Unity3D实用脚本（一）—— 导出场景中的3D资源到本地为.obj格式

在项目开发过程中，有时我们需要将项目中的3D模型分离出来，并保存到本地。

我们今天就来实现这一功能，可实现如下功能：

1.将所有选中的MeshFilters导出成分离的OBJ；

2.将整个选择的资源导出到单个OBJ；

3.将每个被选中资源成分离的OBJ。

代码如下：

using UnityEngine;using UnityEditor;using System.Collections;using System.Collections.Generic;using System.IO;using System.Text;using System;struct ObjMaterial{public string name;public string textureName;}public class EditorObjExporter : ScriptableObject{private static int vertexOffset = 0;private static int normalOffset = 0;private static int uvOffset = 0;//User should probably be able to change this. It is currently left as an excercise for//the reader.private static string targetFolder = "Assets/ExportedObj";private static string MeshToString(MeshFilter mf, Dictionary<string, ObjMaterial> materialList){Mesh m = mf.sharedMesh;Material[] mats = mf.GetComponent<Renderer>().sharedMaterials;StringBuilder sb = new StringBuilder();sb.Append("g ").Append(mf.name).Append("\n");foreach (Vector3 lv in m.vertices){Vector3 wv = mf.transform.TransformPoint(lv);//This is sort of ugly - inverting x-component since we're in//a different coordinate system than "everyone" is "used to".sb.Append(string.Format("v {0} {1} {2}\n", -wv.x, wv.y, wv.z));}sb.Append("\n");foreach (Vector3 lv in m.normals){Vector3 wv = mf.transform.TransformDirection(lv);sb.Append(string.Format("vn {0} {1} {2}\n", -wv.x, wv.y, wv.z));}sb.Append("\n");foreach (Vector3 v in m.uv){sb.Append(string.Format("vt {0} {1}\n", v.x, v.y));}for (int material = 0; material < m.subMeshCount; material++){sb.Append("\n");sb.Append("usemtl ").Append(mats[material].name).Append("\n");sb.Append("usemap ").Append(mats[material].name).Append("\n");//See if this material is already in the materiallist.try{ObjMaterial objMaterial = new ObjMaterial();objMaterial.name = mats[material].name;if (mats[material].mainTexture)objMaterial.textureName = EditorUtility.GetAssetPath(mats[material].mainTexture);elseobjMaterial.textureName = null;materialList.Add(objMaterial.name, objMaterial);}catch (ArgumentException){//Already in the dictionary}int[] triangles = m.GetTriangles(material);for (int i = 0; i < triangles.Length; i += 3){//Because we inverted the x-component, we also needed to alter the triangle winding.sb.Append(string.Format("f {1}/{1}/{1} {0}/{0}/{0} {2}/{2}/{2}\n",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 Clear(){vertexOffset = 0;normalOffset = 0;uvOffset = 0;}private static Dictionary<string, ObjMaterial> PrepareFileWrite(){Clear();return new Dictionary<string, ObjMaterial>();}private static void MaterialsToFile(Dictionary<string, ObjMaterial> materialList, string folder, string filename){using (StreamWriter sw = new StreamWriter(folder + "/" + filename + ".mtl")){foreach (KeyValuePair<string, ObjMaterial> kvp in materialList){sw.Write("\n");sw.Write("newmtl {0}\n", kvp.Key);sw.Write("Ka  0.6 0.6 0.6\n");sw.Write("Kd  0.6 0.6 0.6\n");sw.Write("Ks  0.9 0.9 0.9\n");sw.Write("d  1.0\n");sw.Write("Ns  0.0\n");sw.Write("illum 2\n");if (kvp.Value.textureName != null){string destinationFile = kvp.Value.textureName;int stripIndex = destinationFile.LastIndexOf('/');//FIXME: Should be Path.PathSeparator;if (stripIndex >= 0)destinationFile = destinationFile.Substring(stripIndex + 1).Trim();string relativeFile = destinationFile;destinationFile = folder + "/" + destinationFile;Debug.Log("Copying texture from " + kvp.Value.textureName + " to " + destinationFile);try{//Copy the source fileFile.Copy(kvp.Value.textureName, destinationFile);}catch{}sw.Write("map_Kd {0}", relativeFile);}sw.Write("\n\n\n");}}}private static void MeshToFile(MeshFilter mf, string folder, string filename){Dictionary<string, ObjMaterial> materialList = PrepareFileWrite();using (StreamWriter sw = new StreamWriter(folder + "/" + filename + ".obj")){sw.Write("mtllib ./" + filename + ".mtl\n");sw.Write(MeshToString(mf, materialList));}MaterialsToFile(materialList, folder, filename);}private static void MeshesToFile(MeshFilter[] mf, string folder, string filename){Dictionary<string, ObjMaterial> materialList = PrepareFileWrite();using (StreamWriter sw = new StreamWriter(folder + "/" + filename + ".obj")){sw.Write("mtllib ./" + filename + ".mtl\n");for (int i = 0; i < mf.Length; i++){sw.Write(MeshToString(mf[i], materialList));}}MaterialsToFile(materialList, folder, filename);}private static bool CreateTargetFolder(){try{System.IO.Directory.CreateDirectory(targetFolder);}catch{EditorUtility.DisplayDialog("Error!", "Failed to create target folder!", "");return false;}return true;}[MenuItem("Custom/Export/Export all MeshFilters in selection to separate OBJs")]static void ExportSelectionToSeparate(){if (!CreateTargetFolder())return;Transform[] selection = Selection.GetTransforms(SelectionMode.Editable | SelectionMode.ExcludePrefab);if (selection.Length == 0){EditorUtility.DisplayDialog("No source object selected!", "Please select one or more target objects", "");return;}int exportedObjects = 0;for (int i = 0; i < selection.Length; i++){Component[] meshfilter = selection[i].GetComponentsInChildren(typeof(MeshFilter));for (int m = 0; m < meshfilter.Length; m++){exportedObjects++;MeshToFile((MeshFilter)meshfilter[m], targetFolder, selection[i].name + "_" + i + "_" + m);}}if (exportedObjects > 0)EditorUtility.DisplayDialog("Objects exported", "Exported " + exportedObjects + " objects", "");elseEditorUtility.DisplayDialog("Objects not exported", "Make sure at least some of your selected objects have mesh filters!", "");}[MenuItem("Custom/Export/Export whole selection to single OBJ")]static void ExportWholeSelectionToSingle(){if (!CreateTargetFolder())return;Transform[] selection = Selection.GetTransforms(SelectionMode.Editable | SelectionMode.ExcludePrefab);if (selection.Length == 0){EditorUtility.DisplayDialog("No source object selected!", "Please select one or more target objects", "");return;}int exportedObjects = 0;ArrayList mfList = new ArrayList();for (int i = 0; i < selection.Length; i++){Component[] meshfilter = selection[i].GetComponentsInChildren(typeof(MeshFilter));for (int m = 0; m < meshfilter.Length; m++){exportedObjects++;mfList.Add(meshfilter[m]);}}if (exportedObjects > 0){MeshFilter[] mf = new MeshFilter[mfList.Count];for (int i = 0; i < mfList.Count; i++){mf[i] = (MeshFilter)mfList[i];}string filename = EditorApplication.currentScene + "_" + exportedObjects;int stripIndex = filename.LastIndexOf('/');//FIXME: Should be Path.PathSeparatorif (stripIndex >= 0)filename = filename.Substring(stripIndex + 1).Trim();MeshesToFile(mf, targetFolder, filename);EditorUtility.DisplayDialog("Objects exported", "Exported " + exportedObjects + " objects to " + filename, "");}elseEditorUtility.DisplayDialog("Objects not exported", "Make sure at least some of your selected objects have mesh filters!", "");}[MenuItem("Custom/Export/Export each selected to single OBJ")]static void ExportEachSelectionToSingle(){if (!CreateTargetFolder())return;Transform[] selection = Selection.GetTransforms(SelectionMode.Editable | SelectionMode.ExcludePrefab);if (selection.Length == 0){EditorUtility.DisplayDialog("No source object selected!", "Please select one or more target objects", "");return;}int exportedObjects = 0;for (int i = 0; i < selection.Length; i++){Component[] meshfilter = selection[i].GetComponentsInChildren(typeof(MeshFilter));MeshFilter[] mf = new MeshFilter[0];if (meshfilter != null && meshfilter.Length > 0){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("Objects exported", "Exported " + exportedObjects + " objects", "");}elseEditorUtility.DisplayDialog("Objects not exported", "Make sure at least some of your selected objects have mesh filters!", "");}}