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ModRoundnessT.hh
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41 
46 //=============================================================================
47 //
48 // CLASS ModRoundnessT
49 //
50 //=============================================================================
51 
52 #ifndef OPENMESH_DECIMATER_MODROUNDNESST_HH
53 #define OPENMESH_DECIMATER_MODROUNDNESST_HH
54 
55 
56 //== INCLUDES =================================================================
57 
59 #include <math.h>
60 
61 #if defined(OM_CC_MSVC)
62 # define OM_ENABLE_WARNINGS 4244
63 # pragma warning(disable : OM_ENABLE_WARNINGS )
64 #endif
65 
66 //== NAMESPACE ================================================================
67 
68 namespace OpenMesh { // BEGIN_NS_OPENMESH
69 namespace Decimater { // BEGIN_NS_DECIMATER
70 
71 
72 //== CLASS DEFINITION =========================================================
73 
74 
83 template <class MeshT>
84 class ModRoundnessT : public ModBaseT<MeshT>
85 {
86  public:
87  DECIMATING_MODULE( ModRoundnessT, MeshT, Roundness );
88 
89  public:
90 
91  // typedefs
92  typedef typename MeshT::Point Point;
93  typedef typename vector_traits<Point>::value_type value_type;
94 
95  public:
96 
98  ModRoundnessT( MeshT &_dec ) :
99  Base(_dec, false),
100  min_r_(-1.0)
101  { }
102 
105 
106  public: // inherited
107 
118  float collapse_priority(const CollapseInfo& _ci)
119  {
120  // using namespace OpenMesh;
121 
122  typename Mesh::ConstVertexOHalfedgeIter voh_it(Base::mesh(), _ci.v0);
123  double r;
124  double priority = 0.0; //==LEGAL_COLLAPSE
125  typename Mesh::FaceHandle fhC, fhB;
126  Vec3f B,C;
127 
128  if ( min_r_ < 0.0f ) // continues mode
129  {
130  C = vector_cast<Vec3f>(Base::mesh().point( Base::mesh().to_vertex_handle(*voh_it)));
131  fhC = Base::mesh().face_handle( *voh_it );
132 
133  for (++voh_it; voh_it.is_valid(); ++voh_it)
134  {
135  B = C;
136  fhB = fhC;
137  C = vector_cast<Vec3f>(Base::mesh().point(Base::mesh().to_vertex_handle(*voh_it)));
138  fhC = Base::mesh().face_handle( *voh_it );
139 
140  if ( fhB == _ci.fl || fhB == _ci.fr )
141  continue;
142 
143  // simulate collapse using position of v1
144  r = roundness( vector_cast<Vec3f>(_ci.p1), B, C );
145 
146  // return the maximum non-roundness
147  priority = std::max( priority, (1.0-r) );
148 
149  }
150  }
151  else // binary mode
152  {
153  C = vector_cast<Vec3f>(Base::mesh().point( Base::mesh().to_vertex_handle(*voh_it)));
154  fhC = Base::mesh().face_handle( *voh_it );
155 
156  for (++voh_it; voh_it.is_valid() && (priority==Base::LEGAL_COLLAPSE); ++voh_it)
157  {
158  B = C;
159  fhB = fhC;
160  C = vector_cast<Vec3f>(Base::mesh().point(Base::mesh().to_vertex_handle(*voh_it)));
161  fhC = Base::mesh().face_handle( *voh_it );
162 
163  if ( fhB == _ci.fl || fhB == _ci.fr )
164  continue;
165 
166  priority = ( (r=roundness( vector_cast<Vec3f>(_ci.p1), B, C )) < min_r_)
167  ? Base::ILLEGAL_COLLAPSE : Base::LEGAL_COLLAPSE;
168  }
169  }
170 
171  return (float) priority;
172  }
173 
175  void set_error_tolerance_factor(double _factor) {
176  if (this->is_binary()) {
177  if (_factor >= 0.0 && _factor <= 1.0) {
178  // the smaller the factor, the smaller min_r_ gets
179  // thus creating a stricter constraint
180  // division by error_tolerance_factor_ is for normalization
181  value_type min_roundness = min_r_ * _factor / this->error_tolerance_factor_;
182  set_min_roundness(min_roundness);
183  this->error_tolerance_factor_ = _factor;
184  }
185 }
186  }
187 
188 
189 public: // specific methods
190 
191  void set_min_angle( float _angle, bool /* _binary=true */ )
192  {
193  assert( _angle > 0 && _angle < 60 );
194 
195  _angle = float(M_PI * _angle /180.0);
196 
197  Vec3f A,B,C;
198 
199  A = Vec3f( 0.0f, 0.0f, 0.0f);
200  B = Vec3f( 2.0f * cos(_angle), 0.0f, 0.0f);
201  C = Vec3f( cos(_angle), sin(_angle), 0.0f);
202 
203  double r1 = roundness(A,B,C);
204 
205  _angle = float(0.5 * ( M_PI - _angle ));
206 
207  A = Vec3f( 0.0f, 0.0f, 0.0f);
208  B = Vec3f( 2.0f*cos(_angle), 0.0f, 0.0f);
209  C = Vec3f( cos(_angle), sin(_angle), 0.0f);
210 
211  double r2 = roundness(A,B,C);
212 
213  set_min_roundness( value_type(std::min(r1,r2)), true );
214  }
215 
223  void set_min_roundness( value_type _min_roundness, bool _binary=true )
224  {
225  assert( 0.0 <= _min_roundness && _min_roundness <= 1.0 );
226  min_r_ = _min_roundness;
227  Base::set_binary(_binary);
228  }
229 
232  {
233  min_r_ = -1.0;
234  Base::set_binary(false);
235  }
236 
237  // Compute a normalized roundness of a triangle ABC
238  //
239  // Having
