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LoopT.hh
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43
48 //=============================================================================
49 //
50 // CLASS LoopT
51 //
52 //=============================================================================
53
54 #ifndef OPENMESH_SUBDIVIDER_UNIFORM_LOOPT_HH
55 #define OPENMESH_SUBDIVIDER_UNIFORM_LOOPT_HH
56
57
58 //== INCLUDES =================================================================
59
60 #include <OpenMesh/Core/System/config.hh>
61 #include <OpenMesh/Tools/Subdivider/Uniform/SubdividerT.hh>
62 #include <OpenMesh/Core/Utils/vector_cast.hh>
63 #include <OpenMesh/Core/Utils/Property.hh>
64 // -------------------- STL
65 #include <vector>
66 #if defined(OM_CC_MIPS)
67 # include <math.h>
68 #else
69 # include <cmath>
70 #endif
71
72
73 //== NAMESPACE ================================================================
74
75 namespace OpenMesh { // BEGIN_NS_OPENMESH
76 namespace Subdivider { // BEGIN_NS_DECIMATER
77 namespace Uniform { // BEGIN_NS_DECIMATER
78
79
80 //== CLASS DEFINITION =========================================================
81
90 template <typename MeshType, typename RealType = double>
91 class LoopT : public SubdividerT<MeshType, RealType>
92 {
93 public:
94
95 typedef RealType real_t;
96 typedef MeshType mesh_t;
97 typedef SubdividerT< mesh_t, real_t > parent_t;
98
99 typedef std::pair< real_t, real_t > weight_t;
100 typedef std::vector< std::pair<real_t,real_t> > weights_t;
101
102 public:
103
104
105 LoopT(void) : parent_t(), _1over8( 1.0/8.0 ), _3over8( 3.0/8.0 )
106 { init_weights(); }
107
108
109 explicit LoopT( mesh_t& _m ) : parent_t(_m), _1over8( 1.0/8.0 ), _3over8( 3.0/8.0 )
110 { init_weights(); }
111
112
113 ~LoopT() {}
114
115
116 public:
117
118
119 const char *name() const override { return "Uniform Loop"; }
120
121
123 void init_weights(size_t _max_valence=50)
124 {
125 weights_.resize(_max_valence);
126 std::generate(weights_.begin(), weights_.end(), compute_weight());
127 }
128
129
130 protected:
131
132
133 bool prepare( mesh_t& _m ) override
134 {
135 _m.add_property( vp_pos_ );
136 _m.add_property( ep_pos_ );
137 return true;
138 }
139
140
141 bool cleanup( mesh_t& _m ) override
142 {
143 _m.remove_property( vp_pos_ );
144 _m.remove_property( ep_pos_ );
145 return true;
146 }
147
148
149 bool subdivide( mesh_t& _m, size_t _n, const bool _update_points = true) override
150 {
151
153
154 typename mesh_t::FaceIter fit, f_end;
155 typename mesh_t::EdgeIter eit, e_end;
156 typename mesh_t::VertexIter vit;
157
158 // Do _n subdivisions
159 for (size_t i=0; i < _n; ++i)
160 {
161
162 if(_update_points) {
163 // compute new positions for old vertices
164 for (vit = _m.vertices_begin(); vit != _m.vertices_end(); ++vit) {
165 smooth(_m, *vit);
166 }
167 }
168
169 // Compute position for new vertices and store them in the edge property
170 for (eit=_m.edges_begin(); eit != _m.edges_end(); ++eit)
171 compute_midpoint( _m, *eit );
172
173 // Split each edge at midpoint and store precomputed positions (stored in
174 // edge property ep_pos_) in the vertex property vp_pos_;
175
176 // Attention! Creating new edges, hence make sure the loop ends correctly.
177 for (auto eh : _m.edges())
178 split_edge(_m, eh );
179
180
181 // Commit changes in topology and reconsitute consistency
182
183 // Attention! Creating new faces, hence make sure the loop ends correctly.
184 for (auto fh : _m.faces())
185 split_face(_m, fh );
186
187 if(_update_points) {
188 // Commit changes in geometry
189 for ( vit = _m.vertices_begin();
190 vit != _m.vertices_end(); ++vit) {
191 _m.set_point(*vit, _m.property( vp_pos_, *vit ) );
192 }
193 }
194
195
196 #if defined(_DEBUG) || defined(DEBUG)
197 // Now we have an consistent mesh!
