- static GenRandInitFen() {
- let pieces = { w: new Array(8), b: new Array(8) };
- // Shuffle pieces on first and last rank
- for (let c of ["w", "b"]) {
- let positions = ArrayFun.range(8);
-
- // Get random squares for bishops
- let randIndex = 2 * randInt(4);
- let bishop1Pos = positions[randIndex];
- // The second bishop must be on a square of different color
- let randIndex_tmp = 2 * randInt(4) + 1;
- let bishop2Pos = positions[randIndex_tmp];
- // Remove chosen squares
- positions.splice(Math.max(randIndex, randIndex_tmp), 1);
- positions.splice(Math.min(randIndex, randIndex_tmp), 1);
-
- // Get random squares for knights
- randIndex = randInt(6);
- let knight1Pos = positions[randIndex];
- positions.splice(randIndex, 1);
- randIndex = randInt(5);
- let knight2Pos = positions[randIndex];
- positions.splice(randIndex, 1);
-
- // Get random square for queen
- randIndex = randInt(4);
- let queenPos = positions[randIndex];
- positions.splice(randIndex, 1);
-
- // Random square for king (no castle)
- randIndex = randInt(3);
- let kingPos = positions[randIndex];
- positions.splice(randIndex, 1);
-
- // Rooks positions are now fixed
- let rook1Pos = positions[0];
- let rook2Pos = positions[1];
-
- // Finally put the shuffled pieces in the board array
- pieces[c][rook1Pos] = "r";
- pieces[c][knight1Pos] = "n";
- pieces[c][bishop1Pos] = "b";
- pieces[c][queenPos] = "q";
- pieces[c][kingPos] = "k";
- pieces[c][bishop2Pos] = "b";
- pieces[c][knight2Pos] = "n";
- pieces[c][rook2Pos] = "r";
- }
- return (
- pieces["b"].join("") +
- "/pppppppp/8/8/8/8/PPPPPPPP/" +
- pieces["w"].join("").toUpperCase() +
- " w 0 -"
- ); //en-passant allowed, but no flags
- }