240  // A,B,C corner points of triangle
241  // a,b,c the vectors BC,CA,AB
242  // Area area of triangle
243  //
244  // then define
245  //
246  // radius of circumference
247  // R := -----------------------
248  // length of shortest edge
249  //
250  // ||a|| * ||b|| * ||c||
251  // ---------------------
252  // 4 * Area ||a|| * ||b|| * ||c||
253  // = ----------------------- = -----------------------------------
254  // min( ||a||,||b||,||c||) 4 * Area * min( ||a||,||b||,||c|| )
255  //
256  // ||a|| * ||b|| * ||c||
257  // = -------------------------------------------------------
258  // 4 * 1/2 * ||cross(B-A,C-A)|| * min( ||a||,||b||,||c|| )
259  //
260  // a'a * b'b * c'c
261  // R� = ----------------------------------------------------------
262  // 4 * cross(B-A,C-A)'cross(B-A,C-A) * min( a'a, b'b, c'c )
263  //
264  // a'a * b'b * c'c
265  // R = 1/2 * sqrt(---------------------------)
266  // AA * min( a'a, b'b, c'c )
267  //
268  // At angle 60� R has it's minimum for all edge lengths = sqrt(1/3)
269  //
270  // Define normalized roundness
271  //
272  // nR := sqrt(1/3) / R
273  //
274  // AA * min( a'a, b'b, c'c )
275  // = sqrt(4/3) * sqrt(---------------------------)
276  // a'a * b'b * c'c
277  //
278  double roundness( const Vec3f& A, const Vec3f& B, const Vec3f &C )
279  {
280  const value_type epsilon = value_type(1e-15);
281 
282  static const value_type sqrt43 = value_type(sqrt(4.0/3.0)); // 60�,a=b=c, **)
283 
284  Vec3f vecAC = C-A;
285  Vec3f vecAB = B-A;
286 
287  // compute squared values to avoid sqrt-computations
288  value_type aa = (B-C).sqrnorm();
289  value_type bb = vecAC.sqrnorm();
290  value_type cc = vecAB.sqrnorm();
291  value_type AA = cross(vecAC,vecAB).sqrnorm(); // without factor 1/4 **)
292 
293  if ( AA < epsilon )
294  return 0.0;
295 
296  double nom = AA * std::min( std::min(aa,bb),cc );
297  double denom = aa * bb * cc;
298  double nR = sqrt43 * sqrt(nom/denom);
299 
300  return nR;
301  }
302 
303  private:
304 
305  value_type min_r_;
306 };
307 
308 
309 //=============================================================================
310 } // END_NS_DECIMATER
311 } // END_NS_OPENMESH
312 //=============================================================================
313 #if defined(OM_CC_MSVC) && defined(OM_ENABLE_WARNINGS)
314 # pragma warning(default : OM_ENABLE_WARNINGS)
315 # undef OM_ENABLE_WARNINGS
316 #endif
317 //=============================================================================
318 #endif // OPENMESH_DECIMATER_MODROUNDNESST_HH defined
319 //=============================================================================
320 
Kernel::ConstVertexOHalfedgeIter ConstVertexOHalfedgeIter
Circulator.
Definition: PolyMeshT.hh:169
#define DECIMATING_MODULE(Classname, MeshT, Name)
Convenience macro, to be used in derived modules The macro defines the types.
Definition: ModBaseT.hh:147
Stores information about a halfedge collapse.
Definition: CollapseInfoT.hh:73
Base class for all decimation modules.
Definition: ModBaseT.hh:190
vector_caster< dst_t, src_t >::return_type vector_cast(const src_t &_src)
Cast vector type to another vector type by copying the vector elements.
Definition: vector_cast.hh:170
ModRoundnessT(MeshT &_dec)
Constructor.
Definition: ModRoundnessT.hh:98
Mesh::VertexHandle v0
Vertex to be removed.
Definition: CollapseInfoT.hh:90
~ModRoundnessT()
Destructor.
Definition: ModRoundnessT.hh:104
Mesh::FaceHandle fr
Right face.
Definition: CollapseInfoT.hh:95
float collapse_priority(const CollapseInfo &_ci)
Compute collapse priority due to roundness of triangle.
Definition: ModRoundnessT.hh:118
osg::Vec3f cross(const osg::Vec3f &_v1, const osg::Vec3f &_v2)
Adapter for osg vector member computing a scalar product.
Definition: VectorAdapter.hh:189
Use Roundness of triangles to control decimation.
Definition: ModRoundnessT.hh:84
bool is_binary(void) const
Returns true if criteria returns a binary value.
Definition: ModBaseT.hh:218
Helper class providing information about a vector type.
Definition: vector_traits.hh:86
Base class for all decimation modules.
Mesh::Point p1
Positions of remaining vertex.
Definition: CollapseInfoT.hh:93
Mesh::FaceHandle fl
Left face.
Definition: CollapseInfoT.hh:94
void set_min_roundness(value_type _min_roundness, bool _binary=true)
Set a minimum roundness value.
Definition: ModRoundnessT.hh:223
void unset_min_roundness()
Unset minimum value constraint and enable non-binary mode.
Definition: ModRoundnessT.hh:231
void set_error_tolerance_factor(double _factor)
set the percentage of minimum roundness
Definition: ModRoundnessT.hh:175

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