198 assert( OpenMesh::Utils::MeshCheckerT<mesh_t>(_m).check() );
199 #endif
200 }
201
202 return true;
203 }
204
205 private:
206
209 struct compute_weight
210 {
211 compute_weight() : valence(-1) { }
212 weight_t operator() (void)
213 {
214 #if !defined(OM_CC_MIPS)
215 using std::cos;
216 #endif
217 // 1
218 // alpha(n) = ---- * (40 - ( 3 + 2 cos( 2 Pi / n ) )� )
219 // 64
220
221 if (++valence)
222 {
223 double inv_v = 1.0/double(valence);
224 double t = (3.0 + 2.0 * cos( 2.0 * M_PI * inv_v) );
225 double alpha = (40.0 - t * t)/64.0;
226
227 return weight_t( static_cast<real_t>(1.0-alpha), static_cast<real_t>(inv_v*alpha) );
228 }
229 return weight_t(static_cast<real_t>(0.0), static_cast<real_t>(0.0));
230 }
231 int valence;
232 };
233
234 private: // topological modifiers
235
236 void split_face(mesh_t& _m, const typename mesh_t::FaceHandle& _fh)
237 {
238 typename mesh_t::HalfedgeHandle
239 heh1(_m.halfedge_handle(_fh)),
240 heh2(_m.next_halfedge_handle(_m.next_halfedge_handle(heh1))),
241 heh3(_m.next_halfedge_handle(_m.next_halfedge_handle(heh2)));
242
243 // Cutting off every corner of the 6_gon
244 corner_cutting( _m, heh1 );
245 corner_cutting( _m, heh2 );
246 corner_cutting( _m, heh3 );
247 }
248
249
250 void corner_cutting(mesh_t& _m, const typename mesh_t::HalfedgeHandle& _he)
251 {
252 // Define Halfedge Handles
253 typename mesh_t::HalfedgeHandle
254 heh1(_he),
255 heh5(heh1),
256 heh6(_m.next_halfedge_handle(heh1));
257
258 // Cycle around the polygon to find correct Halfedge
259 for (; _m.next_halfedge_handle(_m.next_halfedge_handle(heh5)) != heh1;
260 heh5 = _m.next_halfedge_handle(heh5))
261 {}
262
263 typename mesh_t::VertexHandle
264 vh1 = _m.to_vertex_handle(heh1),
265 vh2 = _m.to_vertex_handle(heh5);
266
267 typename mesh_t::HalfedgeHandle
268 heh2(_m.next_halfedge_handle(heh5)),
269 heh3(_m.new_edge( vh1, vh2)),
270 heh4(_m.opposite_halfedge_handle(heh3));
271
272 /* Intermediate result
273 *
274 * *
275 * 5 /|\
276 * /_ \
277 * vh2> * *
278 * /|\3 |\
279 * /_ \|4 \
280 * *----\*----\*
281 * 1 ^ 6
282 * vh1 (adjust_outgoing halfedge!)
283 */
284
285 // Old and new Face
286 typename mesh_t::FaceHandle fh_old(_m.face_handle(heh6));
287 typename mesh_t::FaceHandle fh_new(_m.new_face());
288
289
290 // Re-Set Handles around old Face
291 _m.set_next_halfedge_handle(heh4, heh6);
292 _m.set_next_halfedge_handle(heh5, heh4);
293
294 _m.set_face_handle(heh4, fh_old);
295 _m.set_face_handle(heh5, fh_old);
296 _m.set_face_handle(heh6, fh_old);
297 _m.set_halfedge_handle(fh_old, heh4);
298
299 // Re-Set Handles around new Face
300 _m.set_next_halfedge_handle(heh1, heh3);
301 _m.set_next_halfedge_handle(heh3, heh2);
302
303 _m.set_face_handle(heh1, fh_new);
304 _m.set_face_handle(heh2, fh_new);
305 _m.set_face_handle(heh3, fh_new);
306
307 _m.set_halfedge_handle(fh_new, heh1);
308 }
309
310
311 void split_edge(mesh_t& _m, const typename mesh_t::EdgeHandle& _eh)
312 {
313 typename mesh_t::HalfedgeHandle
314 heh = _m.halfedge_handle(_eh, 0),
315 opp_heh = _m.halfedge_handle(_eh, 1);
316
317 typename mesh_t::HalfedgeHandle new_heh, opp_new_heh, t_heh;
318 typename mesh_t::VertexHandle vh;
319 typename mesh_t::VertexHandle vh1(_m.to_vertex_handle(heh));
320 typename mesh_t::Point midP(_m.point(_m.to_vertex_handle(heh)));
321 midP += _m.point(_m.to_vertex_handle(opp_heh));
322 midP *= static_cast<RealType>(0.5);
