store face indices per material for drawing

WFObj.cc

@@ -123,6 +123,7 @@ void WFObj::clear()
     for (int i = 0; i < sizeof(m_vertices)/sizeof(m_vertices[0]); i++)
         m_vertices[i].clear();
     m_faces.clear();
+    m_face_indices.clear();
     m_materials.clear();
     m_valid = false;
     m_path = "";
@@ -451,6 +452,8 @@ bool WFObj::buildVBO()
             it != m_faces.end();
             it++)
     {
+        int first = vid;
+        int num = 0;
         for (vector<Face>::iterator fit = it->second.begin();
                 fit != it->second.end();
                 fit++)
@@ -473,9 +476,13 @@ bool WFObj::buildVBO()
                 if (vf.texture != 0)
                     texture_ref_count++;
                 if (flat_vertices.find(vf) == flat_vertices.end())
+                {
                     flat_vertices[vf] = vid++;
+                    num++;
+                }
             }
         }
+        m_face_indices[it->first] = make_pair(first, num);
     }
     if (texture_ref_count == 0)
         do_textures = false;

WFObj.h

@@ -104,6 +104,7 @@ protected:
     /* variables */
     std::vector<Vertex> m_vertices[VERTEX_TYPES];
     std::map< std::string, std::vector< Face > > m_faces;
+    std::map< std::string, std::pair<int, int> > m_face_indices;
     std::map< std::string, Material > m_materials;
     float m_aabb[6];
     std::string m_path;