source: GTP/trunk/Lib/Vis/Preprocessing/src/GvsPreprocessor.cpp @ 2739

#include "Environment.h"
#include "GvsPreprocessor.h"
#include "GlRenderer.h"
#include "VssRay.h"
#include "ViewCellsManager.h"
#include "Triangle3.h"
#include "IntersectableWrapper.h"
#include "Plane3.h"
#include "RayCaster.h"
#include "Exporter.h"
#include "SamplingStrategy.h"
#include "BvHierarchy.h"
#include "Polygon3.h"
#include "IntersectableWrapper.h"
#include "Timer/PerfTimer.h"
#include "Vector2.h"
#include "RndGauss.h"



namespace GtpVisibilityPreprocessor
{
  
#define GVS_DEBUG 0
#define NOT_ACCOUNTED_OBJECT 0
#define ACCOUNTED_OBJECT 2


static const float MIN_DIST = 0.001f;

static ObjectContainer myobjects;
static int sInvalidSamples = 0;



///////////
//-- timers


static PerfTimer rayTimer;
static PerfTimer kdPvsTimer;
static PerfTimer gvsTimer;
static PerfTimer initialTimer;
static PerfTimer intersectionTimer;
static PerfTimer preparationTimer;
static PerfTimer mainLoopTimer;
static PerfTimer contributionTimer;
static PerfTimer castTimer;
static PerfTimer generationTimer;


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


/** Visualization structure for the GVS algorithm.
*/
struct VizStruct
{
        Polygon3 *enlargedTriangle;
        Triangle3 originalTriangle;
        VssRay *ray;
};

static vector<VizStruct> vizContainer;




GvsPreprocessor::GvsPreprocessor(): 
Preprocessor(), 
mProcessedViewCells(0),
mCurrentViewCell(NULL),
mCurrentViewPoint(Vector3(0.0f, 0.0f, 0.0f)),
mOnlyRandomSampling(false),
//mOnlyRandomSampling(true),
mUseProbablyVisibleSampling(false)
{
        Environment::GetSingleton()->GetIntValue("GvsPreprocessor.totalSamples", mTotalSamples);
        Environment::GetSingleton()->GetIntValue("GvsPreprocessor.initialSamples", mInitialSamples);
        Environment::GetSingleton()->GetIntValue("GvsPreprocessor.gvsSamplesPerPass", mGvsSamplesPerPass);
        Environment::GetSingleton()->GetIntValue("GvsPreprocessor.minContribution", mMinContribution);
        Environment::GetSingleton()->GetFloatValue("GvsPreprocessor.epsilon", mEps);
        Environment::GetSingleton()->GetFloatValue("GvsPreprocessor.threshold", mThreshold);    
        Environment::GetSingleton()->GetBoolValue("GvsPreprocessor.perViewCell", mPerViewCell);
        Environment::GetSingleton()->GetIntValue("GvsPreprocessor.maxViewCells", mMaxViewCells);

        Environment::GetSingleton()->GetBoolValue("Preprocessor.evaluatePixelError", mEvaluatePixelError);

        Environment::GetSingleton()->GetBoolValue("ViewCells.useKdPvs", mUseKdPvs);

        Environment::GetSingleton()->GetFloatValue("GvsPreprocessor.initialJitter", mInitialJitter);
        Environment::GetSingleton()->GetBoolValue("GvsPreprocessor.useDeterministicGvs", mUseDeterministicGvs);

        Environment::GetSingleton()->GetFloatValue("GvsPreprocessor.radiusOfInfluence", mRadiusOfInfluence);

        char gvsStatsLog[100];
        Environment::GetSingleton()->GetStringValue("GvsPreprocessor.stats", gvsStatsLog);
        mGvsStatsStream.open(gvsStatsLog);

        cout << "number of gvs samples per pass: " << mGvsSamplesPerPass << endl;
        cout << "number of samples per pass: " << mSamplesPerPass << endl;
        cout << "only random sampling: " << mOnlyRandomSampling << endl;

        Debug << "Gvs preprocessor options" << endl;
        Debug << "number of total samples: " << mTotalSamples << endl;
        Debug << "number of initial samples: " << mInitialSamples << endl;
        Debug << "threshold: " << mThreshold << endl;
        Debug << "epsilon: " << mEps << endl;
        Debug << "stats: " << gvsStatsLog << endl;
        Debug << "per view cell: " << mPerViewCell << endl;
        Debug << "max view cells: " << mMaxViewCells << endl;
        Debug << "min contribution: " << mMinContribution << endl;

        mDistribution = new ViewCellBasedDistribution(*this, NULL);

        mGvsStats.Reset();

        // hack: some generic statistical values that can be used
        // by an application using the preprocessor
        for (int i = 0; i < 2; ++ i)
                mGenericStats[i] = 0;
}


GvsPreprocessor::~GvsPreprocessor()
{
        delete mDistribution;
        ClearRayQueue();
}


void GvsPreprocessor::ClearRayQueue()
{
        // clean ray queue
        while (!mRayQueue.empty())
        {
                // handle next ray
                VssRay *ray = mRayQueue.top();
                mRayQueue.pop();

                // note: deletion of the ray is handled by ray pool
        }
}


ViewCell *GvsPreprocessor::NextViewCell()
{
        if (mProcessedViewCells == (int)mViewCells.size())
                return NULL; // no more view cells

        ViewCell *vc = mViewCells[mProcessedViewCells];

   if (!vc->GetMesh())
                mViewCellsManager->CreateMesh(vc);

        mGvsStats.mViewCellId = vc->GetId();

        Debug << "vc: " << vc->GetId() << endl;

        ++ mProcessedViewCells;
    
        return vc;
}


int GvsPreprocessor::CheckDiscontinuity(const VssRay &currentRay,
                                                                                const Triangle3 &hitTriangle,
                                                                                const VssRay &oldRay)
{
        // the predicted hitpoint is the point where the ray would have intersected the hit triangle
        Vector3 predictedHit = CalcPredictedHitPoint(currentRay, hitTriangle, oldRay);

        float predictedLen = Magnitude(predictedHit - currentRay.mOrigin);
        float len = Magnitude(currentRay.mTermination - currentRay.mOrigin);
        
        // discrepancy between predicted and actual hit point large => this is likely to be a discontinuity

        // matt: problem: this only finds CLOSER discontinuities, but not discontinuities which are FARTHER away
        if ((predictedLen - len) < mThreshold)
        // q: rather use relative distance?
        //if ((predictedLen / len) < mThreshold)
                return 0;

        SimpleRay simpleRay;

        // apply reverse sampling to find the gap
        if (!ComputeReverseRay(currentRay, hitTriangle, oldRay, simpleRay))
                return 0;

        static VssRayContainer reverseRays;
        reverseRays.clear();

        if (mUseDeterministicGvs)
        {
                VssRay *reverseRay = 
                        mRayCaster->CastRay(simpleRay, mViewCellsManager->GetViewSpaceBox(), !mPerViewCell);

                reverseRays.push_back(reverseRay);
        }
        else
        {
                float scale = 0.01f;

                if (0)
                        CastRayBundle4(simpleRay, reverseRays, mViewCellsManager->GetViewSpaceBox());
                else
                        CastRayBundle16(simpleRay, reverseRays, scale);
        }

        mGvsStats.mReverseSamples += (int)reverseRays.size();

        EnqueueRays(reverseRays);

        return (int)reverseRays.size();
}


int GvsPreprocessor::CheckDiscontinuity2(const VssRay &currentRay,
                                                                                 const Triangle3 &hitTriangle,
                                                                                 const VssRay &oldRay)
{
        // the predicted hitpoint is the point where the ray would have intersected the hit triangle
        Vector3 predictedHit = CalcPredictedHitPoint(currentRay, hitTriangle, oldRay);

        float predictedLen = Magnitude(predictedHit - currentRay.mOrigin);
        float len = Magnitude(currentRay.mTermination - currentRay.mOrigin);
        
        // discrepancy between predicted and actual hit point large 
        // => this is likely to be a discontinuity
        if (fabs(predictedLen - len) < mThreshold)
                return 0;

        static SimpleRayContainer simpleRays;
        simpleRays.clear();

        CreateRandomizedReverseRays(currentRay.mOrigin, predictedHit, hitTriangle, simpleRays, 16);

        static VssRayContainer reverseRays;
        reverseRays.clear();
        CastRays(simpleRays, reverseRays, false, false);

        mGvsStats.mReverseSamples += (int)reverseRays.size();