323
324 // new vertex
325 vh = _m.new_vertex( midP );
326
327 // memorize position, will be set later
328 _m.property( vp_pos_, vh ) = _m.property( ep_pos_, _eh );
329
330
331 // Re-link mesh entities
332 if (_m.is_boundary(_eh))
333 {
334 for (t_heh = heh;
335 _m.next_halfedge_handle(t_heh) != opp_heh;
336 t_heh = _m.opposite_halfedge_handle(_m.next_halfedge_handle(t_heh)))
337 {}
338 }
339 else
340 {
341 for (t_heh = _m.next_halfedge_handle(opp_heh);
342 _m.next_halfedge_handle(t_heh) != opp_heh;
343 t_heh = _m.next_halfedge_handle(t_heh) )
344 {}
345 }
346
347 new_heh = _m.new_edge(vh, vh1);
348 opp_new_heh = _m.opposite_halfedge_handle(new_heh);
349 _m.set_vertex_handle( heh, vh );
350
351 _m.set_next_halfedge_handle(t_heh, opp_new_heh);
352 _m.set_next_halfedge_handle(new_heh, _m.next_halfedge_handle(heh));
353 _m.set_next_halfedge_handle(heh, new_heh);
354 _m.set_next_halfedge_handle(opp_new_heh, opp_heh);
355
356 if (_m.face_handle(opp_heh).is_valid())
357 {
358 _m.set_face_handle(opp_new_heh, _m.face_handle(opp_heh));
359 _m.set_halfedge_handle(_m.face_handle(opp_new_heh), opp_new_heh);
360 }
361
362 _m.set_face_handle( new_heh, _m.face_handle(heh) );
363 _m.set_halfedge_handle( vh, new_heh);
364
365 // We cant reconnect a non existing face, so we skip this here if necessary
366 if ( !_m.is_boundary(heh) )
367 _m.set_halfedge_handle( _m.face_handle(heh), heh );
368
369 _m.set_halfedge_handle( vh1, opp_new_heh );
370
371 // Never forget this, when playing with the topology
372 _m.adjust_outgoing_halfedge( vh );
373 _m.adjust_outgoing_halfedge( vh1 );
374 }
375
376 private: // geometry helper
377
378 void compute_midpoint(mesh_t& _m, const typename mesh_t::EdgeHandle& _eh)
379 {
380 #define V( X ) vector_cast< typename mesh_t::Normal >( X )
381 typename mesh_t::HalfedgeHandle heh, opp_heh;
382
383 heh = _m.halfedge_handle( _eh, 0);
384 opp_heh = _m.halfedge_handle( _eh, 1);
385
386 typename mesh_t::Point
387 pos(_m.point(_m.to_vertex_handle(heh)));
388
389 pos += V( _m.point(_m.to_vertex_handle(opp_heh)) );
390
391 // boundary edge: just average vertex positions
392 if (_m.is_boundary(_eh) )
393 {
394 pos *= static_cast<RealType>(0.5);
395 }
396 else // inner edge: add neighbouring Vertices to sum
397 {
398 pos *= real_t(3.0);
399 pos += V(_m.point(_m.to_vertex_handle(_m.next_halfedge_handle(heh))));
400 pos += V(_m.point(_m.to_vertex_handle(_m.next_halfedge_handle(opp_heh))));
401 pos *= _1over8;
402 }
403 _m.property( ep_pos_, _eh ) = pos;
404 #undef V
405 }
406
407 void smooth(mesh_t& _m, const typename mesh_t::VertexHandle& _vh)
408 {
409 typename mesh_t::Point pos(0.0,0.0,0.0);
410
411 if (_m.is_boundary(_vh) ) // if boundary: Point 1-6-1
412 {
413 typename mesh_t::HalfedgeHandle heh, prev_heh;
414 heh = _m.halfedge_handle( _vh );
415
416 if ( heh.is_valid() )
417 {
418 assert( _m.is_boundary( _m.edge_handle( heh ) ) );
419
420 prev_heh = _m.prev_halfedge_handle( heh );
421
422 typename mesh_t::VertexHandle
423 to_vh = _m.to_vertex_handle( heh ),
424 from_vh = _m.from_vertex_handle( prev_heh );
425
426 // ( v_l + 6 v + v_r ) / 8
427 pos = _m.point( _vh );
428 pos *= real_t(6.0);
429 pos += vector_cast< typename mesh_t::Normal >( _m.point( to_vh ) );
430 pos += vector_cast< typename mesh_t::Normal >( _m.point( from_vh ) );
431 pos *= _1over8;
432
433 }
434 else
435 return;
436 }
