OpenVDB  7.0.0
VelocityFields.h
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1 // Copyright Contributors to the OpenVDB Project
2 // SPDX-License-Identifier: MPL-2.0
3 //
5 //
24 
25 #ifndef OPENVDB_TOOLS_VELOCITY_FIELDS_HAS_BEEN_INCLUDED
26 #define OPENVDB_TOOLS_VELOCITY_FIELDS_HAS_BEEN_INCLUDED
27 
28 #include <tbb/parallel_reduce.h>
29 #include <openvdb/Platform.h>
30 #include <openvdb/openvdb.h>
31 #include "Interpolation.h" // for Sampler, etc.
33 #include <boost/math/constants/constants.hpp>
34 
35 namespace openvdb {
37 namespace OPENVDB_VERSION_NAME {
38 namespace tools {
39 
42 template <typename VelGridT, typename Interpolator = BoxSampler>
44 {
45 public:
46  typedef typename VelGridT::ValueType VectorType;
47  typedef typename VectorType::ValueType ValueType;
48  BOOST_STATIC_ASSERT(boost::is_floating_point<ValueType>::value);
49 
50  DiscreteField(const VelGridT &vel)
51  : mAccessor(vel.tree())
52  , mTransform(&vel.transform())
53  {
54  }
55 
58  : mAccessor(other.mAccessor.tree())
59  , mTransform(other.mTransform)
60  {
61  }
62 
66  const math::Transform& transform() const { return *mTransform; }
67 
72  inline VectorType operator() (const Vec3d& xyz, ValueType/*dummy time*/) const
73  {
74  return Interpolator::sample(mAccessor, mTransform->worldToIndex(xyz));
75  }
76 
81  inline VectorType operator() (const Coord& ijk, ValueType/*dummy time*/) const
82  {
83  return mAccessor.getValue(ijk);
84  }
85 
86 private:
87  const typename VelGridT::ConstAccessor mAccessor;//Not thread-safe
88  const math::Transform* mTransform;
89 
90 }; // end of DiscreteField
91 
93 
100 template <typename ScalarT = float>
102 {
103 public:
104  typedef ScalarT ValueType;
106  BOOST_STATIC_ASSERT(boost::is_floating_point<ScalarT>::value);
107 
109 
114 
117  inline VectorType operator() (const Vec3d& xyz, ValueType time) const;
118 
120  inline VectorType operator() (const Coord& ijk, ValueType time) const
121  {
122  return (*this)(ijk.asVec3d(), time);
123  }
124 }; // end of EnrightField
125 
126 template <typename ScalarT>
127 inline math::Vec3<ScalarT>
129 {
130  const ScalarT pi = boost::math::constants::pi<ScalarT>();
131  const ScalarT phase = pi / ScalarT(3);
132  const ScalarT Px = pi * ScalarT(xyz[0]), Py = pi * ScalarT(xyz[1]), Pz = pi * ScalarT(xyz[2]);
133  const ScalarT tr = math::Cos(ScalarT(time) * phase);
134  const ScalarT a = math::Sin(ScalarT(2)*Py);
135  const ScalarT b = -math::Sin(ScalarT(2)*Px);
136  const ScalarT c = math::Sin(ScalarT(2)*Pz);
137  return math::Vec3<ScalarT>(
138  tr * ( ScalarT(2) * math::Pow2(math::Sin(Px)) * a * c ),
139  tr * ( b * math::Pow2(math::Sin(Py)) * c ),
140  tr * ( b * a * math::Pow2(math::Sin(Pz)) ));
141 }
142 
143 
145 
149 template<typename GridT = Vec3fGrid,
150  bool Staggered = false,
151  size_t Order = 1>
153 {
154 public:
155  typedef typename GridT::ConstAccessor AccessorType;
156  typedef typename GridT::ValueType ValueType;
157 
159  VelocitySampler(const GridT& grid):
160  mGrid(&grid),
161  mAcc(grid.getAccessor())
162  {
163  }
166  mGrid(other.mGrid),
167  mAcc(mGrid->getAccessor())
168  {
169  }
177  template <typename LocationType>
178  inline bool sample(const LocationType& world, ValueType& result) const
179  {
180  const Vec3R xyz = mGrid->worldToIndex(Vec3R(world[0], world[1], world[2]));
181  bool active = Sampler<Order, Staggered>::sample(mAcc, xyz, result);
182  return active;
183  }
184 
190  template <typename LocationType>
191  inline ValueType sample(const LocationType& world) const
