场景管理：八叉树算法C++实现

简单实现了场景管理八叉树算法

代码结构：

• object.h，object.cpp 被管理的对象类
• octree_node.h，octree_node.cpp 八叉树类
• main.cpp程序入口

object.h

#pragma once
/*
//被管理的对象类
*/
class Object
{
public:
	Object(float _x,float _y,float _z,float _xSize,float _ySize,float _zSize);
	~Object();
public:
	//对象的属性，例如坐标和长宽高，以左上角为锚点
	float x;
	float y;
	float z;
	float xSize;
	float ySize;
	float zSize;
};

object.cpp

#include "object.h"


Object::Object(float _x,float _y,float _z,float _xSize,float _ySize,float _zSize):
	x(_x),
	y(_y),
	z(_z),
	xSize(_xSize),
	ySize(_ySize),
	zSize(_zSize)
{
}


Object::~Object()
{
}

octree_node.h

/*
//八叉树节点类，用头节点代表八叉树
//采用opengl右手坐标系，靠近原点的那个角为锚点，方便计算
//本八叉树的策略是：1，一次划分所有节点，是满树；2，当立方体空间完全包含某物体才剔除,当立方体空间与某物体相交或者完全包含时才查询；3，对象放在完全包含它的区域叶子节点内，非根节点不存储对象，默认为物体不可能跨多个叶子节点，都在一个叶子节点的空间范围内部，未考虑交叉的情况
*/
#pragma once
#include 

//八叉树节点类型
enum OctreeType        
{
	ROOT,                   //根
	BOTTOM_LEFT_FRONT,		// 1 
	BOTTOM_RIGHT_FRONT,		// 2 
	BOTTOM_LEFT_BACK,		// 3 
	BOTTOM_RIGHT_BACK,      // 4 
	TOP_LEFT_FRONT,         // 5 
	TOP_RIGHT_FRONT,        // 6 
	TOP_LEFT_BACK,          // 7 
	TOP_RIGHT_BACK          // 8   
};

template 
class OctreeNode
{
public:
	OctreeNode(float _x,float _y,float _z,float _xSize,float _ySize,float _zSize,OctreeType _octreeNodeType,int _level,int _maxLevel);
	~OctreeNode();
public:
	void BuildTree(int level); //建立八叉树，划分到所有子节点
	void InsertObject(T *object); //插入对象
	std::list GetObjectsAt(float px,float py,float pz,float x_size,float y_size,float z_size); //查询对象,获得一片区域里的对象链表,考虑包含或相交,由于
	void RemoveObjectsAt(float px,float py,float pz,float x_size,float y_size,float z_size); //删除对象，删除一片区域里的对象，此处只考虑完全包含的
private:
	bool IsContain(float px,float py,float pz,float x_size,float y_size,float z_size,T *object) const; //判断某个区域是否包含某对象
	bool IsContain(float px,float py,float pz,float x_size,float y_size,float z_size,OctreeNode *octreeNode) const; //重载，判断某个区域是否包含某个节点
	bool IsInterSect(float px,float py,float pz,float x_size,float y_size,float z_size,OctreeNode *octreeNode) const; //判断某个区域是否与节点相交，如果相交，则查询时要递归到其子节点
public:
	std::list objectList; //节点存储的对象列表
private:
	//节点属性
	OctreeType octreeNodeType;
	float x;
	float y;
	float z;
	float xSize;
	float ySize;
	float zSize;
	int level;
	int maxLevel;
	//子节点,根据opengl坐标系，依次坐标增大
	OctreeNode *bottom_left_front_node;
	OctreeNode *bottom_right_front_node;
	OctreeNode *bottom_left_back_node;
	OctreeNode *bottom_right_back_node;
	OctreeNode *top_left_front_node;
	OctreeNode *top_right_front_node;
	OctreeNode *top_left_back_node;
	OctreeNode *top_right_back_node;
};

octree_node.cpp 

#include "octree_node.h"

template 
OctreeNode::OctreeNode(float _x,float _y,float _z,float _xSize,float _ySize,float _zSize,OctreeType _octreeNodeType,int _level,int _maxLevel):
	x(_x),
	y(_y),
	z(_z),
	xSize(_xSize),
	ySize(_ySize),
	zSize(_zSize),
	octreeNodeType(_octreeNodeType),
	level(_level),
	maxLevel(_maxLevel)
{
	//初始子节点都赋空值
	bottom_left_front_node=nullptr;
	bottom_right_front_node=nullptr;
	bottom_left_back_node=nullptr;
	bottom_right_back_node=nullptr;
	top_left_front_node=nullptr;
	top_right_front_node=nullptr;
	top_left_back_node=nullptr;
	top_right_back_node=nullptr;
}

template 
OctreeNode::~OctreeNode()
{
	
}

template 
bool OctreeNode::IsContain(float px,float py,float pz,float x_size,float y_size,float z_size,T *object) const
{
	if(object->x>=px
		&&object->x+object->xSize<=px+x_size
		&&object->y>=py
		&&object->y+object->ySize<=py+y_size
		&&object->z>=pz
		&&object->z+object->zSize<=pz+z_size)
		return true;
	return false;
}

