source: GTP/trunk/Lib/Vis/Preprocessing/src/OspTree.h @ 2538

#ifndef _OspTree_H__
#define _OspTree_H__

#include <stack>

#include "Mesh.h"
#include "Containers.h"
#include "Statistics.h"
#include "VssRay.h"
#include "RayInfo.h"
#include "gzstream.h"
#include "SubdivisionCandidate.h"
#include "IntersectableWrapper.h"
#include "KdTree.h"
#include "HierarchyManager.h"



namespace GtpVisibilityPreprocessor {

class ViewCellLeaf;
class Plane3;
class AxisAlignedBox3;
class Ray;
class ViewCellsStatistics;
class ViewCellsManager;
class MergeCandidate;
class Beam;
class ViewCellsTree;
class Environment;
class VspInterior;
class VspLeaf;
class VspNode;
class KdNode;
class KdInterior;
class KdLeaf;
class OspTree;
class KdIntersectable;
class KdTree;
class VspTree;
class KdTreeStatistics;
class SubdivisionCandidate;
class HierarchyManager;
class KdNode;


/** View space partition statistics.
*/
class OspTreeStatistics: public StatisticsBase
{
public:
        // total number of nodes
        int nodes;
        // number of splits
        int splits[3];
        
        // maximal reached depth
        int maxDepth;
        // minimal depth
        int minDepth;
        
        // max depth nodes
        int maxDepthNodes;
        // minimum depth nodes
        int minDepthNodes;
        // max depth nodes
        int minPvsNodes;
        // minimum area nodes
        int minProbabilityNodes;
        /// nodes termination because of max cost ratio;
        int maxCostNodes;
        // max number of objects per node
        int maxObjectRefs;
        int objectRefs;
        /// samples contributing to pvs
        int contributingSamples;
        /// sample contributions to pvs
        int sampleContributions;
        /// largest pvs
        int maxPvs;
        /// number of invalid leaves
        int invalidLeaves;
        /// accumulated number of rays refs
        int accumRays;
        /// overall potentially visible objects
        int pvs;
        // accumulated depth (used to compute average)
        int accumDepth;
        // global cost ratio violations
        int mGlobalCostMisses;


        // Constructor
        OspTreeStatistics() 
        {
                Reset();
        }

        int Nodes() const {return nodes;}
        int Interior() const { return nodes / 2; }
        int Leaves() const { return (nodes / 2) + 1; }
        
        // TODO: computation wrong
        double AvgDepth() const { return accumDepth / (double)Leaves();}; 
        

        void Reset() 
        {
                nodes = 0;
                for (int i = 0; i < 3; ++ i)
                        splits[i] = 0;
                
                maxDepth = 0;
                minDepth = 99999;
                accumDepth = 0;
        pvs = 0;
                maxDepthNodes = 0;
                minPvsNodes = 0;
                minProbabilityNodes = 0;
                maxCostNodes = 0;
                contributingSamples = 0;
                sampleContributions = 0;
                maxPvs = 0;
                invalidLeaves = 0;
                objectRefs = 0;
                maxObjectRefs = 0;
                mGlobalCostMisses = 0;
        }


        void Print(std::ostream &app) const;

        friend std::ostream &operator<<(std::ostream &s, const OspTreeStatistics &stat) 
        {
                stat.Print(s);
                return s;
        } 
};


/** Object Space Partitioning Kd tree.
*/
class OspTree 
{
        friend class ViewCellsParseHandlers;
        friend class HierarchyManager;

public:
        
        /** Additional data which is passed down the BSP tree during traversal.
        */
        class OspTraversalData
        {  
        public:
                /// the current node
                KdLeaf *mNode;
                /// current depth
                int mDepth;
                /// rays piercing this node
                RayInfoContainer *mRays;
                /// the probability that this node contains view point
                float mProbability;
                /// the bounding box of the node
                AxisAlignedBox3 mBoundingBox;
                /// pvs size
                float mRenderCost;
                /// how often this branch has missed the max-cost ratio
                int mMaxCostMisses;
                // current axis
                int mAxis;
                // current priority
                float mPriority;


