大量多边形求交的C#实现

以下是使用 C# 实现大量多边形求交的示例代码：

using System;
using System.Collections.Generic;

namespace PolygonIntersection
{
    public class Point
    {
        public double X { get; set; }
        public double Y { get; set; }

        public Point(double x, double y)
        {
            X = x;
            Y = y;
        }
    }

    public class Edge
    {
        public Point Start { get; set; }
        public Point End { get; set; }

        public Edge(Point start, Point end)
        {
            Start = start;
            End = end;
        }

        public bool Intersects(Edge other)
        {
            double x1 = Start.X, y1 = Start.Y, x2 = End.X, y2 = End.Y;
            double x3 = other.Start.X, y3 = other.Start.Y, x4 = other.End.X, y4 = other.End.Y;

            double denominator = (y4 - y3) * (x2 - x1) - (x4 - x3) * (y2 - y1);

            if (denominator == 0)
                return false;

            double ua = ((x4 - x3) * (y1 - y3) - (y4 - y3) * (x1 - x3)) / denominator;
            double ub = ((x2 - x1) * (y1 - y3) - (y2 - y1) * (x1 - x3)) / denominator;

            return ua >= 0 && ua <= 1 && ub >= 0 && ub <= 1;
        }
    }

    public class Polygon
    {
        public List<Point> Vertices { get; set; }

        public Polygon(List<Point> vertices)
        {
            Vertices = vertices;
        }

        public bool Intersects(Polygon other)
        {
            List<Edge> edges1 = GetEdges();
            List<Edge> edges2 = other.GetEdges();

            foreach (Edge edge1 in edges1)
            {
                foreach (Edge edge2 in edges2)
                {
                    if (edge1.Intersects(edge2))
                        return true;
                }
            }

            return false;
        }

        private List<Edge> GetEdges()
        {
            List<Edge> edges = new List<Edge>();

            for (int i = 0; i < Vertices.Count - 1; i++)
            {
                edges.Add(new Edge(Vertices[i], Vertices[i + 1]));
            }

            edges.Add(new Edge(Vertices[Vertices.Count - 1], Vertices[0]));

            return edges;
        }
    }

    class Program
    {
        static void Main(string[] args)
        {
            List<Point> vertices1 = new List<Point>()
            {
                new Point(0, 0),
                new Point(0, 2),
                new Point(2, 2),
                new Point(2, 0)
            };

            List<Point> vertices2 = new List<Point>()
            {
                new Point(1, 1),
                new Point(1, 3),
                new Point(3, 3),
                new Point(3, 1)
            };

            Polygon polygon1 = new Polygon(vertices1);
            Polygon polygon2 = new Polygon(vertices2);

            if (polygon1.Intersects(polygon2))
                Console.WriteLine("Polygons intersect");
            else
                Console.WriteLine("Polygons do not intersect");

            Console.ReadLine();
        }
    }
}

上述代码实现了 Point、Edge 和 Polygon 三个类，其中 Point 表示一个点，Edge 表示一条边，Polygon 表示一个多边形。Polygon 类中的 GetEdges 方法用于获取多边形的所有边，Intersects 方法用于判断多边形是否与另一个多边形相交。最后的示例代码中创建了两个多边形并判断其是否相交。