OpenMesh
ModRoundnessT.hh
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48//=============================================================================
49//
50// CLASS ModRoundnessT
51//
52//=============================================================================
53
54#ifndef OPENMESH_DECIMATER_MODROUNDNESST_HH
55#define OPENMESH_DECIMATER_MODROUNDNESST_HH
56
57
58//== INCLUDES =================================================================
59
61#include <math.h>
62
63#if defined(OM_CC_MSVC)
64# define OM_ENABLE_WARNINGS 4244
65# pragma warning(disable : OM_ENABLE_WARNINGS )
66#endif
67
68//== NAMESPACE ================================================================
69
70namespace OpenMesh { // BEGIN_NS_OPENMESH
71namespace Decimater { // BEGIN_NS_DECIMATER
72
73
74//== CLASS DEFINITION =========================================================
75
76
85template <class MeshT>
86class ModRoundnessT : public ModBaseT<MeshT>
87{
88 public:
89 DECIMATING_MODULE( ModRoundnessT, MeshT, Roundness );
90
91 public:
92
93 // typedefs
94 typedef typename MeshT::Point Point;
95 typedef typename vector_traits<Point>::value_type value_type;
96
97 public:
98
100 explicit ModRoundnessT( MeshT &_dec ) :
101 Base(_dec, false),
102 min_r_(-1.0)
103 { }
104
107
108 public: // inherited
109
120 float collapse_priority(const CollapseInfo& _ci) override
121 {
122 // using namespace OpenMesh;
123
124 typename Mesh::ConstVertexOHalfedgeIter voh_it(Base::mesh(), _ci.v0);
125 double r;
126 double priority = 0.0; //==LEGAL_COLLAPSE
127 typename Mesh::FaceHandle fhC, fhB;
128 Vec3f B,C;
129
130 if ( min_r_ < 0.0f ) // continues mode
131 {
132 C = vector_cast<Vec3f>(Base::mesh().point( Base::mesh().to_vertex_handle(*voh_it)));
133 fhC = Base::mesh().face_handle( *voh_it );
134
135 for (++voh_it; voh_it.is_valid(); ++voh_it)
136 {
137 B = C;
138 fhB = fhC;
139 C = vector_cast<Vec3f>(Base::mesh().point(Base::mesh().to_vertex_handle(*voh_it)));
140 fhC = Base::mesh().face_handle( *voh_it );
141
142 if ( fhB == _ci.fl || fhB == _ci.fr )
143 continue;
144
145 // simulate collapse using position of v1
146 r = roundness( vector_cast<Vec3f>(_ci.p1), B, C );
147
148 // return the maximum non-roundness
149 priority = std::max( priority, (1.0-r) );
150
151 }
152 }
153 else // binary mode
154 {
155 C = vector_cast<Vec3f>(Base::mesh().point( Base::mesh().to_vertex_handle(*voh_it)));
156 fhC = Base::mesh().face_handle( *voh_it );
157
158 for (++voh_it; voh_it.is_valid() && (priority==Base::LEGAL_COLLAPSE); ++voh_it)
159 {
160 B = C;
161 fhB = fhC;
162 C = vector_cast<Vec3f>(Base::mesh().point(Base::mesh().to_vertex_handle(*voh_it)));
163 fhC = Base::mesh().face_handle( *voh_it );
164
165 if ( fhB == _ci.fl || fhB == _ci.fr )
166 continue;
167
168 priority = ( (r=roundness( vector_cast<Vec3f>(_ci.p1), B, C )) < min_r_)
169 ? Base::ILLEGAL_COLLAPSE : Base::LEGAL_COLLAPSE;
170 }
171 }
172
173 return (float) priority;
174 }
175
177 void set_error_tolerance_factor(double _factor) override {
178 if (this->is_binary()) {
179 if (_factor >= 0.0 && _factor <= 1.0) {
180 // the smaller the factor, the smaller min_r_ gets
181 // thus creating a stricter constraint
182 // division by error_tolerance_factor_ is for normalization
183 value_type min_roundness = min_r_ * static_cast<value_type>(_factor / this->error_tolerance_factor_);
184 set_min_roundness(min_roundness);
185 this->error_tolerance_factor_ = _factor;
186 }
187}
188 }
189
190
191public: // specific methods
192
193 void set_min_angle( float _angle, bool /* _binary=true */ )
194 {
195 assert( _angle > 0 && _angle < 60 );
196
197 _angle = float(M_PI * _angle /180.0);
198
199 Vec3f A,B,C;
200
201 A = Vec3f( 0.0f, 0.0f, 0.0f);
202 B = Vec3f( 2.0f * cos(_angle), 0.0f, 0.0f);
203 C = Vec3f( cos(_angle), sin(_angle), 0.0f);
204
205 double r1 = roundness(A,B,C);
206
207 _angle = float(0.5 * ( M_PI - _angle ));
208
209 A = Vec3f( 0.0f, 0.0f, 0.0f);
210 B = Vec3f( 2.0f*cos(_angle), 0.0f, 0.0f);
211 C = Vec3f( cos(_angle), sin(_angle), 0.0f);
212
213 double r2 = roundness(A,B,C);
214
215 set_min_roundness( value_type(std::min(r1,r2)), true );
216 }
217
225 void set_min_roundness( value_type _min_roundness, bool _binary=true )
226 {
227 assert( 0.0 <= _min_roundness && _min_roundness <= 1.0 );
228 min_r_ = _min_roundness;
229 Base::set_binary(_binary);
230 }
231
234 {
235 min_r_ = -1.0;
236 Base::set_binary(false);
237 }
238
239 // Compute a normalized roundness of a triangle ABC
240 //
241 // Having
242 // A,B,C corner points of triangle
