valCoord3D function
Implementation
@pragma('vm:prefer-inline')
double valCoord3D(int seed, int x, int y, int z) {
var n = Int32(seed);
n ^= _xPrime * x;
n ^= _yPrime * y;
n ^= _zPrime * z;
return (n * n * n * 60493).toDouble() / 2147483648;
}