.parse(JSON.stringify(this.kingPos[c])) ] //need to duplicate!
+ const color = this.turn; //opponent
+ let res = this.isAttacked(this.kingPos[color], [this.getOppCol(color)])
+ ? [ JSON.parse(JSON.stringify(this.kingPos[color])) ] //need to duplicate!
: [ ];
this.undo(move);
return res;
board[psq.x][psq.y] = psq.c + psq.p;
}
- // Before move is played:
+ // Before move is played, update variables + flags
updateVariables(move)
{
const piece = this.getPiece(move.start.x,move.start.y);
const c = this.getColor(move.start.x,move.start.y);
- const firstRank = (c == "w" ? 7 : 0);
+ const [sizeX,sizeY] = VariantRules.size;
+ const firstRank = (c == "w" ? sizeX-1 : 0);
// Update king position + flags
if (piece == VariantRules.KING && move.appear.length > 0)
{
this.kingPos[c][0] = move.appear[0].x;
this.kingPos[c][1] = move.appear[0].y;
- this.flags[c] = [false,false];
+ this.castleFlags[c] = [false,false];
return;
}
const oppCol = this.getOppCol(c);
- const oppFirstRank = 7 - firstRank;
+ const oppFirstRank = (sizeX-1) - firstRank;
if (move.start.x == firstRank //our rook moves?
&& this.INIT_COL_ROOK[c].includes(move.start.y))
{
- const flagIdx = move.start.y == this.INIT_COL_ROOK[c][0] ? 0 : 1;
- this.flags[c][flagIdx] = false;
+ const flagIdx = (move.start.y == this.INIT_COL_ROOK[c][0] ? 0 : 1);
+ this.castleFlags[c][flagIdx] = false;
}
else if (move.end.x == oppFirstRank //we took opponent rook?
- && this.INIT_COL_ROOK[c].includes(move.end.y))
+ && this.INIT_COL_ROOK[oppCol].includes(move.end.y))
{
- const flagIdx = move.end.y == this.INIT_COL_ROOK[oppCol][0] ? 0 : 1;
- this.flags[oppCol][flagIdx] = false;
+ const flagIdx = (move.end.y == this.INIT_COL_ROOK[oppCol][0] ? 0 : 1);
+ this.castleFlags[oppCol][flagIdx] = false;
}
}
- play(move, ingame)
+ // After move is undo-ed, un-update variables (flags are reset)
+ // TODO: more symmetry, by storing flags increment in move...
+ unupdateVariables(move)
{
- // Save flags (for undo)
- move.flags = JSON.stringify(this.flags); //TODO: less costly
- this.updateVariables(move);
+ // (Potentially) Reset king position
+ const c = this.getColor(move.start.x,move.start.y);
+ if (this.getPiece(move.start.x,move.start.y) == VariantRules.KING)
+ this.kingPos[c] = [move.start.x, move.start.y];
+ }
+ play(move, ingame)
+ {
if (!!ingame)
- {
- move.notation = this.getNotation(move);
- this.moves.push(move);
- }
+ move.notation = [this.getNotation(move), this.getLongNotation(move)];
+ move.flags = JSON.stringify(this.flags); //save flags (for undo)
+ this.updateVariables(move);
+ this.moves.push(move);
this.epSquares.push( this.getEpSquare(move) );
VariantRules.PlayOnBoard(this.board, move);
- this.movesCount++;
}
- undo(move, ingame)
+ undo(move)
{
VariantRules.UndoOnBoard(this.board, move);
this.epSquares.pop();
- this.movesCount--;
-
- if (!!ingame)
- this.moves.pop();
-
- // Update king position, and reset stored/computed flags
- const c = this.getColor(move.start.x,move.start.y);
- if (this.getPiece(move.start.x,move.start.y) == VariantRules.KING)
- this.kingPos[c] = [move.start.x, move.start.y];
-
- this.flags = JSON.parse(move.flags);
+ this.moves.pop();
+ this.unupdateVariables(move);
+ this.parseFlags(JSON.parse(move.flags));
}
//////////////
// END OF GAME
- checkGameOver(color)
+ // Basic check for 3 repetitions (in the last moves only)
+ checkRepetition()
{
- // Check for 3 repetitions
if (this.moves.length >= 8)
{
- // NOTE: crude detection, only moves repetition
const L = this.moves.length;
if (_.isEqual(this.moves[L-1], this.moves[L-5]) &&
_.isEqual(this.moves[L-2], this.moves[L-6]) &&
_.isEqual(this.moves[L-3], this.moves[L-7]) &&
_.isEqual(this.moves[L-4], this.moves[L-8]))
{
- return "1/2 (repetition)";
+ return true;
}
}
+ return false;
+ }
- if (this.atLeastOneMove(color))
- {
- // game not over
+ // Is game over ? And if yes, what is the score ?