template 
bool OctreeNode::IsContain(float px,float py,float pz,float x_size,float y_size,float z_size,OctreeNode *octreeNode) const
{
	if(octreeNode->x>=px
		&&octreeNode->x+octreeNode->xSize<=px+x_size
		&&octreeNode->y>=py
		&&octreeNode->y+octreeNode->ySize<=py+y_size
		&&octreeNode->z>=pz
		&&octreeNode->z+octreeNode->zSize<=pz+z_size)
		return true;
	return false;
}

template 
bool OctreeNode::IsInterSect(float px,float py,float pz,float x_size,float y_size,float z_size,OctreeNode *octreeNode) const
{
	if(octreeNode->x>px+x_size
		||octreeNode->x+xSizey>py+y_size
		||octreeNode->y+ySizez+zSizez>pz+z_size)
		return false;
	return true;
}

template 
void OctreeNode::BuildTree(int level)
{
	//递归地进行八叉树空间划分，直到最大深度
	if(level==maxLevel)
		return;
	//创建子节点
	bottom_left_front_node=new OctreeNode(x,y,z,xSize/2,ySize/2,zSize/2,BOTTOM_LEFT_FRONT,level+1,maxLevel);
	bottom_right_front_node=new OctreeNode(x+xSize/2,y,z,xSize/2,ySize/2,zSize/2,BOTTOM_RIGHT_FRONT,level+1,maxLevel);
	bottom_left_back_node=new OctreeNode(x,y+ySize/2,z,xSize/2,ySize/2,zSize/2,BOTTOM_LEFT_BACK,level+1,maxLevel);
	bottom_right_back_node=new OctreeNode(x+xSize/2,y+ySize/2,z,xSize/2,ySize/2,zSize/2,BOTTOM_RIGHT_BACK,level+1,maxLevel);
	top_left_front_node=new OctreeNode(x,y,z+zSize/2,xSize/2,ySize/2,zSize/2,TOP_LEFT_FRONT,level+1,maxLevel);
	top_right_front_node=new OctreeNode(x+xSize/2,y,z+zSize/2,xSize/2,ySize/2,zSize/2,TOP_RIGHT_FRONT,level+1,maxLevel);
	top_left_back_node=new OctreeNode(x,y+ySize/2,z+zSize/2,xSize/2,ySize/2,zSize/2,TOP_LEFT_BACK,level+1,maxLevel);
	top_right_back_node=new OctreeNode(x+xSize/2,y+ySize/2,z+zSize/2,xSize/2,ySize/2,zSize/2,TOP_RIGHT_BACK,level+1,maxLevel);
	//递归构造
	bottom_left_front_node->BuildTree(level+1);
	bottom_right_front_node->BuildTree(level+1);
	bottom_left_back_node->BuildTree(level+1);
	bottom_right_back_node->BuildTree(level+1);
	top_left_front_node->BuildTree(level+1);
	top_right_front_node->BuildTree(level+1);
	top_left_back_node->BuildTree(level+1);
	top_right_back_node->BuildTree(level+1);
}

template 
void OctreeNode::InsertObject(T *object)
{
	if(level==maxLevel)
	{
		objectList.push_back(object);
		return;
	}
	//递归地插入，直到叶子节点
	//1
	if(bottom_left_front_node&&IsContain(x,y,z,xSize/2,ySize/2,zSize/2,object))
	{
		bottom_left_front_node->InsertObject(object);
		return;
	}
	//2
	if(bottom_right_front_node&&IsContain(x+xSize/2,y,z,xSize/2,ySize/2,zSize/2,object))
	{
		bottom_right_front_node->InsertObject(object);
		return;
	}
	//3
	if(bottom_left_back_node&&IsContain(x,y+ySize/2,z,xSize/2,ySize/2,zSize/2,object))
	{
		bottom_left_back_node->InsertObject(object);
		return;
	}
	//4
	if(bottom_right_back_node&&IsContain(x+xSize/2,y+ySize/2,z,xSize/2,ySize/2,zSize/2,object))
	{
		bottom_right_back_node->InsertObject(object);
		return;
	}
	//5
	if(top_left_front_node&&IsContain(x,y,z+zSize/2,xSize/2,ySize/2,zSize/2,object))
	{
		top_left_front_node->InsertObject(object);
		return;
	}
	//6
	if(top_right_front_node&&IsContain(x+xSize/2,y,z+zSize/2,xSize/2,ySize/2,zSize/2,object))
	{
		top_right_front_node->InsertObject(object);
		return;
	}
	//7
	if(top_left_back_node&&IsContain(x,y+ySize/2,z+zSize/2,xSize/2,ySize/2,zSize/2,object))
	{
		top_left_back_node->InsertObject(object);
		return;
	}
	//8
	if(top_right_back_node&&IsContain(x+xSize/2,y+ySize/2,z+zSize/2,xSize/2,ySize/2,zSize/2,object))
	{
		top_right_back_node->InsertObject(object);
		return;
	}
}

