Obj格式解析以及在Unity3D下导入测试

目前基本实现了导入,注意只能打开含有单个模型的obj文件

四边面模型：

全三角面模型(测试单一材质，自动分了下UV)：

这里介绍下obj格式：

obj格式是waveFront推出的一种3D模型格式，可以存放静态模型以及一些诸如曲线的附加信息。

其格式以文本形式存放，所以解析起来比较方便，它的大体格式如下：

# WaveFront *.obj file (generated by CINEMA 4D)

mtllib ./test.mtl

v -100.00000000000000 -100.00000000000000 -100.00000000000000
v -100.00000000000000 100.00000000000000 -100.00000000000000
v 100.00000000000000 -100.00000000000000 -100.00000000000000
v 100.00000000000000 100.00000000000000 -100.00000000000000
v 100.00000000000000 -100.00000000000000 100.00000000000000
v 100.00000000000000 100.00000000000000 100.00000000000000
v -100.00000000000000 -100.00000000000000 100.00000000000000
v -100.00000000000000 100.00000000000000 100.00000000000000
#  vertices

vn 0.00000000000000 0.00000000000000 -1.00000000000000
vn 1.00000000000000 0.00000000000000 0.00000000000000
vn 0.00000000000000 0.00000000000000 1.00000000000000
vn -1.00000000000000 0.00000000000000 0.00000000000000
vn 0.00000000000000 1.00000000000000 0.00000000000000
vn 0.00000000000000 -1.00000000000000 0.00000000000000
#  normals

vt 0.00000000000000 -1.00000000000000 0.00000000000000
vt 0.00000000000000 -0.00000000000000 0.00000000000000
vt 1.00000000000000 -0.00000000000000 0.00000000000000
vt 1.00000000000000 -1.00000000000000 0.00000000000000
#  texture coordinates

o Cube
usemtl default
f // // // //
f // // // //
f // // // //
f // // // //
f // // // //
f // // // //

Cube(Obj)

常用类型：

#开头表示注释

v表示顶点

vn表示法线，可以共用法线

vt表示uv坐标

f表示一个面，比如参数1/4/1，表示顶点索引/UV索引/法线索引

下面贴一下工具类的代码：

using System;
using System.Linq;
using System.Collections;
using System.Collections.Generic;

namespace Hont
{
    public class ObjFormatAnalyzer
    {
        public struct Vector
        {
            public float X;
            public float Y;
            public float Z;
        }

        public struct FacePoint
        {
            public int VertexIndex;
            public int TextureIndex;
            public int NormalIndex;
        }

        public struct Face
        {
            public FacePoint[] Points;
            public bool IsQuad;
        }

        public Vector[] VertexArr;
        public Vector[] VertexNormalArr;
        public Vector[] VertexTextureArr;
        public Face[] FaceArr;

        public void Analyze(string content)
        {
            content = content.Replace('\r', ' ').Replace('\t', ' ');

            var lines = content.Split('\n');
            var vertexList = new List<Vector>();
            var vertexNormalList = new List<Vector>();
            var vertexTextureList = new List<Vector>();
            var faceList = new List<Face>();

            for (int i = ; i < lines.Length; i++)
            {
                var currentLine = lines[i];

                if (currentLine.Contains("#") || currentLine.Length == )
                {
                    continue;
                }

                if (currentLine.Contains("v "))
                {
                    var splitInfo = currentLine.Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
                    vertexList.Add(new Vector() { X = float.Parse(splitInfo[]), Y = float.Parse(splitInfo[]), Z = float.Parse(splitInfo[]) });
                }
                else if (currentLine.Contains("vt "))
                {
                    var splitInfo = currentLine.Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
                    vertexTextureList.Add(new Vector() { X = splitInfo.Length >  ? float.Parse(splitInfo[]) : , Y = splitInfo.Length >  ? float.Parse(splitInfo[]) : , Z = splitInfo.Length >  ? float.Parse(splitInfo[]) :  });
                }
                else if (currentLine.Contains("vn "))
                {
                    var splitInfo = currentLine.Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
                    vertexNormalList.Add(new Vector() { X = float.Parse(splitInfo[]), Y = float.Parse(splitInfo[]), Z = float.Parse(splitInfo[]) });
                }
                else if (currentLine.Contains("f "))
                {
                    Func<string, int> tryParse = (inArg) =>
                     {
                         var outValue = -;
                         return int.TryParse(inArg, out outValue) ? outValue : ;
                     };

                    var splitInfo = currentLine.Split(" ".ToCharArray(), StringSplitOptions.RemoveEmptyEntries);
                    var isQuad = splitInfo.Length > ;
                    var face1 = splitInfo[].Split('/');
                    var face2 = splitInfo[].Split('/');
                    var face3 = splitInfo[].Split('/');
                    var face4 = isQuad ? splitInfo[].Split('/') : null;
                    var face = new Face();
                    face.Points = new FacePoint[];
                    face.Points[] = new FacePoint() { VertexIndex = tryParse(face1[]), TextureIndex = tryParse(face1[]), NormalIndex = tryParse(face1[]) };
                    face.Points[] = new FacePoint() { VertexIndex = tryParse(face2[]), TextureIndex = tryParse(face2[]), NormalIndex = tryParse(face2[]) };
                    face.Points[] = new FacePoint() { VertexIndex = tryParse(face3[]), TextureIndex = tryParse(face3[]), NormalIndex = tryParse(face3[]) };
                    face.Points[] = isQuad ? new FacePoint() { VertexIndex = tryParse(face4[]), TextureIndex = tryParse(face4[]), NormalIndex = tryParse(face4[]) } : default(FacePoint);
                    face.IsQuad = isQuad;

                    faceList.Add(face);
                }
            }

            VertexArr = vertexList.ToArray();
            VertexNormalArr = vertexNormalList.ToArray();
            VertexTextureArr = vertexTextureList.ToArray();
            FaceArr = faceList.ToArray();
        }
    }
}