+ checkGameOver()
+ {
+ if (this.checkRepetition())
+ return "1/2";
+
+ if (this.atLeastOneMove()) // game not over
return "*";
- }
// Game over
- return this.checkGameEnd(color);
+ return this.checkGameEnd();
}
- // Useful stand-alone for engine
- checkGameEnd(color)
+ // No moves are possible: compute score
+ checkGameEnd()
{
+ const color = this.turn;
// No valid move: stalemate or checkmate?
- if (!this.isAttacked(this.kingPos[color], this.getOppCol(color)))
+ if (!this.isAttacked(this.kingPos[color], [this.getOppCol(color)]))
return "1/2";
// OK, checkmate
return color == "w" ? "0-1" : "1-0";
};
}
+ static get INFINITY() {
+ return 9999; //"checkmate" (unreachable eval)
+ }
+
+ static get THRESHOLD_MATE() {
+ // At this value or above, the game is over
+ return VariantRules.INFINITY;
+ }
+
+ static get SEARCH_DEPTH() {
+ return 3; //2 for high branching factor, 4 for small (Loser chess)
+ }
+
// Assumption: at least one legal move
- getComputerMove(color)
+ // NOTE: works also for extinction chess because depth is 3...
+ getComputerMove()
{
- const oppCol = this.getOppCol(color);
+ this.shouldReturn = false;
+ const maxeval = VariantRules.INFINITY;
+ const color = this.turn;
+ // Some variants may show a bigger moves list to the human (Switching),
+ // thus the argument "computer" below (which is generally ignored)
+ let moves1 = this.getAllValidMoves("computer");
+
+ // Can I mate in 1 ? (for Magnetic & Extinction)
+ for (let i of _.shuffle(_.range(moves1.length)))
+ {
+ this.play(moves1[i]);
+ const finish = (Math.abs(this.evalPosition()) >= VariantRules.THRESHOLD_MATE);
+ this.undo(moves1[i]);
+ if (finish)
+ return moves1[i];
+ }
// Rank moves using a min-max at depth 2
- let moves1 = this.getAllValidMoves(color);
-
for (let i=0; i<moves1.length; i++)
{
- moves1[i].eval = (color=="w" ? -1 : 1) * 1000; //very low, I'm checkmated
- let eval2 = (color=="w" ? 1 : -1) * 1000; //initialized with very high (checkmate) value
+ moves1[i].eval = (color=="w" ? -1 : 1) * maxeval; //very low, I'm checkmated
this.play(moves1[i]);
- // Second half-move:
- let moves2 = this.getAllValidMoves(oppCol);
- // If no possible moves AND underCheck, eval2 is correct.
- // If !underCheck, eval2 is 0 (stalemate).
- if (moves2.length == 0 && this.checkGameEnd(oppCol) == "1/2")
- eval2 = 0;
- for (let j=0; j<moves2.length; j++)
+ let eval2 = undefined;
+ if (this.atLeastOneMove())
+ {
+ eval2 = (color=="w" ? 1 : -1) * maxeval; //initialized with checkmate value
+ // Second half-move:
+ let moves2 = this.getAllValidMoves("computer");
+ for (let j=0; j<moves2.length; j++)
+ {
+ this.play(moves2[j]);
+ let evalPos = undefined;
+ if (this.atLeastOneMove())
+ evalPos = this.evalPosition()
+ else
+ {
+ // Work with scores for Loser variant
+ const score = this.checkGameEnd();
+ evalPos = (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval);
+ }
+ if ((color == "w" && evalPos < eval2) || (color=="b" && evalPos > eval2))
+ eval2 = evalPos;
+ this.undo(moves2[j]);
+ }
+ }
+ else
{
- this.play(moves2[j]);
- let evalPos = this.evalPosition();
- if ((color == "w" && evalPos < eval2) || (color=="b" && evalPos > eval2))
- eval2 = evalPos;
- this.undo(moves2[j]);
+ const score = this.checkGameEnd();
+ eval2 = (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval);
}
if ((color=="w" && eval2 > moves1[i].eval) || (color=="b" && eval2 < moves1[i].eval))
moves1[i].eval = eval2;
this.undo(moves1[i]);
}
moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
-
- // TODO: show current analyzed move for depth 3, allow stopping eval (return moves1[0])
- for (let i=0; i<moves1.length; i++)
- {
- this.play(moves1[i]);
- // 0.1 * oldEval : heuristic to avoid some bad moves (not all...)
