octree_key.h

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#pragma once
 
#include <cstdint>
#include <cstring> // for memcpy
 
namespace pcl {
namespace octree {
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
/** \brief @b Octree key class
 *  \note Octree keys contain integer indices for each coordinate axis in order to
 * address an octree leaf node.
 * \author Julius Kammerl (julius@kammerl.de)
 */
//////////////////////////////////////////////////////////////////////////////////////////////////////////////////////
class OctreeKey {
public:
  /** \brief Empty constructor. */
  OctreeKey() : x(0), y(0), z(0) {}
 
  /** \brief Constructor for key initialization. */
  OctreeKey(unsigned int keyX, unsigned int keyY, unsigned int keyZ)
  : x(keyX), y(keyY), z(keyZ)
  {}
 
  /** \brief Copy constructor. */
  OctreeKey(const OctreeKey& source) { std::memcpy(key_, source.key_, sizeof(key_)); }
 
  OctreeKey&
  operator=(const OctreeKey&) = default;
 
  /** \brief Operator== for comparing octree keys with each other.
   *  \return "true" if leaf node indices are identical; "false" otherwise.
   * */
  bool
  operator==(const OctreeKey& b) const
  {
    return ((b.x == this->x) && (b.y == this->y) && (b.z == this->z));
  }
 
  /** \brief Inequal comparison operator
   * \param[in] other OctreeIteratorBase to compare with
   * \return "true" if the current and other iterators are different ; "false"
   * otherwise.
   */
  bool
  operator!=(const OctreeKey& other) const
  {
    return !operator==(other);
  }
 
  /** \brief Operator<= for comparing octree keys with each other.
   *  \return "true" if key indices are not greater than the key indices of b  ; "false"
   * otherwise.
   * */
  bool
  operator<=(const OctreeKey& b) const
  {
    return ((b.x >= this->x) && (b.y >= this->y) && (b.z >= this->z));
  }
 
  /** \brief Operator>= for comparing octree keys with each other.
   *  \return "true" if key indices are not smaller than the key indices of b  ; "false"
   * otherwise.
   * */
  bool
  operator>=(const OctreeKey& b) const
  {
    return ((b.x <= this->x) && (b.y <= this->y) && (b.z <= this->z));
  }
 
  /** \brief push a child node to the octree key
   *  \param[in] childIndex index of child node to be added (0-7)
   * */
  inline void
  pushBranch(unsigned char childIndex)
  {
    this->x = (this->x << 1) | (!!(childIndex & (1 << 2)));
    this->y = (this->y << 1) | (!!(childIndex & (1 << 1)));
    this->z = (this->z << 1) | (!!(childIndex & (1 << 0)));
  }
 
  /** \brief pop child node from octree key
   * */
  inline void
  popBranch()
  {
    this->x >>= 1;
    this->y >>= 1;
    this->z >>= 1;
  }
 
  /** \brief get child node index using depthMask
   *  \param[in] depthMask bit mask with single bit set at query depth
   *  \return child node index
   * */
  inline unsigned char
  getChildIdxWithDepthMask(unsigned int depthMask) const
  {
    return static_cast<unsigned char>(((!!(this->x & depthMask)) << 2) |
                                      ((!!(this->y & depthMask)) << 1) |
                                      (!!(this->z & depthMask)));
  }
 
  /* \brief maximum depth that can be addressed */
  static const unsigned char maxDepth =
      static_cast<unsigned char>(sizeof(std::uint32_t) * 8);
 
  // Indices addressing a voxel at (X, Y, Z)
 
  union {
    struct {
      std::uint32_t x;
      std::uint32_t y;
      std::uint32_t z;
    };
    std::uint32_t key_[3];
  };
};
} // namespace octree
} // namespace pcl