/*CWBoon 2015 */
#ifdef YADE_POTENTIAL_PARTICLES

#include "Gl1_PotentialParticle.hpp"
#ifdef YADE_OPENGL
#include <lib/opengl/OpenGLWrapper.hpp>
#endif

#include <pkg/dem/ScGeom.hpp>
#include <pkg/potential/KnKsLaw.hpp>
//#include<pkg/dem/Clump.hpp>
#include <core/Aabb.hpp>

#ifdef YADE_VTK

#include <lib/compatibility/VTKCompatibility.hpp> // fix InsertNextTupleValue → InsertNextTuple name change (and others in the future)
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wpragmas"
#pragma GCC diagnostic ignored "-Wsuggest-override"
#include <vtkActor2D.h>
#include <vtkAppendPolyData.h>
#include <vtkCamera.h>
#include <vtkCellArray.h>
#include <vtkCellData.h>
#include <vtkConeSource.h>
#include <vtkContourFilter.h>
#include <vtkDiskSource.h>
#include <vtkExtractVOI.h>
#include <vtkFloatArray.h>
#include <vtkImplicitBoolean.h>
#include <vtkIntArray.h>
#include <vtkLabeledDataMapper.h>
#include <vtkLine.h>
#include <vtkLinearExtrusionFilter.h>
#include <vtkLookupTable.h>
#include <vtkPointData.h>
#include <vtkPolyDataMapper.h>
#include <vtkProperty.h>
#include <vtkRegularPolygonSource.h>
#include <vtkRenderWindowInteractor.h>
#include <vtkSampleFunction.h>
#include <vtkSmartPointer.h>
#include <vtkSphereSource.h>
#include <vtkStructuredPoints.h>
#include <vtkStructuredPointsWriter.h>
#include <vtkTransform.h>
#include <vtkTransformPolyDataFilter.h>
#include <vtkTriangle.h>
#include <vtkUnsignedCharArray.h>
#include <vtkUnstructuredGrid.h>
#include <vtkVectorText.h>
#include <vtkWriter.h>
#include <vtkXMLDataSetWriter.h>
#include <vtkXMLImageDataWriter.h>
#include <vtkXMLPolyDataWriter.h>
#include <vtkXMLStructuredGridWriter.h>
#include <vtkXMLUnstructuredGridWriter.h>
#pragma GCC diagnostic pop

#endif // YADE_VTK

namespace yade { // Cannot have #include directive inside.

#ifdef YADE_OPENGL

void Gl1_PotentialParticle::calcMinMax(const PotentialParticle& pp)
{
	//	int planeNo = pp.d.size();
	//	Real maxD = pp.d[0];

	//	for (int i=0; i<planeNo; ++i) {
	//		if (pp.d[i] > maxD) {
	//			maxD = pp.d[i];
	//		}
	//	}

	min = -aabbEnlargeFactor * pp.minAabb;
	max = aabbEnlargeFactor * pp.maxAabb;

	Real dx = (max[0] - min[0]) / ((Real)(sizeX - 1));
	Real dy = (max[1] - min[1]) / ((Real)(sizeY - 1));
	Real dz = (max[2] - min[2]) / ((Real)(sizeZ - 1));

	isoStep = Vector3r(dx, dy, dz);
}


void Gl1_PotentialParticle::generateScalarField(const PotentialParticle& pp)
{
	for (int i = 0; i < sizeX; i++) {
		for (int j = 0; j < sizeY; j++) {
			for (int k = 0; k < sizeZ; k++) {
				scalarField[i][j][k]
				        = evaluateF(pp, min[0] + Real(i) * isoStep[0], min[1] + Real(j) * isoStep[1], min[2] + Real(k) * isoStep[2]);
			}
		}
	}
}

vector<Gl1_PotentialParticle::scalarF> Gl1_PotentialParticle::SF;
int                                    Gl1_PotentialParticle::sizeX, Gl1_PotentialParticle::sizeY, Gl1_PotentialParticle::sizeZ;
Real                                   Gl1_PotentialParticle::aabbEnlargeFactor;
bool                                   Gl1_PotentialParticle::store;
bool                                   Gl1_PotentialParticle::initialized;
bool                                   Gl1_PotentialParticle::wire;

