source: GTP/trunk/Lib/Vis/Preprocessing/src/VspKdTree.h @ 2015

// ================================================================
// $Id$
// ****************************************************************
// 
// Initial coding by
/**
   @author Jiri Bittner
*/

#ifndef __VSPKDTREE_H__
#define __VSPKDTREE_H__

// Standard headers
#include <iomanip>
#include <vector>
#include <functional>
#include <stack>


// User headers
#include "VssRay.h"
#include "AxisAlignedBox3.h"


#define USE_KDNODE_VECTORS 1
#define _RSS_STATISTICS
#define _RSS_TRAVERSAL_STATISTICS


#include "Statistics.h"
#include "Ray.h"

#include "RayInfo.h"
#include "Containers.h"
#include "ViewCell.h"


namespace GtpVisibilityPreprocessor {

class VspKdLeaf;
class ViewCellsManager;
class ViewCellsStatistics;

/**
        Candidate for leaf merging based on priority.
*/
class VspKdMergeCandidate
{  
public:

        VspKdMergeCandidate(VspKdLeaf *l1, VspKdLeaf *l2);

        /** Computes PVS difference between the leaves.
        */
        //int ComputePvsDifference() const;

        /** If this merge pair is still valid.
        */
        bool Valid() const;

        /** Sets this merge candidate to be valid.
        */
        void SetValid();

        friend bool operator<(const VspKdMergeCandidate &leafa, const VspKdMergeCandidate &leafb)
        {
                return leafb.GetMergeCost() < leafa.GetMergeCost();
        }

        void SetLeaf1(VspKdLeaf *l);
        void SetLeaf2(VspKdLeaf *l);

        VspKdLeaf *GetLeaf1();
        VspKdLeaf *GetLeaf2();

        /** Merge cost of this candidate pair.
        */
        float GetMergeCost() const;

        /** Returns cost of leaf 1.
        */
        float GetLeaf1Cost() const;
        /** Returns cost of leaf 2.
        */
        float GetLeaf2Cost() const;

        /// maximal pvs size
        static int sMaxPvsSize;
        /// overall cost used to normalize cost ratio
        static float sOverallCost;

protected:
        
        /** Evaluates the merge costs of the leaves.
        */
        void EvalMergeCost();

        int mLeaf1Id;
        int mLeaf2Id;

        float mMergeCost;
        
        VspKdLeaf *mLeaf1;
        VspKdLeaf *mLeaf2;
};



/**
        Static statistics for vsp kd-tree search
*/
class VspKdStatistics:  public StatisticsBase
{
public:  
        // total number of nodes
        int nodes;
        // number of splits along each of the axes
        int splits[3];
        // totals number of rays
        int rays;
        // initial size of the pvs
        int initialPvsSize;
        // total number of query domains
        int queryDomains;
        // total number of ray references
        int rayRefs;

        // max depth nodes
        int maxDepthNodes;
        // max depth nodes
        int minPvsNodes;
        // nodes with minimum PVS
        int minRaysNodes;
        // max ray contribution nodes
        int maxRayContribNodes;
        // max depth nodes
        int minSizeNodes;
        
        // max number of rays per node
        int maxRayRefs;
        // maximal PVS size / leaf
        int maxPvsSize;

        // max cost ratio
        int maxCostNodes;

        // number of dynamically added ray refs
        int addedRayRefs;
        // number of dynamically removed ray refs
        int removedRayRefs;
  
        /// for average pvs
        int accPvsSize;

