Jon Martin

//OBJ import for Unity3d 1/3
//OBJ.cs by bartek drozdz of http://www.everyday3d.com (ammendments by Jon Martin of jon-martin.com & fusedworks.com)

using UnityEngine;
using System;
using System.Collections;
using System.Collections.Generic;
using System.Globalization;
using System.Text.RegularExpressions;
using System.IO;

public class OBJ : MonoBehaviour {

    public string objPath;

    /* OBJ file tags */
    private const string O  = "o";
    private const string G  = "g";
    private const string V  = "v";
    private const string VT = "vt";
    private const string VN = "vn";
    private const string F  = "f";
    private const string MTL = "mtllib";
    private const string UML = "usemtl";

    /* MTL file tags */
    private const string NML = "newmtl";
    private const string NS = "Ns"; // Shininess
    private const string KA = "Ka"; // Ambient component (not supported)
    private const string KD = "Kd"; // Diffuse component
    private const string KS = "Ks"; // Specular component
    private const string D = "d";   // Transparency (not supported)
    private const string TR = "Tr"; // Same as 'd'
    private const string ILLUM = "illum"; // Illumination model. 1 - diffuse, 2 - specular
    private const string MAP_KD = "map_Kd"; // Diffuse texture (other textures are not supported)

    private string basepath;
    private string mtllib;
    private GeometryBuffer buffer;

    void Start ()
    {
        buffer = new GeometryBuffer ();
        //ALTERATION 0:- To Cater for Local Files.
        if (!objPath.Contains("http://")) {
            basepath=Path.GetDirectoryName(objPath);
            objPath="file:///"+objPath;
            basepath="file:///"+basepath+Path.DirectorySeparatorChar;
        } else {
            basepath = (objPath.IndexOf("/") == -1) ? "" : objPath.Substring(0, objPath.LastIndexOf("/") + 1);
        }
        StartCoroutine (Load (objPath));
    }

    public IEnumerator Load(string path) {
        WWW loader = new WWW(path);
        yield return loader;
        SetGeometryData(loader.text);

        if(hasMaterials) {
            loader = new WWW(basepath + mtllib);
            yield return loader;

            //ALTERATION 4:- Lets say the user moved the material library elsewhere
            //See also new function in GeometryBuffer ReturnMaterialNames()
            //and correction to OBJ.GetMaterial() to cater for this.
            if (loader.error != null) {
                //Could allow user to choose new path here for material library or create alert!
                string[] emats=buffer.ReturnMaterialNames(); //retrieves material names from groups
                // builds material data with defaults
                materialData = new List<MaterialData>();
                MaterialData nmd = new MaterialData();
                foreach(string mname in emats) {
                    nmd = new MaterialData();
                    nmd.name = mname;
                    nmd.diffuse = new Color(0.5f, 0.5f, 0.5f, 1.0f);
                    materialData.Add(nmd);
                }


            } else {
                SetMaterialData(loader.text);
                foreach(MaterialData m in materialData) {
                    if(m.diffuseTexPath != null) {
                        WWW texloader = new WWW(basepath + m.diffuseTexPath);
                        yield return texloader;
                        m.diffuseTex = texloader.texture;
                    }
                }

            }
        }
        Build();
    }

    private void SetGeometryData(string data) {
        //ALTERATION 1:- Major Problems with different OBJ file format whitespace, this helped:-.
        data = data.Replace("\r\n","\n");

        string[] lines = data.Split("\n".ToCharArray()); //
        for(int i = 0; i < lines.Length; i++) {
            string l = lines[i];
            if(l.IndexOf("#") != -1) l = l.Substring(0, l.IndexOf("#"));

            //ALTERATION 1:- whitespace leading to null values, this helped:-
            l=Regex.Replace(l,@"\s+"," ");
            l=l.Trim();

            string[] p = l.Split(" ".ToCharArray());

            switch(p[0]) {
                case O:
                    buffer.PushObject(p[1].Trim());
                    break;
                case G:
                    buffer.PushGroup(p[1].Trim());
                    break;
                case V:
                    if (p.Length>=3) {
                        buffer.PushVertex( new Vector3( cf(p[1]), cf(p[2]), cf(p[3]) ) );
                    }
                    break;
                case VT:
                    if (p.Length>=2) {
                        buffer.PushUV(new Vector2( cf(p[1]), cf(p[2]) ));
                    }
                    break;
                case VN:
                    if (p.Length>=3) {
                        buffer.PushNormal(new Vector3( cf(p[1]), cf(p[2]), cf(p[3]) ));
                    }
                    break;
                case F:
                    if (p.Length>=4) {
                        string[] c;
                        // ALTERATION 2:- Rough Fix to deal with quads and polys there may be better methods
                        for (int j=0;j<p.Length-3;j++) {    //Amount of Triangles To Make up Face
                            FaceIndices fi = new FaceIndices(); //Get first point
                                c=p[1].Trim().Split("/".ToCharArray());
                                if (c.Length > 0 && c[0] != string.Empty) {fi.vi = ci(c[0])-1;}
                                if (c.Length > 1 && c[1] != string.Empty) {fi.vu = ci(c[1])-1;}
                                if (c.Length > 2 && c[2] != string.Empty) {fi.vn = ci(c[2])-1;}
                            buffer.PushFace(fi);
                            for (int k=0;k<2;k++) {
                                fi = new FaceIndices(); //Get second and third points (depending on p length)
                                    int no=2+k+j;
                                    c=p[no].Trim().Split("/".ToCharArray());
                                    if (c.Length > 0 && c[0] != string.Empty) {fi.vi = ci(c[0])-1;}
                                    if (c.Length > 1 && c[1] != string.Empty) {fi.vu = ci(c[1])-1;}
                                    if (c.Length > 2 && c[2] != string.Empty) {fi.vn = ci(c[2])-1;}
                                buffer.PushFace(fi);
                            }
                        }
                    }
                    break;
                case MTL:
                    mtllib = p[1].Trim();
                    break;
                case UML:
                    buffer.PushMaterialName(p[1].Trim());
                    break;
            }
        }
        buffer.Trace();
    }

