Join bug about clipper2

[AngusJohnson]

Hi Fribur.
Something certainly seems odd but I'll need some data to sort out what's happening.
You'll find a link to my email address here.

Unrelated, I have a hunch line 853 should be _vertexList.Add(curr_v); and not _vertexList.Add(v0);

Yes, that's definitely a bug. Thanks!

[Fribur]

Attached the three integer polygons leading to the result in picture above (consecutive union of 1+2-->result1, then result1+3--result2). Interestingly this only occurs when I add them as PathD. Using Path64 leads to the expected result. Puzzling.

var jobClipper2 = new Clipper2Lib.ClipperD();
...
jobClipper2.Execute(ClipType.Union, FillRule.EvenOdd, result);

Outline_0.txt
Outline_1.txt
Outline_2.txt

[AngusJohnson]

OK, problem found.

private static double DistanceSqr(Point64 pt1, Point64 pt2)
{
  return (double) (pt1.X - pt2.X) * (pt1.X - pt2.X) +
         (double) (pt1.Y - pt2.Y) * (pt1.Y - pt2.Y);
}

The C# compiler indicated that my explicit casting to double in Clipper.Engine.DistanceSqr() was unnecessary (by fading out these casts). Unfortunately I removed them without testing the consequences and it turns out they are very much needed. Now I'm wondering what other casts I've removed that the compiler indicated were superfluous.

[rs0xFFFF]

I assume the math runs on integer (with rounding errors) and converts to float at last step (the result is wrong at that point).

[AngusJohnson]

and converts to float at last step (the result is wrong at that point)

Yep. Anyhow, fixed now.