source: GTP/trunk/Lib/Vis/Preprocessing/src/GvsPreprocessor.cpp @ 1982

#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"


namespace GtpVisibilityPreprocessor
{
  
#define GVS_DEBUG 1

struct VizStruct
{
        Polygon3 *enlargedTriangle;
        Triangle3 originalTriangle;
        VssRay *ray;
};

static vector<VizStruct> vizContainer;

GvsPreprocessor::GvsPreprocessor(): 
Preprocessor(), 
mSamplingType(SamplingStrategy::DIRECTION_BOX_BASED_DISTRIBUTION),
mNumViewCells(0),
mCurrentViewCell(NULL)
{
        Environment::GetSingleton()->GetIntValue("GvsPreprocessor.totalSamples", mTotalSamples);
        Environment::GetSingleton()->GetIntValue("GvsPreprocessor.initialSamples", mInitialSamples);
        Environment::GetSingleton()->GetIntValue("GvsPreprocessor.samplesPerPass", mSamplesPerPass);
        Environment::GetSingleton()->GetFloatValue("GvsPreprocessor.epsilon", mEps);
        Environment::GetSingleton()->GetFloatValue("GvsPreprocessor.threshold", mThreshold);    
        Environment::GetSingleton()->GetBoolValue("GvsPreprocessor.UsePerViewCellSampling", mPerViewCell);

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

        Debug << "Gvs preprocessor options" << endl;
        Debug << "number of total samples: " << mTotalSamples << endl;
        Debug << "number of initial samples: " << mInitialSamples << endl;
        Debug << "number of samples per pass: " << mSamplesPerPass << endl;
        Debug << "threshold: " << mThreshold << endl;
        Debug << "epsilon: " << mEps << endl;
        Debug << "stats: " << gvsStatsLog << endl;

        if (0)
                mOnlyRandomSampling = true;
        else
                mOnlyRandomSampling = false;

        mGvsStats.Reset();
}


bool GvsPreprocessor::NextViewCell()
{
        if (mViewCellsManager->GetNumViewCells() == mNumViewCells)
                return false; // no more view cells

        mCurrentViewCell = mViewCellsManager->GetViewCell(mNumViewCells);
        mViewCellsManager->CreateMesh(mCurrentViewCell);

        ++ mNumViewCells;
    
        return true;
}


bool GvsPreprocessor::CheckDiscontinuity(const VssRay &currentRay,
                                                                                 const Triangle3 &hitTriangle,
                                                                                 const VssRay &oldRay)
{
        // the predicted hitpoint: we expect to hit the same mesh again
        const Vector3 predictedHit = CalcPredictedHitPoint(currentRay, hitTriangle, oldRay);

        const float predictedLen = Magnitude(predictedHit - currentRay.mOrigin);
        const float len = Magnitude(currentRay.mTermination - currentRay.mOrigin);
        
        // distance large => this is likely to be a discontinuity
#if 1
        if ((predictedLen - len) > mThreshold)
#else // rather use relative distance
        if ((predictedLen / len) > mThreshold)
#endif
        {
                //cout << "r";
                // apply reverse sampling to find the gap
                VssRay *newRay = ReverseSampling(currentRay, hitTriangle, oldRay);

                if (!newRay)
                        return false;

                // set flag for visualization
                newRay->mFlags |= VssRay::ReverseSample;
                
                // if ray is not further processed => delete ray
                if (!HandleRay(newRay))
                {
                        delete newRay;
                }
                else if (GVS_DEBUG && (mVssRays.size() < 9))
                {
                        mVssRays.push_back(new VssRay(oldRay));
                        mVssRays.push_back(new VssRay(currentRay));
                        mVssRays.push_back(new VssRay(*newRay));
                }

                return true;
        }

        return false;
}


bool GvsPreprocessor::HandleRay(VssRay *vssRay)
{
        // compute the contribution to the view cells
        const bool storeRaysForViz = GVS_DEBUG;

        if (!mPerViewCell)
        {
                mViewCellsManager->ComputeSampleContribution(*vssRay, 
                                                                                                         true, 
                                                                                                         storeRaysForViz);
        }
        else
        {
                mViewCellsManager->ComputeSampleContribution(*vssRay, 
                                                                                                         true, 
                                                                                                         mCurrentViewCell);
        }

