unity中动态生成网格

Posted 2020-09-03 露夕逝

以下是绘制正方形面片的一个例子，方便之后查阅：

效果如图所示：

红轴为x方向，蓝轴为z方向。

代码如下：

 1 using System.Collections;
 2 using System.Collections.Generic;
 3 using UnityEngine;
 4 public class SingleMesh:MonoBehaviour
 5 {
 6     public int size = 1;//边长
 7     public int segment = 5;//分段数
 8     public Material mat;//mesh材质
 9     private Vector3[] vertices;//顶点
10     private Vector2[] uv;//纹理坐标
11     private int[] triangles;//索引
12 
13 
14     [ContextMenu("Create Mesh")]
15     /// <summary>
16     /// 创建mesh
17     /// </summary>
18     private void CreateMesh()
19     {
20         GameObject obj_cell = new GameObject();
21         obj_cell.name = "cell";
22         Mesh mesh = new Mesh();
23         mesh.Clear();
24         SetVertivesUV();//生成顶点和uv信息
25         SetTriangles();//生成索引
26         mesh.vertices = vertices;
27         mesh.uv = uv;
28         mesh.triangles = triangles;
29         
30         mesh.RecalculateNormals();//重置法线
31      
32         mesh.RecalculateBounds();   //重置范围
33         obj_cell.AddComponent<MeshFilter>().mesh = mesh;
34         obj_cell.AddComponent<MeshRenderer>();
35         obj_cell.GetComponent<MeshRenderer>().material = mat;
36     }
37 
38     /// <summary>
39     /// 设置顶点信息
40     /// </summary>
41     private void SetVertivesUV()
42     {
43         vertices = new Vector3[(segment + 1) * (segment + 1)];
44         uv = new Vector2[vertices.Length];
45         int num = 0;
46         float m = (float)size / (float)segment;
47         for (int i = 0; i < segment + 1; i++)
48             for (int j = 0; j < segment + 1; j++)
49             {
50                 vertices[num] = new Vector3(j * m,0, i * m);
51                 uv[num] = new Vector2((float)j / segment, (float)i / segment);
52                 num++;
53             }
54 
55     }
56     /// <summary>
57     /// 设置索引
58     /// </summary>
59     private void SetTriangles()
60     {
61         triangles = new int[segment * segment * 6];
62         int index = 0;//用来给三角形索引计数
63         for (int i = 0; i < segment; i++)
64             for (int j = 0; j < segment; j++)
65             {
66                 int line = segment + 1;
67                 int self = j + (i * line);
68 
69                 triangles[index] = self;
70                 triangles[index + 1] = self + line + 1;
71                 triangles[index + 2] = self + 1;
72                 triangles[index + 3] = self;
73                 triangles[index + 4] = self + line;
74                 triangles[index + 5] = self + line + 1;
75 
76                 index += 6;
77             }
78     }
79 }

其中triangles索引为链接各定点的顺序，一个小格的链接顺序如下：

准则：三角形有两面，正面可见，背面不可见。三角形的渲染顺序与三角形的正面法线呈左手螺旋定则。大部分按顺时针：012,213