        EnqueueRays(reverseRays);

        return (int)reverseRays.size();
}


int GvsPreprocessor::CountObject(Intersectable *triObj)
{
        int numObjects = 0;

        if ((triObj->mCounter != (NOT_ACCOUNTED_OBJECT + 1)) && 
                (triObj->mCounter != (ACCOUNTED_OBJECT + 1)))
        {
                ++ triObj->mCounter;
                ++ numObjects;
        }

        mGenericStats[1] += numObjects;

        return numObjects;
}


void GvsPreprocessor::UpdateStatsForVisualization(KdIntersectable *kdInt)
{
        int numObj = 0;

        // count new objects in pvs due to kd node conversion   
        myobjects.clear();
        // also gather duplicates to avoid mailing
        mKdTree->CollectObjectsWithDublicates(kdInt->GetItem(), myobjects);

        ObjectContainer::const_iterator oit, oit_end = myobjects.end();

        for (oit = myobjects.begin(); oit != oit_end; ++ oit)
                numObj += CountObject(*oit);

        mViewCellsManager->UpdateStatsForViewCell(mCurrentViewCell, kdInt, numObj);
}       


void GvsPreprocessor::AddKdNodeToPvs(const Vector3 &termination)
{
        kdPvsTimer.Entry();

        // exchange the triangle with the node in the pvs for kd pvs
        KdNode *node = mKdTree->GetPvsNode(termination);

        //KdNode *node = mKdTree->GetPvsNodeCheck(ray.mTermination, obj);
        //if (!node) cerr << "e " << obj->GetBox() << " " << ray.mTermination << endl; else 
        if (!node->Mailed())
        {
                // add to pvs
                node->Mail();
                KdIntersectable *kdInt = mKdTree->GetOrCreateKdIntersectable(node);
                mCurrentViewCell->GetPvs().AddSampleDirty(kdInt, 1.0f);

                if (QT_VISUALIZATION_SHOWN) UpdateStatsForVisualization(kdInt); 
        }

        kdPvsTimer.Exit();
}


bool GvsPreprocessor::HasContribution(VssRay &ray)
{
        if (!ray.mTerminationObject)
                return false;

        contributionTimer.Entry();

        bool result;

        if (!mPerViewCell)
        {
                // store the rays + the intersected view cells
                const bool storeViewCells = false;

                mViewCellsManager->ComputeSampleContribution(ray, 
                                                                                                         true, 
                                                                                                         storeViewCells,
                                                                                                         true);

                result = ray.mPvsContribution > 0;
        }
        else // original per view cell gvs
        {
                // test if triangle was accounted for yet
                result = AddTriangleObject(ray.mTerminationObject);
                
                if (mUseKdPvs)
                        AddKdNodeToPvs(ray.mTermination);
        }

        contributionTimer.Exit();

        return result;
}


bool GvsPreprocessor::HandleRay(VssRay *vssRay)
{
        if (!vssRay || !HasContribution(*vssRay))
                return false;

        if (0 && GVS_DEBUG)
                mVssRays.push_back(new VssRay(*vssRay));

        // add new ray to ray queue
        mRayQueue.push(vssRay);

        ++ mGvsStats.mTotalContribution;

        return true;
}


/** Creates 3 new vertices for triangle vertex with specified index.
*/
void GvsPreprocessor::CreateDisplacedVertices(VertexContainer &vertices,
                                                                                          const Triangle3 &hitTriangle,
                                                                                          const VssRay &ray, 
                                                                                          const int index) const
{
        const int indexU = (index + 1) % 3;
        const int indexL = (index == 0) ? 2 : index - 1;

        const Vector3 a = hitTriangle.mVertices[index] - ray.GetOrigin();
        const Vector3 b = hitTriangle.mVertices[indexU] - hitTriangle.mVertices[index];
        const Vector3 c = hitTriangle.mVertices[index] - hitTriangle.mVertices[indexL];
        
        const float len = Magnitude(a);
        
        const Vector3 dir1 = Normalize(CrossProd(a, b)); //N((pi-xp)×(pi+1- pi));
        const Vector3 dir2 = Normalize(CrossProd(a, c)); // N((pi-xp)×(pi- pi-1))
        const Vector3 dir3 = DotProd(dir2, dir1) > 0 ? // N((pi-xp)×di,i-1+di,i+1×(pi-xp))
                Normalize(dir2 + dir1) : Normalize(CrossProd(a, dir1) + CrossProd(dir2, a)); 

        // compute the new three hit points
        // pi, i + 1:  pi+ e·|pi-xp|·di, j
        const Vector3 pt1 = hitTriangle.mVertices[index] + mEps * len * dir1;
        // pi, i - 1:  pi+ e·|pi-xp|·di, j
    const Vector3 pt2 = hitTriangle.mVertices[index] + mEps * len * dir2;
        // pi, i:  pi+ e·|pi-xp|·di, j
        const Vector3 pt3 = hitTriangle.mVertices[index] + mEps * len * dir3;
        
        vertices.push_back(pt2);
        vertices.push_back(pt3);
        vertices.push_back(pt1);
}


void GvsPreprocessor::EnlargeTriangle(VertexContainer &vertices,
                                                                          const Triangle3 &hitTriangle,
                                                                          const VssRay &ray) const
{
        CreateDisplacedVertices(vertices, hitTriangle, ray, 0);
        CreateDisplacedVertices(vertices, hitTriangle, ray, 1);
        CreateDisplacedVertices(vertices, hitTriangle, ray, 2);
}


Vector3 GvsPreprocessor::CalcPredictedHitPoint(const VssRay &newRay, 
                                                                                           const Triangle3 &hitTriangle,
                                                                                           const VssRay &oldRay) const
{
        // find the intersection of the plane induced by the 
        // hit triangle with the new ray
        Plane3 plane(hitTriangle.GetNormal(), hitTriangle.mVertices[0]);

        const Vector3 hitPt = 
                plane.FindIntersection(newRay.mTermination, newRay.mOrigin);
        
        return hitPt;
}


static bool EqualVisibility(const VssRay &a, const VssRay &b)
{
        return a.mTerminationObject == b.mTerminationObject;
}


int GvsPreprocessor::SubdivideEdge(const Triangle3 &hitTriangle,
                                                                   const Vector3 &p1, 
                                                                   const Vector3 &p2, 
                                                                   const VssRay &ray1, 
                                                                   const VssRay &ray2,
                                                                   const VssRay &oldRay)
{
        //cout <<"y"<<Magnitude(p1 - p2) << " ";
        int castRays = 0;

        if (EqualVisibility(ray1, ray2) || (SqrMagnitude(p1 - p2) <= MIN_DIST))
                return castRays;
        

        // the new subdivision point
        const Vector3 p = (p1 + p2) * 0.5f;
        //cout << "p: " << p << " " << p1 << " " << p2 << endl;

        SimpleRay sray(oldRay.mOrigin, p - oldRay.mOrigin, SamplingStrategy::GVS, 1.0f);

        VssRay *newRay;

        // cast single ray
        castTimer.Entry();

        // cast single ray to check if a triangle was missed. note: not efficient!!
        newRay = mRayCaster->CastRay(sray, mViewCellsManager->GetViewSpaceBox(), !mPerViewCell);
        castTimer.Exit();

        ++ castRays;

        // this ray will not be further processed
        // note: ray deletion is handled by ray pool
        if (!newRay) return castRays;

        rayTimer.Entry();

        // new triangle discovered? => add new ray to queue
        HandleRay(newRay);

        rayTimer.Exit();
        
        //newRay->mFlags |= VssRay::BorderSample;

        // cast reverse rays if necessary
        castRays += CheckDiscontinuity(ray2, hitTriangle, oldRay);

        // subdivide further
        castRays += SubdivideEdge(hitTriangle, p1, p, ray1, *newRay, oldRay);
        castRays += SubdivideEdge(hitTriangle, p, p2, *newRay, ray2, oldRay);
        
        return castRays;
}


int GvsPreprocessor::AdaptiveBorderSampling(const VssRay &currentRay)
{
        Intersectable *tObj = currentRay.mTerminationObject;

        // question matt: can this be possible?
        if (!tObj) return 0;

        Triangle3 hitTriangle;

        // other types not implemented yet
        if (tObj->Type() == Intersectable::TRIANGLE_INTERSECTABLE)
                hitTriangle = static_cast<TriangleIntersectable *>(tObj)->GetItem();
        else
                cout << "border sampling: " << Intersectable::GetTypeName(tObj) << " not yet implemented" << endl;

