Point Cloud Library (PCL)  1.14.0-dev
gp3.h
1 /*
2  * Software License Agreement (BSD License)
3  *
4  * Point Cloud Library (PCL) - www.pointclouds.org
5  * Copyright (c) 2010-2011, Willow Garage, Inc.
6  *
7  * All rights reserved.
8  *
9  * Redistribution and use in source and binary forms, with or without
10  * modification, are permitted provided that the following conditions
11  * are met:
12  *
13  * * Redistributions of source code must retain the above copyright
14  * notice, this list of conditions and the following disclaimer.
15  * * Redistributions in binary form must reproduce the above
16  * copyright notice, this list of conditions and the following
17  * disclaimer in the documentation and/or other materials provided
18  * with the distribution.
19  * * Neither the name of Willow Garage, Inc. nor the names of its
20  * contributors may be used to endorse or promote products derived
21  * from this software without specific prior written permission.
22  *
23  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
24  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
25  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
26  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
27  * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
28  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
29  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
30  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
31  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
32  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
33  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
34  * POSSIBILITY OF SUCH DAMAGE.
35  *
36  * $Id$
37  *
38  */
39 
40 #pragma once
41 
42 // PCL includes
43 #include <pcl/surface/reconstruction.h>
44 
45 #include <pcl/kdtree/kdtree.h>
46 
47 #include <fstream>
48 
49 #include <Eigen/Geometry> // for cross
50 
51 namespace pcl
52 {
53  struct PolygonMesh;
54 
55  /** \brief Returns if a point X is visible from point R (or the origin)
56  * when taking into account the segment between the points S1 and S2
57  * \param X 2D coordinate of the point
58  * \param S1 2D coordinate of the segment's first point
59  * \param S2 2D coordinate of the segment's second point
60  * \param R 2D coordinate of the reference point (defaults to 0,0)
61  * \ingroup surface
62  */
63  inline bool
64  isVisible (const Eigen::Vector2f &X, const Eigen::Vector2f &S1, const Eigen::Vector2f &S2,
65  const Eigen::Vector2f &R = Eigen::Vector2f::Zero ())
66  {
67  double a0 = S1[1] - S2[1];
68  double b0 = S2[0] - S1[0];
69  double c0 = S1[0]*S2[1] - S2[0]*S1[1];
70  double a1 = -X[1];
71  double b1 = X[0];
72  double c1 = 0;
73  if (R != Eigen::Vector2f::Zero())
74  {
75  a1 += R[1];
76  b1 -= R[0];
77  c1 = R[0]*X[1] - X[0]*R[1];
78  }
79  double div = a0*b1 - b0*a1;
80  double x = (b0*c1 - b1*c0) / div;
81  double y = (a1*c0 - a0*c1) / div;
82 
83  bool intersection_outside_XR;
84  if (R == Eigen::Vector2f::Zero())
85  {
86  if (X[0] > 0)
87  intersection_outside_XR = (x <= 0) || (x >= X[0]);
88  else if (X[0] < 0)
89  intersection_outside_XR = (x >= 0) || (x <= X[0]);
90  else if (X[1] > 0)
91  intersection_outside_XR = (y <= 0) || (y >= X[1]);
92  else if (X[1] < 0)
93  intersection_outside_XR = (y >= 0) || (y <= X[1]);
94  else
95  intersection_outside_XR = true;
96  }
97  else
98  {
99  if (X[0] > R[0])
100  intersection_outside_XR = (x <= R[0]) || (x >= X[0]);
101  else if (X[0] < R[0])
102  intersection_outside_XR = (x >= R[0]) || (x <= X[0]);
103  else if (X[1] > R[1])
104  intersection_outside_XR = (y <= R[1]) || (y >= X[1]);
105  else if (X[1] < R[1])
106  intersection_outside_XR = (y >= R[1]) || (y <= X[1]);
107  else
108  intersection_outside_XR = true;
109  }
110  if (intersection_outside_XR)
111  return true;
112  if (S1[0] > S2[0])
113  return (x <= S2[0]) || (x >= S1[0]);
114  if (S1[0] < S2[0])
115  return (x >= S2[0]) || (x <= S1[0]);
116  if (S1[1] > S2[1])
117  return (y <= S2[1]) || (y >= S1[1]);
118  if (S1[1] < S2[1])
119  return (y >= S2[1]) || (y <= S1[1]);
120  return false;
121  }
122 
123  /** \brief GreedyProjectionTriangulation is an implementation of a greedy triangulation algorithm for 3D points
124  * based on local 2D projections. It assumes locally smooth surfaces and relatively smooth transitions between
125  * areas with different point densities.
