首次提交

Assets/Scripts/Editor/MeshAssetObjExporter.cs

@@ -0,0 +1,78 @@
+using UnityEngine;
+using UnityEditor;
+using System.IO;
+using System.Text;
+
+public class MeshAssetObjExporter
+{
+    [MenuItem("Assets/Export Mesh (.asset) to OBJ", true)]
+    static bool ValidateExport()
+    {
+        return Selection.activeObject is Mesh;
+    }
+
+    [MenuItem("Assets/Export Mesh (.asset) to OBJ")]
+    static void ExportMeshAssetToObj()
+    {
+        Mesh mesh = Selection.activeObject as Mesh;
+        if (mesh == null)
+        {
+            Debug.LogWarning("Please select a Mesh .asset file in the Project window.");
+            return;
+        }
+
+        string path = EditorUtility.SaveFilePanel("Export OBJ", "", mesh.name + ".obj", "obj");
+        if (string.IsNullOrEmpty(path)) return;
+
+        ExportMeshToObj(mesh, path);
+        Debug.Log("Mesh exported to: " + path);
+    }
+
+    static Vector3 ConvertToBlender(Vector3 v)
+    {
+        // Unity坐标 (X, Y, Z) → Blender坐标 (X, Z, -Y)
+        return new Vector3(v.x, v.z, -v.y);
+    }
+
+    static void ExportMeshToObj(Mesh mesh, string path)
+    {
+        StringBuilder sb = new StringBuilder();
+        sb.AppendLine("# Exported from Unity MeshAssetObjExporter");
+        sb.AppendLine("g " + mesh.name);
+
+        // 顶点
+        foreach (Vector3 v in mesh.vertices)
+        {
+            Vector3 vBlender = ConvertToBlender(v);
+            sb.AppendFormat("v {0} {1} {2}\n", vBlender.x, vBlender.y, vBlender.z);
+        }
+
+        // 法线
+        foreach (Vector3 n in mesh.normals)
+        {
+            Vector3 nBlender = ConvertToBlender(n);
+            sb.AppendFormat("vn {0} {1} {2}\n", nBlender.x, nBlender.y, nBlender.z);
+        }
+
+        // UV
+        foreach (Vector2 uv in mesh.uv)
+        {
+            sb.AppendFormat("vt {0} {1}\n", uv.x, uv.y);
+        }
+
+        // 面
+        for (int i = 0; i < mesh.subMeshCount; i++)
+        {
+            int[] tris = mesh.GetTriangles(i);
+            for (int j = 0; j < tris.Length; j += 3)
+            {
+                int a = tris[j] + 1;
+                int b = tris[j + 1] + 1;
+                int c = tris[j + 2] + 1;
+                sb.AppendFormat("f {0}/{0}/{0} {1}/{1}/{1} {2}/{2}/{2}\n", a, b, c);
+            }
+        }
+
+        File.WriteAllText(path, sb.ToString());
+    }
+}