LittleTools之网格输出为模型

我经常要在Unity中生成一些网格，但是这些网格需要交给美工修改，所以又要将网格输出为模型。于是就有了下面的代码：

using UnityEngine;
using UnityEditor;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Text;
/// <summary>
/// 将“一个”选中的对象输出为obj格式
/// </summary>
public class EditorObjExporter : ScriptableObject
{
        private static int vertexOffset = 0;
        private static int normalOffset = 0;
        private static int uvOffset = 0;

        private static string targetFolder = "Assets/ExportedObj";//文件路径，创建后需要打开路径才能看到刷新的模型

        //核心代码，将网格转为能被obj读取的数据
        private static string MeshToString(MeshFilter mf, List<string> meshList)
        {
                Mesh m = mf.sharedMesh;
                StringBuilder sb = new StringBuilder ();
                sb.Append ("g").Append (mf.name).Append ("
");
                foreach (Vector3 lv in m.vertices) {
                        Vector3 wv = mf.transform.TransformPoint (lv);

                        sb.Append (string.Format ("v {0} {1} {2} 
", -wv.x, wv.y, wv.z));
                }
                sb.Append ("
");

                foreach (Vector3 lv in m.normals) {
                        Vector3 wv = mf.transform.TransformDirection (lv);

                        sb.Append (string.Format ("vn {0} {1} {2} 
", -wv.x, wv.y, wv.z));
                }
                sb.Append ("
");

                foreach (Vector3 v in m.uv) {
                        sb.Append (string.Format ("vt {0} {1} 
", v.x, v.y));
                }

                for (int material = 0; material < m.subMeshCount; material++) {
                        sb.Append ("
"); 
                        int[] triangles = m.GetTriangles (material);
                        for (int i = 0; i < triangles.Length; i += 3) {               
                                sb.Append (string.Format ("f {1}/{1}/{1} {0}/{0}/{0} {2}/{2}/{2}
", triangles [i] + 1 + vertexOffset, triangles [i + 1] + 1 + normalOffset, triangles [i + 2] + 1 + uvOffset));
                        }
                }

                vertexOffset += m.vertices.Length;
                normalOffset += m.normals.Length;
                uvOffset += m.uv.Length;
               
                return sb.ToString ();
        }

        private static void MeshesToFile(MeshFilter[] mf, string folder, string filename)
        {
                vertexOffset = 0;
                normalOffset = 0;
                uvOffset = 0;
                List<string> meshList = new List<string> ();
                using(StreamWriter sw = new StreamWriter (folder + "/" + filename + ".obj")){//创建一个obj文件
                for (int i = 0; i < mf.Length; i++) {
                        sw.Write (MeshToString (mf [i], meshList));//往obj文件中写入数据，即生成模型
                        }
                }
        } 
        //创建文件夹
        private static bool CreateTargetFolder()
        {
                try {
                        System.IO.Directory.CreateDirectory (targetFolder);//已经创建文件夹时不会再创建
                } catch {                        
                        return false;
                }
                return true;
        }


        [MenuItem("Custom/Export OBJ")]
        static void ExportOBJ()
        {
                if (!CreateTargetFolder ())
                        return;

                Transform[] selection = Selection.GetTransforms (SelectionMode.Editable | SelectionMode.ExcludePrefab);

                if (selection== null) {
                        EditorUtility.DisplayDialog ("未选中", "请选择模型！", "确定");
                        return;
                }

                int exportedObjects = 0;

                for (int i = 0; i < selection.Length; i++) {
                        Component[] meshfilter = selection [i].GetComponentsInChildren<MeshFilter> ();

                        MeshFilter[] mf = new MeshFilter[meshfilter.Length];

                        for (int m = 0; m < meshfilter.Length; m++) {
                                exportedObjects++;
                                mf [m] = (MeshFilter)meshfilter [m];
                        }

                        MeshesToFile (mf, targetFolder, selection [i].name + "_" + i);
                }

                if (exportedObjects > 0) {
                        EditorUtility.DisplayDialog ("成功", "已输出！", "确定");
                } else
                        EditorUtility.DisplayDialog ("失败", "未输出!", "确定");
        }

}