        //cout << "type: " << Intersectable::GetTypeName(tObj) << endl;
        generationTimer.Entry();

        static VertexContainer enlargedTriangle;
        enlargedTriangle.clear();

        /// create 3 new hit points for each vertex
        EnlargeTriangle(enlargedTriangle, hitTriangle, currentRay);
        
        /// create rays from sample points and handle them
        static SimpleRayContainer simpleRays;
        simpleRays.clear();

        VertexContainer::const_iterator vit, vit_end = enlargedTriangle.end();

        for (vit = enlargedTriangle.begin(); vit != vit_end; ++ vit)
        {
                const Vector3 rayDir = (*vit) - currentRay.GetOrigin();

                SimpleRay sr(currentRay.GetOrigin(), rayDir, SamplingStrategy::GVS, 1.0f);
                simpleRays.AddRay(sr);  
        }

        //////////
        //-- fill up simple rays with random rays so we can cast 16 rays at a time

        const int numRandomRays = 16 - (int)simpleRays.size();
        GenerateRays(numRandomRays, *mDistribution, simpleRays, sInvalidSamples);

        generationTimer.Exit();


        /////////////////////
        //-- cast rays to vertices and determine visibility
        
        static VssRayContainer vssRays;
        vssRays.clear();

        // for the original implementation we don't cast double rays
        const bool castDoubleRays = !mPerViewCell;
        // cannot prune invalid rays because we have to compare adjacent rays
        const bool pruneInvalidRays = false;

        //gvsTimer.Entry();
        castTimer.Entry();

        CastRays(simpleRays, vssRays, castDoubleRays, pruneInvalidRays);
        
        castTimer.Exit();
        //gvsTimer.Exit();

        const int numBorderSamples = (int)vssRays.size() - numRandomRays;
        int castRays = (int)simpleRays.size();

        // handle cast rays
        EnqueueRays(vssRays);

        if (0)
        {
                // visualize enlarged triangles
                VizStruct dummy;
                dummy.enlargedTriangle = new Polygon3(enlargedTriangle);
                dummy.originalTriangle = hitTriangle;
        
                vizContainer.push_back(dummy);
        
                // set flags
                VssRayContainer::const_iterator rit, rit_end = vssRays.end();
        
                for (rit = vssRays.begin(); rit != rit_end; ++ rit)
                        (*rit)->mFlags |= VssRay::BorderSample;
        }

    // recursivly subdivide each edge
        for (int i = 0; i < numBorderSamples; ++ i)
        {
                castRays += CheckDiscontinuity(*vssRays[i], hitTriangle, currentRay);

                castRays += SubdivideEdge(hitTriangle,
                                                                  enlargedTriangle[i], 
                                                                  enlargedTriangle[(i + 1) % numBorderSamples], 
                                                                  *vssRays[i], 
                                                                  *vssRays[(i + 1) % numBorderSamples],
                                                                  currentRay);
        }
        
        mGvsStats.mBorderSamples += castRays;
        
        return castRays;
}


int GvsPreprocessor::AdaptiveBorderSamplingOpt(const VssRay &currentRay)
{
        Intersectable *tObj = currentRay.mTerminationObject;

        // question matt: can this be possible?
        if (!tObj) return 0;

        Triangle3 hitTriangle;

        // other types not implemented yet
        if (tObj->Type() == Intersectable::TRIANGLE_INTERSECTABLE)
                hitTriangle = static_cast<TriangleIntersectable *>(tObj)->GetItem();
        else
                cout << "error: gvs sampling for " << Intersectable::GetTypeName(tObj) << " not implemented" << endl;

        generationTimer.Entry();

        static VertexContainer enlargedTriangle;
        enlargedTriangle.clear();
        
        /// create 3 new hit points for each vertex
        EnlargeTriangle(enlargedTriangle, hitTriangle, currentRay);

        static VertexContainer subdivEnlargedTri;       
        subdivEnlargedTri.clear();

        for (size_t i = 0; i < enlargedTriangle.size(); ++ i)
        {
                const Vector3 p1 = enlargedTriangle[i];
                const Vector3 p2 = enlargedTriangle[(i + 1) % enlargedTriangle.size()];

                // the new subdivision point
                const Vector3 p = (p1 + p2) * 0.5f;

                subdivEnlargedTri.push_back(p1);
                subdivEnlargedTri.push_back(p);
        }

        /// create rays from sample points and handle them
        static SimpleRayContainer simpleRays;
        simpleRays.clear();
        
        VertexContainer::const_iterator vit, vit_end = subdivEnlargedTri.end();

        for (vit = subdivEnlargedTri.begin(); vit != vit_end; ++ vit)
        {
                const Vector3 rayDir = (*vit) - currentRay.GetOrigin();

                SimpleRay sr(currentRay.GetOrigin(), rayDir, SamplingStrategy::GVS, 1.0f);
                simpleRays.AddRay(sr);  
        }

        
        //////////
        //-- fill up simple rays with random rays so we can cast 16 rays at a time

        const int numRandomRays = 16 - ((int)simpleRays.size() % 16);

        GenerateImportanceSamples(currentRay, hitTriangle, numRandomRays, simpleRays);
        
        generationTimer.Exit();



        /////////////////////
        //-- cast rays to vertices and determine visibility
        
        static VssRayContainer vssRays;
        vssRays.clear();

        // for the original implementation we don't cast double rays
        const bool castDoubleRays = !mPerViewCell;
        // cannot prune invalid rays because we have to compare adjacent rays
        const bool pruneInvalidRays = false;

        //if ((simpleRays.size() % 16) != 0) cerr << "ray size not aligned" << endl;
        
        //gvsTimer.Entry();
        castTimer.Entry();

        CastRays(simpleRays, vssRays, castDoubleRays, pruneInvalidRays);
        
        castTimer.Exit();
        //gvsTimer.Exit();

        const int numBorderSamples = (int)vssRays.size() - numRandomRays;
        int castRays = (int)simpleRays.size();

        // handle cast rays
        EnqueueRays(vssRays);
        
        for (size_t i = 0; i < vssRays.size(); ++ i)
        {
                // check for discontinuity and cast reverse rays if necessary
                castRays += CheckDiscontinuity2(*vssRays[i], hitTriangle, currentRay);
        }

#if 0
        
    // recursivly subdivide each edge
        for (int i = 0; i < numBorderSamples; ++ i)
        {
                castRays += SubdivideEdge(hitTriangle,
                                                                  subdivEnlargedTri[i], 
                                                                  subdivEnlargedTri[(i + 1) % numBorderSamples], 
                                                                  *vssRays[i], 
                                                                  *vssRays[(i + 1) % numBorderSamples],
                                                                  currentRay);
        }
        
#endif


        mGvsStats.mBorderSamples += castRays;
        
        return castRays;
}


bool GvsPreprocessor::GetPassingPoint(const VssRay &currentRay,
                                                                          const Triangle3 &occluder,
                                                                          const VssRay &oldRay,
                                                                          Vector3 &newPoint) const
{
        /////////////////////////
        //-- We interserct the plane p = (xp, hit(x), hit(xold))
        //-- with the newly found occluder (xold is the previous ray from
        //-- which x was generated). On the intersecting line, we select a point
        //-- pnew which lies just outside of the new triangle so the ray
        //-- just passes through the gap

        const Plane3 plane(currentRay.GetOrigin(), 
                                           currentRay.GetTermination(), 
                                           oldRay.GetTermination());
        
        Vector3 pt1, pt2;

        if (!occluder.GetPlaneIntersection(plane, pt1, pt2))
                return false;

        // get the intersection point on the old ray
        const Plane3 triPlane(occluder.GetNormal(), occluder.mVertices[0]);

        const float t = triPlane.FindT(oldRay.mOrigin, oldRay.mTermination);
        const Vector3 pt3 = oldRay.mOrigin + t * (oldRay.mTermination - oldRay.mOrigin);

        // evaluate new hitpoint just outside the triangle
        // the point is chosen to be on the side closer to the original ray
        if (SqrDistance(pt1, pt3) < SqrDistance(pt2, pt3))
                newPoint = pt1 + mEps * (pt1 - pt2);
        else
                newPoint = pt2 + mEps * (pt2 - pt1);