                OspTraversalData():
                mNode(NULL),
                mRays(NULL),
                mDepth(0),
                mRenderCost(0),
                mProbability(0.0),
                mMaxCostMisses(0), 
                mPriority(0),
                mAxis(0)
                {}
                
                OspTraversalData(KdLeaf *node, 
                                                 const int depth,
                         RayInfoContainer *rays,
                                                 const float rc,
                                                 const float p,
                                                 const AxisAlignedBox3 &box):
                mNode(node), 
                mDepth(depth),
                mRays(rays),
                mRenderCost(rc),
                mProbability(p),
                mBoundingBox(box),
                mMaxCostMisses(0),
                mPriority(0),
                mAxis(0)
                {}

                OspTraversalData(const int depth, 
                        RayInfoContainer *rays,
                        const AxisAlignedBox3 &box): 
                mNode(NULL), 
                mDepth(depth),
                mRays(rays),
                mRenderCost(0),
                mProbability(0),
                mMaxCostMisses(0),
                mAxis(0),
                mBoundingBox(box)
                {}

                /** Returns cost of the traversal data.
                */
                float GetCost() const
                {
                        //cout << mPriority << endl;
                        return mPriority;
                }

                /// deletes contents and sets them to NULL
                void Clear()
                {
                        DEL_PTR(mRays);
                }


                friend bool operator<(const OspTraversalData &a, const OspTraversalData &b)
                {
                        return a.GetCost() < b.GetCost();
                }
    };

        /** Candidate for a view space split.
        */
        class OspSubdivisionCandidate: public SubdivisionCandidate
        {  
        public:
                static OspTree* sOspTree;

                /// the current split plane
                AxisAlignedPlane mSplitPlane;
                /// parent data
                OspTraversalData mParentData;
                
                OspSubdivisionCandidate(const OspTraversalData &tData): mParentData(tData)
                {};

                int Type() const { return OBJECT_SPACE; }
        
                void EvalCandidate(bool computeSplitplane = true)
                {
                        mDirty = false;
                        // todo: avoid computing split plane
                        sOspTree->EvalSubdivisionCandidate(*this);      
                }

                bool GlobalTerminationCriteriaMet() const
                {
                        return sOspTree->GlobalTerminationCriteriaMet(mParentData);
                }

                bool Apply(SplitQueue &splitQueue, bool terminationCriteriaMet, SubdivisionCandidateContainer &dirtyList)
                {
                        KdNode *n = sOspTree->Subdivide(splitQueue ,this,  terminationCriteriaMet);

                        // local or global termination criteria failed
                        return !n->IsLeaf();            
                }

                void CollectDirtyCandidates(SubdivisionCandidateContainer &dirtyList,
                                                                        const bool onlyUnmailed)
                {
                        sOspTree->CollectDirtyCandidates(this, dirtyList, onlyUnmailed);
                }

                float GetPriority() const
                {
                        return mPriority;
                }

                OspSubdivisionCandidate(const AxisAlignedPlane &plane, const OspTraversalData &tData): 
                mSplitPlane(plane), mParentData(tData)
                {}
        };

        /** Struct for traversing line segment.
        */
        struct LineTraversalData 
        {
                KdNode *mNode;
                Vector3 mExitPoint;
                
                float mMaxT;
    
                LineTraversalData () {}
                LineTraversalData (KdNode *n, const Vector3 &p, const float maxt):
                mNode(n), mExitPoint(p), mMaxT(maxt) {}
        };

        /** Default constructor creating an empty tree.
        */ 
        OspTree();

        /** Copies tree from a kd tree.
        */
        OspTree(const KdTree &kdTree);

        /** Default destructor.
        */
        ~OspTree();

        /** Returns tree statistics.
        */
        const OspTreeStatistics &GetStatistics() const; 
  
        /** Returns bounding box of the specified node.
        */
        AxisAlignedBox3 GetBoundingBox(KdNode *node) const;