        /** Default constructor.
        */
        VspKdStatistics() {     Reset(); }
        int Nodes() const { return nodes; }
        int Interior() const { return nodes / 2; }
        int Leaves() const { return (nodes / 2) + 1; }

        void Reset() 
        {
                nodes = 0;

                for (int i=0; i<3; i++)
                        splits[i] = 0;

                rays = queryDomains = 0;
                rayRefs = 0;
                
                maxDepthNodes = 0;
                minPvsNodes = 0;
                minRaysNodes = 0;
                maxRayContribNodes = 0;
                minSizeNodes = 0;
                maxCostNodes = 0;

                maxRayRefs = 0;
                addedRayRefs = removedRayRefs = 0;
                
                initialPvsSize = 0;
                maxPvsSize = 0;
                accPvsSize = 0;
        }

        void Print(ostream &app) const;
        friend ostream &operator<<(ostream &s, const VspKdStatistics &stat) 
        {
            stat.Print(s);
            return s;
        }  
};


class VspKdInterior;


/** Abstract superclass of Vsp-Kd-Tree nodes.
*/
class VspKdNode
{
public:

        friend class VspKdTree;

        enum {EInterior, EIntermediate, ELeaf};

        /** Constructs new interior node from the parent node.
        */
        inline VspKdNode(VspKdNode *p);

        /** Destroys this node and the subtree.
        */
        virtual ~VspKdNode();

        /** Type of the node (Einterior or ELeaf)
        */
        virtual int Type() const = 0;
 
        /** Returns true if this node is a leaf.
        */
        bool IsLeaf() const;
        
        /** Prints node stats.
        */
        virtual void Print(ostream &s) const = 0;

        /** Returns time needed to access this node.
                @NOTE: don't really know how it is used!
        */
        virtual int GetAccessTime(); 

        /** Returns parent node.
        */
        VspKdNode *GetParent() const;

        /** Sets parent node.
        */
        void SetParent(VspKdNode *p);

protected:
        /////////////////////////////////
        // The actual data goes here
  
        /// link to the parent
        VspKdNode *mParent;

        enum {SPLIT_X = 0, SPLIT_Y, SPLIT_Z};
  
        /// splitting axis
        char mAxis;
        
        /// depth
        unsigned char mDepth;
};

// --------------------------------------------------------------
// KD-tree node - interior node
// --------------------------------------------------------------
class VspKdInterior: public VspKdNode
{
public:
        friend class VspKdTree;

        /** Constructs new interior node from parent node.
        */
        VspKdInterior(VspKdInterior *p);
                        
        virtual int GetAccessTime();
        
        virtual int Type() const;
  
        virtual ~VspKdInterior();
    
        virtual void Print(ostream &s) const;

        /** Returns back child.
        */
        VspKdNode *GetBack() const;
        /** Returns front child.
        */
        VspKdNode *GetFront() const;

protected:

        /** Sets pointers to back child and front child.
        */
        void SetupChildLinks(VspKdNode *b, VspKdNode *f);
        /** Replaces the pointer to oldChild with a pointer to newChild.
        */
        void ReplaceChildLink(VspKdNode *oldChild, VspKdNode *newChild);
        /** Computes intersection of the ray with the node boundaries.
        */
        int ComputeRayIntersection(const RayInfo &rayData, float &t);

        // plane in local modelling coordinates
        float mPosition;

        // pointers to children
        VspKdNode *mBack;
        VspKdNode *mFront;

        // the bbox of the node
        AxisAlignedBox3 mBox;

        // data for caching
        long mAccesses;
        long mLastAccessTime;
};


/**
        Node type just before leaf holding abitrary split plane
*/
class VspKdIntermediate: public VspKdNode
{
public:
        friend class VspKdTree;

        /** Constructs new interior node from parent node.
        */
        VspKdIntermediate(VspKdInterior *p);
                        
        //virtual int GetAccessTime();
        
        virtual int Type() const;
  
        virtual ~VspKdIntermediate();
    
        virtual void Print(ostream &s) const;

        /** Returns back child.
        */
        inline VspKdLeaf *GetBack() const;
        /** Returns front child.
        */
        inline VspKdLeaf *GetFront() const;

protected:

        /** Sets pointers to back child and front child.
        */
        void SetupChildLinks(VspKdLeaf *b, VspKdLeaf *f);
        /** Computes intersection of the ray with the node boundaries.
        */
        int ComputeRayIntersection(const RayInfo &rayData, float &t);