- moves1[i].eval = 0.1*moves1[i].eval + this.alphabeta(oppCol, color, 2, -1000, 1000);
- this.undo(moves1[i]);
- }
- moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
+ //console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));
let candidates = [0]; //indices of candidates moves
for (let j=1; j<moves1.length && moves1[j].eval == moves1[0].eval; j++)
candidates.push(j);
+ let currentBest = moves1[_.sample(candidates, 1)];
+ // Skip depth 3+ if we found a checkmate (or if we are checkmated in 1...)
+ if (VariantRules.SEARCH_DEPTH >= 3
+ && Math.abs(moves1[0].eval) < VariantRules.THRESHOLD_MATE)
+ {
+ for (let i=0; i<moves1.length; i++)
+ {
+ if (this.shouldReturn)
+ return currentBest; //depth-2, minimum
+ this.play(moves1[i]);
+ // 0.1 * oldEval : heuristic to avoid some bad moves (not all...)
+ moves1[i].eval = 0.1*moves1[i].eval +
+ this.alphabeta(VariantRules.SEARCH_DEPTH-1, -maxeval, maxeval);
+ this.undo(moves1[i]);
+ }
+ moves1.sort( (a,b) => { return (color=="w" ? 1 : -1) * (b.eval - a.eval); });
+ }
+ else
+ return currentBest;
//console.log(moves1.map(m => { return [this.getNotation(m), m.eval]; }));
+
+ candidates = [0];
+ for (let j=1; j<moves1.length && moves1[j].eval == moves1[0].eval; j++)
+ candidates.push(j);
return moves1[_.sample(candidates, 1)];
}
- alphabeta(color, oppCol, depth, alpha, beta)
+ alphabeta(depth, alpha, beta)
{
- const moves = this.getAllValidMoves(color);
- if (moves.length == 0)
+ const maxeval = VariantRules.INFINITY;
+ const color = this.turn;
+ if (!this.atLeastOneMove())
{
- switch (this.checkGameEnd(color))
+ switch (this.checkGameEnd())
{
- case "1/2": return 0;
- default: return color=="w" ? -1000 : 1000;
+ case "1/2":
+ return 0;
+ default:
+ const score = this.checkGameEnd();
+ return (score=="1/2" ? 0 : (score=="1-0" ? 1 : -1) * maxeval);
}
}
if (depth == 0)
return this.evalPosition();
- let v = color=="w" ? -1000 : 1000;
+ const moves = this.getAllValidMoves("computer");
+ let v = color=="w" ? -maxeval : maxeval;
if (color == "w")
{
for (let i=0; i<moves.length; i++)
{
this.play(moves[i]);
- v = Math.max(v, this.alphabeta(oppCol, color, depth-1, alpha, beta));
+ v = Math.max(v, this.alphabeta(depth-1, alpha, beta));
this.undo(moves[i]);
alpha = Math.max(alpha, v);
if (alpha >= beta)
for (let i=0; i<moves.length; i++)
{
this.play(moves[i]);
- v = Math.min(v, this.alphabeta(oppCol, color, depth-1, alpha, beta));
+ v = Math.min(v, this.alphabeta(depth-1, alpha, beta));
this.undo(moves[i]);
beta = Math.min(beta, v);
if (alpha >= beta)
{
const [sizeX,sizeY] = VariantRules.size;
let evaluation = 0;
- //Just count material for now
+ // Just count material for now
for (let i=0; i<sizeX; i++)
{
for (let j=0; j<sizeY; j++)
////////////
// FEN utils
- // Overridable..
+ // Setup the initial random (assymetric) position
static GenRandInitFen()
{
let pieces = [new Array(8), new Array(8)];
let fen = pieces[0].join("") +
"/pppppppp/8/8/8/8/PPPPPPPP/" +
pieces[1].join("").toUpperCase() +
- " 1111 - 0"; //flags + enPassant + movesCount
+ " 1111"; //add flags
return fen;
}
// Return current fen according to pieces+colors state
getFen()
{
- const L = this.epSquares.length;
- const epSq = this.epSquares[L-1]===undefined
- ? "-"
- : this.epSquares[L-1].x+","+this.epSquares[L-1].y;
- return this.getBaseFen() + " " + this.getFlagsFen()
- + " " + epSq + " " + this.movesCount;
+ return this.getBaseFen() + " " + this.getFlagsFen();
}
+ // Position part of the FEN string
getBaseFen()
{
let fen = "";
return fen;
}
- // Overridable..