        // some pvs contribution for this ray?
        if (!vssRay->mPvsContribution)
                return false;

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

        if (storeRaysForViz)
        {
                VssRay *nray = new VssRay(*vssRay);
                nray->mFlags = vssRay->mFlags;

                // store ray in contributing view cell
                ViewCellContainer::const_iterator vit, vit_end = vssRay->mViewCells.end();
                for (vit = vssRay->mViewCells.begin(); vit != vit_end; ++ vit)
                {                       
                        (*vit)->GetOrCreateRays()->push_back(nray);                             
                }
        }

        ++ mGvsStats.mPassContribution;

        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)
{
        CheckDiscontinuity(ray1, hitTriangle, oldRay);
        CheckDiscontinuity(ray2, hitTriangle, oldRay);

        if (EqualVisibility(ray1, ray2) || (Magnitude(p1 - p2) <= mEps))
        {
                return 0;
        }
        else
        {
                // the new subdivision point
                const Vector3 p = (p1 + p2) * 0.5f;
        
                //cout << "tobj " << ray1.mTerminationObject << " " << ray2.mTerminationObject << " " << p1 << " " << p2 << endl;
                //cout << "term " << ray1.mTermination << " " << ray2.mTermination << endl;

                // cast ray into the new point
                SimpleRay sray(oldRay.mOrigin, p - oldRay.mOrigin, SamplingStrategy::GVS, 1.0f);
        
                VssRay *newRay = mRayCaster->CastRay(sray, mViewCellsManager->GetViewSpaceBox());

                if (!newRay) return 0;

                newRay->mFlags |= VssRay::BorderSample;

                // add new ray to queue
                const bool enqueued = HandleRay(newRay);
                
                // subdivide further
                const int samples1 = SubdivideEdge(hitTriangle, p1, p, ray1, *newRay, oldRay);
                const int samples2 = SubdivideEdge(hitTriangle, p, p2, *newRay, ray2, oldRay);
                        
                // this ray will not be further processed
                if (!enqueued)
                        delete newRay;
                
                return samples1 + samples2 + 1;
        }
}


int GvsPreprocessor::AdaptiveBorderSampling(const VssRay &currentRay)
{
        Intersectable *tObj = currentRay.mTerminationObject;
        Triangle3 hitTriangle;

        // other types not implemented yet
        if (tObj->Type() == Intersectable::TRIANGLE_INTERSECTABLE)
        {
                hitTriangle = dynamic_cast<TriangleIntersectable *>(tObj)->GetItem();
        }
        else
        {
                cout << "not yet implemented" << endl;
        }

        VertexContainer enlargedTriangle;
        
        /// create 3 new hit points for each vertex
        EnlargeTriangle(enlargedTriangle, hitTriangle, currentRay);
        
        /// create rays from sample points and handle them
        SimpleRayContainer simpleRays;
        simpleRays.reserve(9);

        //cout << "currentRay: " << currentRay.mOrigin << " dir: " << currentRay.GetDir() << endl;

        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);

                //cout << "new: " << sr.mOrigin << " dist: " << sr.mDirection << endl;
        }

        if (0)
        {
                // visualize enlarged triangles
                VizStruct dummy;
                dummy.enlargedTriangle = new Polygon3(enlargedTriangle);
                dummy.originalTriangle = hitTriangle;
                vizContainer.push_back(dummy);
        }

        // cast rays to triangle vertices and determine visibility
        VssRayContainer vssRays;

        // don't cast double rays as we need only the forward rays
        const bool castDoubleRays = false;
        // cannot prune invalid rays because we have to 
        // compare adjacent  rays.
        const bool pruneInvalidRays = false;

