OpenVDB  9.0.1
LevelSetSphere.h
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1 // Copyright Contributors to the OpenVDB Project
2 // SPDX-License-Identifier: MPL-2.0
3 ///
4 /// @file LevelSetSphere.h
5 ///
6 /// @brief Generate a narrow-band level set of sphere.
7 ///
8 /// @note By definition a level set has a fixed narrow band width
9 /// (the half width is defined by LEVEL_SET_HALF_WIDTH in Types.h),
10 /// whereas an SDF can have a variable narrow band width.
11 
12 #ifndef OPENVDB_TOOLS_LEVELSETSPHERE_HAS_BEEN_INCLUDED
13 #define OPENVDB_TOOLS_LEVELSETSPHERE_HAS_BEEN_INCLUDED
14 
15 #include <openvdb/Grid.h>
16 #include <openvdb/Types.h>
17 #include <openvdb/math/Math.h>
19 #include "SignedFloodFill.h"
20 #include <openvdb/openvdb.h>
21 #include <type_traits>
22 
23 #include <tbb/enumerable_thread_specific.h>
24 #include <tbb/parallel_for.h>
25 #include <tbb/parallel_reduce.h>
26 #include <tbb/blocked_range.h>
27 #include <thread>
28 
29 namespace openvdb {
31 namespace OPENVDB_VERSION_NAME {
32 namespace tools {
33 
34 /// @brief Return a grid of type @c GridType containing a narrow-band level set
35 /// representation of a sphere.
36 ///
37 /// @param radius radius of the sphere in world units
38 /// @param center center of the sphere in world units
39 /// @param voxelSize voxel size in world units
40 /// @param halfWidth half the width of the narrow band, in voxel units
41 /// @param interrupt a pointer adhering to the util::NullInterrupter interface
42 /// @param threaded if true multi-threading is enabled (true by default)
43 ///
44 /// @note @c GridType::ValueType must be a floating-point scalar.
45 /// @note The leapfrog algorithm employed in this method is best suited
46 /// for a single large sphere. For multiple small spheres consider
47 /// using the faster algorithm in ParticlesToLevelSet.h
48 template<typename GridType, typename InterruptT>
49 typename GridType::Ptr
50 createLevelSetSphere(float radius, const openvdb::Vec3f& center, float voxelSize,
51  float halfWidth = float(LEVEL_SET_HALF_WIDTH),
52  InterruptT* interrupt = nullptr, bool threaded = true);
53 
54 /// @brief Return a grid of type @c GridType containing a narrow-band level set
55 /// representation of a sphere.
56 ///
57 /// @param radius radius of the sphere in world units
58 /// @param center center of the sphere in world units
59 /// @param voxelSize voxel size in world units
60 /// @param halfWidth half the width of the narrow band, in voxel units
61 /// @param threaded if true multi-threading is enabled (true by default)
62 ///
63 /// @note @c GridType::ValueType must be a floating-point scalar.
64 /// @note The leapfrog algorithm employed in this method is best suited
65 /// for a single large sphere. For multiple small spheres consider
66 /// using the faster algorithm in ParticlesToLevelSet.h
67 template<typename GridType>
68 typename GridType::Ptr
69 createLevelSetSphere(float radius, const openvdb::Vec3f& center, float voxelSize,
70  float halfWidth = float(LEVEL_SET_HALF_WIDTH), bool threaded = true)
71 {
72  return createLevelSetSphere<GridType, util::NullInterrupter>(radius,center,voxelSize,halfWidth,nullptr,threaded);
73 }
74 
75 
76 ////////////////////////////////////////
77 
78 
79 /// @brief Generates a signed distance field (or narrow band level
80 /// set) to a single sphere.
81 ///
82 /// @note The leapfrog algorithm employed in this class is best
83 /// suited for a single large sphere. For multiple small spheres consider
84 /// using the faster algorithm in tools/ParticlesToLevelSet.h
85 template<typename GridT, typename InterruptT = util::NullInterrupter>
87 {
88 public:
89  using TreeT = typename GridT::TreeType;
90  using ValueT = typename GridT::ValueType;
91  using Vec3T = typename math::Vec3<ValueT>;
93  "level set grids must have scalar, floating-point value types");
94 
95  /// @brief Constructor
96  ///
97  /// @param radius radius of the sphere in world units
98  /// @param center center of the sphere in world units
99  /// @param interrupt pointer to optional interrupter. Use template
100  /// argument util::NullInterrupter if no interruption is desired.
101  ///
102  /// @note If the radius of the sphere is smaller than
103  /// 1.5*voxelSize, i.e. the sphere is smaller than the Nyquist
104  /// frequency of the grid, it is ignored!