        // plane in local modelling coordinates
        Plane3 mSplitPlane;

        // pointers to children
        VspKdLeaf *mBack;
        VspKdLeaf *mFront;

        // the bbox of the node
        AxisAlignedBox3 mBox;

        // data for caching
        long mAccesses;
        long mLastAccessTime;
};

// --------------------------------------------------------------
// KD-tree node - leaf node
// --------------------------------------------------------------
class VspKdLeaf: public VspKdNode
{
public:

        friend class VspKdTree;

        /** Constructs leaf from parent node.
                @param p the parent node
                @param nRays preallocates memory to store this number of rays
                @parma maxMisses how many times the max cost ratio was missed on the path to the leaf
        */
        VspKdLeaf(VspKdNode *p, const int nRays, const int maxCostMisses = 0);
        
        virtual ~VspKdLeaf();

        virtual int Type() const;  

        virtual void Print(ostream &s) const;
  
        /** Adds a ray to the leaf ray container.
        */
        void AddRay(const RayInfo &data);
        /** Returns size of the leaf PVS as induced by the rays
                @note returns precomputed PVS size, which may not be valid
                anymore. Run UpdatePvsSize to get a valid PVS.
        */
        int GetPvsSize() const;

        /** If PVS is not valid, this function recomputes the leaf 
                PVS as induced by the rays.
        */
        void UpdatePvsSize();

        /** Returns stored rays.
        */
        RayInfoContainer &GetRays();

        /** Returns rays into this ray container.
        */
        void GetRays(VssRayContainer &rays);
        /** Returns average contribution of a ray to the PVS
        */
        inline float GetAvgRayContribution() const;
        /** Returns square of average contribution of a ray.
        */
        inline float GetSqrRayContribution() const;

        /** Extracts PVS from ray set.
        */
        void ExtractPvs(ObjectContainer &objects) const;

        //-- mailing options
        void Mail();

        bool Mailed() const;
  
        /** Returns true if mail equals the leaf mail box.
        */
        bool Mailed(const int mail) const;

        void SetViewCell(VspKdViewCell *viewCell);

        /** Returns mail box of this leaf.
        */
        int GetMailbox() const;

        /** Returns view cell associated with this leaf.
        */
  VspKdViewCell *GetViewCell() {
        return mViewCell;
  }

        /** Returns number of times the max cost ratio was missed until
                this leaf.
        */
        int GetMaxCostMisses();

        ////////////////////////////////////////////
        
        static void NewMail();
        static int sMailId;

        ObjectPvs *mPvs;
        float mVolume;

protected:

        /** Manually sets PVS size.
                @param s the PVS size
        */
        void SetPvsSize(const int s);

        int mMailbox;
  
        /// rays intersecting this leaf.
        RayInfoContainer mRays;
        /// true if mPvsSize is valid => PVS does not have to be updated
        bool mValidPvs;
        /// the view cell associated with this leaf
        VspKdViewCell *mViewCell;
        /// number of times the max cost ratio was missed on the way to the leaf.
        int mMaxCostMisses;

//private:
        /// stores PVS size so we have to evaluate PVS size only once
        int mPvsSize;
};


// ---------------------------------------------------------------
// Main LSDS search class
// ---------------------------------------------------------------
class VspKdTree
{
        // --------------------------------------------------------------
        // For sorting rays
        // -------------------------------------------------------------
        struct SortableEntry
        {
                enum EType 
                {
                        ERayMin,
                        ERayMax
                };

                int type;
                float value;
                VssRay *ray;
  
                SortableEntry() {}
                SortableEntry(const int t, const float v, VssRay *r): type(t),
                                          value(v), ray(r) 
                {
                }
                
                friend bool operator<(const SortableEntry &a, const SortableEntry &b) 
                {
                        return a.value < b.value;
                }
        };

        struct TraversalData
        {  
                VspKdNode *mNode;
                AxisAlignedBox3 mBox;
                //TODO PolygonContainer *mPolys;

                int mDepth;
                //float mPriority;
        