126  * \tparam PointInT Point type must have XYZ and normal information, for example `pcl::PointNormal` or `pcl::PointXYZRGBNormal` or `pcl::PointXYZINormal`
127  * \author Zoltan Csaba Marton
128  * \ingroup surface
129  */
130  template <typename PointInT>
132  {
133  public:
134  using Ptr = shared_ptr<GreedyProjectionTriangulation<PointInT> >;
135  using ConstPtr = shared_ptr<const GreedyProjectionTriangulation<PointInT> >;
136 
140 
142  using KdTreePtr = typename KdTree::Ptr;
143 
147 
148  enum GP3Type
149  {
150  NONE = -1, // not-defined
151  FREE = 0,
152  FRINGE = 1,
153  BOUNDARY = 2,
154  COMPLETED = 3
155  };
156 
157  /** \brief Empty constructor. */
159 
160  /** \brief Set the multiplier of the nearest neighbor distance to obtain the final search radius for each point
161  * (this will make the algorithm adapt to different point densities in the cloud).
162  * \param[in] mu the multiplier
163  */
164  inline void
165  setMu (double mu) { mu_ = mu; }
166 
167  /** \brief Get the nearest neighbor distance multiplier. */
168  inline double
169  getMu () const { return (mu_); }
170 
171  /** \brief Set the maximum number of nearest neighbors to be searched for.
172  * \param[in] nnn the maximum number of nearest neighbors
173  */
174  inline void
175  setMaximumNearestNeighbors (int nnn) { nnn_ = nnn; }
176 
177  /** \brief Get the maximum number of nearest neighbors to be searched for. */
178  inline int
179  getMaximumNearestNeighbors () const { return (nnn_); }
180 
181  /** \brief Set the sphere radius that is to be used for determining the k-nearest neighbors used for triangulating.
182  * \param[in] radius the sphere radius that is to contain all k-nearest neighbors
183  * \note This distance limits the maximum edge length!
184  */
185  inline void
186  setSearchRadius (double radius) { search_radius_ = radius; }
187 
188  /** \brief Get the sphere radius used for determining the k-nearest neighbors. */
189  inline double
190  getSearchRadius () const { return (search_radius_); }
191 
192  /** \brief Set the minimum angle each triangle should have.
193  * \param[in] minimum_angle the minimum angle each triangle should have
194  * \note As this is a greedy approach, this will have to be violated from time to time
195  */
196  inline void
197  setMinimumAngle (double minimum_angle) { minimum_angle_ = minimum_angle; }
198 
199  /** \brief Get the parameter for distance based weighting of neighbors. */
200  inline double
201  getMinimumAngle () const { return (minimum_angle_); }
202 
203  /** \brief Set the maximum angle each triangle can have.
204  * \param[in] maximum_angle the maximum angle each triangle can have
205  * \note For best results, its value should be around 120 degrees
206  */
207  inline void
208  setMaximumAngle (double maximum_angle) { maximum_angle_ = maximum_angle; }
209 
210  /** \brief Get the parameter for distance based weighting of neighbors. */
211  inline double
212  getMaximumAngle () const { return (maximum_angle_); }
213 
214  /** \brief Don't consider points for triangulation if their normal deviates more than this value from the query point's normal.
215  * \param[in] eps_angle maximum surface angle
216  * \note As normal estimation methods usually give smooth transitions at sharp edges, this ensures correct triangulation
217  * by avoiding connecting points from one side to points from the other through forcing the use of the edge points.
