Failing on simple example.

[Scrawk]

Failing on simple example. Any help?

Outputs 0,1,2 and 0, 1, 3

List<int> triangules = new List<int>();
int numPoints = 4;

            //var points = new Point2d[numPoints];
            //GetPoints(points, points.Length);

            var points = new Point2d[]
            {
                    new Point2d(- 1,-1),
                    new Point2d(1,-1),
                    new Point2d(1,1),
                    new Point2d(- 1,1)
            };

            // A polygon can be composed of multiple contours which are all tessellated at the same time.
            var contour = new ContourVertex[numPoints];
            for (int i = 0; i < numPoints; i++)
                contour[i].Position = new Vec3(points[i].x, points[i].y, 0);

            // Create an instance of the tessellator. Can be reused.
            var tess = new Tess();
            // Add the contour with a specific orientation, use "Original" if you want to keep the input orientation.
            tess.AddContour(contour, ContourOrientation.Clockwise);

            // The winding rule determines how the different contours are combined together.
            // See http://www.glprogramming.com/red/chapter11.html (section "Winding Numbers and Winding Rules") for more information.
            // If you want triangles as output, you need to use "Polygons" type as output and 3 vertices per polygon.
            tess.Tessellate(WindingRule.EvenOdd, ElementType.Polygons, 3);

            int numTriangles = tess.ElementCount;
            for (int i = 0; i < numTriangles; i++)
            {
                var a = tess.Elements[i * 3 + 0];
                var b = tess.Elements[i * 3 + 1];
                var c = tess.Elements[i * 3 + 2];

                Console.WriteLine(a);
                Console.WriteLine(b);
                Console.WriteLine(c);

                triangules.Add(a);
                triangules.Add(b);
                triangules.Add(c);
            }

[ambroiseRabier]

I have the same issue (or similar ?). When making a simple Square, it seems to re-order the "Contour" incorrectly.

// correct order
      Vector3[] init = new Vector3[] {
        new Vector3(0f, 0f),
        new Vector3(0f, 0.5f),
        new Vector3(0.5f, 0.5f),
        new Vector3(0.5f, 0f),
      };
      
// wrong order given by tess.Vertices (using CounterClockwise, but Original or Clockwise have the same issue)
      Vector3[] init = new Vector3[] {
        new Vector3(0f, 0f),
        new Vector3(0.5f, 0.5f),
        new Vector3(0.5f, 0f),
        new Vector3(0f, 0.5f),
      };

At first glance we can see that (0.5f, 0.5f) point should never be adjacent with (0f, 0f) point, or we get a diagonal in the square as "Contour".

Strangely, in my particular case, I still end up with a square by using Tess. But when I try to cut that square in two with Clipper2 I end up with very strange results. But results that make sense if I give Clipper2 that bow knot contour instead of a proper square contour.