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Sqrt3T.hh
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43 
48 //=============================================================================
49 //
50 // CLASS Sqrt3T
51 //
52 //=============================================================================
53 
54 #ifndef OPENMESH_SUBDIVIDER_UNIFORM_SQRT3T_HH
55 #define OPENMESH_SUBDIVIDER_UNIFORM_SQRT3T_HH
56 
57 
58 //== INCLUDES =================================================================
59 
60 #include <OpenMesh/Core/Mesh/Handles.hh>
61 #include <OpenMesh/Core/System/config.hh>
63 #if defined(_DEBUG) || defined(DEBUG)
64 // Makes life lot easier, when playing/messing around with low-level topology
65 // changing methods of OpenMesh
66 # include <OpenMesh/Tools/Utils/MeshCheckerT.hh>
67 # define ASSERT_CONSISTENCY( T, m ) \
68  assert(OpenMesh::Utils::MeshCheckerT<T>(m).check())
69 #else
70 # define ASSERT_CONSISTENCY( T, m )
71 #endif
72 // -------------------- STL
73 #include <vector>
74 #if defined(OM_CC_MIPS)
75 # include <math.h>
76 #else
77 # include <cmath>
78 #endif
79 
80 
81 //== NAMESPACE ================================================================
82 
83 namespace OpenMesh { // BEGIN_NS_OPENMESH
84 namespace Subdivider { // BEGIN_NS_DECIMATER
85 namespace Uniform { // BEGIN_NS_DECIMATER
86 
87 
88 //== CLASS DEFINITION =========================================================
89 
90 
97 template <typename MeshType, typename RealType = double>
98 class Sqrt3T : public SubdividerT< MeshType, RealType >
99 {
100 public:
101 
102  typedef RealType real_t;
103  typedef MeshType mesh_t;
105 
106  typedef std::pair< real_t, real_t > weight_t;
107  typedef std::vector< std::pair<real_t,real_t> > weights_t;
108 
109 public:
110 
111 
112  Sqrt3T(void) : parent_t(), _1over3( real_t(1.0/3.0) ), _1over27( real_t(1.0/27.0) )
113  { init_weights(); }
114 
115  explicit Sqrt3T(MeshType &_m) : parent_t(_m), _1over3( real_t(1.0/3.0) ), _1over27( real_t(1.0/27.0) )
116  { init_weights(); }
117 
118  virtual ~Sqrt3T() {}
119 
120 
121 public:
122 
123 
124  const char *name() const override { return "Uniform Sqrt3"; }
125 
126 
128  void init_weights(size_t _max_valence=50)
129  {
130  weights_.resize(_max_valence);
131  std::generate(weights_.begin(), weights_.end(), compute_weight());
132  }
133 
134 
135 protected:
136 
137 
138  bool prepare( MeshType& _m ) override
139  {
140  _m.request_edge_status();
141  _m.add_property( vp_pos_ );
142  _m.add_property( ep_nv_ );
143  _m.add_property( mp_gen_ );
144  _m.property( mp_gen_ ) = 0;
145 
146  return _m.has_edge_status() && vp_pos_.is_valid()
147  && ep_nv_.is_valid() && mp_gen_.is_valid();
148  }
149 
150 
151  bool cleanup( MeshType& _m ) override
152  {
153  _m.release_edge_status();
154  _m.remove_property( vp_pos_ );
155  _m.remove_property( ep_nv_ );
156  _m.remove_property( mp_gen_ );
157  return true;
158  }
159 
160  bool subdivide( MeshType& _m, size_t _n , const bool _update_points = true) override
161  {
162 
164 
165  typename MeshType::Point pos(0,0,0), zero(0,0,0);
166  size_t &gen = _m.property( mp_gen_ );
167 
168  for (size_t l=0; l<_n; ++l)
169  {
170  // tag existing edges
171  for (auto eh : _m.edges())
172  {
173  _m.status( eh ).set_tagged( true );
174  if ( (gen%2) && _m.is_boundary(eh) )
175  compute_new_boundary_points( _m, eh ); // *) creates new vertices
176  }
177 
