ArborX::BoundingVolumeHierarchy::BoundingVolumeHierarchy

ArborX / Spatial indexes / ArborX::BVH

ArborX::BVH<MemorySpace, Value, IndexableGetter, BoundingVolume>::BVH

BVH() noexcept; // (1)

template <typename ExecutionSpace, typename Values>
BVH(ExecutionSpace const& space, Values const& values); // (2)

template <typename ExecutionSpace, typename Values>
BVH(ExecutionSpace const& space, Values const& values, IndexableGetter const& indexable_getter); // (3)

1. Default constructor. Constructs an empty tree.
2. Constructs a bounding volume hierarchy from a given data source.
3. Constructs a bounding volume hierarchy from a given data source and a function tranforming a value into indexable.

Parameters

space: execution space values: values stored in the container indexable_getter: a function object to transform a value into an indexable

Type requirements

• MemorySpace must be accessible from ExecutionSpace (i.e., Kokkos::SpaceAccessibility<ExecutionSpace, MemorySpace>::accessible must be true).
• A specialization of ArborX::AccessTraits must match Values as the template argument.
• The return type of ArborX::AccessTraits<Values, ArborX::PrimitivesTag>::get() must decay to Value. ArborX provides specializations for Kokkos views but a user may specialize it for their types.
• IndexableGetter must provide an operator() taking in a type that decays to Value and returning an indexable (geometric object).

Complexity

O(N log N), where N is the number of primitives passed to the constructor (ArborX::AccessTraits<Values, ArborX::PrimitivesTag>::size(values)).

Exceptions

Memory allocation with Kokkos may throw.

Notes

Example

#include <ArborX_LinearBVH.hpp>

#include <Kokkos_Core.hpp>

#include <iostream>

std::ostream &operator<<(std::ostream &os, ArborX::Point const &p)
{
  os << '(' << p[0] << ',' << p[1] << ',' << p[2] << ')';
  return os;
}

int main(int argc, char *argv[])
{
  Kokkos::ScopeGuard guard(argc, argv);

  Kokkos::View<ArborX::Point<3> *> cloud("point_cloud", 1000);
  Kokkos::parallel_for(1000, KOKKOS_LAMBDA(int i) {
    cloud[i] = {(float)i, (float)i, (float)i};
  });

  using memory_space = decltype(cloud)::memory_space; // where to store the tree
  using execution_space = decltype(cloud)::execution_space; // where to execute code
  ArborX::BVH bvh{execution_space{}, cloud};

  auto const box = bvh.bounds();
  std::cout << box.minCorner() << " - " << box.maxCorner() << '\n';

  return 0;
}

Output

(0,0,0) - (999,999,999)

See also

query : search for all primitives that meet some predicates. bounds : returns the bounding volume that contains all leaves.