Robustness questions

[Chris00]

Thanks for your library. I saw that you use robust for orient2d but I was wondering why you did not use

• robust::incircle for your Point::in_circle;
• hypot for your distance computations.

I can make a PR if you agree to these changes.

[mourner]

• robust::incircle for your Point::in_circle;

This was omitted for consistency with the JavaScript version, which didn't add it because it was not that important for robustness but increased the bundle size notably (see mapbox/delaunator#68):

Adding robust incircle would increase it more significantly (to 5322 bytes), but it doesn't seem necessary since this check only affects which triangles flip, and doesn't affect the integrity of the triangulation unlike orient2d.

Now as for hypot, this is a deliberate optimization because Delaunator doesn't need exact distances, it only calculates squared ones which are much faster since they only need multiplication, without square root.

• hypot for your distance computations.