178  // do relaxation of old vertices, but store new pos in property vp_pos_
179 
180  for (auto vh : _m.vertices())
181  {
182  if ( _m.is_boundary(vh) )
183  {
184  if ( gen%2 )
185  {
186  auto heh = _m.halfedge_handle(vh);
187  if (heh.is_valid()) // skip isolated newly inserted vertices *)
188  {
189  auto prev_heh = _m.prev_halfedge_handle(heh);
190 
191  assert( _m.is_boundary(heh ) );
192  assert( _m.is_boundary(prev_heh) );
193 
194  pos = _m.point(_m.to_vertex_handle(heh));
195  pos += _m.point(_m.from_vertex_handle(prev_heh));
196  pos *= real_t(4.0);
197 
198  pos += real_t(19.0) * _m.point( vh );
199  pos *= _1over27;
200 
201  _m.property( vp_pos_, vh ) = pos;
202  }
203  }
204  else
205  _m.property( vp_pos_, vh ) = _m.point( vh );
206  }
207  else
208  {
209  size_t valence=0;
210 
211  pos = zero;
212  for ( auto vvh : _m.vv_range(vh))
213  {
214  pos += _m.point( vvh );
215  ++valence;
216  }
217  pos *= weights_[ valence ].second;
218  pos += weights_[ valence ].first * _m.point(vh);
219  _m.property( vp_pos_, vh ) = pos;
220  }
221  }
222 
223  // insert new vertices, but store pos in vp_pos_
224  for (auto fh : _m.faces())
225  {
226  if ( (gen%2) && _m.is_boundary(fh))
227  {
228  boundary_split( _m, fh );
229  }
230  else
231  {
232  auto fvit = _m.fv_iter( fh );
233  pos = _m.point( *fvit);
234  pos += _m.point(*(++fvit));
235  pos += _m.point(*(++fvit));
236  pos *= _1over3;
237  auto vh = _m.add_vertex( zero );
238  _m.property( vp_pos_, vh ) = pos;
239  _m.split( fh, vh );
240  }
241  }
242 
243  // commit new positions (now iterating over all vertices)
244  for (auto vh : _m.vertices())
245  _m.set_point(vh, _m.property( vp_pos_, vh ) );
246 
247  // flip old edges
248  for (auto eh : _m.edges())
249  if ( _m.status( eh ).tagged() && !_m.is_boundary( eh ) )
250  _m.flip(eh);
251 
252  // Now we have an consistent mesh!
253  ASSERT_CONSISTENCY( MeshType, _m );
254 
255  // increase generation by one
256  ++gen;
257  }
258  return true;
259  }
260 
261 private:
262 
266  {
267  compute_weight() : valence(-1) { }
268  weight_t operator() (void)
269  {
270 #if !defined(OM_CC_MIPS)
271  using std::cos;
272 #endif
273  if (++valence)
274  {
275  real_t alpha = real_t( (4.0-2.0*cos(2.0*M_PI / real_t(valence)) )/9.0 );
276  return weight_t( real_t(1)-alpha, alpha/real_t(valence) );
277  }
278  return weight_t(real_t(0.0), real_t(0.0) );
279  }
280  int valence;
281  };
282 
283 private:
284 
285  // Pre-compute location of new boundary points for odd generations
286  // and store them in the edge property ep_nv_;
287  void compute_new_boundary_points( MeshType& _m,
288  const typename MeshType::EdgeHandle& _eh)
289  {
290  assert( _m.is_boundary(_eh) );
291 
292  typename MeshType::HalfedgeHandle heh;
293  typename MeshType::VertexHandle vh1, vh2, vh3, vh4, vhl, vhr;
294  typename MeshType::Point zero(0,0,0), P1, P2, P3, P4;
295 
296  /*
297  // *---------*---------*
298  // / \ / \ / \
299  // / \ / \ / \
300  // / \ / \ / \
301  // / \ / \ / \
302  // *---------*--#---#--*---------*
303  //
304  // ^ ^ ^ ^ ^ ^
305  // P1 P2 pl pr P3 P4
306  */
307  // get halfedge pointing from P3 to P2 (outer boundary halfedge)
308 
309  heh = _m.halfedge_handle(_eh,
310  _m.is_boundary(_m.halfedge_handle(_eh,1)));
311 
312  assert( _m.is_boundary( _m.next_halfedge_handle( heh ) ) );
313  assert( _m.is_boundary( _m.prev_halfedge_handle( heh ) ) );
314 