                TraversalData() {}

                TraversalData(VspKdNode *n, const float p):
                mNode(n)//, mPriority(p)
                {}

                TraversalData(VspKdNode *n,     const AxisAlignedBox3 &b, const int d):
                mNode(n), mBox(b), mDepth(d) {}
    
                // comparator for the priority queue
                /*struct less_priority : public binary_function<const TraversalData, const TraversalData, bool> 
                {
                        bool operator()(const TraversalData a, const TraversalData b) {                 
                        return a.mPriority < b.mPriority;               }       };*/

                //    ~TraversalData() {}
                //    TraversalData(const TraversalData &s):node(s.node), bbox(s.bbox), depth(s.depth) {}
    
        friend bool operator<(const TraversalData &a, const TraversalData &b) 
                {
                        // return a.node->queries.size() < b.node->queries.size();
                        VspKdLeaf *leafa = dynamic_cast<VspKdLeaf *>(a.mNode);
                        VspKdLeaf *leafb = dynamic_cast<VspKdLeaf *>(b.mNode);
#if 0
                        return
                                leafa->rays.size() * a.mBox.GetVolume()
                                <
                                leafb->rays.size() * b.mBox.GetVolume();
#endif
#if 0
                        return
                                leafa->GetPvsSize() * a.mBox.GetVolume()
                                <
                                leafb->GetPvsSize() * b.mBox.GetVolume();
#endif
#if 0
                        return
                                leafa->GetPvsSize()
                                <
                                leafb->GetPvsSize();
#endif
#if 0
                        return
                                leafa->GetPvsSize() / (float)(leafa->rays.size() + Limits::Small())
                                >
                                leafb->GetPvsSize() / (float)(leafb->rays.size() + Limits::Small());
#endif
#if 0
                        return
                                leafa->GetPvsSize() * (float)leafa->rays.size()
                                <
                                leafb->GetPvsSize() * (float)leafb->rays.size();
#endif
#if 1
                        return a.mDepth > b.mDepth;
#endif
                }
        };
  
        /** Simplified data for ray traversal only.
        */
        struct RayTraversalData 
        {
                RayInfo mRayData;
                VspKdNode *mNode;

                RayTraversalData() {}
          
                RayTraversalData(VspKdNode *n, const RayInfo &data):
                mRayData(data), mNode(n) {}
        };
        
        struct LineTraversalData 
        {
                VspKdNode *mNode;
                Vector3 mExitPoint;
                
                float mMaxT;
    
                LineTraversalData () {}
                LineTraversalData (VspKdNode *n, const Vector3 &p, const float maxt):
                mNode(n), mExitPoint(p), mMaxT(maxt) {}
        };

public:

        VspKdTree();
        virtual ~VspKdTree();

        virtual void Construct(const VssRayContainer &rays,
                                                   AxisAlignedBox3 *forcedBoundingBox = NULL);

        /** Returns bounding box of the specified node.
        */
        AxisAlignedBox3 GetBBox(VspKdNode *node) const;

        const VspKdStatistics &GetStatistics() const;

        /** Get the root of the tree.
        */
        VspKdNode *GetRoot() const;

        /** Returns average PVS size in tree.
        */
        float GetAvgPvsSize();

        /** Returns memory usage in MB.
        */
        float GetMemUsage() const;
        //?
        float GetRayMemUsage() const;

        /** Collects leaves of this tree.
        */
        void CollectLeaves(vector<VspKdLeaf *> &leaves) const;

        /** Merges view cells created with this tree according to 
                some (global) cost heuristics.
        */
        int MergeViewCells(const VssRayContainer &rays);

        /** Finds neighbours of this node.
                @param n the input node
                @param neighbours the neighbors of the input node
                @param onlyUnmailed if only unmailed neighbors are collected
        */
        int FindNeighbors(VspKdLeaf *n, 
                                          vector<VspKdLeaf *> &neighbors, 
                                          bool onlyUnmailed);

