return super.getPotentialQueenMoves(sq).concat(this.getKnightCaptures(sq));
}
- getPotentialBishopMoves(sq)
+ getPotentialBishopMoves([x,y])
{
- let moves = super.getPotentialQueenMoves(sq)
- .concat(this.getKnightCaptures(sq,"asChameleon"));
- // NOTE: no "addKingCaptures" because the king isn't captured
+ let moves = super.getPotentialQueenMoves([x,y])
+ .concat(this.getKnightCaptures([x,y],"asChameleon"));
this.addPawnCaptures(moves, "asChameleon");
this.addRookCaptures(moves, "asChameleon");
this.addQueenCaptures(moves, "asChameleon");
+ // Add king capture if it's within range
+ const oppKp = this.kingPos[this.getOppCol(this.turn)];
+ if (Math.abs(x-oppKp[0]) <= 1 && Math.abs(y-oppKp[1]) <= 1)
+ moves.push(this.getBasicMove([x,y],oppKp));
// Post-processing: merge similar moves, concatenating vanish arrays
let mergedMoves = {};
const [sizeX,sizeY] = VariantRules.size;
V.steps[V.ROOK].concat(V.steps[V.BISHOP]), "oneStep");
}
- // isAttacked() is OK because the immobilizer doesn't take
-
- isAttackedByPawn([x,y], colors)
+ // TODO: verify this assertion
+ atLeastOneMove()
{
- // Square (x,y) must be surrounded by two enemy pieces,
- // and one of them at least should be a pawn.
- const dirs = [ [1,0],[0,1],[1,1],[-1,1] ];
- const [sizeX,sizeY] = VariantRules.size;
- for (let dir of dirs)
- {
- const [i1,j1] = [x-dir[0],y-dir[1]]; //"before"
- const [i2,j2] = [x+dir[0],y+dir[1]]; //"after"
- if (i1>=0 && i1<sizeX && i2>=0 && i2<sizeX
- && j1>=0 && j1<sizeY && j2>=0 && j2<sizeY
- && this.board[i1][j1]!=VariantRules.EMPTY
- && this.board[i2][j2]!=VariantRules.EMPTY
- && colors.includes(this.getColor(i1,j1))
- && colors.includes(this.getColor(i2,j2))
- && [this.getPiece(i1,j1),this.getPiece(i2,j2)].includes(VariantRules.PAWN))
- {
- return true;
- }
- }
- return false;
+ return true; //always at least one possible move
}
- isAttackedByRook([x,y], colors)
+ underCheck(move)
{
- const [sizeX,sizeY] = VariantRules.size;
- // King must be on same column and a rook on same row (or reverse)
- if (x == this.kingPos[colors[0]][0]) //using colors[0], only element in this case
- {
- // Look for enemy rook on this column
- for (let i=0; i<sizeY; i++)
- {
- if (this.board[x][i] != VariantRules.EMPTY
- && colors.includes(this.getColor(x,i))
- && this.getPiece(x,i) == VariantRules.ROOK)
- {
- return true;
- }
- }
- }
- else if (y == this.kingPos[colors[0]][1])
- {
- // Look for enemy rook on this row
- for (let i=0; i<sizeX; i++)
- {
- if (this.board[i][y] != VariantRules.EMPTY
- && colors.includes(this.getColor(i,y))
- && this.getPiece(i,y) == VariantRules.ROOK)
- {
- return true;
- }
- }
- }
- return false;
+ return false; //there is no check
}
- isAttackedByKnight([x,y], colors)
+ getCheckSquares(move)
{
- // Square (x,y) must be on same line as a knight,
- // and there must be empty square(s) behind.
- const V = VariantRules;
- const steps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
- const [sizeX,sizeY] = V.size;
- for (let step of steps)
- {
- const [i0,j0] = [x+step[0],y+step[1]];
- if (i0>=0 && i0<sizeX && j0>=0 && j0<sizeY && this.board[i0][j0] == V.EMPTY)
- {
- // Try in opposite direction:
- let [i,j] = [x-step[0],y-step[1]];
- while (i>=0 && i<sizeX && j>=0 && j<sizeY && this.board[i][j] == V.EMPTY)
- {
- i -= step[0];
- j -= step[1];
- }
- if (i>=0 && i<sizeX && j>=0 && j<sizeY && colors.includes(this.getColor(i,j))
- && this.getPiece(i,j) == V.KNIGHT)
- {
- return true;
- }
- }
- }
- return false;
+ const c = this.getOppCol(this.turn); //opponent
+ const saveKingPos = this.kingPos[c]; //king might be taken
+ this.play(move);
+ // The only way to be "under check" is to have lost the king (thus game over)
+ let res = this.kingPos[c][0] < 0
+ ? [ JSON.parse(JSON.stringify(saveKingPos)) ]
+ : [ ];
+ this.undo(move);
+ return res;
}
- isAttackedByBishop([x,y], colors)
+ updateVariables(move)
{
- // We cheat a little here: since this function is used exclusively for king,
- // it's enough to check the immediate surrounding of the square.
