OpenVDB  7.0.0
LevelSetSphere.h
Go to the documentation of this file.
1 // Copyright Contributors to the OpenVDB Project
2 // SPDX-License-Identifier: MPL-2.0
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 <type_traits>
21 
22 #include <tbb/enumerable_thread_specific.h>
23 #include <tbb/parallel_for.h>
24 #include <tbb/parallel_reduce.h>
25 #include <tbb/blocked_range.h>
26 #include <thread>
27 
28 namespace openvdb {
30 namespace OPENVDB_VERSION_NAME {
31 namespace tools {
32 
47 template<typename GridType, typename InterruptT>
48 typename GridType::Ptr
49 createLevelSetSphere(float radius, const openvdb::Vec3f& center, float voxelSize,
50  float halfWidth = float(LEVEL_SET_HALF_WIDTH),
51  InterruptT* interrupt = nullptr, bool threaded = true);
52 
66 template<typename GridType>
67 typename GridType::Ptr
68 createLevelSetSphere(float radius, const openvdb::Vec3f& center, float voxelSize,
69  float halfWidth = float(LEVEL_SET_HALF_WIDTH), bool threaded = true)
70 {
71  return createLevelSetSphere<GridType, util::NullInterrupter>(radius,center,voxelSize,halfWidth,nullptr,threaded);
72 }
73 
74 
76 
77 
84 template<typename GridT, typename InterruptT = util::NullInterrupter>
86 {
87 public:
88  using TreeT = typename GridT::TreeType;
89  using ValueT = typename GridT::ValueType;
90  using Vec3T = typename math::Vec3<ValueT>;
91  static_assert(std::is_floating_point<ValueT>::value,
92  "level set grids must have scalar, floating-point value types");
93 
104  LevelSetSphere(ValueT radius, const Vec3T &center, InterruptT* interrupt = nullptr)
105  : mRadius(radius), mCenter(center), mInterrupt(interrupt)
106  {
107  if (mRadius<=0) OPENVDB_THROW(ValueError, "radius must be positive");
108  }
109 
115  typename GridT::Ptr getLevelSet(ValueT voxelSize, ValueT halfWidth, bool threaded = true)
116  {
117  mGrid = createLevelSet<GridT>(voxelSize, halfWidth);
118  this->rasterSphere(voxelSize, halfWidth, threaded);
119  mGrid->setGridClass(GRID_LEVEL_SET);
120  return mGrid;
121  }
122 
123 private:
124  void rasterSphere(ValueT dx, ValueT w, bool threaded)
125  {
126  if (!(dx>0.0f)) OPENVDB_THROW(ValueError, "voxel size must be positive");
127  if (!(w>1)) OPENVDB_THROW(ValueError, "half-width must be larger than one");
128 
129  // Define radius of sphere and narrow-band in voxel units
130  const ValueT r0 = mRadius/dx, rmax = r0 + w;
131 
132  // Radius below the Nyquist frequency
133  if (r0 < 1.5f) return;
134 
135  // Define center of sphere in voxel units
136  const Vec3T c(mCenter[0]/dx, mCenter[1]/dx, mCenter[2]/dx);
137 
138  // Define bounds of the voxel coordinates
139  const int imin=math::Floor(c[0]-rmax), imax=math::Ceil(c[0]+rmax);
140  const int jmin=math::Floor(c[1]-rmax), jmax=math::Ceil(c[1]+rmax);
141  const int kmin=math::Floor(c[2]-rmax), kmax=math::Ceil(c[2]+rmax);
142 
143  // Allocate a ValueAccessor for accelerated random access
144  typename GridT::Accessor accessor = mGrid->getAccessor();
145 
146  if (mInterrupt) mInterrupt->start("Generating level set of sphere");
147 
148  tbb::enumerable_thread_specific<TreeT> pool(mGrid->tree());
149 
150  auto kernel = [&](const tbb::blocked_range<int>& r) {
151  openvdb::Coord ijk;
152  int &i = ijk[0], &j = ijk[1], &k = ijk[2], m=1;
153  TreeT &tree = pool.local();
154  typename GridT::Accessor acc(tree);
155  // Compute signed distances to sphere using leapfrogging in k
156  for (i = r.begin(); i <= r.end(); ++i) {
157  if (util::wasInterrupted(mInterrupt)) return;
158  const auto x2 = math::Pow2(ValueT(i) - c[0]);
159  for (j = jmin; j <= jmax; ++j) {
160  const auto x2y2 = math::Pow2(ValueT(j) - c[1]) + x2;
161  for (k = kmin; k <= kmax; k += m) {
162  m = 1;
163  // Distance in voxel units to sphere
164  const auto v = math::Sqrt(x2y2 + math::Pow2(ValueT(k)-c[2]))-r0;
165  const auto d = math::Abs(v);
166  if (d < w) { // inside narrow band
167  acc.setValue(ijk, dx*v);// distance in world units
168  } else { // outside narrow band
169  m += math::Floor(d-w);// leapfrog
170  }
171  }//end leapfrog over k
172  }//end loop over j
173  }//end loop over i
174  };// kernel
175 
176  if (threaded) {
177  // The code blow is making use of a TLS container to minimize the number of concurrent trees
178  // initially populated by tbb::parallel_for and subsequently merged by tbb::parallel_reduce.