        /** Returns list of leaves with pvs smaller than
                a certain threshold.
                @param onlyUnmailed if only the unmailed leaves should be considered
                @param maxPvs the maximal pvs of a leaf to be added (-1 means unlimited)
        */
        
        void CollectLeaves(vector<KdLeaf *> &leaves) const;

        /** Returns bounding box of the whole tree (= bbox of root node)
        */
        AxisAlignedBox3 GetBoundingBox()const;

        /** Returns root of the view space partitioning tree.
        */
        KdNode *GetRoot() const;

        /** Collects the leaf view cells of the tree
                @param viewCells returns the view cells 
        */
        void CollectViewCells(ViewCellContainer &viewCells, bool onlyValid) const;

        /** 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 CastRay(Ray &ray);

        /** finds neighbouring leaves of this tree node.
        */
        int FindNeighbors(KdLeaf *n, 
                                          vector<VspLeaf *> &neighbors, 
                                          const bool onlyUnmailed) const;

        /** Returns random leaf of BSP tree.
                @param halfspace defines the halfspace from which the leaf is taken.
        */
        KdLeaf *GetRandomLeaf(const Plane3 &halfspace);

        /** Returns random leaf of BSP tree.
                @param onlyUnmailed if only unmailed leaves should be returned.
        */
        KdLeaf *GetRandomLeaf(const bool onlyUnmailed = false);

        /** Returns epsilon of this tree.
        */
        float GetEpsilon() const;

        /** Casts line segment into the tree.
                @param origin the origin of the line segment
                @param termination the end point of the line segment
                @returns view cells intersecting the line segment.
        */
    int CastLineSegment(const Vector3 &origin,
                                                const Vector3 &termination,
                                                ViewCellContainer &viewcells);
        /** Sets pointer to view cells manager.
        */
        void SetViewCellsManager(ViewCellsManager *vcm);
        /** Writes tree to output stream
        */
        bool Export(OUT_STREAM &stream);
        /** Returns or creates a new intersectable for use in a kd based pvs.
                The OspTree is responsible for destruction of the intersectable.
        */
        KdIntersectable *GetOrCreateKdIntersectable(KdNode *node);
        /** Collects rays stored in the leaves.
        */
        void CollectRays(VssRayContainer &rays);
        /** Intersects box with the tree and returns the number of intersected boxes.
                @returns number of view cells found
        */
        int ComputeBoxIntersections(const AxisAlignedBox3 &box, 
                                                                ViewCellContainer &viewCells) const;


        /** Returns kd leaf the point pt lies in, starting from root.
        */
        KdLeaf *GetLeaf(const Vector3 &pt, KdNode *root = NULL) const;


        ViewCellsTree *GetViewCellsTree() const { return mViewCellsTree; }

        void SetViewCellsTree(ViewCellsTree *vt) { mViewCellsTree = vt; }

        float EvalRenderCost(const VssRayContainer &myrays);
        float EvalLeafCost(const OspTraversalData &tData);

        /** Adds this objects to the kd leaf objects.
                @warning: Can corrupt the tree
        */
        void InsertObjects(KdNode *node, const ObjectContainer &objects);

        /** Add the leaf to the pvs of the view cell.
        */
        bool AddLeafToPvs(
                KdLeaf *leaf, 
                ViewCell *vc, 
                const float pdf, 
                float &contribution);

protected:

        // --------------------------------------------------------------
        // For sorting objects
        // --------------------------------------------------------------
        struct SortableEntry
        {
                /** There is a 3th "event" for rays which intersect a
                        box in the middle. These "events" don't induce a change in
                        pvs size, but may induce a change in view cell volume.
                */
                enum EType 
                {
                        BOX_MIN,
                        BOX_MAX,
                        BOX_INTERSECT
                };

                int mType;
                //int mPvs;
                float mPos;
                VssRay *mRay;
                
                Intersectable *mObject;

                SortableEntry() {}

                SortableEntry(const int type,
                        //const float pvs, 
                        const float pos,
                        Intersectable *obj,
                        VssRay *ray):
                mType(type), 
                //mPvs(pvs), 
                mPos(pos), 
                mObject(obj),
                mRay(ray)
                {}

                bool operator<(const SortableEntry &b) const 
                {
                        return mPos < b.mPos;
                }
        };