        CastRays(simpleRays, vssRays, castDoubleRays, pruneInvalidRays);

        // set flags
        VssRayContainer::const_iterator rit, rit_end = vssRays.end();
        for (rit = vssRays.begin(); rit != rit_end; ++ rit)
        {
                (*rit)->mFlags |= VssRay::BorderSample;
        }

        // handle rays
        EnqueueRays(vssRays);
        
        const int n = (int)enlargedTriangle.size();
        int castRays = (int)vssRays.size();

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

        mGvsStats.mBorderSamples += castRays;

        return castRays;
}


Vector3 GvsPreprocessor::GetPassingPoint(const VssRay &currentRay,
                                                                                 const Triangle3 &occluder,
                                                                                 const VssRay &oldRay) const
{
        //-- The plane p = (xp, hit(x), hit(xold)) is intersected
        //-- 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;

        const bool intersects = occluder.GetPlaneIntersection(plane, pt1, pt2);

        if (!intersects)
                cerr << "big error!! no intersection" << endl;

        // 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
        Vector3 newPoint;

        const float eps = mEps;
        // the point is chosen to be on the side closer to the original ray
        if (Distance(pt1, pt3) < Distance(pt2, pt3))
        {
                newPoint = pt1 + eps * (pt1 - pt2);
        }       
        else
        {
                newPoint = pt2 + eps * (pt2 - pt1);
        }

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


VssRay *GvsPreprocessor::ReverseSampling(const VssRay &currentRay,
                                                                                 const Triangle3 &hitTriangle,
                                                                                 const VssRay &oldRay)
{
        // get triangle occluding the path to the hit mesh
        Triangle3 occluder;
        Intersectable *tObj = currentRay.mTerminationObject;

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

        // other types not implemented yet
        if (tObj->Type() == Intersectable::TRIANGLE_INTERSECTABLE)
                occluder = dynamic_cast<TriangleIntersectable *>(tObj)->GetItem();
        else
                cout << "not yet implemented" << endl;
        
        // get a point which is passing just outside of the occluder
    const Vector3 newPoint = GetPassingPoint(currentRay, occluder, oldRay);
        const Vector3 predicted = CalcPredictedHitPoint(currentRay, hitTriangle, oldRay);

        //-- Construct the mutated ray with xnew,
        //-- dir = predicted(x)- pnew as direction vector
        const Vector3 newDir = predicted - newPoint;

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

        static Ray ray(newOrigin, newDir, Ray::LOCAL_RAY);
        ray.Precompute();

        // check if ray intersects view cell
        if (mPerViewCell && !mCurrentViewCell->CastRay(ray))
                return NULL;

        const SimpleRay simpleRay(newOrigin, newDir, SamplingStrategy::GVS, 1.0f);

        VssRay *reverseRay = 
                mRayCaster->CastRay(simpleRay, mViewCellsManager->GetViewSpaceBox());

    ++ mGvsStats.mReverseSamples;

        return reverseRay;
}


int GvsPreprocessor::CastInitialSamples(const int numSamples, 
                                                                                const int sampleType)
{       
        const long startTime = GetTime();

        // generate simple rays
        SimpleRayContainer simpleRays;
        GenerateRays(numSamples, sampleType, simpleRays);

        // generate vss rays
        VssRayContainer samples;
        CastRays(simpleRays, samples, true);
        // add to ray queue
        EnqueueRays(samples);