315  vh1 = _m.to_vertex_handle( _m.next_halfedge_handle( heh ) );
316  vh2 = _m.to_vertex_handle( heh );
317  vh3 = _m.from_vertex_handle( heh );
318  vh4 = _m.from_vertex_handle( _m.prev_halfedge_handle( heh ));
319 
320  P1 = _m.point(vh1);
321  P2 = _m.point(vh2);
322  P3 = _m.point(vh3);
323  P4 = _m.point(vh4);
324 
325  vhl = _m.add_vertex(zero);
326  vhr = _m.add_vertex(zero);
327 
328  _m.property(vp_pos_, vhl ) = (P1 + real_t(16.0f) * P2 + real_t(10.0f) * P3) * _1over27;
329  _m.property(vp_pos_, vhr ) = ( real_t(10.0f) * P2 + real_t(16.0f) * P3 + P4) * _1over27;
330  _m.property(ep_nv_, _eh).first = vhl;
331  _m.property(ep_nv_, _eh).second = vhr;
332  }
333 
334 
335  void boundary_split( MeshType& _m, const typename MeshType::FaceHandle& _fh )
336  {
337  assert( _m.is_boundary(_fh) );
338 
339  typename MeshType::VertexHandle vhl, vhr;
340  typename MeshType::FaceEdgeIter fe_it;
341  typename MeshType::HalfedgeHandle heh;
342 
343  // find boundary edge
344  for( fe_it=_m.fe_iter( _fh ); fe_it.is_valid() && !_m.is_boundary( *fe_it ); ++fe_it ) {};
345 
346  // use precomputed, already inserted but not linked vertices
347  vhl = _m.property(ep_nv_, *fe_it).first;
348  vhr = _m.property(ep_nv_, *fe_it).second;
349 
350  /*
351  // *---------*---------*
352  // / \ / \ / \
353  // / \ / \ / \
354  // / \ / \ / \
355  // / \ / \ / \
356  // *---------*--#---#--*---------*
357  //
358  // ^ ^ ^ ^ ^ ^
359  // P1 P2 pl pr P3 P4
360  */
361  // get halfedge pointing from P2 to P3 (inner boundary halfedge)
362 
363  heh = _m.halfedge_handle(*fe_it,
364  _m.is_boundary(_m.halfedge_handle(*fe_it,0)));
365 
366  typename MeshType::HalfedgeHandle pl_P3;
367 
368  // split P2->P3 (heh) in P2->pl (heh) and pl->P3
369  boundary_split( _m, heh, vhl ); // split edge
370  pl_P3 = _m.next_halfedge_handle( heh ); // store next halfedge handle
371  boundary_split( _m, heh ); // split face
372 
373  // split pl->P3 in pl->pr and pr->P3
374  boundary_split( _m, pl_P3, vhr );
375  boundary_split( _m, pl_P3 );
376 
377  assert( _m.is_boundary( vhl ) && _m.halfedge_handle(vhl).is_valid() );
378  assert( _m.is_boundary( vhr ) && _m.halfedge_handle(vhr).is_valid() );
379  }
380 
381  void boundary_split(MeshType& _m,
382  const typename MeshType::HalfedgeHandle& _heh,
383  const typename MeshType::VertexHandle& _vh)
384  {
385  assert( _m.is_boundary( _m.edge_handle(_heh) ) );
386 
387  typename MeshType::HalfedgeHandle
388  heh(_heh),
389  opp_heh( _m.opposite_halfedge_handle(_heh) ),
390  new_heh, opp_new_heh;
391  typename MeshType::VertexHandle to_vh(_m.to_vertex_handle(heh));
392  typename MeshType::HalfedgeHandle t_heh;
393 
394  /*
395  * P5
396  * *
397  * /|\
398  * / \
399  * / \
400  * / \
401  * / \
402  * /_ heh new \
403  * *-----\*-----\*\-----*
404  * ^ ^ t_heh
405  * _vh to_vh
406  *
407  * P1 P2 P3 P4
408  */
409  // Re-Setting Handles
410 
411  // find halfedge point from P4 to P3
412  for(t_heh = heh;
413  _m.next_halfedge_handle(t_heh) != opp_heh;
414  t_heh = _m.opposite_halfedge_handle(_m.next_halfedge_handle(t_heh)))
415  {}
416 
417  assert( _m.is_boundary( t_heh ) );
418 
419  new_heh = _m.new_edge( _vh, to_vh );
420  opp_new_heh = _m.opposite_halfedge_handle(new_heh);
421 
422  // update halfedge connectivity
423 
424  _m.set_next_halfedge_handle(t_heh, opp_new_heh); // P4-P3 -> P3-P2
425  // P2-P3 -> P3-P5
426  _m.set_next_halfedge_handle(new_heh, _m.next_halfedge_handle(heh));