- const V = VariantRules;
- const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
- const [sizeX,sizeY] = V.size;
- for (let step of adjacentSteps)
+ // Just update king(s) position(s)
+ const piece = this.getPiece(move.start.x,move.start.y);
+ const c = this.getColor(move.start.x,move.start.y);
+ if (piece == VariantRules.KING && move.appear.length > 0)
{
- const [i,j] = [x+step[0],y+step[1]];
- if (i>=0 && i<sizeX && j>=0 && j<sizeY && this.board[i][j]!=V.EMPTY
- && colors.includes(this.getColor(i,j)) && this.getPiece(i,j) == V.BISHOP)
+ this.kingPos[c][0] = move.appear[0].x;
+ this.kingPos[c][1] = move.appear[0].y;
+ }
+ // Does this move takes opponent's king?
+ const oppCol = this.getOppCol(c);
+ for (let psq of move.vanish)
+ {
+ if (psq.p == VariantRules.KING)
{
- return true;
+ this.kingPos[oppCol] = [-1,-1];
+ break;
}
}
- return false;
}
- isAttackedByQueen([x,y], colors)
+ unupdateVariables(move)
{
- // Square (x,y) must be adjacent to a queen, and the queen must have
- // some free space in the opposite direction from (x,y)
- const V = VariantRules;
- const adjacentSteps = V.steps[V.ROOK].concat(V.steps[V.BISHOP]);
- const [sizeX,sizeY] = V.size;
- for (let step of adjacentSteps)
+ super.unupdateVariables(move);
+ const c = this.getColor(move.start.x,move.start.y);
+ const oppCol = this.getOppCol(c);
+ if (this.kingPos[oppCol][0] < 0)
{
- const sq2 = [x+2*step[0],y+2*step[1]];
- if (sq2[0]>=0 && sq2[0]<sizeX && sq2[1]>=0 && sq2[1]<sizeY
- && this.board[sq2[0]][sq2[1]] == V.EMPTY)
+ // Last move took opponent's king
+ for (let psq of move.vanish)
{
- const sq1 = [x+step[0],y+step[1]];
- if (this.board[sq1[0]][sq1[1]] != V.EMPTY
- && colors.includes(this.getColor(sq1[0],sq1[1]))
- && this.getPiece(sq1[0],sq1[1]) == V.QUEEN)
+ if (psq.p == 'k')
{
- return true;
+ this.kingPos[oppCol] = [psq.x, psq.y];
+ break;
}
}
}
- return false;
}
- updateVariables(move)
+ checkGameOver()
{
- // Just update king position
- const piece = this.getPiece(move.start.x,move.start.y);
- const c = this.getColor(move.start.x,move.start.y);
- if (piece == VariantRules.KING && move.appear.length > 0)
- {
- this.kingPos[c][0] = move.appear[0].x;
- this.kingPos[c][1] = move.appear[0].y;
- }
+ if (this.checkRepetition())
+ return "1/2";
+
+ const color = this.turn;
+ // TODO: do we need "atLeastOneMove()"?
+ if (this.atLeastOneMove() && this.kingPos[color][0] >= 0)
+ return "*";
+
+ return this.checkGameEnd();
}
checkGameEnd()
{
- // No valid move: game is lost (stalemate is a win)
+ // No valid move: our king disappeared
return this.turn == "w" ? "0-1" : "1-0";
}
static get SEARCH_DEPTH() { return 2; } //TODO?
+ static get THRESHOLD_MATE() {
+ return 500; //checkmates evals may be slightly below 1000
+ }
+
static GenRandInitFen()
{
let pieces = { "w": new Array(8), "b": new Array(8) };
projects / vchess.git / commitdiff