void Gl1_PotentialParticle::go(const shared_ptr<Shape>& cm, const shared_ptr<State>& /*state*/, bool wire2, const GLViewInfo&)
{
	PotentialParticle* pp      = static_cast<PotentialParticle*>(cm.get());
	int                shapeId = pp->id;

	if (store == false) {
		if (SF.size() > 0) {
			SF.clear();
			initialized = false;
		}
	}

	if (initialized == false) {
		for (const auto& b : *scene->bodies) {
			if (!b) continue;
			PotentialParticle* cmbody = dynamic_cast<PotentialParticle*>(b->shape.get());
			if (!cmbody) continue;
			calcMinMax(*cmbody);
			mc.init(sizeX, sizeY, sizeZ, min, max);
			mc.resizeScalarField(scalarField, sizeX, sizeY, sizeZ);
			SF.push_back(scalarF());
			generateScalarField(*cmbody);
			mc.computeTriangulation(scalarField, 0.0);
			SF[b->id].triangles   = mc.getTriangles();
			SF[b->id].normals     = mc.getNormals();
			SF[b->id].nbTriangles = mc.getNbTriangles();
			for (unsigned int i = 0; i < scalarField.size(); i++) {
				for (unsigned int j = 0; j < scalarField[i].size(); j++)
					scalarField[i][j].clear();
				scalarField[i].clear();
			}
			scalarField.clear();
		}
		initialized = true;
	}

	const vector<Vector3r>& triangles   = SF[shapeId].triangles;   //mc.getTriangles();
	int                     nbTriangles = SF[shapeId].nbTriangles; // //mc.getNbTriangles();
	const vector<Vector3r>& normals     = SF[shapeId].normals;     //mc.getNormals();

	glColor3v(cm->color); //glColor3v is used when lighting is not enabled

	if (wire || wire2) {
		glDisable(GL_CULL_FACE);
		glDisable(GL_LIGHTING);
		glPolygonMode(GL_FRONT_AND_BACK, GL_LINE); // Turn on wireframe mode. Render front and back faces of the wireframe
	} else {
		//TODO: Using glMaterialv(GL_FRONT,...) in conjunction with: glCullFace(GL_BACK); glEnable(GL_CULL_FACE); is the most cost-effective approach, since culling the back faces makes the visualisation lighter. An example why I don't activate this for now, is that in cubePPscaled.py we visualise the faces of the box as hollow, even with wire=False and culling the back faces makes the visualisation of the hollow particles confusing. Thus, for the time being I chose to keep and color the back faces; to be revisited @vsangelidakis
		//			glEnable(GL_NORMALIZE); //Not needed for vertex-based shading. The normals have been normalised inside the Marching Cubes script
		glMaterialv(
		        GL_FRONT_AND_BACK,
		        GL_AMBIENT_AND_DIFFUSE,
		        Vector3r(cm->color[0], cm->color[1], cm->color[2])); //glMaterialv is used when lighting is enabled
		glDisable(GL_CULL_FACE);
		//			glCullFace(GL_BACK); glEnable(GL_CULL_FACE);
		glEnable(GL_LIGHTING);            // 2D
		glPolygonMode(GL_FRONT, GL_FILL); // Turn off wireframe mode
	}

	//			// FACE-BASED SHADING: Use the normal vector of each triangle (makes the shading of each face look sharper)
	//			Vector3r centroid=Vector3r(0,0,0);
	//			glBegin(GL_TRIANGLES);
	//			for(int i=0; i<3*nbTriangles; i+=3) {
	//				const auto a = triangles[i+0];
	//				const auto b = triangles[i+1];
	//				const auto c = triangles[i+2];
	//
	//				Vector3r n=(b-a).cross(c-a); n.normalize();
	//				Vector3r faceCenter=(a+b+c)/3.;
	//				if((faceCenter-centroid).dot(n)<0) n=-n;
	//
	//				glNormal3v(n);
	//				glVertex3v(c); //vertex #2
	//				glVertex3v(b); //vertex #1
	//				glVertex3v(a); //vertex #0
	//			}
	//			glEnd();