 
        /** faster evaluation of split plane cost for kd axis aligned cells.
        */
        float EvalLocalSplitCost(const OspTraversalData &data,
                                                         const AxisAlignedBox3 &box,
                                                         const int axis,
                                                         const float &position,
                                                         float &pFront,
                                                         float &pBack) const;

        /** Evaluates candidate for splitting.
        */
        void EvalSubdivisionCandidate(OspSubdivisionCandidate &splitData);

        /** Computes priority of the traversal data and stores it in tData.
        */
        void EvalPriority(OspTraversalData &tData) const;

        /** Evaluates render cost decrease of next split.
        */
        float EvalRenderCostDecrease(const AxisAlignedPlane &candidatePlane,
                                                                 const OspTraversalData &data,
                                                                 float &normalizedOldRenderCost) const;


        /** Collects view cells in the subtree under root.
        */
        void CollectViewCells(KdNode *root, 
                                                  bool onlyValid, 
                                                  ViewCellContainer &viewCells,
                                                  bool onlyUnmailed = false) const;

        /** Evaluates tree stats in the BSP tree leafs.
        */
        void EvaluateLeafStats(const OspTraversalData &data);

        /** Subdivides node using a best split priority queue.
            @param tQueue the best split priority queue
                @param splitCandidate the candidate for the next split
                @param globalCriteriaMet if the global termination criteria were already met
                @returns new root of the subtree
        */
        KdNode *Subdivide(SplitQueue &tQueue,
                                          SubdivisionCandidate *splitCandidate,
                                          const bool globalCriteriaMet);
        
        /** Subdivides leaf.
                @param leaf the leaf to be subdivided
                
                @param polys the polygons to be split
                @param frontPolys returns the polygons in front of the split plane
                @param backPolys returns the polygons in the back of the split plane
                
                @param rays the polygons to be filtered
                @param frontRays returns the polygons in front of the split plane
                @param backRays returns the polygons in the back of the split plane

                @returns the root of the subdivision
        */
        KdInterior *SubdivideNode(
                const AxisAlignedPlane &splitPlane,
                const OspTraversalData &tData,
                OspTraversalData &frontData,
                OspTraversalData &backData);

        void SplitObjects(KdLeaf *leaf,
                                          const AxisAlignedPlane & splitPlane,
                                          const ObjectContainer &objects,
                                          ObjectContainer &front,
                                          ObjectContainer &back);

        /** does some post processing on the objects in the new child leaves.
        */
        void ProcessMultipleRefs(KdLeaf *leaf) const;

        /** Sorts split candidates for cost heuristics using axis aligned splits.
                @param node the current node
                @param axis the current split axis
        */
        void SortSubdivisionCandidates(const OspTraversalData &data,
                                                         const int axis, 
                                                         float minBand, 
                                                         float maxBand);

        /** Computes best cost for axis aligned planes.
        */
        float EvalLocalCostHeuristics(const OspTraversalData &tData,
                const AxisAlignedBox3 &box,
                const int axis,
                float &position,
                int &objectsFront,
                int &objectsBack);

        /** Subdivides the rays into front and back rays according to the split plane.
                
                @param plane the split plane
                @param rays contains the rays to be split. The rays are 
                           distributed into front and back rays.
                @param frontRays returns rays on the front side of the plane
                @param backRays returns rays on the back side of the plane
                
                @returns the number of splits
        */
        int SplitRays(const AxisAlignedPlane &plane,
                RayInfoContainer &rays, 
                RayInfoContainer &frontRays, 
                RayInfoContainer &backRays) const;

        int FilterRays(KdLeaf *leaf, const RayInfoContainer &rays, RayInfoContainer &filteredRays);

        /** Adds the object to the pvs of the front and back leaf with a given classification.

