+
+ static GenRandInitFen(randomness) {
+ if (randomness == 0)
+ return "rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w 0 -";
+
+ let pieces = { w: new Array(8), b: new Array(8) };
+ for (let c of ["w", "b"]) {
+ if (c == 'b' && randomness == 1) {
+ pieces['b'] = pieces['w'];
+ break;
+ }
+
+ // Get random squares for every piece, totally freely
+ let positions = shuffle(ArrayFun.range(8));
+ const composition = ['b', 'b', 'r', 'r', 'n', 'n', 'k', 'q'];
+ const rem2 = positions[0] % 2;
+ if (rem2 == positions[1] % 2) {
+ // Fix bishops (on different colors)
+ for (let i=2; i<8; i++) {
+ if (positions[i] % 2 != rem2)
+ [positions[1], positions[i]] = [positions[i], positions[1]];
+ }
+ }
+ for (let i = 0; i < 8; i++) pieces[c][positions[i]] = composition[i];
+ }
+ return (
+ pieces["b"].join("") +
+ "/pppppppp/8/8/8/8/PPPPPPPP/" +
+ pieces["w"].join("").toUpperCase() +
+ // En-passant allowed, but no flags
+ " w 0 -"
+ );
+ }