gradCoord3D function
Implementation
@pragma('vm:prefer-inline')
double gradCoord3D(
int seed,
int x,
int y,
int z,
double xd,
double yd,
double zd,
) {
IntX hash = Int32(seed);
hash ^= _xPrime * x;
hash ^= _yPrime * y;
hash ^= _zPrime * z;
hash = hash * hash * hash * 60493;
hash = (hash >> 13) ^ hash;
final g = gradient3d[hash.toInt() & 15];
return xd * g.x + yd * g.y + zd * g.z;
}