        //cout << "passing point: " << newPoint << endl << endl;
        return true;
}


bool GvsPreprocessor::ComputeReverseRay(const VssRay &currentRay,
                                                                                const Triangle3 &hitTriangle,
                                                                                const VssRay &oldRay,
                                                                                SimpleRay &reverseRay)
{
        // optain triangle that occludes the path to the currently processed mesh
        Triangle3 occluder;
        Intersectable *tObj = currentRay.mTerminationObject;

        // q: why can this happen?
        if (!tObj)
                return false;

        // other types not implemented yet
        if (tObj->Type() == Intersectable::TRIANGLE_INTERSECTABLE)
                occluder = static_cast<TriangleIntersectable *>(tObj)->GetItem();
        else
                cout << "reverse sampling: " << tObj->Type() << " not yet implemented" << endl;
        
        // get a point which is passing just outside of the occluder
    Vector3 newPoint;

        // q: why is there sometimes no intersecton found?
        if (!GetPassingPoint(currentRay, occluder, oldRay, newPoint))
                return false;

        const Vector3 predicted = CalcPredictedHitPoint(currentRay, hitTriangle, oldRay);

        //////////////
        //-- Construct the mutated ray with xnew,
        //-- dir = predicted(x)- pnew as direction vector

        Vector3 newDir = newDir = predicted - newPoint;

        // take xnew, p = intersect(viewcell, line(pnew, predicted(x)) as origin ?
        // difficult to say!!
        const float offset = 0.5f;
        Vector3 newOrigin = newPoint - newDir * offset;
        

        //////////////
        //-- for per view cell sampling, we must intersect
        //-- with the current view cell

    if (mPerViewCell)
        {
                if (!IntersectViewCell(newOrigin, newDir))
                        return false;
        }

        reverseRay = SimpleRay(newOrigin, newDir, SamplingStrategy::GVS, 1.0f);

        return true;
}


bool GvsPreprocessor::IntersectViewCell(Vector3 &origin, Vector3 &dir) const
{
        // send ray to view cell
        static Ray testRay;

        testRay.Clear();
        testRay.Init(origin, -dir, Ray::LOCAL_RAY);

        // check if ray intersects view cell
        if (!mCurrentViewCell->CastRay(testRay))
                return false;

        Ray::Intersection &hit = testRay.intersections[0];

        // the ray starts from the view cell
        origin = testRay.Extrap(hit.mT);

        return true;
}


int GvsPreprocessor::CastInitialSamples(int numSamples)
{       
        initialTimer.Entry();

        // generate simple rays
        static SimpleRayContainer simpleRays;
        simpleRays.clear();

        generationTimer.Entry();

        if (mUseProbablyVisibleSampling)// && (RandomValue(0, 1) > 0.5))
        {
                ProbablyVisibleDistribution distr(*this, mCurrentViewCell, &mProbablyVisibleTriangles);
                GenerateRays(numSamples, distr, simpleRays, sInvalidSamples);
        }
        else
        {
                GenerateRays(mUseDeterministicGvs ? numSamples : numSamples / 16, *mDistribution, simpleRays, sInvalidSamples);
        }

        generationTimer.Exit();

        // cast generated samples 
        static VssRayContainer vssRays;
        vssRays.clear();

        castTimer.Entry();

        if (mUseDeterministicGvs)
        {
                const bool castDoubleRays = !mPerViewCell;
                const bool pruneInvalidRays = false;
                //const bool pruneInvalidRays = true;

                CastRays(simpleRays, vssRays, castDoubleRays, pruneInvalidRays);
        }
        else
        {
                if (0)
                        // casting bundles of 4 rays generated from the simple rays
                        CastRayBundles4(simpleRays, vssRays);
                else
                        CastRayBundles16(simpleRays, vssRays, mInitialJitter);
        }

        castTimer.Exit();

        // add to ray queue
        EnqueueRays(vssRays);

        initialTimer.Exit();

        return (int)vssRays.size();
}


void GvsPreprocessor::EnqueueRays(VssRayContainer &samples)
{
        rayTimer.Entry();

        // add samples to ray queue
        VssRayContainer::const_iterator vit, vit_end = samples.end();
        for (vit = samples.begin(); vit != vit_end; ++ vit)
        {
                VssRay *ray = *vit;
                HandleRay(ray);
                // note: deletion of invalid samples handked by ray pool
        }

        rayTimer.Exit();
}


int GvsPreprocessor::ProcessQueue()
{
        gvsTimer.Entry();

        ++ mGvsStats.mGvsRuns;

        int castSamples = 0;

        while (!mRayQueue.empty())
        {
                // handle next ray
                VssRay *ray = mRayQueue.top();
                mRayQueue.pop();
                
                if (mUseDeterministicGvs)
                        castSamples += AdaptiveBorderSampling(*ray);
                else
                        castSamples += AdaptiveBorderSamplingOpt(*ray);

                // note: don't have to delete because handled by ray pool
        }

        gvsTimer.Exit();

        return castSamples;
}


void ExportVssRays(Exporter *exporter, const VssRayContainer &vssRays)
{
        VssRayContainer vcRays, vcRays2, vcRays3;

        VssRayContainer::const_iterator rit, rit_end = vssRays.end();

        // prepare some rays for output
        for (rit = vssRays.begin(); rit != rit_end; ++ rit)
        {
                //const float p = RandomValue(0.0f, (float)vssRays.size());

                if (1)//(p < raysOut)
                {
                        if ((*rit)->mFlags & VssRay::BorderSample)
                                vcRays.push_back(*rit);
                        else if ((*rit)->mFlags & VssRay::ReverseSample)
                                vcRays2.push_back(*rit);
                        else
                                vcRays3.push_back(*rit);
                } 
        }

        exporter->ExportRays(vcRays, RgbColor(1, 0, 0));
        exporter->ExportRays(vcRays2, RgbColor(0, 1, 0));
        exporter->ExportRays(vcRays3, RgbColor(1, 1, 1));
}


void GvsPreprocessor::VisualizeViewCell(const ObjectContainer &objects)
{
    Intersectable::NewMail();
        Material m;
        
        char str[64]; sprintf_s(str, "pass%06d.wrl", mProcessedViewCells);

        Exporter *exporter = Exporter::GetExporter(str);
        if (!exporter)
                return;

        ObjectContainer::const_iterator oit, oit_end = objects.end();

        for (oit = objects.begin(); oit != oit_end; ++ oit)
        {
                Intersectable *intersect = *oit;
                
                m = RandomMaterial();
                exporter->SetForcedMaterial(m);
                exporter->ExportIntersectable(intersect);
        }

        cout << "vssrays: " << (int)mVssRays.size() << endl;
        ExportVssRays(exporter, mVssRays);


        /////////////////
        //-- export view cell geometry

        //exporter->SetWireframe();

        m.mDiffuseColor = RgbColor(0, 1, 0);
        exporter->SetForcedMaterial(m);

        AxisAlignedBox3 bbox = mCurrentViewCell->GetMesh()->mBox;
        exporter->ExportBox(bbox);
        //exporter->SetFilled();

        delete exporter;
}


void GvsPreprocessor::VisualizeViewCells()
{
        char str[64]; sprintf_s(str, "tmp/pass%06d_%04d-", mProcessedViewCells, mPass);
                        
        // visualization
        if (mGvsStats.mPassContribution > 0)
        {
                const bool exportRays = true;
                const bool exportPvs = true;

                mViewCellsManager->ExportSingleViewCells(mObjects, 
                                                                                                 10, 
                                                                                                 false, 
                                                                                                 exportPvs, 
                                                                                                 exportRays, 
                                                                                                 1000, 
                                                                                                 str);
        }

        // remove pass samples
        ViewCellContainer::const_iterator vit, vit_end = mViewCellsManager->GetViewCells().end();

        for (vit = mViewCellsManager->GetViewCells().begin(); vit != vit_end; ++ vit)
        {
                (*vit)->DelRayRefs();
        }
}


void GvsPreprocessor::CompileViewCellsFromPointList()
{
        ViewCell::NewMail();

        // Receive list of view cells from view cells manager
        ViewCellPointsList *vcPoints = mViewCellsManager->GetViewCellPointsList();

        vector<ViewCellPoints *>::const_iterator vit, vit_end = vcPoints->end();

        for (vit = vcPoints->begin(); vit != vit_end; ++ vit)
        {
                ViewCellPoints *vp = *vit;

                if (vp->first) // view cell  specified
                {
                        ViewCell *viewCell = vp->first;

                        if (!viewCell->Mailed())
                        {
                                viewCell->Mail();
                                mViewCells.push_back(viewCell);