192  {
193  const Vec3R xyz = mGrid->worldToIndex(Vec3R(world[0], world[1], world[2]));
194  return Sampler<Order, Staggered>::sample(mAcc, xyz);
195  }
196 
197 private:
198  // holding the Grids for the transforms
199  const GridT* mGrid; // Velocity vector field
200  AccessorType mAcc;
201 };// end of VelocitySampler class
202 
204 
211 template<typename GridT = Vec3fGrid,
212  bool Staggered = false,
213  size_t SampleOrder = 1>
215 {
216 public:
217  typedef typename GridT::ValueType VecType;
218  typedef typename VecType::ValueType ElementType;
219 
220  VelocityIntegrator(const GridT& velGrid):
221  mVelSampler(velGrid)
222  {
223  }
228  template<size_t OrderRK, typename LocationType>
229  inline void rungeKutta(const ElementType dt, LocationType& world) const
230  {
231  BOOST_STATIC_ASSERT(OrderRK <= 4);
232  VecType P(static_cast<ElementType>(world[0]),
233  static_cast<ElementType>(world[1]),
234  static_cast<ElementType>(world[2]));
235  // Note the if-branching below is optimized away at compile time
236  if (OrderRK == 0) {
237  return;// do nothing
238  } else if (OrderRK == 1) {
239  VecType V0;
240  mVelSampler.sample(P, V0);
241  P = dt * V0;
242  } else if (OrderRK == 2) {
243  VecType V0, V1;
244  mVelSampler.sample(P, V0);
245  mVelSampler.sample(P + ElementType(0.5) * dt * V0, V1);
246  P = dt * V1;
247  } else if (OrderRK == 3) {
248  VecType V0, V1, V2;
249  mVelSampler.sample(P, V0);
250  mVelSampler.sample(P + ElementType(0.5) * dt * V0, V1);
251  mVelSampler.sample(P + dt * (ElementType(2.0) * V1 - V0), V2);
252  P = dt * (V0 + ElementType(4.0) * V1 + V2) * ElementType(1.0 / 6.0);
253  } else if (OrderRK == 4) {
254  VecType V0, V1, V2, V3;
255  mVelSampler.sample(P, V0);
256  mVelSampler.sample(P + ElementType(0.5) * dt * V0, V1);
257  mVelSampler.sample(P + ElementType(0.5) * dt * V1, V2);
258  mVelSampler.sample(P + dt * V2, V3);
259  P = dt * (V0 + ElementType(2.0) * (V1 + V2) + V3) * ElementType(1.0 / 6.0);
260  }
261  typedef typename LocationType::ValueType OutType;
262  world += LocationType(static_cast<OutType>(P[0]),
263  static_cast<OutType>(P[1]),
264  static_cast<OutType>(P[2]));
265  }
266 private:
268 };// end of VelocityIntegrator class
269 
270 
271 } // namespace tools
272 } // namespace OPENVDB_VERSION_NAME
273 } // namespace openvdb
274 
275 #endif // OPENVDB_TOOLS_VELOCITY_FIELDS_HAS_BEEN_INCLUDED
openvdb::v7_0::tools::VelocitySampler::AccessorType
GridT::ConstAccessor AccessorType
Definition: VelocityFields.h:155
openvdb::v7_0::Vec3fGrid
Vec3SGrid Vec3fGrid
Definition: openvdb.h:56
openvdb::v7_0::tools::DiscreteField::VectorType
VelGridT::ValueType VectorType
Definition: VelocityFields.h:46
openvdb::v7_0::Vec3R
math::Vec3< Real > Vec3R
Definition: Types.h:49
openvdb::v7_0::math::Coord
Signed (x, y, z) 32-bit integer coordinates.
Definition: Coord.h:26
openvdb::v7_0::tools::VelocitySampler
Definition: VelocityFields.h:153
openvdb::v7_0::tools::Sampler
Provises a unified interface for sampling, i.e. interpolation.
Definition: Interpolation.h:64
openvdb::v7_0::tools::DiscreteField::transform
const math::Transform & transform() const
Definition: VelocityFields.h:66
openvdb::v7_0::tools::EnrightField::transform
math::Transform transform() const
Definition: VelocityFields.h:113
openvdb::v7_0::tools::VelocityIntegrator::VecType
GridT::ValueType VecType
Definition: VelocityFields.h:217
openvdb::v7_0::tools::VelocityIntegrator
Performs Runge-Kutta time integration of variable order in a static velocity field.
