using UnityEngine;

 using System.Collections;

 public class CombineMeshAndMaterials : MonoBehaviour

 {

     void Start()

     {

         CombineMesh();

     }

     void CombineMesh()

     {

         //收集要合并的贴图

         MeshRenderer[] oldMRArray = GetComponentsInChildren<MeshRenderer>();

         Material[] oldMArray = new Material[oldMRArray.Length];

         Texture2D[] textures = new Texture2D[oldMRArray.Length];

         for (int i = , iMax = oldMRArray.Length; i < iMax; ++i)

         {

             oldMArray[i] = oldMRArray[i].sharedMaterial;

             Texture2D t2d = oldMArray[i].GetTexture("_MainTex") as Texture2D;

             Texture2D _t2d = new Texture2D(t2d.width, t2d.height, TextureFormat.ARGB32, false);

             _t2d.SetPixels(t2d.GetPixels(, , t2d.width, t2d.height));

             _t2d.Apply();

             textures[i] = _t2d;

         }

         //创建合并后的材质

         MeshRenderer newMR = gameObject.AddComponent<MeshRenderer>();

         Material newM = new Material(oldMArray[].shader);

         newM.CopyPropertiesFromMaterial(oldMArray[]);

         newMR.sharedMaterial = newM;

         //创建合并后的贴图，

         Texture2D newTex = new Texture2D(, );

         newM.SetTexture("_MainTex", newTex);   //将合并后的贴图赋给合并后的材质

         //重新计算贴图UV

         MeshFilter[] oldMF = GetComponentsInChildren<MeshFilter>();

         CombineInstance[] combines = new CombineInstance[oldMF.Length];

         Rect[] rects = newTex.PackTextures(textures, , );  //贴图打包 ，矩形的数组包含每个输入的纹理的UV坐标

         for (int i = , iMax = oldMF.Length; i < iMax; ++i)

         {

             Rect rect = rects[i];

             Mesh mesh = oldMF[i].mesh;

             Vector2[] newUVs = new Vector2[mesh.uv.Length];

             //刷新uv

             for (int j = , jMax = mesh.uv.Length; j < jMax; ++j)

             {

                 //如果这里看不太懂，说明对uv的确切含义不太明白

                 //uv是一个比值,u = 横向第u个像素/原始贴图的宽度    v = 竖向第v个像素/原始贴图的高度

                 //rect.x : 原贴图在合并后的贴图的 x 坐标，  rect.y : 原贴图在合并后的贴图的 y 坐标

                 newUVs[j].x = mesh.uv[j].x * rect.width + rect.x;

                 newUVs[j].y = mesh.uv[j].y * rect.height + rect.y;

             }

             mesh.uv = newUVs;

             combines[i].mesh = mesh;

             combines[i].transform = oldMF[i].transform.localToWorldMatrix;  //没有这句,合并后的网格无法看到

             oldMF[i].gameObject.SetActive(false);

         }

         //创建合并后的网格

         MeshFilter newMF = gameObject.AddComponent<MeshFilter>();

         Mesh newMesh = new Mesh();

         newMesh.CombineMeshes(combines, true, true);

         newMF.mesh = newMesh;

     }

 }