+ // Flags part of the FEN string
getFlagsFen()
{
let fen = "";
for (let i of ['w','b'])
{
for (let j=0; j<2; j++)
- fen += this.flags[i][j] ? '1' : '0';
+ fen += (this.castleFlags[i][j] ? '1' : '0');
}
return fen;
}
// Context: just before move is played, turn hasn't changed
getNotation(move)
{
- if (move.appear.length == 2)
- {
- // Castle
- if (move.end.y < move.start.y)
- return "0-0-0";
- else
- return "0-0";
- }
+ if (move.appear.length == 2 && move.appear[0].p == VariantRules.KING) //castle
+ return (move.end.y < move.start.y ? "0-0-0" : "0-0");
// Translate final square
- let finalSquare =
+ const finalSquare =
String.fromCharCode(97 + move.end.y) + (VariantRules.size[0]-move.end.x);
- let piece = this.getPiece(move.start.x, move.start.y);
+ const piece = this.getPiece(move.start.x, move.start.y);
if (piece == VariantRules.PAWN)
{
// Pawn move
let notation = "";
- if (move.vanish.length > 1)
+ if (move.vanish.length > move.appear.length)
{
// Capture
- let startColumn = String.fromCharCode(97 + move.start.y);
+ const startColumn = String.fromCharCode(97 + move.start.y);
notation = startColumn + "x" + finalSquare;
}
else //no capture
else
{
// Piece movement
- return piece.toUpperCase() + (move.vanish.length > 1 ? "x" : "") + finalSquare;
+ return piece.toUpperCase() +
+ (move.vanish.length > move.appear.length ? "x" : "") + finalSquare;
}
}
+ // Complete the usual notation, may be required for de-ambiguification
+ getLongNotation(move)
+ {
+ const startSquare =
+ String.fromCharCode(97 + move.start.y) + (VariantRules.size[0]-move.start.x);
+ const finalSquare =
+ String.fromCharCode(97 + move.end.y) + (VariantRules.size[0]-move.end.x);
+ return startSquare + finalSquare; //not encoding move. But short+long is enough
+ }
+
// The score is already computed when calling this function
- getPGN(mycolor, score, fenStart)
+ getPGN(mycolor, score, fenStart, mode)
{
+ const zeroPad = x => { return (x<10 ? "0" : "") + x; };
let pgn = "";
pgn += '[Site "vchess.club"]<br>';
const d = new Date();
- pgn += '[Date "' + d.getFullYear() + '-' + d.getMonth() + '-' + d.getDate() + '"]<br>';
- pgn += '[White "' + (mycolor=='w'?'Myself':'Anonymous') + '"]<br>';
- pgn += '[Black "' + (mycolor=='b'?'Myself':'Anonymous') + '"]<br>';
- pgn += '[Fen "' + fenStart + '"]<br>';
+ const opponent = mode=="human" ? "Anonymous" : "Computer";
+ pgn += '[Variant "' + variant + '"]<br>';
+ pgn += '[Date "' + d.getFullYear() + '-' + (d.getMonth()+1) + '-' + zeroPad(d.getDate()) + '"]<br>';
+ pgn += '[White "' + (mycolor=='w'?'Myself':opponent) + '"]<br>';
+ pgn += '[Black "' + (mycolor=='b'?'Myself':opponent) + '"]<br>';
+ pgn += '[FenStart "' + fenStart + '"]<br>';
+ pgn += '[Fen "' + this.getFen() + '"]<br>';
pgn += '[Result "' + score + '"]<br><br>';
+ // Standard PGN
+ for (let i=0; i<this.moves.length; i++)
+ {
+ if (i % 2 == 0)
+ pgn += ((i/2)+1) + ".";
+ pgn += this.moves[i].notation[0] + " ";
+ }
+ pgn += "<br><br>";
+
+ // "Complete moves" PGN (helping in ambiguous cases)
for (let i=0; i<this.moves.length; i++)
{
if (i % 2 == 0)
pgn += ((i/2)+1) + ".";
- pgn += this.moves[i].notation + " ";
+ pgn += this.moves[i].notation[1] + " ";
}
- pgn += score;
return pgn;
}
}
projects / vchess.git / blobdiff