                                if (mViewCells.size() >= mMaxViewCells)
                                        break;
                        }
                }
                else // no view cell specified => compute view cells using view point
                {
                        SimpleRayContainer::const_iterator rit, rit_end = vp->second.end();

                        for (rit = vp->second.begin(); rit != rit_end; ++ rit)
                        {
                                SimpleRay ray = *rit;

                                ViewCell *viewCell = mViewCellsManager->GetViewCell(ray.mOrigin);

                                if (viewCell && !viewCell->Mailed())
                                {
                                        viewCell->Mail();
                                        mViewCells.push_back(viewCell);

                                        if (mViewCells.size() >= mMaxViewCells)
                                                break;
                                }
                        }
                }
        }
}


void GvsPreprocessor::CompileViewCellsList()
{
        if (!mViewCellsManager->GetViewCellPointsList()->empty())
        {
                cout << "processing view point list" << endl;
                CompileViewCellsFromPointList();
        }
        else
        {
                ViewCell::NewMail();

                while ((int)mViewCells.size() < mMaxViewCells)
                {
                        const int tries = 10000;
                        int i = 0;

                        for (i = 0; i < tries; ++ i)
                        {
                                const int idx = (int)RandomValue(0.0f, (float)mViewCellsManager->GetNumViewCells() - 0.5f);

                                ViewCell *viewCell = mViewCellsManager->GetViewCell(idx);

                                if (!viewCell->Mailed())
                                {
                                        viewCell->Mail();
                                        break;
                                }

                                mViewCells.push_back(viewCell);
                        }

                        if (i == tries)
                        {
                                cerr << "big error! no view cell found" << endl;
                                break;
                        }
                }
        }

        cout << "\ncomputing list of " << mViewCells.size() << " view cells" << endl;
}


void GvsPreprocessor::ComputeViewCellGeometryIntersection()
{
        intersectionTimer.Entry();

        AxisAlignedBox3 box = mCurrentViewCell->GetBox();

        int oldTrianglePvs = (int)mTrianglePvs.size();
        int newKdObj = 0;

        // compute pvs kd nodes that intersect view cell
        ObjectContainer kdobjects;

        // find intersecting objects not in pvs (i.e., only unmailed)
        mKdTree->CollectKdObjects(box, kdobjects);

        ObjectContainer pvsKdObjects;

        ObjectContainer::const_iterator oit, oit_end = kdobjects.end();

        for (oit = kdobjects.begin(); oit != oit_end; ++ oit)
        {
        KdIntersectable *kdInt = static_cast<KdIntersectable *>(*oit);
        
                myobjects.clear();
                mKdTree->CollectObjectsWithDublicates(kdInt->GetItem(), myobjects);

                // account for kd object pvs
                bool addkdobj = false;

                ObjectContainer::const_iterator oit, oit_end = myobjects.end();

                for (oit = myobjects.begin(); oit != oit_end; ++ oit)
                {
                        TriangleIntersectable *triObj = static_cast<TriangleIntersectable *>(*oit);
             
                        // test if the triangle itself intersects
                        if (box.Intersects(triObj->GetItem()))
                                addkdobj = AddTriangleObject(triObj);
                }
                
                // add node to kd pvs
                if (1 && addkdobj)
                {
                        ++ newKdObj;
                        mCurrentViewCell->GetPvs().AddSampleDirty(kdInt, 1.0f);
                        //mCurrentViewCell->GetPvs().AddSampleDirtyCheck(kdInt, 1.0f);
                        if (QT_VISUALIZATION_SHOWN) UpdateStatsForVisualization(kdInt);
                }
        }

        cout << "added " << (int)mTrianglePvs.size() - oldTrianglePvs << " triangles (" << newKdObj << " objects) by intersection" << endl;

        intersectionTimer.Exit();
}


void GvsPreprocessor::PerViewCellComputation()
{
        while (mCurrentViewCell = NextViewCell())
        {
                preparationTimer.Entry();

                // hack: reset counters (could be done with a mailing-like approach
                ObjectContainer::const_iterator oit, oit_end = mObjects.end();
                for (oit = mObjects.begin(); oit != oit_end; ++ oit)
                        (*oit)->mCounter = NOT_ACCOUNTED_OBJECT;

                preparationTimer.Exit();

                mDistribution->SetViewCell(mCurrentViewCell);

        ComputeViewCell();
        }
}


void GvsPreprocessor::PerViewCellComputation2()
{
        while (1)
        {
                if (!mRendererWidget)
                        continue;

        mCurrentViewCell = mViewCellsManager->GetViewCell(mRendererWidget->GetViewPoint());

                // no valid view cell or view cell already computed
                if (!mCurrentViewCell || !mCurrentViewCell->GetPvs().Empty() || !mRendererWidget->mComputeGVS)
                        continue;

                mRendererWidget->mComputeGVS = false;
                // hack: reset counters
                ObjectContainer::const_iterator oit, oit_end = mObjects.end();

                for (oit = mObjects.begin(); oit != oit_end; ++ oit)
                        (*oit)->mCounter = NOT_ACCOUNTED_OBJECT;

                ComputeViewCell();
                ++ mProcessedViewCells;
        }
}


void GvsPreprocessor::StorePvs(const ObjectContainer &objectPvs)
{
        ObjectContainer::const_iterator oit, oit_end = objectPvs.end();

        for (oit = objectPvs.begin(); oit != oit_end; ++ oit)
        {
                mCurrentViewCell->GetPvs().AddSample(*oit, 1);
        }
}


void GvsPreprocessor::UpdatePvs(ViewCell *currentViewCell)
{
        ObjectPvs newPvs;
        BvhLeaf::NewMail();

        ObjectPvsIterator pit = currentViewCell->GetPvs().GetIterator();

        // output PVS of view cell
        while (pit.HasMoreEntries())
        {               
                Intersectable *intersect = pit.Next();

                BvhLeaf *bv = intersect->mBvhLeaf;

                if (!bv || bv->Mailed())
                        continue;
                
                bv->Mail();

                //m.mDiffuseColor = RgbColor(1, 0, 0);
                newPvs.AddSampleDirty(bv, 1.0f);
        }

        newPvs.SimpleSort();

        currentViewCell->SetPvs(newPvs);
}

 
void GvsPreprocessor::GetObjectPvs(ObjectContainer &objectPvs) const
{
        BvhLeaf::NewMail();

        objectPvs.reserve((int)mTrianglePvs.size());

        ObjectContainer::const_iterator oit, oit_end = mTrianglePvs.end();

        for (oit = mTrianglePvs.begin(); oit != oit_end; ++ oit)
        {
                Intersectable *intersect = *oit;
        
                BvhLeaf *bv = intersect->mBvhLeaf;

                // hack: reset counter
                (*oit)->mCounter = NOT_ACCOUNTED_OBJECT;

                if (!bv || bv->Mailed())
                        continue;

                bv->Mail();
                objectPvs.push_back(bv);
        }
}


void GvsPreprocessor::GlobalComputation()
{
        int passSamples = 0;
        int randomSamples = 0;
        int gvsSamples = 0;
        int oldContribution = 0;

        while (mGvsStats.mTotalSamples < mTotalSamples) 
        {
                mRayCaster->InitPass();

                int newRandomSamples, newGvsSamples;

                // Ray queue empty => 
                // cast a number of uniform samples to fill ray queue
                newRandomSamples = CastInitialSamples(mInitialSamples);
                
                if (!mOnlyRandomSampling)
                        newGvsSamples = ProcessQueue();

                passSamples += newRandomSamples + newGvsSamples;
                mGvsStats.mTotalSamples += newRandomSamples + newGvsSamples;

                mGvsStats.mRandomSamples += newRandomSamples;
                mGvsStats.mGvsSamples += newGvsSamples;


                if (passSamples % (mGvsSamplesPerPass + 1) == mGvsSamplesPerPass)
                {
                        ++ mPass;

                        mGvsStats.mPassContribution = mGvsStats.mTotalContribution - oldContribution;
                        
                        ////////
                        //-- stats

                        //cout << "\nPass " << mPass << " #samples: " << mGvsStats.mTotalSamples << " of " << mTotalSamples << endl;
                        mGvsStats.mPass = mPass;
                        mGvsStats.Stop();
                        mGvsStats.Print(mGvsStatsStream);

                        // reset
                        oldContribution = mGvsStats.mTotalContribution;
                        mGvsStats.mPassContribution = 0;
                        passSamples = 0;

