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@icebreaker
Forked from NewEXE/ConvertToObj.cs
Created August 30, 2021 17:06
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Export Unity Game Objects to Wavefront OBJ
// On the basis: https://forum.unity.com/threads/export-obj-while-runtime.252262/
// How to use:
// Put file to Assets/Editor folder
// then select GameObject -> Export selected objects
// in Unity's main panel.
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;
// Output folder.
private static string targetFolder = "_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();
string groupName = mf.name;
if (string.IsNullOrEmpty(groupName)) {
groupName = getRandomStr();
}
sb.Append("g ").Append(groupName).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",
floatToStr(-wv.x),
floatToStr(wv.y),
floatToStr(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",
floatToStr(-wv.x),
floatToStr(wv.y),
floatToStr(wv.z)
));
}
sb.Append("\n");
foreach (Vector3 v in m.uv) {
sb.Append(string.Format(
"vt {0} {1}\n",
floatToStr(v.x),
floatToStr(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 material list.
try {
ObjMaterial objMaterial = new ObjMaterial {name = mats[material].name};
if (mats[material].mainTexture)
objMaterial.textureName = EditorUtility.GetAssetPath(mats[material].mainTexture);
else
objMaterial.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 + 0] + 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 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));
}
}
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));
}
}
}
private static bool CreateTargetFolder() {
try {
Directory.CreateDirectory(targetFolder);
} catch {
return false;
}
return true;
}
[MenuItem("GameObject/Export selected objects")]
static void ExportWholeSelectionToSingle() {
if (!CreateTargetFolder()) {
EditorUtility.DisplayDialog(
"Folder creating error!",
"Failed to create target folder " + targetFolder,
"OK"
);
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",
"OK"
);
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: Path.PathSeparator here (?)
if (stripIndex >= 0)
filename = filename.Substring(stripIndex + 1).Trim();
MeshesToFile(mf, targetFolder, filename);
EditorUtility.DisplayDialog(
"Objects exported",
"Exported " + exportedObjects + " objects to " + filename,
"OK, thanks!"
);
} else {
EditorUtility.DisplayDialog(
"Objects not exported",
"Make sure at least some of your selected objects have mesh filters!",
"OK"
);
}
}
private static string floatToStr(float number) {
return String.Format("{0:0.######}", number);
}
private static string getRandomStr() {
string s = Path.GetRandomFileName() + DateTime.Now.Millisecond.ToString();
s = s.Replace(".", "");
return s;
}
}
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