Unity导出场景地形网格到.obj文件

需求

using UnityEngine;
using System.Collections;
using System.IO;
using System.Text;
using UnityEditor;
using UnityEditor.SceneManagement;

/// <summary>
/// 描述：导出网格数据到.Obj文件
/// </summary>
public sealed class ExportMesh {

public static void ExportMeshToObj()
{
GameObject[] roots = EditorUtil.GetRootGameObjects();

bool isSuccess = false;
foreach (GameObject gObj in roots)
{
if (ExportGameObjectMesh(gObj)) isSuccess = true;
}

EditorUtility.DisplayDialog("提示", isSuccess ? "已成功导出Mesh到.obj文件" : "当前场景没有找到可导出的资源", "OK");
}

/// <summary>
/// 导出网格信息
/// </summary>
/// <param name="gObj"></param>
private static bool ExportGameObjectMesh(GameObject gObj)
{
MeshFilter[] meshFilters = gObj.GetComponentsInChildren<MeshFilter>();
if (meshFilters == null || meshFilters.Length <= 0) return false;

int offsetVertice = 0;
StringBuilder buf = new StringBuilder();
foreach (MeshFilter mf in meshFilters)
{
offsetVertice += parseMeshFilter(buf, mf , offsetVertice);
}

writeObjFile(buf);
return true;
}

/// <summary>
/// 解析MeshFilter数据
/// </summary>
/// <param name="buf"></param>
/// <param name="mf"></param>
/// <param name="offsetVertices">顶点偏移量</param>
private static int parseMeshFilter(StringBuilder buf, MeshFilter mf , int offsetVertices)
{
Mesh mesh = mf.sharedMesh;
if (!mesh)
{
Debugger.LogError("<<ExportMesh , parseMeshFilter>> Error !!! Cant find Mesh ! name is " + mf.gameObject.name);
return 0;
}
buf.AppendFormat("# {0}.obj" , mf.name );
buf.AppendLine("#" + System.DateTime.Now.ToLongDateString());
buf.AppendLine("#" + System.DateTime.Now.ToLongTimeString());
buf.AppendLine("#-------\n\n");

buf.AppendFormat("g {0} \n", mf.name);
Transform meshTrans = mf.transform;

Vector3[] allVertices = mesh.vertices;
foreach (Vector3 vertice in allVertices)
{
Vector3 v = meshTrans.TransformPoint(vertice);
buf.AppendFormat("v {0} {1} {2} \n", v.x, v.y, -v.z);
}

foreach (Vector3 normal in mesh.normals)
{
Vector3 vn = meshTrans.TransformDirection(normal);
buf.AppendFormat("vn {0} {1} {2} \n", -vn.x, -vn.y, vn.z);
}

foreach (Vector2 uv in mesh.uv)
{
buf.AppendFormat("vt {0} {1}\n", uv.x, uv.y);
}

Material[] mats = meshTrans.GetComponent<Renderer>().sharedMaterials;
for (int i = 0; i < mesh.subMeshCount; i++)
{
buf.Append("usemtl ").Append(mats[i].name).Append("\n");
buf.Append("usemap ").Append(mats[i].name).Append("\n");

int[] triangles = mesh.GetTriangles(i);
for (int j = 0; j < triangles.Length; j += 3)
{
buf.AppendFormat("f {0}/{0}/{0} {1}/{1}/{1} {2}/{2}/{2}\n",
triangles[j] + 1 + offsetVertices, triangles[j + 1] + 1 + offsetVertices, triangles[j + 2] + 1 + offsetVertices);
}
}

return allVertices.Length;
}

/// <summary>
/// 保持OBJ文件
/// </summary>
/// <param name="buf"></param>
private static void writeObjFile(StringBuilder buf)
{
string filePath = Path.Combine(You_EXPORT_MESH_OBJ_PATH, EditorSceneManager.GetActiveScene().name + ".obj");
EditorUtil.SwapnDirectory(filePath);

using (StreamWriter writer = new StreamWriter(filePath))
{
writer.Write(buf.ToString());
}
}
}

using UnityEngine;
using System.Collections;
using System.Collections.Generic;
using System.IO;

/// <summary>
/// 描述：工具开发常用工具集
/// </summary>
public sealed class EditorUtil  {

/// <summary>
/// 获得当前场景的所有根结点
/// </summary>
/// <returns></returns>
public static GameObject[] GetRootGameObjects()
{
List<GameObject> goList = new List<GameObject>();
GameObject[] objArr = UnityEngine.Object.FindObjectsOfType<GameObject>();
foreach (GameObject obj in objArr)
{
if (obj.transform.parent == null)
goList.Add(obj);
}
return goList.ToArray();
}

/// <summary>
/// 检测目录是否存在，如果不存在，则创建目录
/// </summary>
/// <param name="path"></param>
public static void SwapnDirectory(string path)
{
string dir = Path.GetDirectoryName(path);
if (!Directory.Exists(dir)) Directory.CreateDirectory(dir);
}
}