vdpmanalyzer.cc

penMesh is a generic and efficient data structure for representing and manipulating polygonal meshes

  // recover mapping between basemesh vertices to roots of vertex hierarchy
  for (i=0; i<n_base_vertices_; ++i)
  {
    node_handle = vhierarchy_.root_handle(i);
    vertex_handle = vhierarchy_.node(node_handle).vertex_handle();
    
    mesh_.vertex(vertex_handle).set_vhierarchy_node_handle(node_handle);
  }

  pmiter_ = pminfos_.begin();
  n_current_res_ = 0;
  n_max_res_ = n_details_;
 

  // update face and vertex normals
  mesh_.update_face_normals();
  mesh_.update_vertex_normals();   

  // bounding box
  Mesh::ConstVertexIter
    vIt(mesh_.vertices_begin()), 
    vEnd(mesh_.vertices_end());

  Mesh::Point bbMin, bbMax;

  bbMin = bbMax = mesh_.point(vIt);
  for (; vIt!=vEnd; ++vIt)
  {
    bbMin.minimize(mesh_.point(vIt));
    bbMax.maximize(mesh_.point(vIt));
  }

  // info
  std::cerr << mesh_.n_vertices() << " vertices, "
	    << mesh_.n_edges()    << " edge, "
	    << mesh_.n_faces()    << " faces, "
	    << n_details_ << " detail vertices\n";
}


// ----------------------------------------------------------------------------

void
save_vd_prog_mesh(const std::string &_filename)
{
  unsigned i;
  int fvi[3];
  Mesh::Point           p;
  Vec3f                 normal;
  float                 radius, sin_square, mue_square, sigma_square;
  Mesh::FaceIter        f_it;
  Mesh::HalfedgeHandle  hh;
  Mesh::VertexHandle    vh;
  VHierarchyNodeIndex   node_index;
  VHierarchyNodeIndex   fund_lcut_index, fund_rcut_index;
  VHierarchyNodeHandle  node_handle, lchild_handle, rchild_handle;
  std::map<VertexHandle, unsigned int>  handle2index_map;

  std::ofstream ofs(_filename.c_str(), std::ios::binary);
  if (!ofs)
  {
    std::cerr << "write error\n";
    exit(1);
  }
  
  //
  bool swap = Endian::local() != Endian::LSB;

  // write header
  ofs << "VDProgMesh";

  IO::store(ofs, n_base_vertices_, swap);
  IO::store(ofs, n_base_faces_, swap);
  IO::store(ofs, n_details_, swap);

  // write base mesh  
  coarsen(0);
  mesh_.garbage_collection( false, true, true );

  for (i=0; i<n_base_vertices_; ++i)
  {
    node_handle = vhierarchy_.root_handle(i);
    vh = vhierarchy_.node(node_handle).vertex_handle();
    
    p             = mesh_.point(vh);
    radius        = vhierarchy_.node(node_handle).radius();
    normal        = vhierarchy_.node(node_handle).normal();
    sin_square    = vhierarchy_.node(node_handle).sin_square();
    mue_square    = vhierarchy_.node(node_handle).mue_square();
    sigma_square  = vhierarchy_.node(node_handle).sigma_square();

    IO::store(ofs, p, swap);
    IO::store(ofs, radius, swap);
    IO::store(ofs, normal, swap);
    IO::store(ofs, sin_square, swap);
    IO::store(ofs, mue_square, swap);
    IO::store(ofs, sigma_square, swap);

    handle2index_map[vh] = i;
  }

 
  for (f_it=mesh_.faces_begin(); f_it!=mesh_.faces_end(); ++f_it) {
    hh = mesh_.halfedge_handle(f_it.handle());
    vh = mesh_.to_vertex_handle(hh);
    fvi[0] = handle2index_map[vh];

    hh = mesh_.next_halfedge_handle(hh);
    vh = mesh_.to_vertex_handle(hh);
    fvi[1] = handle2index_map[vh];

    hh = mesh_.next_halfedge_handle(hh);
    vh = mesh_.to_vertex_handle(hh);
    fvi[2] = handle2index_map[vh];

    IO::store(ofs, fvi[0], swap);
    IO::store(ofs, fvi[1], swap);
    IO::store(ofs, fvi[2], swap);
  }


  // write progressive detail (vertex hierarchy)

  for (i=0; i<n_details_; ++i)
  {
    PMInfo  pminfo = *pmiter_;

    p = mesh_.point(pminfo.v0);

    IO::store(ofs, p, swap);


    node_handle   = mesh_.vertex(pminfo.v1).vhierarchy_node_handle();
    lchild_handle = vhierarchy_.lchild_handle(node_handle);
    rchild_handle = vhierarchy_.rchild_handle(node_handle);

    node_index      = vhierarchy_.node(node_handle).node_index();
    fund_lcut_index = vhierarchy_.node(node_handle).fund_lcut_index();
    fund_rcut_index = vhierarchy_.node(node_handle).fund_rcut_index();

