/// <summary>
/// Triagulate a polygon using the 'clipping ear' theorem
/// see: http://www-cgrl.cs.mcgill.ca/~godfried/teaching/cg-projects/97/Ian/algorithm2.html
/// </summary>
/// <param name="p"></param>
/// <returns></returns>
public static Triangle[] Triangulate(Polygon p)
{
List<Triangle> triList = new List<Triangle>();
// Make sure the points are ordered clockwise, else this method will fail
List<Point2D> points = Point2D.SortPoints(true, Point2D.DeepCopy(p.points));
// Search for an ear for as long as this polygon isn't reduced to a triangle itself
while (points.Count > 3)
for (int i = 0; i < points.Count; i++) {
Point2D p1 = points[i];
Point2D p2 = points[(i + 1) % points.Count];
Point2D p3 = points[(i + 2) % points.Count];
Triangle t;
if (Polygon.IsEar(p1, p2, p3, points, out t)) {
triList.Add(t);
break;
}
}
// Add the remaining 3 points as a triangle
triList.Add(new Triangle(points[0], points[1], points[2]));
return triList.ToArray();
}
public PolygonR(Polygon po)
{
PointF[] p = new PointF[po.Points.Length];
for (int i = 0; i < po.Points.Length; i++) {
p[i] = new PointF((float)po.Points[i].X, (float)po.Points[i].Y);
}
Points = p;
}