218  */
219  inline void
220  setMaximumSurfaceAngle (double eps_angle) { eps_angle_ = eps_angle; }
221 
222  /** \brief Get the maximum surface angle. */
223  inline double
224  getMaximumSurfaceAngle () const { return (eps_angle_); }
225 
226  /** \brief Set the flag if the input normals are oriented consistently.
227  * \param[in] consistent set it to true if the normals are consistently oriented
228  */
229  inline void
230  setNormalConsistency (bool consistent) { consistent_ = consistent; }
231 
232  /** \brief Get the flag for consistently oriented normals. */
233  inline bool
234  getNormalConsistency () const { return (consistent_); }
235 
236  /** \brief Set the flag to order the resulting triangle vertices consistently (positive direction around normal).
237  * @note Assumes consistently oriented normals (towards the viewpoint) -- see setNormalConsistency ()
238  * \param[in] consistent_ordering set it to true if triangle vertices should be ordered consistently
239  */
240  inline void
241  setConsistentVertexOrdering (bool consistent_ordering) { consistent_ordering_ = consistent_ordering; }
242 
243  /** \brief Get the flag signaling consistently ordered triangle vertices. */
244  inline bool
246 
247  /** \brief Get the state of each point after reconstruction.
248  * \note Options are defined as constants: FREE, FRINGE, COMPLETED, BOUNDARY and NONE
249  */
250  inline std::vector<int>
251  getPointStates () const { return (state_); }
252 
253  /** \brief Get the ID of each point after reconstruction.
254  * \note parts are numbered from 0, a -1 denotes unconnected points
255  */
256  inline std::vector<int>
257  getPartIDs () const { return (part_); }
258 
259 
260  /** \brief Get the sfn list. */
261  inline pcl::Indices
262  getSFN () const { return (sfn_); }
263 
264  /** \brief Get the ffn list. */
265  inline pcl::Indices
266  getFFN () const { return (ffn_); }
267 
268  protected:
269  /** \brief The nearest neighbor distance multiplier to obtain the final search radius. */
270  double mu_{0.0};
271 
272  /** \brief The nearest neighbors search radius for each point and the maximum edge length. */
273  double search_radius_{0.0};
274 
275  /** \brief The maximum number of nearest neighbors accepted by searching. */
276  int nnn_{100};
277 
278  /** \brief The preferred minimum angle for the triangles. */
279  double minimum_angle_{M_PI/18};
280 
281  /** \brief The maximum angle for the triangles. */
282  double maximum_angle_{2*M_PI/3};
283 
284  /** \brief Maximum surface angle. */
285  double eps_angle_{M_PI/4};
286 
287  /** \brief Set this to true if the normals of the input are consistently oriented. */
288  bool consistent_{false};
289 
290  /** \brief Set this to true if the output triangle vertices should be consistently oriented. */
291  bool consistent_ordering_{false};
292 
293  private:
294  /** \brief Struct for storing the angles to nearest neighbors **/
295  struct nnAngle
296  {
297  double angle;
298  pcl::index_t index;
299  pcl::index_t nnIndex;
300  bool visible;
301  };
302 
303  /** \brief Struct for storing the edges starting from a fringe point **/
304  struct doubleEdge
305  {
306  doubleEdge () = default;
307  int index{0};
308  Eigen::Vector2f first;
309  Eigen::Vector2f second;
310  };
311 
312  // Variables made global to decrease the number of parameters to helper functions
313 
314  /** \brief Temporary variable to store a triangle (as a set of point indices) **/
315  pcl::Vertices triangle_{};