Definition: VelocityFields.h:215
openvdb::v7_0::tools::VelocitySampler::VelocitySampler
VelocitySampler(const VelocitySampler &other)
Copy-constructor.
Definition: VelocityFields.h:165
openvdb::v7_0::tools::VelocityIntegrator::VelocityIntegrator
VelocityIntegrator(const GridT &velGrid)
Definition: VelocityFields.h:220
Platform.h
openvdb::v7_0::math::Cos
float Cos(const float &x)
Return cos x.
Definition: Math.h:672
openvdb::v7_0::tools::VelocitySampler::VelocitySampler
VelocitySampler(const GridT &grid)
Constructor from a grid.
Definition: VelocityFields.h:159
openvdb::v7_0::tools::VelocitySampler::sample
bool sample(const LocationType &world, ValueType &result) const
Samples the velocity at world position onto result. Supports both staggered (i.e. MAC) and collocated...
Definition: VelocityFields.h:178
openvdb::v7_0::math::Vec3d
Vec3< double > Vec3d
Definition: Vec3.h:662
openvdb::v7_0::math::Pow2
Type Pow2(Type x)
Return x2.
Definition: Math.h:495
openvdb::v7_0::math::Sin
float Sin(const float &x)
Return sin x.
Definition: Math.h:663
FiniteDifference.h
openvdb::v7_0::tools::EnrightField::ValueType
ScalarT ValueType
Definition: VelocityFields.h:104
openvdb::v7_0::tools::EnrightField::VectorType
math::Vec3< ScalarT > VectorType
Definition: VelocityFields.h:105
openvdb::v7_0::math::Coord::asVec3d
Vec3d asVec3d() const
Definition: Coord.h:144
openvdb::v7_0::tools::DiscreteField::DiscreteField
DiscreteField(const VelGridT &vel)
Definition: VelocityFields.h:50
openvdb::v7_0::tools::EnrightField
Analytical, divergence-free and periodic velocity field.
Definition: VelocityFields.h:102
openvdb::v7_0::tools::DiscreteField::DiscreteField
DiscreteField(const DiscreteField &other)
Copy constructor.
Definition: VelocityFields.h:57
openvdb::v7_0::math::Vec3
Definition: Mat.h:170
Interpolation.h
openvdb::v7_0::tools::VelocitySampler::ValueType
GridT::ValueType ValueType
Definition: VelocityFields.h:156
openvdb::v7_0::tools::VelocityIntegrator::rungeKutta
void rungeKutta(const ElementType dt, LocationType &world) const
Variable order Runge-Kutta time integration for a single time step.
Definition: VelocityFields.h:229
OPENVDB_USE_VERSION_NAMESPACE
#define OPENVDB_USE_VERSION_NAMESPACE
Definition: version.h:154
openvdb::v7_0::tools::DiscreteField::ValueType
VectorType::ValueType ValueType
Definition: VelocityFields.h:47
openvdb::v7_0::tools::VelocitySampler::sample
ValueType sample(const LocationType &world) const
Samples the velocity at world position onto result. Supports both staggered (i.e. MAC) and co-located...
Definition: VelocityFields.h:191
openvdb::v7_0::tools::DiscreteField::BOOST_STATIC_ASSERT
BOOST_STATIC_ASSERT(boost::is_floating_point< ValueType >::value)
openvdb::v7_0::tools::DiscreteField
Thin wrapper class for a velocity grid.
Definition: VelocityFields.h:44
openvdb::v7_0::tools::VelocityIntegrator::ElementType
VecType::ValueType ElementType
Definition: VelocityFields.h:218
openvdb::v7_0::math::Transform
Definition: Transform.h:40
openvdb::v7_0::tools::EnrightField::EnrightField
EnrightField()
Definition: VelocityFields.h:108
OPENVDB_VERSION_NAME
#define OPENVDB_VERSION_NAME
The version namespace name for this library version.
Definition: version.h:102
openvdb
Definition: Exceptions.h:13
openvdb::v7_0::tools::EnrightField::BOOST_STATIC_ASSERT
BOOST_STATIC_ASSERT(boost::is_floating_point< ScalarT >::value)
openvdb.h