+ // Sum white pieces attacking a square, and remove black pieces count.
+ sumAttacks([x, y]) {
+ const getSign = (color) => {
+ return (color == 'w' ? 1 : -1);
+ };
+ let res = 0;
+ // Knights:
+ V.steps[V.KNIGHT].forEach(s => {
+ const [i, j] = [x + s[0], y + s[1]];
+ if (V.OnBoard(i, j) && this.getPiece(i, j) == V.KNIGHT)
+ res += getSign(this.getColor(i, j));
+ });
+ // Kings:
+ V.steps[V.ROOK].concat(V.steps[V.BISHOP]).forEach(s => {
+ const [i, j] = [x + s[0], y + s[1]];
+ if (V.OnBoard(i, j) && this.getPiece(i, j) == V.KING)
+ res += getSign(this.getColor(i, j));
+ });
+ // Pawns:
+ for (let c of ['w', 'b']) {
+ for (let shift of [-1, 1]) {
+ const sign = getSign(c);
+ const [i, j] = [x + sign, y + shift];
+ if (
+ V.OnBoard(i, j) &&
+ this.getPiece(i, j) == V.PAWN &&
+ this.getColor(i, j) == c
+ ) {
+ res += sign;
+ }
+ }
+ }
+ // Other pieces (sliders):
+ V.steps[V.ROOK].concat(V.steps[V.BISHOP]).forEach(s => {
+ let [i, j] = [x + s[0], y + s[1]];
+ let compatible = [V.QUEEN];
+ compatible.push(s[0] == 0 || s[1] == 0 ? V.ROOK : V.BISHOP);
+ let firstCol = undefined;
+ while (V.OnBoard(i, j)) {
+ if (this.board[i][j] != V.EMPTY) {
+ if (!(compatible.includes(this.getPiece(i, j)))) break;
+ const colIJ = this.getColor(i, j);
+ if (!firstCol) firstCol = colIJ;
+ if (colIJ == firstCol) res += getSign(colIJ);
+ else break;
+ }
+ i += s[0];
+ j += s[1];
+ }
+ });
+ return res;
+ }
+
+ getPotentialMovesFrom([x, y]) {
+ let moves = super.getPotentialMovesFrom([x, y]);
+ const color = this.turn;
+ if (this.getPiece(x, y) == V.KING && this.underCheck(color))
+ // The king under check can only move as usual
+ return moves;
+ // Remember current final squares to not add moves twice:
+ const destinations = {};
+ moves.forEach(m => destinations[m.end.x + "_" + m.end.y] = true);
+ for (let i=0; i<8; i++) {
+ for (let j=0; j<8; j++) {
+ if (this.board[i][j] == V.EMPTY && !destinations[i + "_" + j]) {
+ const sa = this.sumAttacks([i, j]);
+ if ((color == 'w' && sa > 0) || (color == 'b' && sa < 0))
+ moves.push(this.getBasicMove([x, y], [i, j]));
+ }
+ }
+ }
+ return moves;
+ }
+
+ static get SEARCH_DEPTH() {
+ return 1;
+ }
projects / vchess.git / commitdiff