316  /** \brief Temporary variable to store point coordinates **/
317  std::vector<Eigen::Vector3f, Eigen::aligned_allocator<Eigen::Vector3f> > coords_{};
318 
319  /** \brief A list of angles to neighbors **/
320  std::vector<nnAngle> angles_{};
321  /** \brief Index of the current query point **/
322  pcl::index_t R_{};
323  /** \brief List of point states **/
324  std::vector<int> state_{};
325  /** \brief List of sources **/
326  pcl::Indices source_{};
327  /** \brief List of fringe neighbors in one direction **/
328  pcl::Indices ffn_{};
329  /** \brief List of fringe neighbors in other direction **/
330  pcl::Indices sfn_{};
331  /** \brief Connected component labels for each point **/
332  std::vector<int> part_{};
333  /** \brief Points on the outer edge from which the mesh has to be grown **/
334  std::vector<int> fringe_queue_{};
335 
336  /** \brief Flag to set if the current point is free **/
337  bool is_current_free_{false};
338  /** \brief Current point's index **/
339  pcl::index_t current_index_{};
340  /** \brief Flag to set if the previous point is the first fringe neighbor **/
341  bool prev_is_ffn_{false};
342  /** \brief Flag to set if the next point is the second fringe neighbor **/
343  bool prev_is_sfn_{false};
344  /** \brief Flag to set if the next point is the first fringe neighbor **/
345  bool next_is_ffn_{false};
346  /** \brief Flag to set if the next point is the second fringe neighbor **/
347  bool next_is_sfn_{false};
348  /** \brief Flag to set if the first fringe neighbor was changed **/
349  bool changed_1st_fn_{false};
350  /** \brief Flag to set if the second fringe neighbor was changed **/
351  bool changed_2nd_fn_{false};
352  /** \brief New boundary point **/
353  pcl::index_t new2boundary_{};
354 
355  /** \brief Flag to set if the next neighbor was already connected in the previous step.
356  * To avoid inconsistency it should not be connected again.
357  */
358  bool already_connected_{false};
359 
360  /** \brief Point coordinates projected onto the plane defined by the point normal **/
361  Eigen::Vector3f proj_qp_;
362  /** \brief First coordinate vector of the 2D coordinate frame **/
363  Eigen::Vector3f u_;
364  /** \brief Second coordinate vector of the 2D coordinate frame **/
365  Eigen::Vector3f v_;
366  /** \brief 2D coordinates of the first fringe neighbor **/
367  Eigen::Vector2f uvn_ffn_;
368  /** \brief 2D coordinates of the second fringe neighbor **/
369  Eigen::Vector2f uvn_sfn_;
370  /** \brief 2D coordinates of the first fringe neighbor of the next point **/
371  Eigen::Vector2f uvn_next_ffn_;
372  /** \brief 2D coordinates of the second fringe neighbor of the next point **/
373  Eigen::Vector2f uvn_next_sfn_;
374 
375  /** \brief Temporary variable to store 3 coordinates **/
376  Eigen::Vector3f tmp_;
377 
378  /** \brief The actual surface reconstruction method.
379  * \param[out] output the resultant polygonal mesh
380  */
381  void
382  performReconstruction (pcl::PolygonMesh &output) override;
383 
384  /** \brief The actual surface reconstruction method.
385  * \param[out] polygons the resultant polygons, as a set of vertices. The Vertices structure contains an array of point indices.
386  */
387  void
388  performReconstruction (std::vector<pcl::Vertices> &polygons) override;
389 
390  /** \brief The actual surface reconstruction method.
391  * \param[out] polygons the resultant polygons, as a set of vertices. The Vertices structure contains an array of point indices.