                        if (GVS_DEBUG)
                                VisualizeViewCells();
                }
        }
}


bool GvsPreprocessor::ComputeVisibility()
{
        cout << "Gvs Preprocessor started\n" << flush;
        const long startTime = GetTime();

        //Randomize(0);
        mGvsStats.Reset();
        mGvsStats.Start();

        if (!mLoadViewCells)
        {       
                /// construct the view cells from the scratch
                ConstructViewCells();
                // reset pvs already gathered during view cells construction
                mViewCellsManager->ResetPvs();
                cout << "finished view cell construction" << endl;
        }

        if (mPerViewCell)
        {
#if 1
                // provide list of view cells to compute
                CompileViewCellsList();

                // start per view cell gvs
                PerViewCellComputation();
#else
                PerViewCellComputation2();

#endif
        }
        else
        {
                GlobalComputation();
        }

        cout << "cast " << mGvsStats.mTotalSamples / (1e3f * TimeDiff(startTime, GetTime())) << "M single rays/s" << endl;

        if (GVS_DEBUG)
        {
                Visualize();
                CLEAR_CONTAINER(mVssRays);
        }
        
        // export the preprocessed information to a file
        if (0 && mExportVisibility)
                ExportPreprocessedData(mVisibilityFileName);
        
        // compute the pixel error of this visibility solution
        if (0 && mEvaluatePixelError)
                ComputeRenderError();

        return true;
}


void GvsPreprocessor::DeterminePvsObjects(VssRayContainer &rays)
{
        // store triangle directly
        mViewCellsManager->DeterminePvsObjects(rays, true);
}


void GvsPreprocessor::Visualize()
{
        Exporter *exporter = Exporter::GetExporter("gvs.wrl");

        if (!exporter)
                return;
        
        vector<VizStruct>::const_iterator vit, vit_end = vizContainer.end();
        
        for (vit = vizContainer.begin(); vit != vit_end; ++ vit)
        {
                exporter->SetWireframe();
                exporter->ExportPolygon((*vit).enlargedTriangle);
                //Material m;
                exporter->SetFilled();
                Polygon3 poly = Polygon3((*vit).originalTriangle);
                exporter->ExportPolygon(&poly);
        }

        VssRayContainer::const_iterator rit, rit_end = mVssRays.end();

        for (rit = mVssRays.begin(); rit != rit_end; ++ rit)
        {
                Intersectable *obj = (*rit)->mTerminationObject;
                exporter->ExportIntersectable(obj);
        }

        ExportVssRays(exporter, mVssRays);
        
        delete exporter;
}


void GvsStatistics::Print(ostream &app) const
{
        app << "#ViewCells\n" << mViewCells << endl;
        app << "#Id\n" << mViewCellId << endl;
        app << "#Time\n" << mTimePerViewCell << endl;;
        app << "#TriPvs\n" << mTrianglePvs << endl;
        app << "#ObjectPvs\n" << mPerViewCellPvs << endl;
        app << "#UpdatedPvs\n" << (int)mPvsCost << endl;

        app << "#PerViewCellSamples\n" << mPerViewCellSamples << endl;
        app << "#RaysPerSec\n" << RaysPerSec() << endl;
        
        app << "#TotalPvs\n" << mTotalPvs << endl;
        app << "#TotalTime\n" << mTotalTime << endl;
        app << "#TotalSamples\n" << mTotalSamples << endl;

        app << "#AvgPvs: " << mPvsCost / mViewCells << endl;
        app << "#TotalTrianglePvs\n" << mTotalTrianglePvs << endl;
        
        if (0)
        {
                app << "#ReverseSamples\n" << mReverseSamples << endl;
                app << "#BorderSamples\n" << mBorderSamples << endl;

                app << "#Pass\n" << mPass << endl;
                app << "#ScDiff\n" << mPassContribution << endl;
                app << "#GvsRuns\n" << mGvsRuns << endl;        

                app     << "#SamplesContri\n" << mTotalContribution << endl;
        }

        app << endl;
}


void GvsPreprocessor::ComputeViewCell()
{
        const long startTime = GetTime();

        // initialise
        mGvsStats.mPerViewCellSamples = 0;
        mGvsStats.mRandomSamples = 0;
        mGvsStats.mGvsSamples = 0;
        mUseProbablyVisibleSampling = false;
        //renderer->mPvsStat.currentPass = 0;

        mPass = 0;

        int oldContribution = 0;
        int passSamples = 0;

        for (int i = 0; i < 2; ++ i)
                mGenericStats[i] = 0;

        mTrianglePvs.clear();


        // hack: take bounding box of view cell as view cell bounds
        mCurrentViewCell->GetMesh()->ComputeBoundingBox();

        // use mailing for kd node pvs
        KdNode::NewMail();

        cout << "\n***********************\n" 
                << "computing view cell " << mProcessedViewCells 
                << " (id: " << mCurrentViewCell->GetId() << ")" << endl;
        cout << "bb: " << mCurrentViewCell->GetBox() << endl;

        mainLoopTimer.Entry();

        while (1)
        {
                sInvalidSamples = 0;
                int oldPvsSize = mCurrentViewCell->GetPvs().GetSize();
                
                mRayCaster->InitPass();

                int newRandomSamples, newGvsSamples, newSamples;

                // Ray queue empty => 
                // cast a number of uniform samples to fill ray queue
                newRandomSamples = CastInitialSamples(mInitialSamples);
                
                //if (!mUseProbablyVisibleSampling && !mOnlyRandomSampling)
                if (!mOnlyRandomSampling)
                        newGvsSamples = ProcessQueue();

                newSamples = newRandomSamples + newGvsSamples;

                passSamples += newSamples;
                mGvsStats.mPerViewCellSamples += newSamples;

                mGvsStats.mRandomSamples += newRandomSamples;
                mGvsStats.mGvsSamples += newGvsSamples;


                if (passSamples >= mGvsSamplesPerPass)
                {
                        if (GVS_DEBUG) VisualizeViewCell(mTrianglePvs);

                        //const bool convertPerPass = true;
                        const bool convertPerPass = false;

                        if (convertPerPass)
                        {       
                                int newObjects = ConvertObjectPvs();

                                cout << "added " << newObjects << " triangles to triangle pvs" << endl;
                                mGvsStats.mTotalContribution += newObjects;
                        }

                        ++ mPass;
                        mGvsStats.mPassContribution = mGvsStats.mTotalContribution - oldContribution;

                        if (!mUseDeterministicGvs && (mGvsStats.mPassContribution < 2000))
                                mUseProbablyVisibleSampling = true;
                        
                        if (mUseProbablyVisibleSampling)
                                PrepareProbablyVisibleSampling();


                        ////////
                        //-- stats

                        mGvsStats.mPass = mPass;

                        cout << "\nPass " << mPass << " #samples: " << mGvsStats.mPerViewCellSamples << endl;
                        cout << "contribution=" << mGvsStats.mPassContribution << " (of " << mMinContribution << ")" << endl;
                        cout << "obj contri=" << mCurrentViewCell->GetPvs().GetSize() - oldPvsSize << " (of " << mMinContribution << ")" << endl;

                        // termination criterium
                        if (mGvsStats.mPassContribution < mMinContribution)
                                break;

                        // reset stats
                        oldContribution = mGvsStats.mTotalContribution;
                        mGvsStats.mPassContribution = 0;
                        passSamples = 0;
                        
                        // compute the pixel error of this visibility solution
                        if (0 && mEvaluatePixelError)
                                ComputeRenderError();
                }
        }
        
        mainLoopTimer.Exit();

        // at last compute objects that directly intersect view cell
        ComputeViewCellGeometryIntersection();
                
        // compute the pixel error of this visibility solution
        if (mEvaluatePixelError)
                ComputeRenderError();

        ////////
        //-- stats

        // timing
        mGvsStats.mTimePerViewCell = TimeDiff(startTime, GetTime()) * 1e-3f;

        ComputeStats();
}


void GvsPreprocessor::ComputeStats()
{
        // compute pvs size using larger (bvh objects)
        // note: for kd pvs we had to do this during gvs computation
        if (!mUseKdPvs)
        {
                ObjectContainer objectPvs;

                // optain object pvs
                GetObjectPvs(objectPvs);