ObjFormatAnalyzer

工厂类，目前只有输出GameObject：

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

namespace Hont
{
    public static class ObjFormatAnalyzerFactory
    {
        public static GameObject AnalyzeToGameObject(string objFilePath)
        {
            if (!File.Exists(objFilePath)) return null;

            var objFormatAnalyzer = new ObjFormatAnalyzer();

            objFormatAnalyzer.Analyze(File.ReadAllText(objFilePath));

            var go = new GameObject();
            var meshRenderer = go.AddComponent<MeshRenderer>();
            var meshFilter = go.AddComponent<MeshFilter>();

            var mesh = new Mesh();

            var sourceVertexArr = objFormatAnalyzer.VertexArr;
            var sourceUVArr = objFormatAnalyzer.VertexTextureArr;
            var faceArr = objFormatAnalyzer.FaceArr;
            var notQuadFaceArr = objFormatAnalyzer.FaceArr.Where(m => !m.IsQuad).ToArray();
            var quadFaceArr = objFormatAnalyzer.FaceArr.Where(m => m.IsQuad).ToArray();
            var vertexList = new List<Vector3>();
            var uvList = new List<Vector2>();

            var triangles = new int[notQuadFaceArr.Length *  + quadFaceArr.Length * ];
            for (int i = , j = ; i < faceArr.Length; i++)
            {
                var currentFace = faceArr[i];

                triangles[j] = j;
                triangles[j + ] = j + ;
                triangles[j + ] = j + ;

                var vec = sourceVertexArr[currentFace.Points[].VertexIndex - ];
                vertexList.Add(new Vector3(vec.X, vec.Y, vec.Z));

                var uv = sourceUVArr[currentFace.Points[].TextureIndex - ];
                uvList.Add(new Vector2(uv.X, uv.Y));

                vec = sourceVertexArr[currentFace.Points[].VertexIndex - ];
                vertexList.Add(new Vector3(vec.X, vec.Y, vec.Z));

                uv = sourceUVArr[currentFace.Points[].TextureIndex - ];
                uvList.Add(new Vector2(uv.X, uv.Y));

                vec = sourceVertexArr[currentFace.Points[].VertexIndex - ];
                vertexList.Add(new Vector3(vec.X, vec.Y, vec.Z));

                uv = sourceUVArr[currentFace.Points[].TextureIndex - ];
                uvList.Add(new Vector2(uv.X, uv.Y));

                if (currentFace.IsQuad)
                {
                    triangles[j + ] = j + ;
                    triangles[j + ] = j + ;
                    triangles[j + ] = j + ;
                    j += ;

                    vec = sourceVertexArr[currentFace.Points[].VertexIndex - ];
                    vertexList.Add(new Vector3(vec.X, vec.Y, vec.Z));

                    uv = sourceUVArr[currentFace.Points[].TextureIndex - ];
                    uvList.Add(new Vector2(uv.X, uv.Y));

                    vec = sourceVertexArr[currentFace.Points[].VertexIndex - ];
                    vertexList.Add(new Vector3(vec.X, vec.Y, vec.Z));

                    uv = sourceUVArr[currentFace.Points[].TextureIndex - ];
                    uvList.Add(new Vector2(uv.X, uv.Y));

                    vec = sourceVertexArr[currentFace.Points[].VertexIndex - ];
                    vertexList.Add(new Vector3(vec.X, vec.Y, vec.Z));

                    uv = sourceUVArr[currentFace.Points[].TextureIndex - ];
                    uvList.Add(new Vector2(uv.X, uv.Y));
                }

                j += ;
            }

            mesh.vertices = vertexList.ToArray();
            mesh.uv = uvList.ToArray();
            mesh.triangles = triangles;

            meshFilter.mesh = mesh;
            meshRenderer.material = new Material(Shader.Find("Standard"));

            return go;
        }
    }
}

ObjFormatAnalyzerFactory

测试使用脚本：

public class ObjFormatAnalyzerTest : MonoBehaviour
{
    void Start()
    {
        var go = ObjFormatAnalyzerFactory.AnalyzeToGameObject(@"D:\TestObj\centaur.obj");

        WWW www = new WWW("file:/D:/TestObj/texture.jpg");

        while (!www.isDone) { }

        go.GetComponent<MeshRenderer>().material.mainTexture = www.texture;
    }
}

然后挂载运行即可。

目前可能还有点小问题，因为没有实现材质的绑定，所以只能支持单一材质。