392  */
393  bool
394  reconstructPolygons (std::vector<pcl::Vertices> &polygons);
395 
396  /** \brief Class get name method. */
397  std::string
398  getClassName () const override { return ("GreedyProjectionTriangulation"); }
399 
400  /** \brief Forms a new triangle by connecting the current neighbor to the query point
401  * and the previous neighbor
402  * \param[out] polygons the polygon mesh to be updated
403  * \param[in] prev_index index of the previous point
404  * \param[in] next_index index of the next point
405  * \param[in] next_next_index index of the point after the next one
406  * \param[in] uvn_current 2D coordinate of the current point
407  * \param[in] uvn_prev 2D coordinates of the previous point
408  * \param[in] uvn_next 2D coordinates of the next point
409  */
410  void
411  connectPoint (std::vector<pcl::Vertices> &polygons,
412  const pcl::index_t prev_index,
413  const pcl::index_t next_index,
414  const pcl::index_t next_next_index,
415  const Eigen::Vector2f &uvn_current,
416  const Eigen::Vector2f &uvn_prev,
417  const Eigen::Vector2f &uvn_next);
418 
419  /** \brief Whenever a query point is part of a boundary loop containing 3 points, that triangle is created
420  * (called if angle constraints make it possible)
421  * \param[out] polygons the polygon mesh to be updated
422  */
423  void
424  closeTriangle (std::vector<pcl::Vertices> &polygons);
425 
426  /** \brief Get the list of containing triangles for each vertex in a PolygonMesh
427  * \param[in] polygonMesh the input polygon mesh
428  */
429  std::vector<std::vector<std::size_t> >
430  getTriangleList (const pcl::PolygonMesh &input);
431 
432  /** \brief Add a new triangle to the current polygon mesh
433  * \param[in] a index of the first vertex
434  * \param[in] b index of the second vertex
435  * \param[in] c index of the third vertex
436  * \param[out] polygons the polygon mesh to be updated
437  */
438  inline void
439  addTriangle (pcl::index_t a, pcl::index_t b, pcl::index_t c, std::vector<pcl::Vertices> &polygons)
440  {
441  triangle_.vertices.resize (3);
443  {
444  const PointInT p = input_->at (indices_->at (a));
445  const Eigen::Vector3f pv = p.getVector3fMap ();
446  if (p.getNormalVector3fMap ().dot (
447  (pv - input_->at (indices_->at (b)).getVector3fMap ()).cross (
448  pv - input_->at (indices_->at (c)).getVector3fMap ()) ) > 0)
449  {
450  triangle_.vertices[0] = a;
451  triangle_.vertices[1] = b;
452  triangle_.vertices[2] = c;
453  }
454  else
455  {
456  triangle_.vertices[0] = a;
457  triangle_.vertices[1] = c;
458  triangle_.vertices[2] = b;
459  }
460  }
461  else
462  {
463  triangle_.vertices[0] = a;
464  triangle_.vertices[1] = b;
465  triangle_.vertices[2] = c;
466  }
467  polygons.push_back (triangle_);
468  }
469 
470  /** \brief Add a new vertex to the advancing edge front and set its source point
471  * \param[in] v index of the vertex that was connected
472  * \param[in] s index of the source point
473  */
474  inline void
475  addFringePoint (int v, int s)
476  {
477  source_[v] = s;
478  part_[v] = part_[s];
479  fringe_queue_.push_back(v);
480  }
481 
482  /** \brief Function for ascending sort of nnAngle, taking visibility into account
483  * (angles to visible neighbors will be first, to the invisible ones after).
484  * \param[in] a1 the first angle
485  * \param[in] a2 the second angle
486  */
487  static inline bool
488  nnAngleSortAsc (const nnAngle& a1, const nnAngle& a2)
489  {
490  if (a1.visible == a2.visible)
491  return (a1.angle < a2.angle);
492  return a1.visible;
493  }
494  };
495 
496 } // namespace pcl
497 
498 #ifdef PCL_NO_PRECOMPILE
499 #include <pcl/surface/impl/gp3.hpp>
500 #endif
GreedyProjectionTriangulation is an implementation of a greedy triangulation algorithm for 3D points ...
Definition: gp3.h:132
void setSearchRadius(double radius)
Set the sphere radius that is to be used for determining the k-nearest neighbors used for triangulati...
Definition: gp3.h:186
double eps_angle_
Maximum surface angle.
Definition: gp3.h:285
double maximum_angle_
The maximum angle for the triangles.
Definition: gp3.h:282
double getMaximumAngle() const
Get the parameter for distance based weighting of neighbors.
Definition: gp3.h:212
int getMaximumNearestNeighbors() const
Get the maximum number of nearest neighbors to be searched for.
Definition: gp3.h:179
void setConsistentVertexOrdering(bool consistent_ordering)
Set the flag to order the resulting triangle vertices consistently (positive direction around normal)...
Definition: gp3.h:241
typename PointCloudIn::ConstPtr PointCloudInConstPtr
Definition: gp3.h:146
bool getNormalConsistency() const
Get the flag for consistently oriented normals.
Definition: gp3.h:234
pcl::Indices getFFN() const
Get the ffn list.