                // add pvs
                ObjectContainer::const_iterator it, it_end = objectPvs.end();

                for (it = objectPvs.begin(); it != it_end; ++ it)
                {
                        mCurrentViewCell->GetPvs().AddSampleDirty(*it, 1.0f);
                }

                cout << "triangle pvs of " << (int)mTrianglePvs.size() 
                        << " was converted to object pvs of " << (int)objectPvs.size() << endl;

                mGvsStats.mPerViewCellPvs = (int)objectPvs.size();
                mGvsStats.mPvsCost = 0; // todo objectPvs.EvalPvsCost();
        }
        else
        {
                 if (0) // compute pvs kd nodes that intersect view cell
                 {
                         ObjectContainer mykdobjects;

                         // extract kd pvs
                         ObjectContainer::const_iterator it, it_end = mTrianglePvs.end();

                         for (it = mTrianglePvs.begin(); it != it_end; ++ it)
                         {
                                 Intersectable *obj = *it;
                                 // find intersecting objects not yet in pvs (i.e., only unmailed)
                                 mKdTree->CollectKdObjects(obj->GetBox(), mykdobjects);
                         }

                         // add pvs
                         it_end = mykdobjects.end();

                         for (it = mykdobjects.begin(); it != it_end; ++ it)
                         {
                                 mCurrentViewCell->GetPvs().AddSampleDirty(*it, 1.0f);
                         }
                 
                         cout << "added " << (int)mykdobjects.size() << " new objects " << endl;
                 }

                 mGvsStats.mPerViewCellPvs = mCurrentViewCell->GetPvs().GetSize();
                 mGvsStats.mPvsCost = mCurrentViewCell->GetPvs().EvalPvsCost();

        }

        mGvsStats.mTrianglePvs = (int)mTrianglePvs.size();


        ////////////////
        // global values

        mGvsStats.mViewCells = mProcessedViewCells;
        mGvsStats.mTotalTrianglePvs += mGvsStats.mTrianglePvs;
        mGvsStats.mTotalTime += mGvsStats.mTimePerViewCell;
    mGvsStats.mTotalPvs += mGvsStats.mPerViewCellPvs;
        mGvsStats.mTotalSamples += mGvsStats.mPerViewCellSamples;

        cout << "id: " << mCurrentViewCell->GetId() << endl;
        cout << "pvs cost "  << mGvsStats.mPvsCost / 1000000 << " M" << endl;
        cout << "pvs tri: " << mTrianglePvs.size() << endl;
        cout << "samples: " << mGvsStats.mTotalSamples / 1000000 << " M" << endl;
        printf("contri: %f tri / K rays\n", 1000.0f * (float)mTrianglePvs.size() / mGvsStats.mTotalSamples);

        //cout << "invalid samples ratio: " << (float)sInvalidSamples / mGvsStats.mPerViewCellSamples << endl;

        double rayTime = rayTimer.TotalTime();
        double kdPvsTime = kdPvsTimer.TotalTime();
        double gvsTime = gvsTimer.TotalTime();
        double initialTime = initialTimer.TotalTime();
        double intersectionTime = intersectionTimer.TotalTime();
        double preparationTime = preparationTimer.TotalTime();
        double mainLoopTime = mainLoopTimer.TotalTime();
        double contributionTime = contributionTimer.TotalTime();
        double castTime = castTimer.TotalTime();
        double generationTime = generationTimer.TotalTime();
        double rawCastTime = mRayCaster->rawCastTimer.TotalTime();

        cout << "handleRay              : " << rayTime << endl;
        cout << "kd pvs                 : " << kdPvsTime << endl;
        cout << "gvs sampling           : " << gvsTime << endl;
        cout << "initial sampling       : " << initialTime << endl;
        cout << "view cell intersection : " << intersectionTime << endl;
        cout << "preparation            : " << preparationTime << endl;
        cout << "main loop              : " << mainLoopTime << endl;
        cout << "has contribution       : " << contributionTime << endl;
        cout << "cast time              : " << castTime << endl;
        cout << "generation time        : " << generationTime << endl;
        cout << "raw cast time          : " << rawCastTime << endl;

        double randomRaysPerSec = mGvsStats.mRandomSamples / (1e6 * initialTime);
        double gvsRaysPerSec = mGvsStats.mGvsSamples / (1e6 * gvsTime);
        double rawRaysPerSec = mGvsStats.mPerViewCellSamples / (1e6 * rawCastTime);

        cout << "cast " << randomRaysPerSec << " M random rays/s: " << endl;
        cout << "cast " << gvsRaysPerSec << " M gvs rays/s: " << endl;
        cout << "cast " << rawRaysPerSec << " M raw rays/s: " << endl;

        mGvsStats.Stop();
        mGvsStats.Print(mGvsStatsStream);
}


int GvsPreprocessor::ConvertObjectPvs()
{
        static ObjectContainer triangles;

        int newObjects = 0;

        ObjectPvsIterator pit = mCurrentViewCell->GetPvs().GetIterator();

        triangles.clear();

        // output PVS of view cell
        while (pit.HasMoreEntries())
        {               
                KdIntersectable *kdInt = static_cast<KdIntersectable *>(pit.Next());

                mKdTree->CollectObjectsWithDublicates(kdInt->GetItem(), triangles);

                ObjectContainer::const_iterator oit, oit_end = triangles.end();

                for (oit = triangles.begin(); oit != oit_end; ++ oit)
                {
                        if (AddTriangleObject(*oit))
                                ++ newObjects;
                }
        }

        return newObjects;
}


bool GvsPreprocessor::AddTriangleObject(Intersectable *triObj)
{
        if ((triObj->mCounter < ACCOUNTED_OBJECT))
        {
                triObj->mCounter += ACCOUNTED_OBJECT;

                mTrianglePvs.push_back(triObj);
                mGenericStats[0] = (int)mTrianglePvs.size();

                return true;
        }

        return false;
}


void GvsPreprocessor::CastRayBundles4(const SimpleRayContainer &rays, VssRayContainer &vssRays)
{
        AxisAlignedBox3 box = mViewCellsManager->GetViewSpaceBox();

        SimpleRayContainer::const_iterator it, it_end = rays.end();

        for (it = rays.begin(); it != it_end; ++ it)
                CastRayBundle4(*it, vssRays, box);
}


void GvsPreprocessor::CastRayBundle4(const SimpleRay &ray, 
                                                                         VssRayContainer &vssRays, 
                                                                         const AxisAlignedBox3 &box)
{
        const float pertubDir = 0.01f;
        static Vector3 pertub;

        static int hit_triangles[4];
        static float dist[4];
        static Vector3 dirs[4];
        static Vector3 origs[4];

        origs[0] = ray.mOrigin;
        dirs[0] = ray.mDirection;

        for (int i = 1; i < 4; ++ i) 
        {
                origs[i] = ray.mOrigin;

                pertub.x = RandomValue(-pertubDir, pertubDir);
                pertub.y = RandomValue(-pertubDir, pertubDir);
                pertub.z = RandomValue(-pertubDir, pertubDir);

                dirs[i] = ray.mDirection + pertub;
                dirs[i] *= 1.0f / Magnitude(dirs[i]);
        }

        Cast4Rays(dist, dirs, origs, vssRays, box);
}


void GvsPreprocessor::CastRays4(const SimpleRayContainer &rays, VssRayContainer &vssRays)
{
        SimpleRayContainer::const_iterator it, it_end = rays.end();
        
        static float dist[4];
        static Vector3 dirs[4];
        static Vector3 origs[4];

        AxisAlignedBox3 box = mViewCellsManager->GetViewSpaceBox();

        for (it = rays.begin(); it != it_end; ++ it)
        {
                for (int i = 1; i < 4; ++ i) 
                {
                        origs[i] = rays[i].mOrigin;
                        dirs[i] = rays[i].mDirection;
                }
        }

        Cast4Rays(dist, dirs, origs, vssRays, box);
}


void GvsPreprocessor::Cast4Rays(float *dist,
                                                                Vector3 *dirs,
                                                                Vector3 *origs,
                                                                VssRayContainer &vssRays,
                                                                const AxisAlignedBox3 &box)
{
        static int hit_triangles[4];

        mRayCaster->CastRaysPacket4(box.Min(), box.Max(), origs, dirs, hit_triangles,   dist);       

        VssRay *ray;

        for (int i = 0; i < 4; ++ i)
        {
                if (hit_triangles[i] != -1)
                {
                        TriangleIntersectable *triObj = static_cast<TriangleIntersectable *>(mObjects[hit_triangles[i]]);

