import { ChessRules, Move, PiPo } from "@/base_rules";
-export const VariantRules = class CheckeredRules extends ChessRules {
+export class CheckeredRules extends ChessRules {
static board2fen(b) {
const checkered_codes = {
p: "s",
getPotentialMovesFrom([x, y]) {
let standardMoves = super.getPotentialMovesFrom([x, y]);
const lastRank = this.turn == "w" ? 0 : 7;
- // King has to be treated differently (for castles)
+ // King is treated differently: it never turn checkered
if (this.getPiece(x, y) == V.KING) return standardMoves;
let moves = [];
standardMoves.forEach(m => {
if (
Math.abs(m.end.x - m.start.x) == 2 &&
!this.pawnFlags[this.turn][m.start.y]
- )
+ ) {
return; //skip forbidden 2-squares jumps
+ }
if (
this.board[m.end.x][m.end.y] == V.EMPTY &&
m.vanish.length == 2 &&
return; //checkered pawns cannot take en-passant
}
}
- if (m.vanish.length == 1) moves.push(m);
- // No capture
+ if (m.vanish.length == 1)
+ // No capture
+ moves.push(m);
else {
// A capture occured (m.vanish.length == 2)
m.appear[0].c = "c";
moves.push(m);
if (
- m.appear[0].p != m.vanish[1].p && //avoid promotions (already treated):
+ // Avoid promotions (already treated):
+ m.appear[0].p != m.vanish[1].p &&
(m.vanish[0].p != V.PAWN || m.end.x != lastRank)
) {
// Add transformation into captured piece
}
getPotentialPawnMoves([x, y]) {
- const color = this.turn;
- let moves = [];
- const [sizeX, sizeY] = [V.size.x, V.size.y];
- const shiftX = color == "w" ? -1 : 1;
- const startRank = color == "w" ? sizeX - 2 : 1;
- const lastRank = color == "w" ? 0 : sizeX - 1;
- const pawnColor = this.getColor(x, y); //can be checkered
-
- const finalPieces =
- x + shiftX == lastRank
- ? [V.ROOK, V.KNIGHT, V.BISHOP, V.QUEEN]
- : [V.PAWN];
- if (this.board[x + shiftX][y] == V.EMPTY) {
- // One square forward
- for (let piece of finalPieces) {
- moves.push(
- this.getBasicMove([x, y], [x + shiftX, y], {
- c: pawnColor,
- p: piece
- })
- );
- }
- if (
- x == startRank &&
- this.board[x + 2 * shiftX][y] == V.EMPTY
- ) {
- // Two squares jump
- moves.push(this.getBasicMove([x, y], [x + 2 * shiftX, y]));
- }
- }
- // Captures
- for (let shiftY of [-1, 1]) {
- if (
- y + shiftY >= 0 &&
- y + shiftY < sizeY &&
- this.board[x + shiftX][y + shiftY] != V.EMPTY &&
- this.canTake([x, y], [x + shiftX, y + shiftY])
- ) {
- for (let piece of finalPieces) {
- moves.push(
- this.getBasicMove([x, y], [x + shiftX, y + shiftY], {
- c: pawnColor,
- p: piece
- })
- );
- }
- }
- }
-
- // En passant
- const Lep = this.epSquares.length;
- const epSquare = this.epSquares[Lep - 1]; //always at least one element
- if (
- !!epSquare &&
- epSquare.x == x + shiftX &&
- Math.abs(epSquare.y - y) == 1
- ) {
- let enpassantMove = this.getBasicMove([x, y], [epSquare.x, epSquare.y]);
- enpassantMove.vanish.push({
- x: x,
- y: epSquare.y,
- p: "p",
- c: this.getColor(x, epSquare.y)
+ let moves = super.getPotentialPawnMoves([x, y]);
+ // Post-process: set right color for checkered moves
+ if (this.getColor(x, y) == 'c')
+ moves.forEach(m => {
+ m.appear[0].c = 'c'; //may be done twice if capture
+ m.vanish[0].c = 'c';
});
- moves.push(enpassantMove);
- }
-
- return moves;
- }
-
- // Same as in base_rules but with an array given to isAttacked:
- getCastleMoves([x, y]) {
- const c = this.getColor(x, y);
- if (x != (c == "w" ? V.size.x - 1 : 0) || y != this.INIT_COL_KING[c])
- return []; //x isn't first rank, or king has moved (shortcut)
-
- // Castling ?
- const oppCol = V.GetOppCol(c);
- let moves = [];
- let i = 0;
- // King, then rook:
- const finalSquares = [
- [2, 3],
- [V.size.y - 2, V.size.y - 3]
- ];
- castlingCheck: for (
- let castleSide = 0;
- castleSide < 2;
- castleSide++ //large, then small
- ) {
- if (this.castleFlags[c][castleSide] >= V.size.y) continue;
- // If this code is reached, rooks and king are on initial position
-
- // Nothing on the path of the king ? (and no checks)
- const finDist = finalSquares[castleSide][0] - y;
- let step = finDist / Math.max(1, Math.abs(finDist));
- i = y;
- do {
- 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))))
- ) {
- continue castlingCheck;
- }
- i += step;
- } while (i != finalSquares[castleSide][0]);
-
- // Nothing on the path to the rook?
- step = castleSide == 0 ? -1 : 1;
- const rookPos = this.castleFlags[c][castleSide];
- for (i = y + step; i != rookPos; i += step) {
- if (this.board[x][i] != V.EMPTY) continue castlingCheck;
- }
-
- // Nothing on final squares, except maybe king and castling rook?
- for (i = 0; i < 2; i++) {
- if (
- this.board[x][finalSquares[castleSide][i]] != V.EMPTY &&
- this.getPiece(x, finalSquares[castleSide][i]) != V.KING &&
- finalSquares[castleSide][i] != rookPos
- ) {
- continue castlingCheck;
- }
- }
-
- // If this code is reached, castle is valid
- moves.push(
- new Move({
- appear: [
- new PiPo({ x: x, y: finalSquares[castleSide][0], p: V.KING, c: c }),
- new PiPo({ x: x, y: finalSquares[castleSide][1], p: V.ROOK, c: c })
- ],
- vanish: [
- new PiPo({ x: x, y: y, p: V.KING, c: c }),
- new PiPo({ x: x, y: rookPos, p: V.ROOK, c: c })
- ],
- end:
- Math.abs(y - rookPos) <= 2
- ? { x: x, y: rookPos }
- : { x: x, y: y + 2 * (castleSide == 0 ? -1 : 1) }
- })
- );
- }
-
return moves;
}
// colors: array, generally 'w' and 'c' or 'b' and 'c'
isAttacked(sq, colors) {
+ if (!Array.isArray(colors)) colors = [colors];
return (
this.isAttackedByPawn(sq, colors) ||
this.isAttackedByRook(sq, colors) ||
projects / vchess.git / blobdiff