Definition: gp3.h:266
bool consistent_ordering_
Set this to true if the output triangle vertices should be consistently oriented.
Definition: gp3.h:291
GreedyProjectionTriangulation()=default
Empty constructor.
shared_ptr< const GreedyProjectionTriangulation< PointInT > > ConstPtr
Definition: gp3.h:135
bool getConsistentVertexOrdering() const
Get the flag signaling consistently ordered triangle vertices.
Definition: gp3.h:245
int nnn_
The maximum number of nearest neighbors accepted by searching.
Definition: gp3.h:276
double getMaximumSurfaceAngle() const
Get the maximum surface angle.
Definition: gp3.h:224
pcl::Indices getSFN() const
Get the sfn list.
Definition: gp3.h:262
typename PointCloudIn::Ptr PointCloudInPtr
Definition: gp3.h:145
double mu_
The nearest neighbor distance multiplier to obtain the final search radius.
Definition: gp3.h:270
double search_radius_
The nearest neighbors search radius for each point and the maximum edge length.
Definition: gp3.h:273
typename KdTree::Ptr KdTreePtr
Definition: gp3.h:142
void setNormalConsistency(bool consistent)
Set the flag if the input normals are oriented consistently.
Definition: gp3.h:230
void setMaximumNearestNeighbors(int nnn)
Set the maximum number of nearest neighbors to be searched for.
Definition: gp3.h:175
bool consistent_
Set this to true if the normals of the input are consistently oriented.
Definition: gp3.h:288
std::vector< int > getPartIDs() const
Get the ID of each point after reconstruction.
Definition: gp3.h:257
double getSearchRadius() const
Get the sphere radius used for determining the k-nearest neighbors.
Definition: gp3.h:190
double getMu() const
Get the nearest neighbor distance multiplier.
Definition: gp3.h:169
double getMinimumAngle() const
Get the parameter for distance based weighting of neighbors.
Definition: gp3.h:201
void setMinimumAngle(double minimum_angle)
Set the minimum angle each triangle should have.
Definition: gp3.h:197
double minimum_angle_
The preferred minimum angle for the triangles.
Definition: gp3.h:279
shared_ptr< GreedyProjectionTriangulation< PointInT > > Ptr
Definition: gp3.h:134
void setMaximumAngle(double maximum_angle)
Set the maximum angle each triangle can have.
Definition: gp3.h:208
void setMu(double mu)
Set the multiplier of the nearest neighbor distance to obtain the final search radius for each point ...
Definition: gp3.h:165
std::vector< int > getPointStates() const
Get the state of each point after reconstruction.
Definition: gp3.h:251
void setMaximumSurfaceAngle(double eps_angle)
Don't consider points for triangulation if their normal deviates more than this value from the query ...
Definition: gp3.h:220
KdTree represents the base spatial locator class for kd-tree implementations.
Definition: kdtree.h:56
shared_ptr< KdTree< PointT > > Ptr
Definition: kdtree.h:69
MeshConstruction represents a base surface reconstruction class.
PointCloudConstPtr input_
The input point cloud dataset.
Definition: pcl_base.h:147
IndicesPtr indices_
A pointer to the vector of point indices to use.
Definition: pcl_base.h:150
shared_ptr< PointCloud< PointInT > > Ptr
Definition: point_cloud.h:413
shared_ptr< const PointCloud< PointInT > > ConstPtr
Definition: point_cloud.h:414
bool isVisible(const Eigen::Vector2f &X, const Eigen::Vector2f &S1, const Eigen::Vector2f &S2, const Eigen::Vector2f &R=Eigen::Vector2f::Zero())
Returns if a point X is visible from point R (or the origin) when taking into account the segment bet...
Definition: gp3.h:64
detail::int_type_t< detail::index_type_size, detail::index_type_signed > index_t
Type used for an index in PCL.
Definition: types.h:112
IndicesAllocator<> Indices
Type used for indices in PCL.
Definition: types.h:133
#define M_PI
Definition: pcl_macros.h:201
Describes a set of vertices in a polygon mesh, by basically storing an array of indices.
Definition: Vertices.h:15
Indices vertices
Definition: Vertices.h:18