	//			// VERTEX-BASED SHADING: Use the normal vector of each vertex of each triangle (makes the shading of each face look smoother)
	glBegin(GL_TRIANGLES)
		;
		for (int i = 0; i < 3 * nbTriangles; i += 3) {
			glNormal3v(normals[i + 2]);
			glVertex3v(triangles[i + 2]); //vertex #2 The sequence of the vertices specifies which side of the faces is front and which is back
			glNormal3v(normals[i + 1]);
			glVertex3v(triangles[i + 1]); //vertex #1
			glNormal3v(normals[i + 0]);
			glVertex3v(triangles[i + 0]); //vertex #0
		}
	glEnd();
	glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
	return;
}


Real Gl1_PotentialParticle::evaluateF(const PotentialParticle& pp, Real x, Real y, Real z)
{
	Real k = pp.k;
	Real r = pp.r;
	Real R = pp.R;

	int planeNo = pp.a.size();

	vector<Real> a;
	vector<Real> b;
	vector<Real> c;
	vector<Real> d;
	vector<Real> p;
	Real         pSum3 = 0.0;
	for (int i = 0; i < planeNo; i++) {
		a.push_back(pp.a[i]);
		b.push_back(pp.b[i]);
		c.push_back(pp.c[i]);
		d.push_back(pp.d[i]);
		Real plane = a[i] * x + b[i] * y + c[i] * z - d[i];
		if (plane < pow(10, -15)) { plane = 0.0; }
		p.push_back(plane);
		pSum3 += pow(p[i], 2);
	}

	Real sphere = (pow(x, 2) + pow(y, 2) + pow(z, 2));
	Real f      = (1.0 - k) * (pSum3 / pow(r, 2) - 1.0) + k * (sphere / pow(R, 2) - 1.0);

	return f;
}

YADE_PLUGIN((Gl1_PotentialParticle));

#endif // YADE_OPENGL

#ifdef YADE_VTK
ImpFunc* ImpFunc::New()
{
	// Skip factory stuff - create class
	return new ImpFunc;
}


// Create the function
ImpFunc::ImpFunc()
{
	clump = false;
	// Initialize members here if you need
}

ImpFunc::~ImpFunc()
{
	// Initialize members here if you need
}

// Evaluate function
Real ImpFunc::FunctionValue(Real x[3])
{
	int          planeNo = a.size();
	vector<Real> p;
	Real         pSum2 = 0.0;
	if (!clump) {
		Vector3r xori(x[0], x[1], x[2]);
		Vector3r xlocal = rotationMatrix * xori;
		xlocal[0]       = rotationMatrix(0, 0) * x[0] + rotationMatrix(0, 1) * x[1] + rotationMatrix(0, 2) * x[2];
		xlocal[1]       = rotationMatrix(1, 0) * x[0] + rotationMatrix(1, 1) * x[1] + rotationMatrix(1, 2) * x[2];
		xlocal[2]       = rotationMatrix(2, 0) * x[0] + rotationMatrix(2, 1) * x[1] + rotationMatrix(2, 2) * x[2];
		//std::cout<<"rotationMatrix: "<<endl<<rotationMatrix<<endl;
		//x[0]=xlocal[0]; x[1]=xlocal[1]; x[2]=xlocal[2];

		for (int i = 0; i < planeNo; i++) {
			Real plane = a[i] * xlocal[0] + b[i] * xlocal[1] + c[i] * xlocal[2] - d[i];
			if (plane < pow(10, -15)) { plane = 0.0; }
			p.push_back(plane);
			pSum2 += pow(p[i], 2);
		}
		Real sphere = (pow(xlocal[0], 2) + pow(xlocal[1], 2) + pow(xlocal[2], 2));
		Real f      = (1.0 - k) * (pSum2 / pow(r, 2) - 1.0) + k * (sphere / pow(R, 2) - 1.0);
		return f;
	} else {
		Vector3r xori(x[0], x[1], x[2]);
		Vector3r clumpMemberCentre(clumpMemberCentreX, clumpMemberCentreY, clumpMemberCentreZ);
		Vector3r xlocal = xori - clumpMemberCentre;
		//xlocal[0] = rotationMatrix[0]*x[0] + rotationMatrix[3]*x[1] + rotationMatrix[6]*x[2];
		//xlocal[1] = rotationMatrix[1]*x[0] + rotationMatrix[4]*x[1] + rotationMatrix[7]*x[2];
		//xlocal[2] = rotationMatrix[2]*x[0] + rotationMatrix[5]*x[1] + rotationMatrix[8]*x[2];
		//std::cout<<"rotationMatrix: "<<endl<<rotationMatrix<<endl;
		//x[0]=xlocal[0]; x[1]=xlocal[1]; x[2]=xlocal[2];

