JJBB/Assets/Project/Script/Common/Utilities/Editor/ExtractSceneMeshes.cs

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Text;
using Module.Log;
using UnityEditor;
using UnityEngine;
using UnityEngine.SceneManagement;
using Object = UnityEngine.Object;

public class ExtractSceneMeshes
{
    [MenuItem("Scene/Extract SceneMesh To SubMeshes")]
    public static void Extract()
    {
        if (EditorUtility.DisplayDialog("逐一导出场景模型", "需要按当前位置逐个导出场景模型？", "确认", "取消"))
        {
            var vertices = new List<Vector3>();
            var uv = new List<Vector2>();
            var normal = new List<Vector3>();
            var subMeshes = new Dictionary<Material, SubMeshInfo>();
            var meshFilters = Object.FindObjectsOfType<MeshFilter>();
            for (var i = 0; i < meshFilters.Length; i++)
            {
                var filter = meshFilters[i];
                if (!filter.gameObject.activeInHierarchy)
                {
                }
                else if (filter.sharedMesh == null)
                {
                    LogModule.ErrorLog("Filter has no mesh " + filter.transform.GetHierarchyName());
                }
                else if (!filter.sharedMesh.isReadable)
                {
                    LogModule.WarningLog("Mesh isn't readable " + filter.sharedMesh.name);
                }
                else
                {
                    var renderer = filter.GetComponent<MeshRenderer>();
                    if (renderer == null)
                        LogModule.WarningLog("Unable to find renderer on " + filter.sharedMesh.name);
                    else
                    {
                        var start = vertices.Count;
                        // 添加顶点次序
                        var trs = Matrix4x4.TRS(filter.transform.position, filter.transform.rotation,
                            filter.transform.localScale);
                        var meshVertices = filter.sharedMesh.vertices;
                        var meshUv = filter.sharedMesh.uv;
                        var meshNormal = filter.sharedMesh.normals;
                        for (var j = 0; j < meshVertices.Length; j++)
                            vertices.Add(trs.MultiplyPoint3x4(meshVertices[j]));
                        for (var j = 0; j < meshNormal.Length; j++)
                            normal.Add(filter.transform.rotation * meshNormal[j]);
                        for (var j = 0; j < meshUv.Length; j++)
                            uv.Add(meshUv[j]);
                        for (var k = 0; k < filter.sharedMesh.subMeshCount; k++)
                        {
                            var matId = Mathf.Min(k, renderer.sharedMaterials.Length - 1);
                            var material = renderer.sharedMaterials[matId];
                            if (material != null)
                            {
                                SubMeshInfo subMesh;
                                if (!subMeshes.TryGetValue(material, out subMesh))
                                {
                                    subMesh = new SubMeshInfo(material, subMeshes.Count);
                                    subMeshes.Add(material, subMesh);
                                    Debug.Log("Add Sub Mesh");
                                }
                                var meshTriangle = filter.sharedMesh.GetTriangles(k);
                                for (var j = 0; j < meshTriangle.Length; j++)
                                    subMesh.AddPoint(meshTriangle[j] + start);
                            }
                        }
                    }
                }
            }

            var sceneName = SceneManager.GetActiveScene().name;
            if (string.IsNullOrEmpty(sceneName))
                sceneName = "NewScene";
            var path = Application.dataPath.MoveUp().Open("SceneMesh").Open(sceneName);
            if (!Directory.Exists(path))
                Directory.CreateDirectory(path);
            var subMeshList = subMeshes.Values.ToList();
            ObjExtract(vertices, uv, normal, subMeshList, path.Open("SceneMesh.obj"));
            foreach (var subMesh in subMeshList)
            {
                var shader = subMesh.material.shader;
                if (shader != null)
                {
                    var texturePath = path.Open(subMesh.materialName);
                    if (!Directory.Exists(texturePath))
                        Directory.CreateDirectory(texturePath);
                    var count = ShaderUtil.GetPropertyCount(shader);
                    for (var i = 0; i < count; i++)
                    {
                        if (ShaderUtil.GetPropertyType(shader, i) == ShaderUtil.ShaderPropertyType.TexEnv)
                        {
                            var texture =
                                subMesh.material.GetTexture(ShaderUtil.GetPropertyName(shader, i)) as Texture2D;
                            if (texture)
                            {
                                AssetExtractor.ExtractTextureAtPath(texture, texturePath.Open(texture.name + ".png"));
                            }
                        }
                    }
                }
            }
            AssetDatabase.Refresh();
            LogModule.WarningLog("Mesh Exported at " + path);
        }
    }
    
    public static void ObjExtract(IList<Vector3> vertices, IList<Vector2> uv, IList<Vector3> normal, IList<SubMeshInfo> triangleList, string path)
    {
        var builder = new StringBuilder();
        var sceneName = Path.GetFileNameWithoutExtension(path);
        builder.Append("#" + sceneName + ".obj"
                       + "\n#" + DateTime.Now.ToLongDateString()
                       + "\n#" + DateTime.Now.ToLongTimeString()
                       + "\n#-------"
                       + "\n\n");
        builder.Append("g ").Append(sceneName).Append("\n");
        builder.Append("#").Append(sceneName).Append("\n#-------").Append("\n");
        foreach (var v in vertices)
            builder.Append(string.Format("v {0} {1} {2}\n", -v.x, v.y, v.z));
        builder.Append("\n");
        foreach (var v in normal)
            builder.Append(string.Format("vn {0} {1} {2}\n", -v.x, v.y, v.z));
        builder.Append("\n");
        foreach (var v in uv)
            builder.Append(string.Format("vt {0} {1}\n", v.x, v.y));
        foreach (var subMesh in triangleList)
        {
            builder.Append("\n");
            builder.Append("usemtl ").Append(subMesh.materialName).Append("\n");
            builder.Append("usemap ").Append(subMesh.materialName).Append("\n");
            var triangles = subMesh.triangles;
            for (var i = 0; i < triangles.Count; i += 3)
                builder.Append(string.Format("f {0}/{0}/{0} {2}/{2}/{2} {1}/{1}/{1}\n",
                    triangles[i] + 1, triangles[i + 1] + 1, triangles[i + 2] + 1));
        }
        File.WriteAllText(path, builder.ToString());
    }

    public class SubMeshInfo
    {
        public Material material;
        public string materialName;
        public List<int> triangles;

        public SubMeshInfo(Material material, int index)
        {
            this.material = material;
            materialName = index.ToString().PadLeft(3, '0');
            triangles = new List<int>();
        }

        public void AddPoint(int index)
        {
            triangles.Add(index);
        }
    }
}