    private float cf(string v) {
            return Convert.ToSingle(v.Trim(), new CultureInfo("en-US"));
    }

    private int ci(string v) {
            return Convert.ToInt32(v.Trim(), new CultureInfo("en-US"));
    }

    private bool hasMaterials {
        get {
            return mtllib != null;
        }
    }

    /* ############## MATERIALS */
    private List<MaterialData> materialData;
    private class MaterialData {
        public string name;
        public Color ambient;
        public Color diffuse;
        public Color specular;
        public float shininess;
        public float alpha;
        public int illumType;
        public string diffuseTexPath;
        public Texture2D diffuseTex;
    }

    private void SetMaterialData(string data) {
        //ALTERATION 1:- Major Problems with different OBJ file format whitespace, this helped:-.
        data = data.Replace("\r\n","\n");

        string[] lines = data.Split("\n".ToCharArray());

        materialData = new List<MaterialData>();
        MaterialData current = new MaterialData();

        for(int i = 0; i < lines.Length; i++) {
            string l = lines[i];

            if(l.IndexOf("#") != -1) l = l.Substring(0, l.IndexOf("#"));
            //ALTERATION 1:- whitespace leading to null values, this helped:-
            l=Regex.Replace(l,@"\s+"," ");
            l=l.Trim();

            string[] p = l.Split(" ".ToCharArray());

            switch(p[0]) {
                case NML:
                    current = new MaterialData();
                    current.name = p[1].Trim();
                    materialData.Add(current);
                    break;
                case KA:
                    current.ambient = gc(p);
                    break;
                case KD:
                    current.diffuse = gc(p);
                    break;
                case KS:
                    current.specular = gc(p);
                    break;
                case NS:
                    current.shininess = cf(p[1]) / 1000;
                    break;
                case D:
                case TR:
                    current.alpha = cf(p[1]);
                    break;
                case MAP_KD:
                    current.diffuseTexPath = p[1].Trim();
                    break;
                case ILLUM:
                    current.illumType = ci(p[1]);
                    break;

            }
        }
    }

    private Material GetMaterial(MaterialData md) {
        Material m;

        if(md.illumType == 2) {
            m =  new Material(Shader.Find("Specular"));
            m.SetColor("_SpecColor", md.specular);
            m.SetFloat("_Shininess", md.shininess);
        } else {
            m =  new Material(Shader.Find("Diffuse"));
        }

        m.SetColor("_Color", md.diffuse);

        if(md.diffuseTex != null) m.SetTexture("_MainTex", md.diffuseTex);

        return m;
    }

    private Color gc(string[] p) {
        return new Color( cf(p[1]), cf(p[2]), cf(p[3]) );
    }

    private void Build() {
        Dictionary<string, Material> materials = new Dictionary<string, Material>();

        if(hasMaterials) {
            foreach(MaterialData md in materialData) {
                materials.Add(md.name, GetMaterial(md));
            }
        } else {
            //ALTERATION 3:- No Material library Found error found on a turbosquid .obj I downloaded
            //Updated GeometryBuffer.PushGroup() adding g.materialName = "default";  as usemtl entry normally folows g group entry in obj file and will overwrite this "default" material name.
            //This now works for object with no mtl libraries
            Material m =  new Material(Shader.Find("Diffuse"));
            m.SetColor("_Color", new Color(0.5f, 0.5f, 0.5f, 1.0f));
            materials.Add("default", m);
        }

        GameObject[] ms = new GameObject[buffer.numObjects];

        if(buffer.numObjects == 1) {
            gameObject.AddComponent(typeof(MeshFilter));
            gameObject.AddComponent(typeof(MeshRenderer));
            ms[0] = gameObject;
        } else if(buffer.numObjects > 1) {
            for(int i = 0; i < buffer.numObjects; i++) {
                GameObject go = new GameObject();
                go.transform.parent = gameObject.transform;
                go.AddComponent(typeof(MeshFilter));
                go.AddComponent(typeof(MeshRenderer));
                ms[i] = go;
            }
        }

        buffer.PopulateMeshes(ms, materials);
    }
}