Loading .obj file using c++ and opengl [closed]

Question

Actually there are many solutions if you search in Google. Here is one simple solution as below.

First define one model containing face and vertex info:

class obj3dmodel
{
   struct vertex{
        double x;
        double y;
        double z;
   };
   struct face{
         unsigned int v1,v2,v3;
   };
   std::vector<vertex> vetexes;
   std::vector<face> faces;

public:
  void readfile(const char* filename);
  void draw();
};

Then read file in readfile():

void obj3dmodel::readfile(const char *filename) 
{
   string s;
   ifstream fin(filename);
   if(!fin)
         return;
   while(fin>>s)
   {
         switch(*s.c_str())
         {
         case 'v':
              {
                    vertex v;
                    fin>>v.x>>v.y>>v.z;
                    this->vetexes.push_back(v);
              }
              break;            
         case 'f':
              {
                    face f;
                    fin>>f.v1>>f.v2>>f.v3;
                    faces.push_back(f);
              }
              break;
        }
   }     
}

Now you could use vertex and face information to do draw():

void obj3dmodel::draw()
{
   glBegin(GL_TRIANGLES);
   for(int i=0;i<faces.size();i++)
   {                         
      vertex v1= vetexes[faces[i].v1-1];
      vertex v2=vetexes[faces[i].v2-1];
      vertex v3=vetexes[faces[i].v3-1];

      glVertex3f(v1.x,v1.y,v1.z);
      glVertex3f(v2.x,v2.y,v2.z);
      glVertex3f(v3.x,v3.y,v3.z);
   }
   glEnd(GL_TRIANGLES);
 }