Function quad_index2

tutorials/common/scenegraph/scenegraph.cpp:1230–1237

  }
  
  std::pair<int,int> quad_index2(int p, int a0, int a1, int b0, int b1)
  {
    if      (b0 == a0) return std::make_pair(p-1,b1);
    else if (b0 == a1) return std::make_pair(p+0,b1);
    else if (b1 == a0) return std::make_pair(p-1,b0);
    else if (b1 == a1) return std::make_pair(p+0,b0);
    else return std::make_pair(0,-1);
  }
  
  std::pair<int,int> quad_index3(int a0, int a1, int a2, int b0, int b1, int b2)
  {