Geogram  Version 1.9.1
A programming library of geometric algorithms
cavity.h
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39 
40 
41 #ifndef GEOGRAM_DELAUNAY_CAVITY
42 #define GEOGRAM_DELAUNAY_CAVITY
43 
44 #include <geogram/basic/common.h>
45 #include <geogram/basic/memory.h>
46 #include <geogram/basic/numeric.h>
47 #include <string.h>
48 
49 // Uncomment to display histogram of
50 // number of collisions per set() and
51 // get() operations.
52 // There is probably room for improvement
53 // in my hash function, but for large
54 // pointsets, more then 99% of queries are
55 // in the first slot (seems to be good enough).
56 //#define CAVITY_WITH_STATS
57 #ifdef CAVITY_WITH_STATS
58 #define CAVITY_STATS(x) x
59 #else
60 #define CAVITY_STATS(x)
61 #endif
62 
63 namespace GEO {
64 
69  class Cavity {
70 
71  public:
72 
77 
81  Cavity() {
82  clear();
83 #ifdef CAVITY_WITH_STATS
84  Memory::clear(stats_set_, sizeof(stats_set_));
85  Memory::clear(stats_get_, sizeof(stats_get_));
86 #endif
87  }
88 
92  void clear() {
93  nb_f_ = 0;
94  OK_ = true;
95  ::memset(h2t_, END_OF_LIST, sizeof(h2t_));
96  }
97 
98  ~Cavity() {
99 #ifdef CAVITY_WITH_STATS
100  for(index_t i=0; i<MAX_H; ++i) {
101  std::cerr << i << ": get=" << stats_get_[i]
102  << " set=" << stats_set_[i] << std::endl;
103  }
104 #endif
105  }
106 
113  bool OK() const {
114  return OK_;
115  }
116 
124  void new_facet(
125  index_t tglobal, index_t boundary_f,
127  ) {
128  if(!OK_) {
129  return;
130  }
131 
132  geo_debug_assert(v0 != v1);
133  geo_debug_assert(v1 != v2);
134  geo_debug_assert(v2 != v0);
135 
136  local_index_t new_t = local_index_t(nb_f_);
137 
138  if(nb_f_ == MAX_F) {
139  OK_ = false;
140  return;
141  }
142 
143  set_vv2t(v0, v1, new_t);
144  set_vv2t(v1, v2, new_t);
145  set_vv2t(v2, v0, new_t);
146 
147  if(!OK_) {
148  return;
149  }
150 
151  ++nb_f_;
152  tglobal_[new_t] = tglobal;
153  boundary_f_[new_t] = boundary_f;
154  f2v_[new_t][0] = v0;
155  f2v_[new_t][1] = v1;
156  f2v_[new_t][2] = v2;
157  }
158 
163  index_t nb_facets() const {
164  return nb_f_;
165  }
166 
174  return tglobal_[f];
175  }
176 
184  tglobal_[f] = t;
185  }
186 
196  return boundary_f_[f];
197  }
198 
207  geo_debug_assert(lv < 3);
208  return f2v_[f][lv];
209  }
210 
218  index_t f, index_t& t0, index_t& t1, index_t& t2
219  ) const {
220  signed_index_t v0 = f2v_[f][0];
221  signed_index_t v1 = f2v_[f][1];
222  signed_index_t v2 = f2v_[f][2];
223  t0 = tglobal_[get_vv2t(v2,v1)];
224  t1 = tglobal_[get_vv2t(v0,v2)];
225  t2 = tglobal_[get_vv2t(v1,v0)];
226  }
227 
228  private:
229  static constexpr index_t MAX_H = 1033;
230  static constexpr local_index_t END_OF_LIST = 255;
231  static constexpr index_t MAX_F = 128;
232 
239  index_t hash(signed_index_t v1, signed_index_t v2) const {
240  return (
241  ((index_t(v1+1) * 73856093) ^
242  (index_t(v2+1) * 83492791)) % MAX_H
243  );
244  }
245 
252  void set_vv2t(
254  ) {
255  CAVITY_STATS(index_t cnt = 0;)
256  index_t h = hash(v1,v2);
257  index_t cur = h;
258  do {
259  if(h2t_[cur] == END_OF_LIST) {
260  h2t_[cur] = f;
261 #ifdef GARGANTUA
262  h2v_[cur][0] = v1;
263  h2v_[cur][1] = v2;
264 #else
265  h2v_[cur] = (Numeric::uint64(v1+1) << 32) |
266  Numeric::uint64(v2+1);
267 #endif
