private void CombineMesh()

    {

        //获取自身和所有子物体中所有的 MeshRenderer 组件

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

        //材质球数组

        Material[] materials = new Material[meshRenderers.Length];

        for (int i = ; i < meshRenderers.Length; i++)

        {

            materials[i] = meshRenderers[i].sharedMaterial;

        }

        // 合并 Mesh

        // 后去自身和子物体中所有 MsehFilter 组件

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

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

        for (int i = ; i < meshFilters.Length; i++)

        {

            combines[i].mesh = meshFilters[i].sharedMesh;

            // 矩阵（Matrix）自身空间坐标的点转换成世界空间坐标的点

            combines[i].transform = meshFilters[i].transform.localToWorldMatrix;

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

        }

        //重新生成mesh

        MeshFilter meshFilter = transform.GetComponent<MeshFilter>();

        if (meshFilter == null)

        {

            meshFilter = gameObject.AddComponent<MeshFilter>();

        }

        // 给 MeshFilter 组件的 mesh 赋值

        meshFilter.mesh = new Mesh();

        //合并Mesh， 第二个参数 false，表示并不合并为一个网格，而是一个自网格列表

        transform.GetComponent<MeshFilter>().mesh.CombineMeshes(combines, false);

        transform.gameObject.SetActive(true);

        //为合并后的新Mesh 指定材质

        //transform.GetComponent<MeshRenderer>().sharedMaterials = materials;

        MeshRenderer meshRender = transform.GetComponent<MeshRenderer>();

        if (meshRender == null)

        {

            meshRender = gameObject.AddComponent<MeshRenderer>();

        }

        meshRender.sharedMaterials = materials;

    }