CameraBuddy.Spectate.Data.Region.PointInPolygon C# (CSharp) Method

        private static int PointInPolygon(Point[] path, Vector3 pt)
        {
            //returns 0 if false, +1 if true, -1 if pt ON polygon boundary
            //See "The Point in Polygon Problem for Arbitrary Polygons" by Hormann & Agathos
            //http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.88.5498&rep=rep1&type=pdf
            int result = 0, cnt = path.Length;
            if (cnt < 3) return 0;
            Point ip = path[0];
            for (int i = 1; i <= cnt; ++i)
            {
                Point ipNext = (i == cnt ? path[0] : path[i]);
                if (ipNext.Y == pt.Y)
                {
                    if ((ipNext.X == pt.X) || (ip.Y == pt.Y && ((ipNext.X > pt.X) == (ip.X < pt.X))))
                        return -1;
                }
                if ((ip.Y < pt.Y) != (ipNext.Y < pt.Y))
                {
                    if (ip.X >= pt.X)
                    {
                        if (ipNext.X > pt.X) result = 1 - result;
                        else
                        {
                            double d = (double) (ip.X - pt.X)*(ipNext.Y - pt.Y) - (double) (ipNext.X - pt.X)*(ip.Y - pt.Y);
                            if (d == 0) return -1;
                            else if ((d > 0) == (ipNext.Y > ip.Y)) result = 1 - result;
                        }
                    }
                    else
                    {
                        if (ipNext.X > pt.X)
                        {
                            double d = (double) (ip.X - pt.X)*(ipNext.Y - pt.Y) - (double) (ipNext.X - pt.X)*(ip.Y - pt.Y);
                            if (d == 0) return -1;
                            else if ((d > 0) == (ipNext.Y > ip.Y)) result = 1 - result;
                        }
                    }
                }
                ip = ipNext;
            }
            return result;
        }