        
        /** Sets pointer to view cells manager.
        */
        void SetViewCellsManager(ViewCellsManager *vcm);

        /** A ray is cast possible intersecting the tree.
                @param the ray that is cast.
                @returns the number of intersections with objects stored in the tree.
        */
        int CastLineSegment(const Vector3 &origin,
                                                const Vector3 &termination,
                                                vector<ViewCell *> &viewcells);

        /** Collects view cells generated by this tree.
        */
        void CollectViewCells(ViewCellContainer &viewCells) const;
        
        /** Refines view cells using shuffling, i.e., border leaves 
                of two view cells are exchanged if the resulting view cells
                are tested to be "better" than the old ones.
                @returns number of refined view cells
        */
        int RefineViewCells(const VssRayContainer &rays);

        /** Collects candidates for the merge in the merge queue.
        */
        void CollectMergeCandidates();

        /** Collapses the tree with respect to the view cell partition.
                @returns number of collapsed nodes
        */
        int CollapseTree();

protected:

        /** Collapses the tree with respect to the view cell partition,
                i.e. leaves having the same view cell are collapsed.
                @param node the root of the subtree to be collapsed
                @param collapsed returns the number of collapsed nodes
                @returns node of type leaf if the node could be collapsed, 
                this node otherwise
        */
        VspKdNode *CollapseTree(VspKdNode *node, int &collapsed);

        // incremental construction
        virtual void UpdateRays(VssRayContainer &remove, VssRayContainer &add);

        virtual void AddRays(VssRayContainer &add);

        VspKdNode *Locate(const Vector3 &v);
        
        VspKdNode *SubdivideNode(VspKdLeaf *leaf,
                                                                 const AxisAlignedBox3 &box,
                                                                 AxisAlignedBox3 &backBox,
                                                                 AxisAlignedBox3 &frontBox);
        
        VspKdNode *Subdivide(const TraversalData &tdata);
        
        int SelectPlane(VspKdLeaf *leaf,
                                        const AxisAlignedBox3 &box,
                                        float &position,
                                        int &raysBack,
                                        int &raysFront,
                                        int &pvsBack,
                                        int &pvsFront);

        void SortSplitCandidates(VspKdLeaf *node,
                                                         const int axis);       
  
        float BestCostRatioHeuristic(VspKdLeaf *node,
                                                                 const AxisAlignedBox3 &box,
                                                                 int &axis,
                                                                 float &position,
                                                                 int &raysBack,
                                                                 int &raysFront,
                                                                 int &pvsBack,
                                                                 int &pvsFront);

        float BestCostRatioRegular(VspKdLeaf *node,
                                                           const AxisAlignedBox3 &box,
                                                           int &axis,
                                                           float &position,
                                                           int &raysBack,
                                                           int &raysFront,
                                                           int &pvsBack,
                                                           int &pvsFront);
        
        float EvalCostRatio(VspKdLeaf *node,
                                                const AxisAlignedBox3 &box,
                                                const int axis,
                                                const float position,
                                                int &raysBack,
                                                int &raysFront,
                                                int &pvsBack,
                                                int &pvsFront);


        VspKdNode * SubdivideLeaf(VspKdLeaf *leaf,
                                                                  const float SAThreshold);

        void RemoveRay(VssRay *ray,
                                   vector<VspKdLeaf *> *affectedLeaves,
                                   const bool removeAllScheduledRays);

        void AddRay(VssRay *ray);
        
        void TraverseInternalNode(RayTraversalData &data,
                                                         stack<RayTraversalData> &tstack);

        void EvaluateLeafStats(const TraversalData &data);


        int     GetRootPvsSize() const;
        
        int     GetPvsSize(VspKdNode *node, const AxisAlignedBox3 &box) const;

        void GetRayContributionStatistics(float &minRayContribution,
                                                                          float &maxRayContribution,
                                                                          float &avgRayContribution);

        int GenerateRays(const float ratioPerLeaf,
                                         SimpleRayContainer &rays);

