objReader.h

//------------------------------------------------------------------------------
//  Copyright 2007-2014 by Jyh-Ming Lien and George Mason University
//  See the file "LICENSE" for more information
//------------------------------------------------------------------------------

#ifndef _OBJ_READER_H_
#define _OBJ_READER_H_

#include <string>
#include <fstream>
#include <iostream>
#include <list>
#include <vector>
#include <ctype.h>
#include <math.h>

using namespace std;

#include <Point.h>
#include <Quaternion.h>
#include <Vector.h>
using namespace mathtool;

class Vpt
{
public:
    Vpt(){ x=y=z=nx=ny=nz=0; }

    void normalize()
    {
        double norm=(double)sqrt(nx*nx+ny*ny+nz*nz);
        nx/=norm;
        ny/=norm;
        nz/=norm;
    }

    double x, y, z, nx, ny, nz;
};

class V
{
public:
    V(){ x=y=z=0; }
    double x, y, z;
};

class polygon
{
public:
    list<int> pts;
    list<int> normals;
};

class objModel
{
public:
    objModel() { }
    
    void compute_v_normal()
    {
        //check if normal information is valid from the obj file
        if(normals.empty()){ //compute normal
            for(list<polygon>::iterator i=polys.begin();i!=polys.end();i++)
            {
                //get 3 points, compute normal and assign to all vertices
                list<int>::iterator pi=i->pts.begin();
                vector<Point3d> v3;
                for( ;pi!=i->pts.end();pi++){
                    Vpt& pt=pts[*pi];
                    Point3d pos(pt.x,pt.y,pt.z);
                    v3.push_back(pos);
                    if(v3.size()==3) break; //we've collected 3 points
                }
                //compute normal
                Vector3d n=((v3[1]-v3[0])%(v3[2]-v3[0])).normalize();
                //copy normals
                pi=i->pts.begin();
                for( ;pi!=i->pts.end();pi++){
                    Vpt& pt=pts[*pi];
                    pt.nx+=n[0];
                    pt.ny+=n[1];
                    pt.nz+=n[2];
                }//end copying normals
            }//end looping polygons
        }
        else{ // use the information provided
            for(list<polygon>::iterator i=polys.begin();i!=polys.end();i++)
            {
                list<int>::iterator ni=i->normals.begin();
                list<int>::iterator pi=i->pts.begin();

                for( ;pi!=i->pts.end();pi++,ni++){
                    V& n=normals[*ni];
                    Vpt& pt=pts[*pi];
                    pt.nx+=n.x;
                    pt.ny+=n.y;
                    pt.nz+=n.z;
                }//end copying normals

            }//end looping polygons
        }

        //normalize
        for(vector<Vpt>::iterator i=pts.begin();i!=pts.end();i++)
        {
            i->normalize();
        }
    }

    vector<Vpt> pts;
    vector<V> normals;
    list<polygon> polys;
};

class objReader
{
public:
    objReader(const string& name){ m_filename=name; }

    bool Read(){
        ifstream in(m_filename.c_str());
        if( !in.good() ){
            cerr<<"Error: Can't open file "<<m_filename<<endl;
            return false;
        }
        bool r=Read(in);
        in.close();
        return r;
    }

    const objModel& getModel() const { return data; }
    objModel& getModel() { return data; }

private:

    bool Read(istream& in){

        string tmp;
        
        //read pts
        while(true){
            in>>tmp;
            if( tmp=="f" ) break;
            if( tmp=="v" ){
                Vpt pt;
                in>>pt.x>>pt.y>>pt.z;
                data.pts.push_back(pt);
            }
            else if( tmp=="vn" ){
                V pt;
                in>>pt.x>>pt.y>>pt.z;
                data.normals.push_back(pt);
            }
            getline(in,tmp);
        }

        //read faces
        polygon poly;
		while (true)
		{
			//string tmp;
			if( !(in >> tmp) ) break;

            if( isdigit(tmp[0]) ){ //this defines a vetex

                int pos1=tmp.find('/');
                int pos2=tmp.rfind('/');

                int id_v=atoi(tmp.substr(0,pos1).c_str())-1;
                int id_n=atoi(tmp.substr(pos2+1).c_str())-1;

                poly.pts.push_back(id_v);
                poly.normals.push_back(id_n);
            }
            else if( tmp=="f" )
            {
                data.polys.push_back(poly);
                poly.pts.clear();
                poly.normals.clear();
            }
			else {
				getline(in, tmp);
			}

        }
        

        data.polys.push_back(poly);
        data.compute_v_normal();

        return true;
    }

    string m_filename;
    objModel data;
};

#endif //_OBJ_READER_H_