template 
std::list OctreeNode::GetObjectsAt(float px,float py,float pz,float x_size,float y_size,float z_size)
{
	if(level==maxLevel)
		return objectList;
	std::list resObjects;
	//递归地判断选定区域是否与某个节点相交（包含或被包含都算）
	//1
	if(bottom_left_front_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,bottom_left_front_node))
	{
		std::list childObjects1=bottom_left_front_node->GetObjectsAt(px,py,pz,x_size,y_size,z_size);
		resObjects.insert(resObjects.end(),childObjects1.begin(),childObjects1.end());
	}
	//2
	if(bottom_right_front_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,bottom_right_front_node))
	{
		std::list childObjects2=bottom_right_front_node->GetObjectsAt(px,py,pz,x_size,y_size,z_size);
		resObjects.insert(resObjects.end(),childObjects2.begin(),childObjects2.end());
	}
	//3
	if(bottom_left_back_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,bottom_left_back_node))
	{
		std::list childObjects3=bottom_left_back_node->GetObjectsAt(px,py,pz,x_size,y_size,z_size);
		resObjects.insert(resObjects.end(),childObjects3.begin(),childObjects3.end());
	}
	//4
	if(bottom_right_back_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,bottom_right_back_node))
	{
		std::list childObjects4=bottom_right_back_node->GetObjectsAt(px,py,pz,x_size,y_size,z_size);
		resObjects.insert(resObjects.end(),childObjects4.begin(),childObjects4.end());
	}
	//5
	if(top_left_front_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,top_left_front_node))
	{
		std::list childObjects5=top_left_front_node->GetObjectsAt(px,py,pz,x_size,y_size,z_size);
		resObjects.insert(resObjects.end(),childObjects5.begin(),childObjects5.end());
	}
	//6
	if(top_right_front_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,top_right_front_node))
	{
		std::list childObjects6=top_right_front_node->GetObjectsAt(px,py,pz,x_size,y_size,z_size);
		resObjects.insert(resObjects.end(),childObjects6.begin(),childObjects6.end());
	}
	//7
	if(top_left_back_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,top_left_back_node))
	{
		std::list childObjects7=top_left_back_node->GetObjectsAt(px,py,pz,x_size,y_size,z_size);
		resObjects.insert(resObjects.end(),childObjects7.begin(),childObjects7.end());
	}
	//8
	if(top_right_back_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,top_right_back_node))
	{
		std::list childObjects8=top_right_back_node->GetObjectsAt(px,py,pz,x_size,y_size,z_size);
		resObjects.insert(resObjects.end(),childObjects8.begin(),childObjects8.end());
	}

	return resObjects;
}

template 
void OctreeNode::RemoveObjectsAt(float px,float py,float pz,float x_size,float y_size,float z_size)
{
	if(level==maxLevel)
	{
		if(IsContain(px,py,pz,x_size,y_size,z_size,this))
			objectList.clear(); //到了叶子节点且完全被包含就把该节点存储的对象清空
		return;
	}
	//递归地判断选定区域是否与某个节点相交（包含或被包含都算）,没有相交就不用再递归了
	//1
	if(bottom_left_front_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,bottom_left_front_node))
		bottom_left_front_node->RemoveObjectsAt(px,py,pz,x_size,y_size,z_size);
	//2
	if(bottom_right_front_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,bottom_right_front_node))
		bottom_right_front_node->RemoveObjectsAt(px,py,pz,x_size,y_size,z_size);
	//3
	if(bottom_left_back_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,bottom_left_back_node))
		bottom_left_back_node->RemoveObjectsAt(px,py,pz,x_size,y_size,z_size);
	//4
	if(bottom_right_back_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,bottom_right_back_node))
		bottom_right_back_node->RemoveObjectsAt(px,py,pz,x_size,y_size,z_size);
	//5
	if(top_left_front_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,top_left_front_node))
		top_left_front_node->RemoveObjectsAt(px,py,pz,x_size,y_size,z_size);
	//6
	if(top_right_front_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,top_right_front_node))
		top_right_front_node->RemoveObjectsAt(px,py,pz,x_size,y_size,z_size);
	//7
	if(top_left_back_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,top_left_back_node))
		top_left_back_node->RemoveObjectsAt(px,py,pz,x_size,y_size,z_size);
	//8
	if(top_right_back_node&&IsInterSect(px,py,pz,x_size,y_size,z_size,top_right_back_node))
		top_right_back_node->RemoveObjectsAt(px,py,pz,x_size,y_size,z_size);
}

main.cpp

#include 
#include "object.h"
#include "octree_node.h"
#include "octree_node.cpp" //模板分开写要包含h和cpp
using namespace std;
int main()
{
	OctreeNode