pcl outofcore源码解析

PCL（Point Cloud Library）是一个开源的、跨平台的点云处理框架，它提供了大量的点云处理算法和工具，其中之一就是 Out-of-Core（OOC）模块。OOC模块可以在内存不足的情况下处理大规模点云数据，它将点云数据分成多个块（chunks）进行处理，每个块可以被存储到硬盘上，不需要全部加载到内存中。

Out-of-Core模块的源代码位于PCL库的pcl/outofcore目录下，它包含了多个类和文件，其中最核心的是OutofcoreOctree类。下面是OutofcoreOctree类的主要代码结构和功能解析：

1. 类定义:

template<typename Container, typename PointT, typename LeafT>
class OutofcoreOctreeBaseNode;

template<typename Container, typename PointT, typename LeafT>
class OutofcoreOctreeAbstractNode;

template<typename Container, typename PointT, typename LeafT>
class OutofcoreOctreeDiskContainer;

template<typename Container, typename PointT, typename LeafT>
class OutofcoreOctreeRamContainer;

template<typename Container, typename PointT, typename LeafT>
class OutofcoreOctreeBase;

template<typename PointT, typename LeafT>
class OutofcoreOctreeBaseNode<OutofcoreOctreeBase<OutofcoreOctreeDiskContainer<OutofcoreOctreeBaseNode<OutofcoreOctreeDiskContainer<PointT>, PointT, LeafT>, PointT, LeafT> >, PointT, LeafT>;

template<typename PointT, typename LeafT>
class OutofcoreOctreeBaseNode<OutofcoreOctreeBase<OutofcoreOctreeRamContainer<OutofcoreOctreeBaseNode<OutofcoreOctreeRamContainer<PointT>, PointT, LeafT>, PointT, LeafT> >, PointT, LeafT>;

template<typename PointT, typename LeafT>
class OutofcoreOctreeBase<OutofcoreOctreeDiskContainer<OutofcoreOctreeBaseNode<OutofcoreOctreeDiskContainer<PointT>, PointT, LeafT>, PointT, LeafT> >;

template<typename PointT, typename LeafT>
class OutofcoreOctreeBase<OutofcoreOctreeRamContainer<OutofcoreOctreeBaseNode<OutofcoreOctreeRamContainer<PointT>, PointT, LeafT>, PointT, LeafT> >;

template<typename PointT, typename LeafT>
class OutofcoreOctreeDiskContainer<OutofcoreOctreeBaseNode<OutofcoreOctreeDiskContainer<PointT>, PointT, LeafT>, PointT, LeafT>;

template<typename PointT, typename LeafT>
class OutofcoreOctreeRamContainer<OutofcoreOctreeBaseNode<OutofcoreOctreeRamContainer<PointT>, PointT, LeafT>, PointT, LeafT>;

template<typename PointT, typename LeafT>
class OutofcoreOctreeDiskContainer<boost::shared_ptr<OutofcoreOctreeBaseNode<OutofcoreOctreeDiskContainer<PointT>, PointT, LeafT> >, PointT, LeafT>;

template<typename PointT, typename LeafT>
class OutofcoreOctreeRamContainer<boost::shared_ptr<OutofcoreOctreeBaseNode<OutofcoreOctreeRamContainer<PointT>, PointT, LeafT> >, PointT, LeafT>;

template<typename Container, typename PointT, typename LeafT>
class OutofcoreOctreeBaseNode
{
};

template<typename Container, typename PointT, typename LeafT>
class OutofcoreOctreeAbstractNode
{
};

template<typename Container, typename PointT, typename LeafT>
class OutofcoreOctreeDiskContainer
{
};

template<typename Container, typename PointT, typename LeafT>
class OutofcoreOctreeRamContainer
{
};

template<typename Container, typename PointT, typename LeafT>
class OutofcoreOctreeBase
{
};

2. OutofcoreOctreeBaseNode类：

OutofcoreOctreeBaseNode是OutofcoreOctree模块的最基本的节点类型，它是一个模板类，需要指定点云数据容器类型(Container)、点云类型(PointT)和叶子节点类型(LeafT)。OutofcoreOctreeBaseNode类定义了节点的基本属性和行为，例如节点的索引、节点的深度、节点的父节点和子节点等。OutofcoreOctreeBaseNode还提供了一些方法，如添加点云数据、获取包围盒等。

3. OutofcoreOctreeAbstractNode类：

OutofcoreOctreeAbstractNode类是OutofcoreOctreeBaseNode类的基类，它定义了纯虚函数，需要在子类中实现。OutofcoreOctreeAbstractNode类主要提供了节点的一些抽象方法，如获取节点的包围盒、获取节点的点云数据等。

4. OutofcoreOctreeDiskContainer类和OutofcoreOctreeRamContainer类：

OutofcoreOctreeDiskContainer类和OutofcoreOctreeRamContainer类是点云数据容器类，它们分别用于处理硬盘存储和内存存储的点云数据。这两个类都继承自OutofcoreOctreeAbstractNode类，因此都需要实现OutofcoreOctreeAbstractNode类中的纯虚函数。OutofcoreOctreeDiskContainer类和OutofcoreOctreeRamContainer类都提供了一些方法，如添加点云数据、获取包围盒等。

5. OutofcoreOctreeBase类：

OutofcoreOctreeBase类是OutofcoreOctree模块的主要类，它是一个模板类，需要指定点云数据容器类型(Container)、点云类型(PointT)和叶子节点类型(LeafT)。OutofcoreOctreeBase类封装了OutofcoreOctreeBaseNode类和OutofcoreOctreeAbstractNode类的一些方法，提供了一些高级的功能，如点云数据的读取、写入、压缩、解压等。OutofcoreOctreeBase类还提供了一些方法，如获取节点、获取包围盒等。

总体来说，Out-of-Core模块的源代码结构比较复杂，涉及到多个类和文件，但其核心代码就是OutofcoreOctree类。OutofcoreOctree类的实现非常精简和高效，它通过将点云数据分块存储到硬盘上，实现了对大规模点云数据的高效处理。