    IO::store(ofs, node_index.value(), swap);
    IO::store(ofs, fund_lcut_index.value(), swap);
    IO::store(ofs, fund_rcut_index.value(), swap);

    radius        = vhierarchy_.node(lchild_handle).radius();
    normal        = vhierarchy_.node(lchild_handle).normal();
    sin_square    = vhierarchy_.node(lchild_handle).sin_square();
    mue_square    = vhierarchy_.node(lchild_handle).mue_square();
    sigma_square  = vhierarchy_.node(lchild_handle).sigma_square();

    IO::store(ofs, radius, swap);
    IO::store(ofs, normal, swap);
    IO::store(ofs, sin_square, swap);
    IO::store(ofs, mue_square, swap);
    IO::store(ofs, sigma_square, swap);

    radius        = vhierarchy_.node(rchild_handle).radius();
    normal        = vhierarchy_.node(rchild_handle).normal();
    sin_square    = vhierarchy_.node(rchild_handle).sin_square();
    mue_square    = vhierarchy_.node(rchild_handle).mue_square();
    sigma_square  = vhierarchy_.node(rchild_handle).sigma_square();

    IO::store(ofs, radius, swap);
    IO::store(ofs, normal, swap);
    IO::store(ofs, sin_square, swap);
    IO::store(ofs, mue_square, swap);
    IO::store(ofs, sigma_square, swap);

    refine(i);
  }
  
  ofs.close();

  std::cout << "save view-dependent progressive mesh" << std::endl;
}

//-----------------------------------------------------------------------------

void refine(unsigned int _n)
{
  while (n_current_res_ < _n && pmiter_ != pminfos_.end())
  {
    mesh_.vertex_split(pmiter_->v0,
		       pmiter_->v1,
		       pmiter_->vl,
		       pmiter_->vr);

    VHierarchyNodeHandle
      parent_handle = mesh_.vertex(pmiter_->v1).vhierarchy_node_handle();

    VHierarchyNodeHandle  
      lchild_handle = vhierarchy_.lchild_handle(parent_handle),
      rchild_handle = vhierarchy_.rchild_handle(parent_handle);

    mesh_.vertex(pmiter_->v0).set_vhierarchy_node_handle(lchild_handle);
    mesh_.vertex(pmiter_->v1).set_vhierarchy_node_handle(rchild_handle);

    ++pmiter_;
    ++n_current_res_;
  }
}


//-----------------------------------------------------------------------------


void coarsen(unsigned int _n)
{
  while (n_current_res_ > _n && pmiter_ != pminfos_.begin()) 
  {
    --pmiter_;

    Mesh::HalfedgeHandle hh = 
      mesh_.find_halfedge(pmiter_->v0, pmiter_->v1);
    mesh_.collapse(hh);

    VHierarchyNodeHandle  
      rchild_handle = mesh_.vertex(pmiter_->v1).vhierarchy_node_handle();

    VHierarchyNodeHandle
      parent_handle = vhierarchy_.parent_handle(rchild_handle);

    mesh_.vertex(pmiter_->v1).set_vhierarchy_node_handle(parent_handle);
    
    --n_current_res_;
  }
}


//-----------------------------------------------------------------------------


void 
vdpm_analysis()
{
  unsigned int                    i;
  Mesh::VertexHandle            vh;
  Mesh::VertexIter              v_it;
  Mesh::HalfedgeIter            h_it;
  Mesh::HalfedgeHandle          h, o, hn, op, hpo, on, ono;
  VHierarchyNodeHandleContainer   leaf_nodes;
 
  OpenMesh::Utils::Timer tana;
  tana.start();
 
  refine(n_max_res_);
  
  mesh_.update_face_normals();
  mesh_.update_vertex_normals();

  std::cout << "Init view-dependent PM analysis" << std::endl;
  
  // initialize
  for (h_it=mesh_.halfedges_begin(); h_it!=mesh_.halfedges_end(); ++h_it)
  {
    vh = mesh_.to_vertex_handle(h_it.handle());    
    h_it->set_vhierarchy_leaf_node_handle(mesh_.vertex(vh).vhierarchy_node_handle());
  }

  for (v_it=mesh_.vertices_begin(); v_it!=mesh_.vertices_end(); ++v_it)
  {
    VHierarchyNodeHandle  
      node_handle = mesh_.vertex(v_it.handle()).vhierarchy_node_handle();
    
    vhierarchy_.node(node_handle).set_normal(mesh_.normal(v_it.handle()));
  }
  
  std::cout << "Start view-dependent PM analysis" << std::endl;