437 else // inner vertex: (1-a) * p + a/n * Sum q, q in one-ring of p
438 {
439 typedef typename mesh_t::Normal Vec;
440 typename mesh_t::VertexVertexIter vvit;
441 size_t valence(0);
442
443 // Calculate Valence and sum up neighbour points
444 for (vvit=_m.vv_iter(_vh); vvit.is_valid(); ++vvit) {
445 ++valence;
446 pos += vector_cast< Vec >( _m.point(*vvit) );
447 }
448 pos *= weights_[valence].second; // alpha(n)/n * Sum q, q in one-ring of p
449 pos += weights_[valence].first
450 * vector_cast<Vec>(_m.point(_vh)); // + (1-a)*p
451 }
452
453 _m.property( vp_pos_, _vh ) = pos;
454 }
455
456 private: // data
457
458 OpenMesh::VPropHandleT< typename mesh_t::Point > vp_pos_;
459 OpenMesh::EPropHandleT< typename mesh_t::Point > ep_pos_;
460
461 weights_t weights_;
462
463 const real_t _1over8;
464 const real_t _3over8;
465
466 };
467
468
469 //=============================================================================
470 } // END_NS_UNIFORM
471 } // END_NS_SUBDIVIDER
472 } // END_NS_OPENMESH
473 //=============================================================================
474 #endif // OPENMESH_SUBDIVIDER_UNIFORM_COMPOSITELOOPT_HH defined
475 //=============================================================================
OpenMesh::vector_cast
void vector_cast(const src_t &_src, dst_t &_dst, GenProg::Int2Type< n >)
Cast vector type to another vector type by copying the vector elements.
Definition: vector_cast.hh:81
OpenMesh::VPropHandleT< typename mesh_t::Point >
OpenMesh::Subdivider::Uniform::LoopT::subdivide
bool subdivide(mesh_t &_m, size_t _n, const bool _update_points=true) override
Subdivide mesh _m _n times.
Definition: LoopT.hh:149
OpenMesh::Subdivider::Uniform::LoopT::init_weights
void init_weights(size_t _max_valence=50)
Pre-compute weights.
Definition: LoopT.hh:123
OpenMesh::PolyMeshT::VertexVertexIter
Kernel::VertexVertexIter VertexVertexIter
Circulator.
Definition: PolyMeshT.hh:162
OpenMesh::Subdivider::Uniform::SubdividerT::operator()
bool operator()(MeshType &_m, size_t _n, const bool _update_points=true)
Subdivide the mesh _m _n times.
Definition: SubdividerT.hh:122
OpenMesh::PolyMeshT::Normal
Kernel::Normal Normal
Normal type.
Definition: PolyMeshT.hh:114
OpenMesh::Subdivider::Uniform::LoopT::cleanup
bool cleanup(mesh_t &_m) override
Cleanup mesh after usage, e.g. remove added properties.
Definition: LoopT.hh:141
OpenMesh::Subdivider::Uniform::LoopT
Uniform Loop subdivision algorithm.
Definition: LoopT.hh:91
OpenMesh::EPropHandleT< typename mesh_t::Point >
OpenMesh::Subdivider::Uniform::LoopT::name
const char * name() const override
Return name of subdivision algorithm.
Definition: LoopT.hh:119
OpenMesh::Subdivider::Uniform::SubdividerT
Abstract base class for uniform subdivision algorithms.
Definition: SubdividerT.hh:88
OpenMesh::Subdivider::Uniform::LoopT::prepare
bool prepare(mesh_t &_m) override
Prepare mesh, e.g. add properties.
Definition: LoopT.hh:133
OpenMesh::PolyMeshT::Point
Kernel::Point Point
Coordinate type.
Definition: PolyMeshT.hh:112
OpenMesh::Utils::MeshCheckerT
Check integrity of mesh.
Definition: MeshCheckerT.hh:73
SubdividerT.hh
OpenMesh
Contains all the mesh ingredients like the polygonal mesh, the triangle mesh, different mesh kernels ...
Definition: MeshItems.hh:59
OpenMesh::PolyMeshT::VertexHandle
Kernel::VertexHandle VertexHandle
Handle for referencing the corresponding item.
Definition: PolyMeshT.hh:136