Clipping Poligon CS

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;


namespace Clipping
{
    class Program
    {

        struct Point
        {
            public double x, y;
            public Point(double px, double py)
            {
                x = px;
                y = py;
            }
        }

        static bool inside(Point p, Point cp1, Point cp2)
        {
            return (cp2.x - cp1.x) * (p.x - cp1.y) > (cp2.y - cp1.y) * (p.x - cp1.x);
        }

        static Point intersection(Point cp1, Point cp2, Point s, Point e)
        {
            Point dc = new Point(cp1.x - cp2.x, cp1.y - cp2.y);
            Point dp = new Point(s.x - e.x, s.y - e.y);
            double n1 = cp1.x * cp2.y - cp1.y * cp2.x;
            double n2 = s.x * e.y - s.y * e.x;
            double n3 = 1.0 / (dc.x * dp.y - dc.y * dp.x);

            return new Point((n1 * dp.x - n2 * dc.x) * n3, (n1 * dp.y - n2 * dc.y) * n3);
        }

        static void Main(string[] args)
        {
            List<Point> subjectPolypon = new List<Point>();
            subjectPolypon.Add(new Point(50, 150));
            subjectPolypon.Add(new Point(200, 50));
            subjectPolypon.Add(new Point(350, 150));
            subjectPolypon.Add(new Point(350, 300));
            subjectPolypon.Add(new Point(250, 300));
            subjectPolypon.Add(new Point(200, 250));
            subjectPolypon.Add(new Point(150, 350));
            subjectPolypon.Add(new Point(100, 250));
            subjectPolypon.Add(new Point(100, 200));


            List<Point> clipPolypon = new List<Point>();
            clipPolypon.Add(new Point(100, 100));
            clipPolypon.Add(new Point(300, 100));
            clipPolypon.Add(new Point(300, 300));
            clipPolypon.Add(new Point(100, 300));

            List<Point> clippingOut = subjectPolypon.ToList();
            List<Point> inputList = subjectPolypon.ToList();
            Point cp1 = clipPolypon.Last<Point>();

            Point temp = new Point(1, 1);

            foreach (Point clipNode in clipPolypon)
            {
                Point cp2 = clipNode;
                inputList = clippingOut.ToList();
                clippingOut.Clear();
                Point s = inputList.Last();

                foreach (Point subjectNode in inputList)
                {
                    Point e = subjectNode;

                    if (inside(e, cp1, cp2))
                    {
                        if (!inside(s, cp1, cp2))
                        {
                            clippingOut.Add(intersection(cp1, cp2, s, e));
                        }
                        clippingOut.Add(intersection(cp1, cp2, s, e));
                    }
                    else if (inside(s, cp1, cp2))
                    {
                        clippingOut.Add(intersection(cp1, cp2, s, e));
                    }

                    s = e;

                }

                cp1 = cp2;

            }

            Console.WriteLine(clippingOut.Count);

            Console.ReadKey();
        }
    }
}