		for (int i = 0; i < planeNo; i++) {
			Real plane = a[i] * xlocal[0] + b[i] * xlocal[1] + c[i] * xlocal[2] - d[i];
			if (plane < pow(10, -15)) { plane = 0.0; }
			p.push_back(plane);
			pSum2 += pow(p[i], 2);
		}
		Real sphere = (pow(xlocal[0], 2) + pow(xlocal[1], 2) + pow(xlocal[2], 2));
		Real f      = (1.0 - k) * (pSum2 / pow(r, 2) - 1.0) + k * (sphere / pow(R, 2) - 1.0);
		return f;
		// return 0;
	}
	// the value of the function
}


void PotentialParticleVTKRecorder::action()
{
	if (fileName.size() == 0) return;
	auto pbPos          = vtkSmartPointer<vtkPointsReal>::New();
	auto appendFilter   = vtkSmartPointer<vtkAppendPolyData>::New();
	auto appendFilterID = vtkSmartPointer<vtkAppendPolyData>::New();
	//auto transformFilter = vtkSmartPointer<vtkTransformPolyDataFilter>::New();
	//auto transform = vtkSmartPointer<vtkTransform>::New();

	// interactions ###############################################
	auto intrBodyPos = vtkSmartPointer<vtkPoints>::New();
	auto intrCells   = vtkSmartPointer<vtkCellArray>::New();
	auto intrForceN  = vtkSmartPointer<vtkFloatArray>::New();
	intrForceN->SetNumberOfComponents(3);
	intrForceN->SetName("forceN");
	auto intrAbsForceT = vtkSmartPointer<vtkFloatArray>::New();
	intrAbsForceT->SetNumberOfComponents(1);
	intrAbsForceT->SetName("absForceT");
	// interactions ###############################################

	// interaction contact point ###############################################
	auto pbContactPoint = vtkSmartPointer<vtkPointsReal>::New();
	auto pbCellsContact = vtkSmartPointer<vtkCellArray>::New();
	auto pbNormalForce  = vtkSmartPointer<vtkFloatArray>::New();
	pbNormalForce->SetNumberOfComponents(3);
	pbNormalForce->SetName("normalForce"); //Linear velocity in Vector3 form
	auto pbShearForce = vtkSmartPointer<vtkFloatArray>::New();
	pbShearForce->SetNumberOfComponents(3);
	pbShearForce->SetName("shearForce"); //Angular velocity in Vector3 form
	// interactions contact point###############################################


	// velocity ###################################################
	auto pbCells     = vtkSmartPointer<vtkCellArray>::New();
	auto pbLinVelVec = vtkSmartPointer<vtkFloatArray>::New();
	pbLinVelVec->SetNumberOfComponents(3);
	pbLinVelVec->SetName("linVelVec"); //Linear velocity in Vector3 form

	auto pbLinVelLen = vtkSmartPointer<vtkFloatArray>::New();
	pbLinVelLen->SetNumberOfComponents(1);
	pbLinVelLen->SetName("linVelLen"); //Length (magnitude) of linear velocity

	auto pbAngVelVec = vtkSmartPointer<vtkFloatArray>::New();
	pbAngVelVec->SetNumberOfComponents(3);
	pbAngVelVec->SetName("angVelVec"); //Angular velocity in Vector3 form

	auto pbAngVelLen = vtkSmartPointer<vtkFloatArray>::New();
	pbAngVelLen->SetNumberOfComponents(1);
	pbAngVelLen->SetName("angVelLen"); //Length (magnitude) of angular velocity
	// velocity ####################################################