                @param obj the object to be added
                @param cf the ray classification regarding the split plane
                @param frontPvs returns the PVS of the front partition
                @param backPvs returns the PVS of the back partition
        
        */
        void UpdateObjPvsContri(Intersectable *obj, 
                                         const int cf, 
                                         float &frontPvs, 
                                         float &backPvs, 
                                         float &totalPvs) const;
        
        /** Returns true if tree can be terminated.
        */
        bool LocalTerminationCriteriaMet(const OspTraversalData &data) const;

        /** Returns true if global tree can be terminated.
        */
        bool GlobalTerminationCriteriaMet(const OspTraversalData &data) const;

        /** Selects an axis aligned for the next split.
                @returns cost for this split
        */
        float SelectSplitPlane(
                const OspTraversalData &tData,
                AxisAlignedPlane &plane);
        
        /** Propagates valid flag up the tree.
        */
        void PropagateUpValidity(KdNode *node);

        /** Writes the node to disk
                @note: should be implemented as visitor.
        */
        void ExportNode(KdNode *node, OUT_STREAM &stream);

        /** Returns estimated memory usage of tree.
        */
        float GetMemUsage() const;

        /** Evaluate the contributions of view cell volume of the left and the right view cell.
        */
        void EvalRayContribution(
                KdLeaf *leaf,
                const VssRay &ray, 
                float &renderCost);
        
        void EvalViewCellContribution(
                KdLeaf *leaf, 
                ViewCell *viewCell,
                float &renderCost);

        /** Evaluates the influence on the pvs of the event.
                @param ve the visibility event
                @param pvsLeft updates the left pvs
                @param rightPvs updates the right pvs
        */
        void EvalHeuristicsContribution(KdLeaf *leaf,
                const SortableEntry &ci,
                float &renderCost,
                ViewCellContainer &touchedViewCells);

        /** Prepares objects for the cost heuristics.
                @returns pvs size of the node
        */
        float PrepareHeuristics(
                const OspTraversalData &tData, 
                ViewCellContainer &touchedViewCells);

        /** Prepares heuristics for a particular ray.
        */
        void PrepareHeuristics(
                const VssRay &ray, 
                ViewCellContainer &touchedViewCells);

        /** Prepares construction for vsp and osp trees.
        */
        void ComputeBoundingBox(const ObjectContainer &objects);

        void CollectDirtyCandidates(OspSubdivisionCandidate *sc,
                                                                vector<SubdivisionCandidate *> &dirtyList,
                                                                const bool onlyUnmailed);

        /** Collect view cells which see this kd leaf.
        */
        void CollectViewCells(KdLeaf *leaf, 
                ViewCellContainer &viewCells);

        /** Rays will be clipped to the bounding box.
        */
        void PreprocessRays(
                KdLeaf *root, 
                const VssRayContainer &sampleRays,
                RayInfoContainer &rays);

        /** Reads parameters from environment singleton.
        */
        void ReadEnvironment();

        /** Returns true if the specified ray end points is inside the kd leaf.
                @param isTermination if origin or termination point should be checked
        */
        bool EndPointInsideNode(KdLeaf *leaf, VssRay &ray, bool isTermination) const;

        void AddViewCellVolumeContri(
                ViewCell *vc, 
                float &frontVol, 
                float &backVol,
                float &frontAndBackVol) const;

        /** Classifies and mail view cell with respect to the heuristics contribution.
                Set view cell mail box according to it's influence on 
                front (0), back (1) and front / back node (2).
        */
        void  MailViewCell(ViewCell *vc, const int cf) const;

        int ClassifyRay(VssRay *ray, KdLeaf *leaf, const AxisAlignedPlane &plane) const;

        void EvalSubdivisionStats(const SubdivisionCandidate &tData);

        void AddSubdivisionStats(const int viewCells,
                                                         const float renderCostDecr,
                                                         const float totalRenderCost);

        void EvalViewCellsForHeuristics(const VssRay &ray, 
                                                                        float &volLeft, 
                                                                        float &volRight);

        float EvalViewCellsVolume(KdLeaf *leaf, const RayInfoContainer &rays) const;
        
        int RemoveParentViewCellsPvs(KdLeaf *leaf,  const RayInfoContainer &rays) const;

