BlottoBeats.Client.AdvancedSettings.pointInPolygon C# (CSharp) Method

        private bool pointInPolygon(Point p, Point[] poly)
        {
            Point p1, p2;
            bool inside = false;

            if (poly.Length < 3)
                return inside;

            Point oldPoint = new Point(poly[poly.Length - 1].X, poly[poly.Length - 1].Y);

            for (int i = 0; i < poly.Length; i++)
            {
                Point newPoint = new Point(poly[i].X, poly[i].Y);

                if (newPoint.X > oldPoint.X)
                {
                    p1 = oldPoint;
                    p2 = newPoint;
                }
                else
                {
                    p1 = newPoint;
                    p2 = oldPoint;
                }

                if ((newPoint.X < p.X) == (p.X <= oldPoint.X) && ((long)p.Y - (long)p1.Y) * (long)(p2.X - p1.X) < ((long)p2.Y - (long)p1.Y) * (long)(p.X - p1.X))
                    inside = !inside;

                oldPoint = newPoint;
            }

            return inside;
        }