        /** Collapses this subtree and releases the memory.
                @returns number of collapsed rays.
        */
        int CollapseSubtree(VspKdNode *sroot, const int time);
        
        int ReleaseMemory(const int time);

        bool TerminationCriteriaMet(const VspKdLeaf *leaf, 
                                                                const AxisAlignedBox3 &box) const;

        /** Computes PVS size of this node given a global ray set.
                @returns PVS size of the intersection of this node bounding box with the rays.
        */
        int ComputePvsSize(VspKdNode *node, 
                                           const RayInfoContainer &globalRays) const;


        /** Generates view cell for this leaf taking the ray contributions.
        */
        void GenerateViewCell(VspKdLeaf *leaf);

        /** Merges view cells of the two leaves.
        */
        bool MergeViewCells(VspKdLeaf *l1, VspKdLeaf *l2);
        
        /** Helper function revalidating the view cell leaf list after merge.
        */
        void RepairViewCellsLeafLists();

        /** Shuffles the leaves, i.e., tests if exchanging
                the view cells the leaves belong to helps in improving the view cells.
        */
        bool ShuffleLeaves(VspKdLeaf *leaf1, VspKdLeaf *leaf2) const;

        /** Shuffles, i.e. takes border leaf from view cell 1 and adds it 
                to view cell 2.
        */
        void ShuffleLeaf(VspKdLeaf *leaf,
                                         VspKdViewCell *vc1, 
                                         VspKdViewCell *vc2) const;
protected:
        

        /////////////////////////////
        // The core pointer
        VspKdNode *mRoot;
  
        /////////////////////////////
        // Basic properties

        // total number of nodes of the tree
        int mNumNodes;
        
        // axis aligned bounding box of the scene
        AxisAlignedBox3 mBox;

        // epsilon used for the construction
        float mEpsilon;

        // ratio between traversal and intersection costs
        float mCtDivCi;
        
        // type of the splitting to use for the tree construction
        enum {ESplitRegular, ESplitHeuristic};
        int splitType;
        
        // maximum alovable memory in MB
        float mMaxTotalMemory;

        // maximum alovable memory for static kd tree in MB
        float mMaxStaticMemory;

        // this is used during the construction depending
        // on the type of the tree and queries...
        float mMaxMemory;

        // minimal acess time for collapse
        int mAccessTimeThreshold;

        // minimal depth at which to perform collapse
        int mMinCollapseDepth;
        
        // reusable array of split candidates
        vector<SortableEntry> *mSplitCandidates;
        
        ViewCellsManager *mViewCellsManager;

        priority_queue<VspKdMergeCandidate> mMergeQueue;


        /////////////////////////////
        // Construction parameters

        /// max depth of the tree
        int mTermMaxDepth;
        /// minimal ratio of the volume of the cell and the query volume
        float mTermMinSize;
        /// minimal pvs per node to still get subdivided
        int mTermMinPvs;
        /// minimal ray number per node to still get subdivided
        int mTermMinRays;
        /// maximal acceptable cost ratio to continue subdivision
        float mTermMaxCostRatio;
        /// maximal contribution per ray to subdivide the node
        float mTermMaxRayContribution;
        /// tolerance value indicating how often the max cost ratio can be failed
        int mTermMissTolerance;

        /// maximal numbers of view cells
        int mMaxViewCells;

        /// maximal cost ratio of a merge
        float mMergeMaxCostRatio;
        
        /// minimal number of view cells
        int mMergeMinViewCells;

        /// if only the "driving axis", i.e., the axis with the biggest extent
        /// should be used for subdivision
        bool mOnlyDrivingAxis;

        /////////////////////////////
        VspKdStatistics mStat;  
};

}

#endif // __VSP_KDTREE_H__