Mesh

简介

所有图形都是三角形组成的，绘制包括三部分

• vertices：图形的所有顶点坐标
• triangles：图形的绘制顺序，选三个顶点组成一个三角形，顺序必须顺时针，逆时针会绘制在背面
• uv：材质的贴图要和图形对应，uv左下角(0,0)，右上角(1,1)，就是将每一个顶点坐标对应到贴图上，可先将顶点坐标移至正右上角区域，然后进行比例缩放到1

实例

• 三角形 正方形

      //3
      Vector3[] v_3 = new Vector3[] {
          new Vector3(1, 1, 0),
          new Vector3(0, 0, 0),
          new Vector3(0, 1, 0)
      };
  
      int[] t_3 = new int[] {
          0,1,2
      };
  
      Vector2[] uv_3 = new Vector2[] {
          new Vector2(1,1),
          new Vector2(0,0),
          new Vector2(0,1),
      };
  
      //4
      Vector3[] v_4 = new Vector3[] {
          new Vector3(1, 1, 0),
          new Vector3(1, 0, 0),
          new Vector3(0, 0, 0),
          new Vector3(0, 1, 0)
      };
  
      int[] t_4 = new int[] {
          0,2,3,
          1,2,3
      };
  
      Vector2[] uv_4 = new Vector2[] {
          new Vector2(1,1),
          new Vector2(1,0),
          new Vector2(0,0),
          new Vector2(0,1),
      };
  
      void Start()
      {
          Creater("obj3", v_3, t_3, uv_3, Mat.Green);
          Creater("obj4", v_4, t_4, uv_4, Mat.Red);
      }
      
       void Creater(string name, Vector3[] ver, int[] tri, Vector2[] uv, Mat mat)
      {
          GameObject obj = new GameObject();
          obj.name = name;
          obj.transform.localPosition = Vector3.zero;
          obj.transform.localScale = Vector3.one;
          obj.transform.localRotation = Quaternion.identity;
  
          obj.AddComponent<MeshFilter>();
          Mesh mesh = obj.GetComponent<MeshFilter>().mesh;
          mesh.Clear();
  
          mesh.vertices = ver;
          mesh.triangles = tri;
  
          obj.AddComponent<MeshRenderer>();
          obj.GetComponent<MeshRenderer>().material = mats[(int)mat];
          mesh.uv = uv;
      }
  
  

• 圆形，由圆心与圆上点组成三角形

  
      void CreateCircle(Vector2 center, float r, int num)
      {
          GameObject obj = new GameObject();
          obj.name = "circle";
          obj.transform.localPosition = CreatePos * CreateNum;
          obj.transform.localScale = Vector3.one;
          obj.transform.localRotation = Quaternion.identity;
          CreateNum += 1;
  
          obj.AddComponent<MeshFilter>();
          Mesh mesh = obj.GetComponent<MeshFilter>().mesh;
          mesh.Clear();
  
          Vector3[] ver = new Vector3[num + 1];
          int[] tri = new int[3 * num];
          Vector2[] uv = new Vector2[num + 1];
  
          float deltaAngle = 360 / num;
          ver[num] = (Vector3)center;
  
          for (int i = 0; i < num; i++)
          {
              float angle = (90 - i * deltaAngle) * Mathf.Deg2Rad;
              ver[i] = new Vector3(r * Mathf.Cos(angle) + center.x, r * Mathf.Sin(angle) + center.y, 0);
  
              tri[i * 3] = i;
              if (i == num - 1) tri[i * 3 + 1] = 0;
              else tri[i * 3 + 1] = i + 1;
              tri[i * 3 + 2] = num;
          }
          mesh.vertices = ver;
          mesh.triangles = tri;
  
          obj.AddComponent<MeshRenderer>();
          obj.GetComponent<MeshRenderer>().material = mats[1];
          for (int i = 0; i < ver.Length; i++)
          {
              uv[i] = new Vector2(ver[i].x - center.x + r, ver[i].y - center.y + r)/2/r;
          }
          mesh.uv = uv;
      }
  

• 电风扇型

      void CreateCircle1(Vector2 center, float r, int num)
      {
          GameObject obj = new GameObject();
          obj.name = "circle1";
          obj.transform.localPosition = CreatePos * CreateNum;
          obj.transform.localScale = Vector3.one;
          obj.transform.localRotation = Quaternion.identity;
          CreateNum += 1;
  
          obj.AddComponent<MeshFilter>();
          Mesh mesh = obj.GetComponent<MeshFilter>().mesh;
          mesh.Clear();
  