  // locate fundamental cut vertices in each edge collapse
  OpenMesh::Utils::Timer t;

  for (i=n_max_res_; i>0; --i)
  {
    t.start();
    PMInfo   pminfo   = pminfos_[i-1];

    if (verbose)
      std::cout << "Analyzing " << i << "-th detail vertex" << std::endl;

    // maintain leaf node pointers & locate fundamental cut vertices
    h   = mesh_.find_halfedge(pminfo.v0, pminfo.v1);
    o   = mesh_.opposite_halfedge_handle(h);
    hn  = mesh_.next_halfedge_handle(h);
    hpo = mesh_.opposite_halfedge_handle(mesh_.prev_halfedge_handle(h));
    op  = mesh_.prev_halfedge_handle(o);
    on  = mesh_.next_halfedge_handle(o);
    ono = mesh_.opposite_halfedge_handle(on);

    VHierarchyNodeHandle  
      rchild_handle = mesh_.vertex(pminfo.v1).vhierarchy_node_handle();

    VHierarchyNodeHandle
      parent_handle = vhierarchy_.parent_handle(rchild_handle);
    
    if (pminfo.vl != Mesh::InvalidVertexHandle)
    {
      VHierarchyNodeHandle  
	fund_lcut_handle  = mesh_.halfedge(hn).vhierarchy_leaf_node_handle();

      VHierarchyNodeHandle
        left_leaf_handle  = mesh_.halfedge(hpo).vhierarchy_leaf_node_handle();

      mesh_.halfedge(hn).set_vhierarchy_leaf_node_handle(left_leaf_handle);

      vhierarchy_.node(parent_handle).
	set_fund_lcut(vhierarchy_.node_index(fund_lcut_handle));
    }

    if (pminfo.vr != Mesh::InvalidVertexHandle)
    {
      VHierarchyNodeHandle
	fund_rcut_handle  = mesh_.halfedge(on).vhierarchy_leaf_node_handle(),
	right_leaf_handle = mesh_.halfedge(ono).vhierarchy_leaf_node_handle();

      mesh_.halfedge(op).set_vhierarchy_leaf_node_handle(right_leaf_handle);

      vhierarchy_.node(parent_handle).
	set_fund_rcut(vhierarchy_.node_index(fund_rcut_handle));
    }

    coarsen(i-1);
    
    leaf_nodes.clear();

    get_leaf_node_handles(parent_handle, leaf_nodes);
    compute_bounding_box(parent_handle, leaf_nodes);
    compute_cone_of_normals(parent_handle, leaf_nodes);
    compute_screen_space_error(parent_handle, leaf_nodes);

    t.stop();

    if (verbose)
    {
      std::cout << "  radius of bounding sphere: "
                << vhierarchy_.node(parent_handle).radius() << std::endl;
      std::cout << "  direction of cone of normals: " 
                << vhierarchy_.node(parent_handle).normal() << std::endl;
      std::cout << "  sin(semi-angle of cone of normals) ^2: " 
                << vhierarchy_.node(parent_handle).sin_square() << std::endl;
      std::cout << "  (mue^2, sigma^2) : (" 
                << vhierarchy_.node(parent_handle).mue_square()   << ", " 
                << vhierarchy_.node(parent_handle).sigma_square() << ")" 
                << std::endl;
      std::cout << "- " << t.as_string() << std::endl;
    }

  } // end for all collapses

  tana.stop();
  std::cout << "Analyzing step completed in " 
            << tana.as_string() << std::endl;
}


// ----------------------------------------------------------------------------

void 
get_leaf_node_handles(VHierarchyNodeHandle           node_handle, 
		      VHierarchyNodeHandleContainer &leaf_nodes)
{
  if (vhierarchy_.node(node_handle).is_leaf())
  {
    leaf_nodes.push_back(node_handle);
  }
  else
  {
    get_leaf_node_handles(vhierarchy_.node(node_handle).lchild_handle(), 
			  leaf_nodes);
    get_leaf_node_handles(vhierarchy_.node(node_handle).rchild_handle(), 
			  leaf_nodes);
  }
}


// ----------------------------------------------------------------------------

void 
compute_bounding_box(VHierarchyNodeHandle node_handle, VHierarchyNodeHandleContainer &leaf_nodes)
{
  float             max_distance;
  Vec3f   p, lp;
  VHierarchyNodeHandleContainer::iterator   n_it, n_end(leaf_nodes.end());

  max_distance = 0.0f;
  VertexHandle  vh = vhierarchy_.node(node_handle).vertex_handle();
  p = mesh_.point(vh);
  for ( n_it = leaf_nodes.begin(); n_it != n_end; ++n_it )
  {