朋友那边最近有个需求，需要框选一个选区，然后根据选区中的点求出面积。并且让我尝试用Delaunay来解决

似乎音译过来应该是德诺类

 

大致如下：

 

我在github上找了一个可以用的Delaunay库

 

但是需要注意这个只能针对凸多边形创建三角面。

 

因为创建出来的始终是三角面，把顶点顺序除以3进行遍历

然后根据差乘求平行四边形面积的方法，得到总面积

using UnityEngine;using System.Linq;using System.Collections;[RequireComponent(typeof(MeshFilter))][RequireComponent(typeof(MeshRenderer))]public class DelaunayTest : MonoBehaviour{    public Transform[] points;    MeshFilter meshFilter;    Triangulator tr;    void Start()    {        meshFilter = GetComponentInChildren
     
      () as MeshFilter;    }    void Update()    {        tr = new Triangulator();        meshFilter.mesh = tr.CreateInfluencePolygon(points.Select(m => new Vector2(m.localPosition.x, m.localPosition.z)).ToArray());        var vertices = meshFilter.mesh.vertices;        var triangles = meshFilter.mesh.triangles;        var vertexCount = meshFilter.mesh.triangles.Length;        var finalArea = 0f;        for (int i = 0; i < meshFilter.mesh.triangles.Length; i += 3)        {            var a = vertices[triangles[i]];            var b = vertices[triangles[i + 1]];            var c = vertices[triangles[i + 2]];            finalArea += Area(a, b, c);        }        Debug.Log("Final Area: " + finalArea);    }    float Area(Vector3 p1, Vector3 p2, Vector3 p3)    {        float area = Vector3.Cross(p2 - p1, p3 - p2).magnitude * 0.5f;        return area;    }}