class cGameHost : public CD3DApplication, public cSingleton<cGameHost>{。。。。。。    cSceneNode        m_rootNode;//场景树根节点    cCamera            m_defaultCamera;    cCamera*        m_pActiveCamera;    cQuadTree        m_quadTree;//四叉树    cRect3d            m_worldExtents;

    tchar    m_rootPath[MAX_PATH];

bool    m_frameReady;

// Invalid Functions...    cGameHost(const cGameHost& Src);    cGameHost& operator=(const cGameHost& Src);};

class cSceneObject : public cSceneNode{    。。。。。。void attachToQuadTree(cQuadTree* parentTree);//挂接到四叉树

    cQuadTreeNode* quadTreeNode()const;    u32Flags zMask()const;    cSceneObject* forwardTreeLink()const;    cSceneObject* rearTreeLink()const;

const cRect3d& localBounds()const;const cRect3d& worldBounds()const;

//// temporary functions//    void setWorldBounds(const cRect3d& box)    {        m_worldBounds = box;    }

private:

// bounding box information    u32Flags m_objectFlags;    cRect3d m_localBounds;    cRect3d m_worldBounds;

// world QuadTree membership information    cQuadTree*        m_pQuadTree;    cQuadTreeNode*  m_pQuadTreeNode;    u32Flags        m_quadTreeZMask;    cSceneObject*    m_pForwardTreeLink;    cSceneObject*    m_pRearTreeLink;

// QuadTree search result links    cSceneObject*    m_pForwardSearchLink;    cSceneObject*    m_pRearSearchLink;

// private functions    void setForwardSearchLink(cSceneObject* pForwardLink);void setRearSearchLink(cSceneObject* pForwardLink);virtual void refreshQuadTreeMembership();

    friend cQuadTreeNode;void setQuadTreeData(cQuadTreeNode* parentNode, u32Flags zMask);void setForwardTreeLink(cSceneObject* link);void setRearTreeLink(cSceneObject* link);};

class cQuadTree{public:

// Data Types & Constants...    enum eConstants    {        k_minimumTreeDepth = 1,         k_maximumTreeDepth = 9, //  must be a value between 1 and 9    };

// Public Data...

// Creators...

    cQuadTree();    ~cQuadTree();

void create(const cRect3d& worldExtents, int depth);void destroy();

// Operators...

// Mutators...    cSceneObject* buildSearchResults(const cRect3d& worldRect, const cFrustum* pOptionalFrustum=0); //四叉树搜索，即剪裁，可以选用视锥体和包围盒    u32Flags addOrUpdateSceneObject(cSceneObject* newNode);

// Accessors...    bool isReady()const;

private:

// Private Data...    cQuadTreeNode* m_levelNodes[k_maximumTreeDepth];//四叉树节点2维数组    cVector3 m_worldExtents;    cVector3 m_worldScale;    cVector3 m_worldOffset;int m_depth;    uint32 m_memorySize;

// Private Functions...    void findTreeNodeInfo(const cQuadTreeRect& worldByteRect, int& level, int& levelX, int& levelY);    cQuadTreeNode* findTreeNode(const cQuadTreeRect& worldByteRect);    cQuadTreeNode* getNodeFromLevelXY(int level, int x, int y);void buildByteRect(const cRect3d& worldRect, cQuadTreeRect& worldByteRect);};

class cQuadTreeNode{public:

    cQuadTreeNode();    ~cQuadTreeNode();

    uint32 addOrUpdateMember(cSceneObject* member, const cQuadTreeRect& rect);void removeMember(cSceneObject* member);

void testLocalMembersForSearchResults(        cSceneObject** pResultList,         cSceneObject** pResultListTail,         u32Flags zMask, float zMin, float zMax,const cFrustum* pOptionalFrustum=0);

void testLocalMembersForSearchResults(        cSceneObject** pResultList,         cSceneObject** pResultListTail,         u32Flags zMask, const cRect3d& trueRect,const cFrustum* pOptionalFrustum=0);

bool empty()const;    u32Flags zMask()const;    u32Flags zLocalMask()const;

private:

// Private Data...    cQuadTreeNode* m_pChildNode[4];//子节点    cQuadTreeNode* m_pParentNode;    cSceneObject* m_pFirstMember;//挂接的cSceneObject列表

    u32Flags m_zLocalMask;    u32Flags m_zMask;

// Private Functions...    void descendantMemberAdded(u32Flags zMask);void descendantMemberRemoved();void rebuildLocalZMask();void rebuildZMask();

// functions available to the quad tree    friend cQuadTree;void setup(cQuadTreeNode* parent, cQuadTreeNode* child0, cQuadTreeNode* child1, cQuadTreeNode* child2, cQuadTreeNode* child3);//在四叉树上配置节点};