427  _m.set_next_halfedge_handle(heh, new_heh); // P1-P2 -> P2-P3
428  _m.set_next_halfedge_handle(opp_new_heh, opp_heh); // P3-P2 -> P2-P1
429 
430  // both opposite halfedges point to same face
431  _m.set_face_handle(opp_new_heh, _m.face_handle(opp_heh));
432 
433  // let heh finally point to new inserted vertex
434  _m.set_vertex_handle(heh, _vh);
435 
436  // let heh and new_heh point to same face
437  _m.set_face_handle(new_heh, _m.face_handle(heh));
438 
439  // let opp_new_heh be the new outgoing halfedge for to_vh
440  // (replaces for opp_heh)
441  _m.set_halfedge_handle( to_vh, opp_new_heh );
442 
443  // let opp_heh be the outgoing halfedge for _vh
444  _m.set_halfedge_handle( _vh, opp_heh );
445  }
446 
447  void boundary_split( MeshType& _m,
448  const typename MeshType::HalfedgeHandle& _heh)
449  {
450  assert( _m.is_boundary( _m.opposite_halfedge_handle( _heh ) ) );
451 
452  typename MeshType::HalfedgeHandle
453  heh(_heh),
454  n_heh(_m.next_halfedge_handle(heh));
455 
456  typename MeshType::VertexHandle
457  to_vh(_m.to_vertex_handle(heh));
458 
459  typename MeshType::HalfedgeHandle
460  heh2(_m.new_edge(to_vh,
461  _m.to_vertex_handle(_m.next_halfedge_handle(n_heh)))),
462  heh3(_m.opposite_halfedge_handle(heh2));
463 
464  typename MeshType::FaceHandle
465  new_fh(_m.new_face()),
466  fh(_m.face_handle(heh));
467 
468  // Relink (half)edges
469 
470 #define set_next_heh set_next_halfedge_handle
471 #define next_heh next_halfedge_handle
472 
473  _m.set_face_handle(heh, new_fh);
474  _m.set_face_handle(heh2, new_fh);
475  _m.set_next_heh(heh2, _m.next_heh(_m.next_heh(n_heh)));
476  _m.set_next_heh(heh, heh2);
477  _m.set_face_handle( _m.next_heh(heh2), new_fh);
478 
479  // _m.set_face_handle( _m.next_heh(_m.next_heh(heh2)), new_fh);
480 
481  _m.set_next_heh(heh3, n_heh);
482  _m.set_next_heh(_m.next_halfedge_handle(n_heh), heh3);
483  _m.set_face_handle(heh3, fh);
484  // _m.set_face_handle(n_heh, fh);
485 
486  _m.set_halfedge_handle( fh, n_heh);
487  _m.set_halfedge_handle(new_fh, heh);
488 
489 #undef set_next_halfedge_handle
490 #undef next_halfedge_handle
491 
492  }
493 
494 private:
495 
496  weights_t weights_;
498  OpenMesh::EPropHandleT< std::pair< typename MeshType::VertexHandle,
499  typename MeshType::VertexHandle> > ep_nv_;
501 
502  const real_t _1over3;
503  const real_t _1over27;
504 };
505 
506 
507 //=============================================================================
508 } // END_NS_UNIFORM
509 } // END_NS_SUBDIVIDER
510 } // END_NS_OPENMESH
511 //=============================================================================
512 #endif // OPENMESH_SUBDIVIDER_UNIFORM_SQRT3T_HH
513 //=============================================================================
const char * name() const override
Return name of subdivision algorithm.
Definition: Sqrt3T.hh:124
bool cleanup(MeshType &_m) override
Cleanup mesh after usage, e.g. remove added properties.
Definition: Sqrt3T.hh:151
bool is_valid() const
The handle is valid iff the index is not negative.
Definition: Handles.hh:72
void init_weights(size_t _max_valence=50)
Pre-compute weights.
Definition: Sqrt3T.hh:128
bool prepare(MeshType &_m) override
Prepare mesh, e.g. add properties.
Definition: Sqrt3T.hh:138
bool subdivide(MeshType &_m, size_t _n, const bool _update_points=true) override
Subdivide mesh _m _n times.
Definition: Sqrt3T.hh:160