179  // Experiments have demonstrated this approach to outperform others, including serial reduction
180  // and a custom concurrent reduction implementation.
181  tbb::parallel_for(tbb::blocked_range<int>(imin, imax, 128), kernel);
182  using RangeT = tbb::blocked_range<typename tbb::enumerable_thread_specific<TreeT>::iterator>;
183  struct Op {
184  const bool mDelete;
185  TreeT *mTree;
186  Op(TreeT &tree) : mDelete(false), mTree(&tree) {}
187  Op(const Op& other, tbb::split) : mDelete(true), mTree(new TreeT(other.mTree->background())) {}
188  ~Op() { if (mDelete) delete mTree; }
189  void operator()(RangeT &r) { for (auto i=r.begin(); i!=r.end(); ++i) this->merge(*i);}
190  void join(Op &other) { this->merge(*(other.mTree)); }
191  void merge(TreeT &tree) { mTree->merge(tree, openvdb::MERGE_ACTIVE_STATES); }
192  } op( mGrid->tree() );
193  tbb::parallel_reduce(RangeT(pool.begin(), pool.end(), 4), op);
194  } else {
195  kernel(tbb::blocked_range<int>(imin, imax));//serial
196  mGrid->tree().merge(*pool.begin(), openvdb::MERGE_ACTIVE_STATES);
197  }
198 
199  // Define consistent signed distances outside the narrow-band
200  tools::signedFloodFill(mGrid->tree(), threaded);
201 
202  if (mInterrupt) mInterrupt->end();
203  }
204 
205  const ValueT mRadius;
206  const Vec3T mCenter;
207  InterruptT* mInterrupt;
208  typename GridT::Ptr mGrid;
209 };// LevelSetSphere
210 
211 
213 
214 
215 template<typename GridType, typename InterruptT>
216 typename GridType::Ptr
217 createLevelSetSphere(float radius, const openvdb::Vec3f& center, float voxelSize,
218  float halfWidth, InterruptT* interrupt, bool threaded)
219 {
220  // GridType::ValueType is required to be a floating-point scalar.
221  static_assert(std::is_floating_point<typename GridType::ValueType>::value,
222  "level set grids must have scalar, floating-point value types");
223 
224  using ValueT = typename GridType::ValueType;
225  LevelSetSphere<GridType, InterruptT> factory(ValueT(radius), center, interrupt);
226  return factory.getLevelSet(ValueT(voxelSize), ValueT(halfWidth), threaded);
227 }
228 
229 } // namespace tools
230 } // namespace OPENVDB_VERSION_NAME
231 } // namespace openvdb
232 
233 #endif // OPENVDB_TOOLS_LEVELSETSPHERE_HAS_BEEN_INCLUDED
static const Real LEVEL_SET_HALF_WIDTH
Definition: Types.h:460
Definition: Types.h:506
General-purpose arithmetic and comparison routines, most of which accept arbitrary value types (or at...
int Ceil(float x)
Return the ceiling of x.
Definition: Math.h:803
#define OPENVDB_THROW(exception, message)
Definition: Exceptions.h:82
Coord Abs(const Coord &xyz)
Definition: Coord.h:515
GridT::Ptr getLevelSet(ValueT voxelSize, ValueT halfWidth, bool threaded=true)
Definition: LevelSetSphere.h:115
Type Pow2(Type x)
Return x2.
Definition: Math.h:495
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:68
typename GridT::ValueType ValueT
Definition: LevelSetSphere.h:89
Definition: Exceptions.h:65
#define OPENVDB_VERSION_NAME
The version namespace name for this library version.
Definition: version.h:102
typename GridT::TreeType TreeT
Definition: LevelSetSphere.h:88
Propagate the signs of distance values from the active voxels in the narrow band to the inactive valu...
Definition: Exceptions.h:13
int Floor(float x)
Return the floor of x.
Definition: Math.h:795
bool wasInterrupted(T *i, int percent=-1)
Definition: NullInterrupter.h:49
float Sqrt(float x)
Return the square root of a floating-point value.
Definition: Math.h:708
Definition: Mat.h:170
Generates a signed distance field (or narrow band level set) to a single sphere.
Definition: LevelSetSphere.h:85
#define OPENVDB_USE_VERSION_NAMESPACE
Definition: version.h:154
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:266
typename math::Vec3< ValueT > Vec3T
Definition: LevelSetSphere.h:90
Definition: Types.h:454
LevelSetSphere(ValueT radius, const Vec3T &center, InterruptT *interrupt=nullptr)
Constructor.
Definition: LevelSetSphere.h:104