	// bodyId ##############################################################
	auto pbPosID   = vtkSmartPointer<vtkPointsReal>::New();
	auto pbIdCells = vtkSmartPointer<vtkCellArray>::New();
	auto blockId   = vtkSmartPointer<vtkIntArray>::New();
	blockId->SetNumberOfComponents(1);
	blockId->SetName("id");
	// bodyId ##############################################################
	int                                       countID = 0;
	vtkSmartPointer<vtkVectorText>            textArray2[scene->bodies->size()];
	vtkSmartPointer<vtkPolyDataMapper>        txtMapper[scene->bodies->size()];
	vtkSmartPointer<vtkLinearExtrusionFilter> extrude[scene->bodies->size()];
	vtkSmartPointer<vtkActor>                 textActor[scene->bodies->size()];


	for (const auto& b : *scene->bodies) {
		if (!b) continue;
		if (b->isClump() == true) continue;
		const PotentialParticle* pb = dynamic_cast<PotentialParticle*>(b->shape.get());
		if (!pb) continue;

		if (REC_ID == true) {
			blockId->InsertNextValue(b->getId());
			vtkIdType pid[1];
			Vector3r  pos(b->state->pos);
			pid[0] = pbPosID->InsertNextPoint(pos);
			pbIdCells->InsertNextCell(1, pid);

			countID++;
		}
		//vtkSmartPointer<ImpFunc> function = ImpFunc::New();
		function->a           = pb->a;
		function->b           = pb->b;
		function->c           = pb->c;
		function->d           = pb->d;
		function->R           = pb->R;
		function->r           = pb->r;
		function->k           = pb->k;
		Matrix3r directionCos = b->state->ori.conjugate().toRotationMatrix();
		int      count        = 0;
		for (int i = 0; i < 3; i++) {
			for (int j = 0; j < 3; j++) {
				//function->rotationMatrix[count] = directionCos(j,i);
				function->rotationMatrix(i, j) = directionCos(j, i);
				count++;
			}
		}


		auto sample = vtkSmartPointer<vtkSampleFunctionReal>::New();
		sample->SetImplicitFunction(function);

		Real xmin = -std::max(pb->minAabb.x(), pb->maxAabb.x());
		Real xmax = -xmin;
		Real ymin = -std::max(pb->minAabb.y(), pb->maxAabb.y());
		Real ymax = -ymin;
		Real zmin = -std::max(pb->minAabb.z(), pb->maxAabb.z());
		Real zmax = -zmin;

		if (twoDimension == true) {
			if (sampleY < 2) {
				ymin = 0.0;
				ymax = 0.0;
			} else if (sampleZ < 2) {
				zmin = 0.0;
				zmax = 0.0;
			}
		}

		sample->SetModelBounds(Vector3r(xmin, ymin, zmin), Vector3r(xmax, ymax, zmax));
		//sample->SetModelBounds(pb->minAabb.x(), pb->maxAabb.x(), pb->minAabb.y(), pb->maxAabb.y(), pb->minAabb.z(), pb->maxAabb.z());
		int sampleXno = sampleX;
		int sampleYno = sampleY;
		int sampleZno = sampleZ;
		if (fabs(xmax - xmin) / static_cast<Real>(sampleX) > maxDimension) { sampleXno = static_cast<int>(fabs(xmax - xmin) / maxDimension); }
		if (fabs(ymax - ymin) / static_cast<Real>(sampleY) > maxDimension) { sampleYno = static_cast<int>(fabs(ymax - ymin) / maxDimension); }
		if (fabs(zmax - zmin) / static_cast<Real>(sampleZ) > maxDimension) { sampleZno = static_cast<int>(fabs(zmax - zmin) / maxDimension); }

		if (twoDimension == true) {
			if (sampleY < 2) {
				sampleYno = 1;
			} else if (sampleZ < 2) {
				sampleZno = 1;
			}
		}

		sample->SetSampleDimensions(sampleXno, sampleYno, sampleZno);
		sample->ComputeNormalsOff();
		//sample->Update();
		auto contours = vtkSmartPointer<vtkContourFilter>::New();
		contours->SetInputConnection(sample->GetOutputPort());

		contours->SetNumberOfContours(1);
		contours->SetValue(0, 0.0);
		auto polydata = vtkSmartPointer<vtkPolyData>::New();
		contours->Update();
		polydata->DeepCopy(contours->GetOutput());
		//polydata->Update();

		auto pbColors = vtkSmartPointer<vtkUnsignedCharArray>::New();
		pbColors->SetName("pbColors");
		pbColors->SetNumberOfComponents(3);
		Vector3r color = pb->color; //Vector3r(0,100,0);
		if (b->isDynamic() == false) { color = Vector3r(157, 157, 157); }
		unsigned char c[3]; //c = {color[0],color[1],color[2]};
		c[0]        = (unsigned char)(color[0]);
		c[1]        = (unsigned char)(color[1]);
		c[2]        = (unsigned char)(color[2]);
		int nbCells = polydata->GetNumberOfPoints();
		for (int i = 0; i < nbCells; i++) {
			pbColors->INSERT_NEXT_TYPED_TUPLE(c);
		}
		polydata->GetPointData()->SetScalars(pbColors);
		//polydata->Update();