105  LevelSetSphere(ValueT radius, const Vec3T &center, InterruptT* interrupt = nullptr)
106  : mRadius(radius), mCenter(center), mInterrupt(interrupt)
107  {
108  if (mRadius<=0) OPENVDB_THROW(ValueError, "radius must be positive");
109  }
110 
111  /// @return a narrow-band level set of the sphere
112  ///
113  /// @param voxelSize Size of voxels in world units
114  /// @param halfWidth Half-width of narrow-band in voxel units
115  /// @param threaded If true multi-threading is enabled (true by default)
116  typename GridT::Ptr getLevelSet(ValueT voxelSize, ValueT halfWidth, bool threaded = true)
117  {
118  mGrid = createLevelSet<GridT>(voxelSize, halfWidth);
119  this->rasterSphere(voxelSize, halfWidth, threaded);
120  mGrid->setGridClass(GRID_LEVEL_SET);
121  return mGrid;
122  }
123 
124 private:
125  void rasterSphere(ValueT dx, ValueT w, bool threaded)
126  {
127  if (!(dx>0.0f)) OPENVDB_THROW(ValueError, "voxel size must be positive");
128  if (!(w>1)) OPENVDB_THROW(ValueError, "half-width must be larger than one");
129 
130  // Define radius of sphere and narrow-band in voxel units
131  const ValueT r0 = mRadius/dx, rmax = r0 + w;
132 
133  // Radius below the Nyquist frequency
134  if (r0 < 1.5f) return;
135 
136  // Define center of sphere in voxel units
137  const Vec3T c(mCenter[0]/dx, mCenter[1]/dx, mCenter[2]/dx);
138 
139  // Define bounds of the voxel coordinates
140  const int imin=math::Floor(c[0]-rmax), imax=math::Ceil(c[0]+rmax);
141  const int jmin=math::Floor(c[1]-rmax), jmax=math::Ceil(c[1]+rmax);
142  const int kmin=math::Floor(c[2]-rmax), kmax=math::Ceil(c[2]+rmax);
143 
144  // Allocate a ValueAccessor for accelerated random access
145  typename GridT::Accessor accessor = mGrid->getAccessor();
146 
147  if (mInterrupt) mInterrupt->start("Generating level set of sphere");
148 
149  tbb::enumerable_thread_specific<TreeT> pool(mGrid->tree());
150 
151  auto kernel = [&](const tbb::blocked_range<int>& r) {
152  openvdb::Coord ijk;
153  int &i = ijk[0], &j = ijk[1], &k = ijk[2], m=1;
154  TreeT &tree = pool.local();
155  typename GridT::Accessor acc(tree);
156  // Compute signed distances to sphere using leapfrogging in k
157  for (i = r.begin(); i != r.end(); ++i) {
158  if (util::wasInterrupted(mInterrupt)) return;
159  const auto x2 = math::Pow2(ValueT(i) - c[0]);
160  for (j = jmin; j <= jmax; ++j) {
161  const auto x2y2 = math::Pow2(ValueT(j) - c[1]) + x2;
162  for (k = kmin; k <= kmax; k += m) {
163  m = 1;
164  // Distance in voxel units to sphere
165  const auto v = math::Sqrt(x2y2 + math::Pow2(ValueT(k)-c[2]))-r0;
166  const auto d = math::Abs(v);
167  if (d < w) { // inside narrow band
168  acc.setValue(ijk, dx*v);// distance in world units
169  } else { // outside narrow band
170  m += math::Floor(d-w);// leapfrog
171  }
172  }//end leapfrog over k
173  }//end loop over j
174  }//end loop over i
175  };// kernel
176 
177  if (threaded) {
178  // The code blow is making use of a TLS container to minimize the number of concurrent trees
179  // initially populated by tbb::parallel_for and subsequently merged by tbb::parallel_reduce.
180  // Experiments have demonstrated this approach to outperform others, including serial reduction
181  // and a custom concurrent reduction implementation.
182  tbb::parallel_for(tbb::blocked_range<int>(imin, imax, 128), kernel);
183  using RangeT = tbb::blocked_range<typename tbb::enumerable_thread_specific<TreeT>::iterator>;
184  struct Op {
185  const bool mDelete;
186  TreeT *mTree;
187  Op(TreeT &tree) : mDelete(false), mTree(&tree) {}
188  Op(const Op& other, tbb::split) : mDelete(true), mTree(new TreeT(other.mTree->background())) {}
189  ~Op() { if (mDelete) delete mTree; }
190  void operator()(RangeT &r) { for (auto i=r.begin(); i!=r.end(); ++i) this->merge(*i);}
191  void join(Op &other) { this->merge(*(other.mTree)); }
192  void merge(TreeT &tree) { mTree->merge(tree, openvdb::MERGE_ACTIVE_STATES); }
193  } op( mGrid->tree() );
194  tbb::parallel_reduce(RangeT(pool.begin(), pool.end(), 4), op);
195  } else {
196  kernel(tbb::blocked_range<int>(imin, imax));//serial
197  mGrid->tree().merge(*pool.begin(), openvdb::MERGE_ACTIVE_STATES);
198  }
199 
200  // Define consistent signed distances outside the narrow-band
201  tools::signedFloodFill(mGrid->tree(), threaded);
202 
203  if (mInterrupt) mInterrupt->end();
204  }
205 
206  const ValueT mRadius;
207  const Vec3T mCenter;
208  InterruptT* mInterrupt;
209  typename GridT::Ptr mGrid;
210 };// LevelSetSphere
211 
212 
213 ////////////////////////////////////////
214 
215 
216 template<typename GridType, typename InterruptT>
217 typename GridType::Ptr
218 createLevelSetSphere(float radius, const openvdb::Vec3f& center, float voxelSize,
219  float halfWidth, InterruptT* interrupt, bool threaded)
220 {
221  // GridType::ValueType is required to be a floating-point scalar.