268  CAVITY_STATS(++stats_set_[cnt];)
269  return;
270  }
271  cur = (cur+1)%MAX_H;
272  CAVITY_STATS(++cnt;)
273  } while(cur != h);
274  OK_ = false;
275  }
276 
283  local_index_t get_vv2t(signed_index_t v1, signed_index_t v2) const {
284 #ifndef GARGANTUA
285  Numeric::uint64 K = (Numeric::uint64(v1+1) << 32) |
286  Numeric::uint64(v2+1);
287 #endif
288  CAVITY_STATS(index_t cnt = 0;)
289  index_t h = hash(v1,v2);
290  index_t cur = h;
291  do {
292 #ifdef GARGANTUA
293  if((h2v_[cur][0] == v1) && (h2v_[cur][1] == v2)) {
294 #else
295  if(h2v_[cur] == K) {
296 #endif
297  CAVITY_STATS(++stats_get_[cnt];)
298  return h2t_[cur];
299  }
300  cur = (cur+1)%MAX_H;
301  CAVITY_STATS(++cnt;)
302  } while(cur != h);
304  }
305 
307  local_index_t h2t_[MAX_H];
308 
310 #ifdef GARGANTUA
311  signed_index_t h2v_[MAX_H][2];
312 #else
313  Numeric::uint64 h2v_[MAX_H];
314 #endif
315 
317  index_t nb_f_;
318 
320  index_t tglobal_[MAX_F];
321 
323  index_t boundary_f_[MAX_F];
324 
326  signed_index_t f2v_[MAX_F][3];
327 
328 
333  bool OK_;
334 
335  CAVITY_STATS(mutable index_t stats_set_[MAX_H];)
336  CAVITY_STATS(mutable index_t stats_get_[MAX_H];)
337  };
338 
339  }
340 
341 #endif
#define geo_assert_not_reached
Sets a non reachable point in the program.
Definition: assert.h:177
#define geo_debug_assert(x)
Verifies that a condition is met.
Definition: assert.h:196
Represents the set of tetrahedra on the boundary of the cavity in a 3D Delaunay triangulation.
Definition: cavity.h:69
Cavity()
Cavity constructor.
Definition: cavity.h:81
index_t nb_facets() const
Gets the number of facets.
Definition: cavity.h:163
Numeric::uint8 local_index_t
Type used for local indices.
Definition: cavity.h:76
bool OK() const
Tests whether this Cavity is valid.
Definition: cavity.h:113
void clear()
Clears this cavity.
Definition: cavity.h:92
signed_index_t facet_vertex(index_t f, index_t lv) const
Gets the vertex of a facet.
Definition: cavity.h:205
index_t facet_facet(index_t f) const
Gets the local tetrahedron facet that corresponds to a facet.
Definition: cavity.h:194
void set_facet_tet(index_t f, index_t t)
Sets the tetrahedron associated with a facet.
Definition: cavity.h:182
void get_facet_neighbor_tets(index_t f, index_t &t0, index_t &t1, index_t &t2) const
Gets the neighbors of a facet.
Definition: cavity.h:217
void new_facet(index_t tglobal, index_t boundary_f, signed_index_t v0, signed_index_t v1, signed_index_t v2)
Inserts a new boundary facet in the structure.
Definition: cavity.h:124
index_t facet_tet(index_t f) const
Gets the tetrahedron associated with a facet.
Definition: cavity.h:172
Common include file, providing basic definitions. Should be included before anything else by all head...
Types and functions for memory manipulation.
void clear(void *addr, size_t size)
Clears a memory block.
Definition: memory.h:116
uint8_t uint8
Definition: numeric.h:135
uint64_t uint64
Definition: numeric.h:144
Global Vorpaline namespace.
Definition: basic.h:55
geo_signed_index_t signed_index_t
The type for storing and manipulating indices differences.
Definition: numeric.h:343
geo_index_t index_t
The type for storing and manipulating indices.
Definition: numeric.h:329
Types and functions for numbers manipulation.
Functions for string manipulation.