Unity --- MeshRenderer之网格合并

创建如图所示的对象结构,parent为空对象，然后将下面的代码挂载到parent对象上运行即可。

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 = 0, 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(0, 0, 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[0].shader);
        newM.CopyPropertiesFromMaterial(oldMArray[0]);
        newMR.sharedMaterial = newM;

        //创建合并后的贴图，
        Texture2D newTex = new Texture2D(1024, 1024);
        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, 10, 1024);  //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 = 0, 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 = 0, 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;
    }
}