223  "level set grids must have scalar, floating-point value types");
224 
225  using ValueT = typename GridType::ValueType;
226  LevelSetSphere<GridType, InterruptT> factory(ValueT(radius), center, interrupt);
227  return factory.getLevelSet(ValueT(voxelSize), ValueT(halfWidth), threaded);
228 }
229 
230 
231 ////////////////////////////////////////
232 
233 
234 // Explicit Template Instantiation
235 
236 #ifdef OPENVDB_USE_EXPLICIT_INSTANTIATION
237 
238 #ifdef OPENVDB_INSTANTIATE_LEVELSETSPHERE
240 #endif
241 
242 #define _FUNCTION(TreeT) \
243  Grid<TreeT>::Ptr createLevelSetSphere<Grid<TreeT>>(float, const openvdb::Vec3f&, float, float, \
244  util::NullInterrupter*, bool)
246 #undef _FUNCTION
247 
248 #endif // OPENVDB_USE_EXPLICIT_INSTANTIATION
249 
250 
251 } // namespace tools
252 } // namespace OPENVDB_VERSION_NAME
253 } // namespace openvdb
254 
255 #endif // OPENVDB_TOOLS_LEVELSETSPHERE_HAS_BEEN_INCLUDED
bool wasInterrupted(T *i, int percent=-1)
Definition: NullInterrupter.h:49
LevelSetSphere(ValueT radius, const Vec3T &center, InterruptT *interrupt=nullptr)
Constructor.
Definition: LevelSetSphere.h:105
#define OPENVDB_THROW(exception, message)
Definition: Exceptions.h:74
General-purpose arithmetic and comparison routines, most of which accept arbitrary value types (or at...
Definition: Exceptions.h:65
int Ceil(float x)
Return the ceiling of x.
Definition: Math.h:859
int Floor(float x)
Return the floor of x.
Definition: Math.h:851
GridT::Ptr getLevelSet(ValueT voxelSize, ValueT halfWidth, bool threaded=true)
Definition: LevelSetSphere.h:116
typename GridT::TreeType TreeT
Definition: LevelSetSphere.h:89
typename math::Vec3< ValueT > Vec3T
Definition: LevelSetSphere.h:91
float Sqrt(float x)
Return the square root of a floating-point value.
Definition: Math.h:764
Generates a signed distance field (or narrow band level set) to a single sphere.
Definition: LevelSetSphere.h:86
Propagate the signs of distance values from the active voxels in the narrow band to the inactive valu...
Definition: Exceptions.h:13
ValueT value
Definition: GridBuilder.h:1287
GridType::Ptr createLevelSetSphere(float radius, const openvdb::Vec3f &center, float voxelSize, float halfWidth=float(LEVEL_SET_HALF_WIDTH), bool threaded=true)
Return a grid of type GridType containing a narrow-band level set representation of a sphere...
Definition: LevelSetSphere.h:69
Definition: Mat.h:187
void signedFloodFill(TreeOrLeafManagerT &tree, bool threaded=true, size_t grainSize=1, Index minLevel=0)
Set the values of all inactive voxels and tiles of a narrow-band level set from the signs of the acti...
Definition: SignedFloodFill.h:267
Definition: Types.h:416
#define OPENVDB_REAL_TREE_INSTANTIATE(Function)
Definition: version.h.in:147
typename GridT::ValueType ValueT
Definition: LevelSetSphere.h:90
Coord Abs(const Coord &xyz)
Definition: Coord.h:514
Type Pow2(Type x)
Return x2.
Definition: Math.h:551
#define OPENVDB_VERSION_NAME
The version namespace name for this library version.
Definition: version.h.in:116
Definition: Types.h:468
static const Real LEVEL_SET_HALF_WIDTH
Definition: Types.h:422
#define OPENVDB_USE_VERSION_NAMESPACE
Definition: version.h.in:202