                        if (DotProd(triObj->GetItem().GetNormal(), dirs[i] >= 0))
                                ray = NULL;
                        else
                                ray = mRayCaster->RequestRay(origs[i], origs[i] + dirs[i] * dist[i], NULL, triObj, mPass, 1.0f);
                }
                else
                {
                        ray = NULL;
                }

                vssRays.push_back(ray);
        }
}


void GvsPreprocessor::CastRayBundle16(const SimpleRay &ray, VssRayContainer &vssRays, float scale)
{
        static SimpleRayContainer simpleRays;
        simpleRays.clear();

        simpleRays.push_back(ray);
        GenerateJitteredRays(simpleRays, ray, 15, 0, scale);

        CastRays(simpleRays, vssRays, false, false);
}


void GvsPreprocessor::CastRayBundles16(const SimpleRayContainer &rays, VssRayContainer &vssRays, float scale)
{
        SimpleRayContainer::const_iterator it, it_end = rays.end();

        for (it = rays.begin(); it != it_end; ++ it)
                CastRayBundle16(*it, vssRays, scale);
}


void GvsPreprocessor::ComputeRenderError()
{
        // compute rendering error      
        if (renderer && renderer->mPvsStatFrames) 
        {
                if (!mViewCellsManager->GetViewCellPointsList()->empty()) 
                {
                        ViewCellPointsList *vcPoints = mViewCellsManager->GetViewCellPointsList();
                        ViewCellPointsList::const_iterator vit = vcPoints->begin(),     vit_end = vcPoints->end();

                        SimpleRayContainer viewPoints;

                        for (; vit != vit_end; ++ vit) 
                        {
                                ViewCellPoints *vp = *vit;
                                
                                SimpleRayContainer::const_iterator rit = vp->second.begin(), rit_end = vp->second.end();
                        
                                for (; rit!=rit_end; ++rit)
                                {
                                        ViewCell *vc = mViewCellsManager->GetViewCell((*rit).mOrigin);
                                        if (vc == mCurrentViewCell)
                                                viewPoints.push_back(*rit);
                                }
                        }

                        renderer->mPvsErrorBuffer.clear();

                        if (viewPoints.size() != renderer->mPvsErrorBuffer.size()) 
                        {
                                renderer->mPvsErrorBuffer.resize(viewPoints.size());
                                renderer->ClearErrorBuffer();
                        }

                        cout << "evaluating list of " << viewPoints.size() << " pts" << endl;
                        renderer->EvalPvsStat(viewPoints);
                } 
                else
                {
                        cout << "evaluating random points" << endl;
                        renderer->EvalPvsStat();
                }

                mStats <<
                        "#AvgPvsRenderError\n" <<renderer->mPvsStat.GetAvgError()<<endl<<
                        "#AvgPixelError\n" <<renderer->GetAvgPixelError()<<endl<<
                        "#MaxPixelError\n" <<renderer->GetMaxPixelError()<<endl<<
                        "#MaxPvsRenderError\n" <<renderer->mPvsStat.GetMaxError()<<endl<<
                        "#ErrorFreeFrames\n" <<renderer->mPvsStat.GetErrorFreeFrames()<<endl<<
                        "#AvgRenderPvs\n" <<renderer->mPvsStat.GetAvgPvs()<<endl;
        }
}


void GvsPreprocessor::GenerateImportanceSamples(const VssRay &ray, 
                                                                                                const Triangle3 &triangle, 
                                                                                                int numSamples,
                                                                                                SimpleRayContainer &simpleRays)
{
        const size_t samplesSize = simpleRays.size();

        while (simpleRays.size() < (samplesSize + numSamples))
        {
                SimpleRay sray;
                if (GenerateImportanceSample(ray, triangle, sray))
                        simpleRays.push_back(sray);
        }
}


bool GvsPreprocessor::GenerateImportanceSample(const VssRay &ray, 
                                                                                           const Triangle3 &triangle, 
                                                                                           SimpleRay &sray)
{
        Vector3 d = ray.GetDir();
  
        // Compute right handed coordinate system from direction
        Vector3 U, V;

        Vector3 nd = Normalize(d);
        nd.RightHandedBase(U, V);
        
        Vector3 origin = ray.mOrigin;
        Vector3 termination = ray.mTermination;

        float rr[2];

        rr[0] = RandomValue(0, 1);
        rr[1] = RandomValue(0, 1);

        Vector2 vr2(rr[0], rr[1]);
        const float sigma = triangle.GetBoundingBox().Radius() * mRadiusOfInfluence;
        Vector2 gaussvec2;

        GaussianOn2D(vr2, sigma, // input
                         gaussvec2); // output
        
        const Vector3 shift = gaussvec2.xx * U + gaussvec2.yy * V;

        //cout << "t: " << termination;
        termination += shift;
        //cout << " new t: " << termination << endl;
        Vector3 direction = termination - origin;

        const float len = Magnitude(direction);
        
        if (len < Limits::Small)
                return false;
  
        direction /= len;

        // $$ jb the pdf is yet not correct for all sampling methods!
        const float pdf = 1.0f;
        sray = SimpleRay(origin, direction, SamplingStrategy::GVS, pdf);
        
        return true;
}


void GvsPreprocessor::PrepareProbablyVisibleSampling()
{
        
        // warning: using mailing!
        Intersectable::NewMail();

        mProbablyVisibleTriangles.clear();
        CollectProbablyVisibleTriangles(mProbablyVisibleTriangles);
}


void GvsPreprocessor::CollectProbablyVisibleTriangles(ObjectContainer &triangles)
{
        ObjectPvsIterator pit = mCurrentViewCell->GetPvs().GetIterator();

        static ObjectContainer tmpTriangles;

        while (pit.HasMoreEntries())
        {       
                tmpTriangles.clear();

                KdIntersectable *kdObj = static_cast<KdIntersectable *>(pit.Next());
                mKdTree->CollectObjectsWithDublicates(kdObj->GetItem(), tmpTriangles);

                ObjectContainer::const_iterator oit, oit_end = tmpTriangles.end();

                for (oit = tmpTriangles.begin(); oit != oit_end; ++ oit)
                {
                        TriangleIntersectable *triObj = static_cast<TriangleIntersectable *>(*oit);

                        // find objects which are not yet accounted for yet contained in kd pvs objects
                        if (!triObj->Mailed() && (triObj->mCounter < ACCOUNTED_OBJECT))
                        {
                                triObj->Mail();
                                triangles.push_back(triObj);
                        }
                }
        }
}


void GvsPreprocessor::CreateRandomizedReverseRays(const Vector3 &origin, 
                                                                                                  const Vector3 &termination, 
                                                                                                  const Triangle3 &triangle,                   
                                                                                                  SimpleRayContainer &rays, 
                                                                                                  int number)
{
        size_t currentNumber = rays.size();

        while ((rays.size() - currentNumber) < number)
        {
                SimpleRay ray;
                if (CreateRandomizedReverseRay(origin, termination, triangle, ray))
                        rays.push_back(ray);
        }
}


bool GvsPreprocessor::CreateRandomizedReverseRay(const Vector3 &origin, 
                                                                                                 const Vector3 &termination, 
                                                                                                 const Triangle3 &triangle,                   
                                                                                                 SimpleRay &ray)
{
        Vector3 nd = triangle.GetNormal();
  
        // Compute right handed coordinate system from direction
        Vector3 U, V;
        nd.RightHandedBase(U, V);
        
        float rr[2];

        rr[0] = RandomValue(0, 1);
        rr[1] = RandomValue(0, 1);

        Vector2 vr2(rr[0], rr[1]);
        const float sigma = triangle.GetBoundingBox().Radius() * mRadiusOfInfluence;
        Vector2 gaussvec2;

        GaussianOn2D(vr2, sigma, // input
                         gaussvec2); // output
        
        const Vector3 shift = gaussvec2.xx * U + gaussvec2.yy * V;

        Vector3 newOrigin = origin;

        //cout << "t: " << termination;
        newOrigin += shift;
        //cout << " new t: " << termination << endl;
        Vector3 direction = termination - newOrigin;

        const float len = Magnitude(direction);
        
        if (len < Limits::Small)
                return false;
  
        direction /= len;

        if (!IntersectViewCell(newOrigin, direction))
                return false;

        // $$ jb the pdf is yet not correct for all sampling methods!
        const float pdf = 1.0f;
        ray = SimpleRay(newOrigin, direction, SamplingStrategy::GVS, pdf);
        
        return true;
}


}