        //Debug << "generated " <<  numSamples << " samples in " << TimeDiff(startTime, GetTime()) * 1e-3 << " secs" << endl;
        return (int)samples.size();
}


void GvsPreprocessor::EnqueueRays(VssRayContainer &samples)
{
        // add samples to ray queue
        VssRayContainer::const_iterator vit, vit_end = samples.end();
        for (vit = samples.begin(); vit != vit_end; ++ vit)
        {
                HandleRay(*vit);
        }
}


int GvsPreprocessor::Pass()
{
        // reset samples
        int castSamples = 0;
        mGvsStats.mPassContribution = 0;

        while (castSamples < mSamplesPerPass) 
        {       
                // Ray queue empty => 
                // cast a number of uniform samples to fill ray queue
                castSamples += CastInitialSamples(mInitialSamples, mSamplingType);

                if (!mOnlyRandomSampling)
                        castSamples += ProcessQueue();
        }

        mGvsStats.mTotalContribution += mGvsStats.mPassContribution;
        return castSamples;
}


int GvsPreprocessor::ProcessQueue()
{
        int castSamples = 0;
        ++ mGvsStats.mGvsPass;

        while (!mRayQueue.empty()) 
        {
                // handle next ray
                VssRay *ray = mRayQueue.top();
                mRayQueue.pop();

                castSamples += AdaptiveBorderSampling(*ray);
                delete ray;
        }
        
        return castSamples;
}


void GvsPreprocessor::VisualizeViewCells()
{
        char str[64]; sprintf(str, "tmp/pass%06d_%04d-", mNumViewCells, 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::PerViewCellComputation()
{
        const int maxViewCells = 5;

        while (NextViewCell() && mNumViewCells < maxViewCells)
        {
                cout << "processing view cell " << mNumViewCells << endl;

                while (mGvsStats.mTotalSamples < mTotalSamples) 
                {
                        ++ mPass;

                        mGvsStats.mTotalSamples += Pass();
                                
                        ////////
                        //-- stats

                        cout << "\nPass " << mPass << " #samples: " << mGvsStats.mTotalSamples 
                                 << " of " << mTotalSamples << endl;

                        mGvsStats.mPass = mPass;
                        mGvsStats.Stop();
                        mGvsStats.Print(mGvsStatsStream);
                        //mViewCellsManager->PrintPvsStatistics(mGvsStats);

                        if (GVS_DEBUG)
                                VisualizeViewCells();
                }

                // ComputeRenderError();
        }
}


void GvsPreprocessor::GlobalComputation()
{
        while (mGvsStats.mTotalSamples < mTotalSamples) 
        {
                ++ mPass;

                mGvsStats.mTotalSamples += Pass();
                                
                ////////
                //-- stats

                cout << "\nPass " << mPass << " #samples: " << mGvsStats.mTotalSamples 
                         << " of " << mTotalSamples << endl;

                mGvsStats.mPass = mPass;
                mGvsStats.Stop();
                mGvsStats.Print(mGvsStatsStream);
                //mViewCellsManager->PrintPvsStatistics(mGvsStats);

                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;
        }
        else if (0)
        {       
                //-- test successful view cells loading by exporting them again
                VssRayContainer dummies;
                mViewCellsManager->Visualize(mObjects, dummies);
                mViewCellsManager->ExportViewCells("test.xml.gz", mViewCellsManager->GetExportPvs(), mObjects);
        }

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

        if (mPerViewCell)
        {
                PerViewCellComputation();
        }
        else
        {
                GlobalComputation();
        }

        cout << "cast " << 2 * mGvsStats.mTotalSamples / (1e3f * TimeDiff(startTime, GetTime())) << "M rays/s" << endl;

        if (GVS_DEBUG)
        {
                Visualize();
                CLEAR_CONTAINER(mVssRays);
        }

        return 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);
        }

        VssRayContainer vcRays, vcRays2, vcRays3;

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

        //exporter->ExportRays(mVssRays);
        delete exporter;
}


void GvsStatistics::Print(ostream &app) const
{
        app << "#Pass\n" << mPass << endl;
        app << "#Time\n" << Time() << endl;
        app << "#TotalSamples\n" << mTotalSamples << endl;
        app << "#ScDiff\n" << mPassContribution << endl;
        app     << "#SamplesContri\n" << mTotalContribution << endl;
        app << "#ReverseSamples\n" << mReverseSamples << endl;
        app << "#BorderSamples\n" << mBorderSamples << endl;            
        app << "#GvsRuns\n" << mGvsPass << endl;
}


}