        int UpdateViewCellsPvs(KdLeaf *leaf, const RayInfoContainer &rays) const;
        
        int CheckViewCellsPvs(KdLeaf *leaf, const RayInfoContainer &rays) const;

        bool AddViewCellToObjectPvs(Intersectable *obj,
                                                                ViewCell *vc, 
                                                                float &contribution,
                                                                bool onlyUnmailed) const;

        int ClassifyRays(const RayInfoContainer &rays, 
                                         KdLeaf *leaf, 
                                         const AxisAlignedPlane &plane,
                                         RayInfoContainer &frontRays,
                                         RayInfoContainer &backRays) const;

        void CollectTouchedViewCells(const RayInfoContainer &rays, 
                                                                 ViewCellContainer &touchedViewCells) const;

        void AddObjectContribution(KdLeaf *leaf,
                                                           Intersectable * obj,
                                                           ViewCellContainer &touchedViewCells,
                                                           float &renderCost);

        void SubtractObjectContribution(KdLeaf *leaf,
                                                                        Intersectable *obj,
                                                                        ViewCellContainer &touchedViewCells,
                                                                        float &renderCost);

        void PrepareConstruction(SplitQueue &tQueue,
                                                         const VssRayContainer &sampleRays,
                                                         const ObjectContainer &objects,
                             RayInfoContainer &rays);


protected:
        
        /// pointer to the hierarchy of view cells
        ViewCellsTree *mViewCellsTree;

        /// pointer to the view space partition
        /// note: should be handled over the hierarchy manager
        VspTree *mVspTree;

        /// pointer to the hierarchy manager
        HierarchyManager *mHierarchyManager;

        /// The view cells manager
        ViewCellsManager *mViewCellsManager;

        /// candidates for placing split planes during cost heuristics
        vector<SortableEntry> *mSubdivisionCandidates;

        /// Pointer to the root of the tree
        KdNode *mRoot;
                
        /// Statistics for the object space partition
        OspTreeStatistics mOspStats;
        
        /// box around the whole view domain
        AxisAlignedBox3 mBoundingBox;


        //////////////////////////////
        //-- local termination

        /// maximal possible depth
        int mTermMaxDepth;
        /// mininum probability
        float mTermMinProbability;
        /// minimal number of objects
        int mTermMinObjects;
        /// maximal contribution per ray
        float mTermMaxRayContribution;
        /// maximal acceptable cost ratio
        float mTermMaxCostRatio;
        /// tolerance value indicating how often the max cost ratio can be failed
        int mTermMissTolerance;


        ////////////////////////
        //-- global criteria

        float mTermMinGlobalCostRatio;
        int mTermGlobalCostMissTolerance;
        int mGlobalCostMisses;

        /// maximal number of view cells
        int mTermMaxLeaves;
        /// maximal tree memory
        float mMaxMemory;
        /// the tree is out of memory
        bool mOutOfMemory;


        ///////////////////////////////////////////
        //-- split heuristics based parameters
        
        bool mUseCostHeuristics;
        /// balancing factor for PVS criterium
        float mCtDivCi; 
        /// if only driving axis should be used for split
        bool mOnlyDrivingAxis;
        /// represents min and max band for sweep
        float mSplitBorder;

        ////////////////////////////////////////////////

        /// current time stamp (used for keeping split history)
        int mTimeStamp;
        // if rays should be stored in leaves
        bool mStoreRays;
        /// epsilon for geometric comparisons
        float mEpsilon;
        /// subdivision stats output file
        std::ofstream  mSubdivisionStats;
        /// keeps track of cost during subdivision
        float mTotalCost;
        /// keeps track of overall pvs size during subdivision
        int mTotalPvsSize;
        /// number of currenly generated view cells
        int mCreatedLeaves;
        
        /// weight between  render cost decrease and node render cost
        float mRenderCostDecreaseWeight;

    /// stores the kd node intersectables used for pvs
  KdIntersectableMap mKdIntersectables;
        
private:

        bool mCopyFromKdTree;
};


}

#endif