          Vector3[] ver = new Vector3[num + 1];
          int[] tri = new int[3 * num];
          Vector2[] uv = new Vector2[num + 1];
  
          float deltaAngle = 360 / num;
          ver[num] = (Vector3)center;
  
          for (int i = 0; i < num; i++)
          {
              float angle = (90 - i * deltaAngle) * Mathf.Deg2Rad;
              ver[i] = new Vector3(r * Mathf.Cos(angle) + center.x, r * Mathf.Sin(angle) + center.y, 0);
  
              if (i % 2 == 1)
              {
                  tri[i * 3] = num;
                  tri[i * 3 + 1] = num;
                  tri[i * 3 + 2] = num;
              }
              else
              {
                  tri[i * 3] = i;
                  if (i == num - 1) tri[i * 3 + 1] = 0;
                  else tri[i * 3 + 1] = i + 1;
                  tri[i * 3 + 2] = num;
              }
          }
  
          mesh.vertices = ver;
          mesh.triangles = tri;
  
          obj.AddComponent<MeshRenderer>();
          obj.GetComponent<MeshRenderer>().material = mats[1];
          for (int i = 0; i < ver.Length; i++)
          {
              uv[i] = new Vector2(ver[i].x - center.x + r, ver[i].y - center.y + r) / 2 / r;
          }
          mesh.uv = uv;
      }
  

• 圆环，有一个个小梯形组成，每个梯形又可以由两个三角形组成

      void CreateCircle2(Vector2 center, float r1, float r2, int num)
      {
          GameObject obj = new GameObject();
          obj.name = "circle2";
          obj.transform.localPosition = CreatePos * CreateNum;
          obj.transform.localScale = Vector3.one;
          obj.transform.localRotation = Quaternion.identity;
          CreateNum += 1;
  
          obj.AddComponent<MeshFilter>();
          Mesh mesh = obj.GetComponent<MeshFilter>().mesh;
          mesh.Clear();
  
          Vector3[] ver = new Vector3[num * 2];
          int[] tri = new int[3 * num * 2];
          Vector2[] uv = new Vector2[num * 2];
  
          float deltaAngle = 360 / num;
  
          for (int i = 0; i < num; i++)
          {
              float angle = (90 - i * deltaAngle) * Mathf.Deg2Rad;
              ver[i] = new Vector3(r1 * Mathf.Cos(angle) + center.x, r1 * Mathf.Sin(angle) + center.y, 0);
              ver[i + num] = new Vector3(r2 * Mathf.Cos(angle) + center.x, r2 * Mathf.Sin(angle) + center.y, 0);
  
              //连接处
              if (i == num - 1)
              {
                  tri[i * 3 * 2] = i;
                  tri[i * 3 * 2 + 1] = 0;
                  tri[i * 3 * 2 + 2] = num;
                  tri[i * 3 * 2 + 3] = i;
                  tri[i * 3 * 2 + 4] = num;
                  tri[i * 3 * 2 + 5] = i + num;
              }
              else
              {
                  tri[i * 3 * 2] = i;
                  tri[i * 3 * 2 + 1] = i + 1;
                  tri[i * 3 * 2 + 2] = i + 1 + num;
                  tri[i * 3 * 2 + 3] = i;
                  tri[i * 3 * 2 + 4] = i + 1 + num;
                  tri[i * 3 * 2 + 5] = i + num;
              }
          }
          mesh.vertices = ver;
          mesh.triangles = tri;
  
          obj.AddComponent<MeshRenderer>();
          obj.GetComponent<MeshRenderer>().material = mats[1];
          for (int i = 0; i < ver.Length; i++)
          {
              uv[i] = new Vector2(ver[i].x - center.x + r1, ver[i].y - center.y + r1) / 2 / r1;
          }
          mesh.uv = uv;
      }
  

• 圆弧形

      void Creater(float r1, float r2, float angle)
      {
          GameObject obj = new GameObject();
          obj.transform.parent = gameObject.transform;
          obj.transform.localPosition = Vector3.zero;
          obj.transform.localScale = Vector3.one;
          obj.transform.localRotation = Quaternion.identity;
  
          obj.AddComponent<MeshFilter>();
          Mesh mesh = obj.GetComponent<MeshFilter>().mesh;
          mesh.Clear();
  
          //默认一圈分割成60份，6度一份
          float deltaAngle = 6;
  
          int num = Mathf.CeilToInt(angle * 2 / 2 / deltaAngle) + 1;  //5
          Vector3[] ver = new Vector3[num * 2]; //10
          int[] tri = new int[(num - 1) * 2 * 3];
          for (int i = 0; i < num; i++)
          {
              float rad = (i * deltaAngle - angle / 2) * Mathf.Deg2Rad;
              ver[i] = new Vector3(r1 * Mathf.Cos(rad), 0, r1 * Mathf.Sin(rad));
              ver[i + num] = new Vector3(r2 * Mathf.Cos(rad), 0, r2 * Mathf.Sin(rad));
              if (i == num - 1)
              {
                  continue;
              }
              else
              {
                  tri[i * 3 * 2] = i + 1 + num;
                  tri[i * 3 * 2 + 1] = i + 1;
                  tri[i * 3 * 2 + 2] = i;
                  tri[i * 3 * 2 + 3] = i + num;
                  tri[i * 3 * 2 + 4] = i + 1 + num;
                  tri[i * 3 * 2 + 5] = i;
              }
          }
  
          mesh.vertices = ver;
          mesh.triangles = tri;
  
          Material material = new Material(Shader.Find("Diffuse"));
          material.SetColor("_Color", Color.white);
          obj.AddComponent<MeshRenderer>();
          obj.GetComponent<MeshRenderer>().material = material;
  
          obj.AddComponent<MeshCollider>();
      }
  

总结

参考