Net.Like.Xue.Tokyo/Assets/Plugins/MeshCombineStudio/Editor/ObjExporter.cs

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

namespace MeshCombineStudio
{
    public class ObjExporterScript
    {
        private static int StartIndex = 0;

        public static void Start()
        {
            StartIndex = 0;
        }
        public static void End()
        {
            StartIndex = 0;
        }


        public static string MeshToString(MeshRenderer mr, MeshFilter mf, Transform t)
        {
            // Vector3 s = t.localScale;
            // Vector3 p = t.localPosition;
            Quaternion r = t.localRotation;

            int numVertices = 0;
            Mesh m = mf.sharedMesh;
            if (m == null) return "####Error####";

            Material[] mats = mr.sharedMaterials;

            StringBuilder sb = new StringBuilder();

            foreach (Vector3 vv in m.vertices)
            {
                Vector3 v = t.TransformPoint(vv);
                numVertices++;
                sb.Append(string.Format("v {0} {1} {2}\n", v.x, v.y, -v.z));
            }
            sb.Append("\n");
            foreach (Vector3 nn in m.normals)
            {
                Vector3 v = r * nn;
                sb.Append(string.Format("vn {0} {1} {2}\n", -v.x, -v.y, v.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");

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

            StartIndex += numVertices;
            return sb.ToString();
        }
    }

    public class ObjExporter : ScriptableObject
    {
        [MenuItem("GameObject/Export/Wavefront OBJ")]
        static void DoExportWSubmeshes()
        {
            DoExport(true);
        }

        [MenuItem("GameObject/Export/Wavefront OBJ (No Submeshes)")]
        static void DoExportWOSubmeshes()
        {
            DoExport(false);
        }


        static void DoExport(bool makeSubmeshes)
        {
            if (Selection.gameObjects.Length == 0)
            {
                Debug.Log("Didn't Export Any Meshes; Nothing was selected!");
                return;
            }

            string meshName = Selection.gameObjects[0].name;
            string fileName = EditorUtility.SaveFilePanel("Export .obj file", "", meshName, "obj");

            ObjExporterScript.Start();

            StringBuilder meshString = new StringBuilder();

            meshString.Append("#" + meshName + ".obj"
                                + "\n#" + System.DateTime.Now.ToLongDateString()
                                + "\n#" + System.DateTime.Now.ToLongTimeString()
                                + "\n#-------"
                                + "\n\n");

            Transform t = Selection.gameObjects[0].transform;

            Vector3 originalPosition = t.position;
            t.position = Vector3.zero;

            if (!makeSubmeshes)
            {
                meshString.Append("g ").Append(t.name).Append("\n");
            }
            meshString.Append(processTransform(t, makeSubmeshes));

            WriteToFile(meshString.ToString(), fileName);

            t.position = originalPosition;

            ObjExporterScript.End();
            Debug.Log("Exported Mesh: " + fileName);
        }

        static string processTransform(Transform t, bool makeSubmeshes)
        {
            StringBuilder meshString = new StringBuilder();

            meshString.Append("#" + t.name
                            + "\n#-------"
                            + "\n");

            if (makeSubmeshes)
            {
                meshString.Append("g ").Append(t.name).Append("\n");
            }

            MeshFilter mf = t.GetComponent<MeshFilter>();
            if (mf)
            {
                MeshRenderer mr = t.GetComponent<MeshRenderer>();
                if (mr != null)
                {
                    meshString.Append(ObjExporterScript.MeshToString(mr, mf, t));
                }
            }

            for (int i = 0; i < t.childCount; i++)
            {
                meshString.Append(processTransform(t.GetChild(i), makeSubmeshes));
            }

            return meshString.ToString();
        }

        static void WriteToFile(string s, string filename)
        {
            using (StreamWriter sw = new StreamWriter(filename))
            {
                sw.Write(s);
            }
        }
    }
}