source: GTP/trunk/Lib/Vis/Preprocessing/src/GvsPreprocessor.cpp @ 1533

#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"


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

static vector<VizStruct> vizContainer;

GvsPreprocessor::GvsPreprocessor(): 
Preprocessor(), mSamplingType(0), mSampleContriPerPass(0), mTotalSampleContri(0),
mReverseSamples(0), mBorderSamples(0)
{
        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);    

        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 << "eps: " << mEps << endl;

        mStats.open("gvspreprocessor.log");
}


bool GvsPreprocessor::CheckDiscontinuity(const VssRay &currentRay,
                                                                                 const Triangle3 &hitTriangle,
                                                                                 const VssRay &oldRay)
{
        const float dist = Magnitude(oldRay.GetDir());
        const float newDist = Magnitude(currentRay.GetDir());
 
#if 0
        if ((dist - newDist) > mThresHold)
#else // rather take relative distance
        if ((dist / newDist) > mThreshold)
#endif
        {
                VssRay *newRay = ReverseSampling(currentRay, hitTriangle, oldRay);
                if (!HandleRay(newRay))
                {
                        delete newRay;
                }

                return true;
        }

        return false;
}


bool GvsPreprocessor::HandleRay(VssRay *vssRay)
{
        mViewCellsManager->ComputeSampleContribution(*vssRay, true, false);
                
        // some pvs contribution for this ray?
        if (vssRay->mPvsContribution > 0)
        {
                //cout << " h " << mSampleContriPerPass << " " << mSamplesPerPass << " " << mTotalSamples << endl;
                mRayQueue.push(vssRay);
                mVssRays.push_back(new VssRay(*vssRay));
        
                ++ mSampleContriPerPass;

                return true;
        }

        return false;
}


/** Creates 3 new vertices for triangle vertex with specified index.
*/
static void CreateNewVertices(VertexContainer &vertices,
                                                          const Triangle3 &hitTriangle,
                                                          const VssRay &ray, 
                                                          const int index,
                                                          const float eps)
{
        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] + eps * len * dir1;
        // pi, i - 1:  pi+ e·|pi-xp|·di, j
    const Vector3 pt2 = hitTriangle.mVertices[index] + eps * len * dir2;
        // pi, i:  pi+ e·|pi-xp|·di, j
        const Vector3 pt3 = hitTriangle.mVertices[index] + eps * 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)
{
        CreateNewVertices(vertices, hitTriangle, ray, 0, mEps);
        CreateNewVertices(vertices, hitTriangle, ray, 1, mEps);
        CreateNewVertices(vertices, hitTriangle, ray, 2, mEps);
}


static Vector3 CalcPredictedHitPoint(const VssRay &newRay, 
                                                                         const Triangle3 &hitTriangle,
                                                                         const VssRay &oldRay)
{
        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 &x, 
                                                                   const VssRay &y,
                                                                   const VssRay &oldRay)
{
        // the predicted hitpoint expects to hit the same mesh again
        const Vector3 predictedHitX = CalcPredictedHitPoint(x, hitTriangle, oldRay);
        const Vector3 predictedHitY = CalcPredictedHitPoint(y, hitTriangle, oldRay);

        CheckDiscontinuity(x, hitTriangle, oldRay);
        CheckDiscontinuity(y, hitTriangle, oldRay);

        if (EqualVisibility(x, y))
        {
                return 0;
        }
        else
        {
                cout << "s";
                const Vector3 p = (p1 + p2) * 0.5f;
                SimpleRay sray(oldRay.mOrigin, p - oldRay.mOrigin);
        
                VssRay *newRay = mRayCaster->CastSingleRay(sray, mViewSpaceBox);

                if (!newRay) 
                        return 0;

                const bool enqueued = HandleRay(newRay);
                
                const int s1 = SubdivideEdge(hitTriangle, p1, p, x, *newRay, oldRay);
                const int s2 = SubdivideEdge(hitTriangle, p, p2, *newRay, y, oldRay);
                                
                if (!enqueued)
                        delete newRay;
                
                return s1 + s2 + 1;
        }
}


int GvsPreprocessor::AdaptiveBorderSampling(const VssRay &currentRay)
{
        cout << "a";
        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);

