Unity3D之Mesh（二）为三角形添加纹理

一、直接開始上步驟

首先繪製一個三角形

創建一個材質，以便後續使用：

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1）材質使用的貼圖

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2）上代碼

　

 using UnityEngine;
 using System.Collections;

 /* ==============================================================================
  * 功能描述：创建三角形Mesh
  * ==============================================================================*/
 [RequireComponent(typeof(MeshRenderer), typeof(MeshFilter))]
 public class NewBehaviourScript1 : MonoBehaviour
 {
     public float sideLength = ;
     public float angleDegree = ;
     private static readonly int ANGLE_DEGREE_PRECISION = ;
     private static readonly int SIDE_LENGTH_PRECISION = ;

     private MeshFilter meshFilter;

     private TriangleMeshCreator creator = new TriangleMeshCreator();

     [ExecuteInEditMode]
     private void Awake()
     {

         meshFilter = GetComponent<MeshFilter>();
     }

     private void Update()
     {
         meshFilter.mesh = creator.CreateMesh(sideLength, angleDegree);
     }
     void OnDrawGizmos()
     {
         Gizmos.color = Color.gray;
         DrawMesh();
     }

     void OnDrawGizmosSelected()
     {
         Gizmos.color = Color.green;
         DrawMesh();
     }

     private void DrawMesh()
     {
         Mesh mesh = creator.CreateMesh(sideLength, angleDegree);
         int[] tris = mesh.triangles;
         Gizmos.DrawLine(transformToWorld(mesh.vertices[tris[]]), transformToWorld(mesh.vertices[tris[]]));
         Gizmos.DrawLine(transformToWorld(mesh.vertices[tris[]]), transformToWorld(mesh.vertices[tris[]]));
         Gizmos.DrawLine(transformToWorld(mesh.vertices[tris[]]), transformToWorld(mesh.vertices[tris[]]));
     }

     private Vector3 transformToWorld(Vector3 src)
     {
         return transform.TransformPoint(src);
     }

     private class TriangleMeshCreator
     {
         private float _sideLength;
         private float _angleDegree;

         private Mesh _cacheMesh;
         public Mesh CreateMesh(float sideLength, float angleDegree)
         {
             if (checkDiff(sideLength, angleDegree))
             {
                 Mesh newMesh = Create(sideLength, angleDegree);
                 if (newMesh != null)
                 {
                     _cacheMesh = newMesh;
                     this._sideLength = sideLength;
                     this._angleDegree = angleDegree;
                 }
             }
             return _cacheMesh;
         }

         private Mesh Create(float sideLength, float angleDegree)
         {
             Mesh mesh = new Mesh();
             Vector3[] vertices = new Vector3[];

             float angle = Mathf.Deg2Rad * angleDegree;
             float halfAngle = angle / ;
             vertices[] = Vector3.zero;
             float cosA = Mathf.Cos(halfAngle);
             float sinA = Mathf.Sin(halfAngle);
             vertices[] = new Vector3(cosA * sideLength, , sinA * sideLength);
             vertices[] = new Vector3(cosA * sideLength, , -sinA * sideLength);

             int[] triangles = new int[];
             triangles[] = ;
             triangles[] = ;
             triangles[] = ;

             mesh.vertices = vertices;
             mesh.triangles = triangles;

             //Vector2[] uvs = new Vector2[vertices.Length];
             //for (int i = 0; i < uvs.Length; i++)
             //{
             //    uvs[i] = Vector2.zero;
             //}
             Vector2[] uvs = new Vector2[vertices.Length];
             uvs[] = new Vector2(, 0.5f);
             uvs[] = Vector2.one;
             uvs[] = Vector2.right;
             mesh.uv = uvs;
             mesh.uv = uvs;

             return mesh;
         }

         private bool checkDiff(float sideLength, float angleDegree)
         {
             return (int)((sideLength - this._sideLength) * SIDE_LENGTH_PRECISION) !=  ||
                 (int)((angleDegree - this._angleDegree) * ANGLE_DEGREE_PRECISION) != ;
         }
     }

 }

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注意： 只能在运行的时候才看得到这个三角形，编辑器里看不到怎么办？

简单来讲就是在编辑器模式下，绘制辅助线框。以下三个方法是为了在编辑模式下看到三角形；

关于OnDrawGizmos和OnDrawGizmosSelected可以参考这个链接http://www.ceeger.com/Script/Gizmos/Gizmos.html

 void OnDrawGizmos()
    {
        Gizmos.color = Color.gray;
        DrawMesh();
    }

    void OnDrawGizmosSelected()
    {
        Gizmos.color = Color.green;
        DrawMesh();
    }

    private void DrawMesh()
    {
        Mesh mesh = creator.CreateMesh(sideLength, angleDegree);
        int[] tris = mesh.triangles;
        Gizmos.DrawLine(transformToWorld(mesh.vertices[tris[]]), transformToWorld(mesh.vertices[tris[]]));
        Gizmos.DrawLine(transformToWorld(mesh.vertices[tris[]]), transformToWorld(mesh.vertices[tris[]]));
        Gizmos.DrawLine(transformToWorld(mesh.vertices[tris[]]), transformToWorld(mesh.vertices[tris[]]));
    }

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3）把Mesh Renderer这个组件上的Material设为我们新建的材质。

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效果：

分情況實驗：

1、

 uvs[] = new Vector2(, 0.5f);
            uvs[] = Vector2.one;
            uvs[] = Vector2.right;

2、

uvs[] = new Vector2(, 0.5f);
 uvs[] = Vector2.one;
uvs[] = Vector2.right;

3、

 uvs[] = new Vector2(, 0.5f);
 uvs[] = Vector2.one;
 uvs[] = Vector2.right;

通过上面的例子，我们知道：

第二種情況下：

三处的三角形顶点对应的uv坐标是(0,0.5f),(1,1)和(1,0)。

这样我们就可以知道，uv坐标系是从0到1，从左到右，自下而上增加的坐标系。即：

賦值順序變化，会显示出不同的效果。

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