ArborX::BoundingVolumeHierarchy::BoundingVolumeHierarchy

ArborX / Spatial indexes / ArborX::BVH

ArborX::BVH<MemorySpace>::BVH

BVH() noexcept; // (1)

template <typename ExecutionSpace, typename Primitives>
BVH(ExecutionSpace const& space, Primitives const& primitives); // (2)

1. Default constructor. Constructs an empty tree.
2. Constructs a bounding volume hierarchy from the given data source.

Parameters

space : the execution space.
primitives : geometrical objects one wishes to index.

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 Primitives as the first template argument and ArborX::PrimitivesTag as second argument.
• The return type of ArborX::AccessTraits<Primitives,ArborX::PrimitivesTag>::get() must decay either to ArborX::Point or ArborX::Box. ArborX provides specializations for Kokkos views but a user may specialize it for their types.

Complexity

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

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 *> 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<memory_space> 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.