        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);
                simpleRays.AddRay(sr);
        }

        VizStruct dummy;
        dummy.enlargedTriangle = new Polygon3(enlargedTriangle);
        dummy.originalTriangle = hitTriangle;
        //dummy.ray = new VssRay(currentRay);
        vizContainer.push_back(dummy);

        // cast rays to triangle vertices and determine visibility
        VssRayContainer vssRays;
        CastRays(simpleRays, vssRays, false, false);

        // add to ray queue
        EnqueueRays(vssRays);
        
        const int n = (int)enlargedTriangle.size();
        int castRays = (int)vssRays.size();
#if 1
    // 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);
        }
#endif

        mBorderSamples = castRays;
        return castRays;
}


static Vector3 GetPassingPoint(const VssRay &currentRay,
                                                           const Triangle3 &hitTriangle,
                                                           const VssRay &oldRay)
{
        // intersect triangle plane with plane spanned by current samples
        Plane3 plane(currentRay.GetOrigin(), currentRay.GetTermination(), oldRay.GetTermination());
        Plane3 triPlane(hitTriangle.GetNormal(), hitTriangle.mVertices[0]);

        SimpleRay intersectLine = GetPlaneIntersection(plane, triPlane);

        // Evaluate new hitpoint just outside the triangle
        const float factor = 0.95f;
        float t = triPlane.FindT(intersectLine);
        const Vector3 newPoint = intersectLine.mOrigin + t * factor * intersectLine.mDirection;

        return newPoint;
}


VssRay *GvsPreprocessor::ReverseSampling(const VssRay &currentRay,
                                                                                 const Triangle3 &hitTriangle,
                                                                                 const VssRay &oldRay)
{
        cout << "r";
        ++ mReverseSamples;

        //-- The plane p = (xp, hit(x), hit(xold)) is intersected
        //-- with the newly found triangle (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 by inside the gap
    const Vector3 newPoint = GetPassingPoint(currentRay, hitTriangle, 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 Vector3 newOrigin = newDir * -5000.0f;

        return new VssRay(currentRay);
}


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()
{
        const int mSampleType = 0;
        // reset samples
        int castSamples = 0;
        mSampleContriPerPass = 0;
        
        while (castSamples < mSamplesPerPass) 
        {       
                // Ray queue empty => 
                // cast a number of uniform samples to fill ray Queue
                castSamples += CastInitialSamples(mInitialSamples, mSampleType);
                castSamples += ProcessQueue();
                cout << "\ncast " << castSamples << " samples in a processing pass" << endl;
        }

        mTotalSampleContri += mSampleContriPerPass;

        return castSamples;
}


int GvsPreprocessor::ProcessQueue()
{
        int castSamples = 0;

        while (!mRayQueue.empty()) 
        {
                // handle next ray
                VssRay *ray = mRayQueue.top();
                mRayQueue.pop();
        
                castSamples += AdaptiveBorderSampling(*ray);
                
                delete ray;
        }
        
        return castSamples;
}


bool GvsPreprocessor::ComputeVisibility()
{
        cout << "Gvs Preprocessor started\n" << flush;

        Randomize(0);
        const long startTime = GetTime();
        int castSamples = 0;
        mViewSpaceBox = mKdTree->GetBox();
        
        if (!mLoadViewCells)
        {       /// construct the view cells from the scratch
                ConstructViewCells(mViewSpaceBox);
                cout << "view cells loaded" << endl;
        }

        while (castSamples < mTotalSamples) 
        {
                castSamples += Pass();
                                
                ////////
                //-- stats
                //cout << "+";
                cout << "\nsamples cast: " << castSamples << " of " << mTotalSamples << endl;

                //mVssRays.PrintStatistics(mStats);
                mStats << "#Time\n" << TimeDiff(startTime, GetTime())*1e-3 << endl
                           << "#TotalSamples\n" << castSamples << endl
                           << "#ContributingSamples\n" << mTotalSampleContri << endl
                           << "#Reverse samples\n" << mReverseSamples << endl
                           << "#Border samples\n" << mBorderSamples << endl;
                                

                mViewCellsManager->PrintPvsStatistics(mStats);
                // ComputeRenderError();
        }

        Visualize();    
        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);
        }

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

}