noise2XBeforeY method
2D SuperSimplex noise, with Y pointing down the main diagonal.
Might be better for a 2D sandbox style game, where Y is vertical. Probably slightly less optimal for heightmaps or continent maps.
Implementation
@override
double noise2XBeforeY(double x, double y) {
// Skew transform and rotation baked into one.
double xx = x * 0.7071067811865476;
double yy = y * 1.224744871380249;
return _noise2Base(yy + xx, yy - xx);
}