243 // a,b,c the vectors BC,CA,AB
244 // Area area of triangle
245 //
246 // then define
247 //
248 // radius of circumference
249 // R := -----------------------
250 // length of shortest edge
251 //
252 // ||a|| * ||b|| * ||c||
253 // ---------------------
254 // 4 * Area ||a|| * ||b|| * ||c||
255 // = ----------------------- = -----------------------------------
256 // min( ||a||,||b||,||c||) 4 * Area * min( ||a||,||b||,||c|| )
257 //
258 // ||a|| * ||b|| * ||c||
259 // = -------------------------------------------------------
260 // 4 * 1/2 * ||cross(B-A,C-A)|| * min( ||a||,||b||,||c|| )
261 //
262 // a'a * b'b * c'c
263 // R� = ----------------------------------------------------------
264 // 4 * cross(B-A,C-A)'cross(B-A,C-A) * min( a'a, b'b, c'c )
265 //
266 // a'a * b'b * c'c
267 // R = 1/2 * sqrt(---------------------------)
268 // AA * min( a'a, b'b, c'c )
269 //
270 // At angle 60� R has it's minimum for all edge lengths = sqrt(1/3)
271 //
272 // Define normalized roundness
273 //
274 // nR := sqrt(1/3) / R
275 //
276 // AA * min( a'a, b'b, c'c )
277 // = sqrt(4/3) * sqrt(---------------------------)
278 // a'a * b'b * c'c
279 //
280 double roundness( const Vec3f& A, const Vec3f& B, const Vec3f &C )
281 {
282 const value_type epsilon = value_type(1e-15);
283
284 static const value_type sqrt43 = value_type(sqrt(4.0/3.0)); // 60�,a=b=c, **)
285
286 Vec3f vecAC = C-A;
287 Vec3f vecAB = B-A;
288
289 // compute squared values to avoid sqrt-computations
290 value_type aa = sqrnorm(B-C);
291 value_type bb = sqrnorm(vecAC);
292 value_type cc = sqrnorm(vecAB);
293 value_type AA = sqrnorm(cross(vecAC,vecAB)); // without factor 1/4 **)
294
295 if ( AA < epsilon )
296 return 0.0;
297
298 double nom = AA * std::min( std::min(aa,bb),cc );
299 double denom = aa * bb * cc;
300 double nR = sqrt43 * sqrt(nom/denom);
301
302 return nR;
303 }
304
305 private:
306
307 value_type min_r_;
308};
309
310
311//=============================================================================
312} // END_NS_DECIMATER
313} // END_NS_OPENMESH
314//=============================================================================
315#if defined(OM_CC_MSVC) && defined(OM_ENABLE_WARNINGS)
316# pragma warning(default : OM_ENABLE_WARNINGS)
317# undef OM_ENABLE_WARNINGS
318#endif
319//=============================================================================
320#endif // OPENMESH_DECIMATER_MODROUNDNESST_HH defined
321//=============================================================================
322
Base class for all decimation modules.
#define DECIMATING_MODULE(Classname, MeshT, Name)
Convenience macro, to be used in derived modules The macro defines the types.
Definition: ModBaseT.hh:149
Contains all the mesh ingredients like the polygonal mesh, the triangle mesh, different mesh kernels ...
Definition: MeshItems.hh:59
VectorT< float, 3 > Vec3f
3-float vector
Definition: Vector11T.hh:851
Kernel::FaceHandle FaceHandle
Scalar type.
Definition: PolyMeshT.hh:139
Kernel::ConstVertexOHalfedgeIter ConstVertexOHalfedgeIter
Circulator.
Definition: PolyMeshT.hh:173
Helper class providing information about a vector type.
Definition: vector_traits.hh:89
Stores information about a halfedge collapse.
Definition: CollapseInfoT.hh:74
Mesh::FaceHandle fr
Right face.
Definition: CollapseInfoT.hh:87
Mesh::Point p1
Positions of remaining vertex.
Definition: CollapseInfoT.hh:85
Mesh::VertexHandle v0
Vertex to be removed.
Definition: CollapseInfoT.hh:82
Mesh::FaceHandle fl
Left face.
Definition: CollapseInfoT.hh:86
Base class for all decimation modules.
Definition: ModBaseT.hh:193
bool is_binary(void) const
Returns true if criteria returns a binary value.
Definition: ModBaseT.hh:220
Use Roundness of triangles to control decimation.
Definition: ModRoundnessT.hh:87
void unset_min_roundness()
Unset minimum value constraint and enable non-binary mode.
Definition: ModRoundnessT.hh:233
ModRoundnessT(MeshT &_dec)
Constructor.
Definition: ModRoundnessT.hh:100
~ModRoundnessT()
Destructor.
Definition: ModRoundnessT.hh:106
void set_min_roundness(value_type _min_roundness, bool _binary=true)
Set a minimum roundness value.
Definition: ModRoundnessT.hh:225
float collapse_priority(const CollapseInfo &_ci) override
Compute collapse priority due to roundness of triangle.
Definition: ModRoundnessT.hh:120
void set_error_tolerance_factor(double _factor) override
set the percentage of minimum roundness
Definition: ModRoundnessT.hh:177

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