		Vector3r    centre(b->state->pos[0], b->state->pos[1], b->state->pos[2]);
		Quaternionr orientation = b->state->ori;
		orientation.normalize();
		AngleAxisr aa(orientation);
		//Vector3r axis = aa.axis();
		auto transformFilter = vtkSmartPointer<vtkTransformPolyDataFilter>::New();
		transformFilter->SetInputData(polydata);
		auto transform = vtkSmartPointer<vtkTransformReal>::New();

		transformFilter->SetTransform(transform);
		transform->PostMultiply();

		transform->Translate(centre);
		//transform->RotateWXYZ(angle,xAxis, yAxis, zAxis);
		//transformFilter->Update();
		appendFilter->AddInputConnection(transformFilter->GetOutputPort());


		// ################## velocity ####################
		if (REC_VELOCITY == true) {
			vtkIdType pid[1];
			Vector3r  pos(b->state->pos);
			pid[0] = pbPos->InsertNextPoint(pos);
			pbCells->InsertNextCell(1, pid);
			const Vector3r& vel = b->state->vel;
			float           v[3]; //v = { vel[0],vel[1],vel[2] };
			v[0] = (float)(vel[0]);
			v[1] = (float)(vel[1]);
			v[2] = (float)(vel[2]);
			pbLinVelVec->INSERT_NEXT_TUPLE(v);
			pbLinVelLen->InsertNextValue((float)(vel.norm()));
			const Vector3r& angVel = b->state->angVel;
			float           av[3]; //av = { angVel[0],angVel[1],angVel[2] };
			av[0] = (float)(angVel[0]);
			av[1] = (float)(angVel[1]);
			av[2] = (float)(angVel[2]);
			pbAngVelVec->INSERT_NEXT_TUPLE(av);
			pbAngVelLen->InsertNextValue((float)(angVel.norm()));
		}
		// ################ velocity ###########################
		polydata->DeleteCells();
		//function->Delete();
	}

	if (REC_VELOCITY == true) {
		auto pbUg = vtkSmartPointer<vtkUnstructuredGrid>::New();
		pbUg->SetPoints(pbPos);
		pbUg->SetCells(VTK_VERTEX, pbCells);
		pbUg->GetPointData()->AddArray(pbLinVelVec);
		pbUg->GetPointData()->AddArray(pbAngVelVec);
		pbUg->GetPointData()->AddArray(pbLinVelLen);
		pbUg->GetPointData()->AddArray(pbAngVelLen);
		auto writerA = vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New();
		writerA->SetDataModeToAscii();
		string fv = fileName + "vel." + std::to_string(scene->iter) + ".vtu";
		writerA->SetFileName(fv.c_str());
		writerA->SetInputData(pbUg);
		writerA->Write();
	}

	//###################### bodyId ###############################
	if (REC_ID == true) {
		auto pbUg = vtkSmartPointer<vtkUnstructuredGrid>::New();
		pbUg->SetPoints(pbPosID);
		pbUg->SetCells(VTK_VERTEX, pbIdCells);
		pbUg->GetPointData()->AddArray(blockId);
		auto writerA = vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New();
		writerA->SetDataModeToAscii();
		string fv = fileName + "Id." + std::to_string(scene->iter) + ".vtu";
		writerA->SetFileName(fv.c_str());
		writerA->SetInputData(pbUg);
		writerA->Write();
	}


	// ################## contact point ####################
	if (REC_INTERACTION == true) {
		int count = 0;
		FOREACH(const shared_ptr<Interaction>& I, *scene->interactions)
		{
			if (!I->isReal()) { continue; }
			const KnKsPhys* phys = YADE_CAST<KnKsPhys*>(I->phys.get());
			const ScGeom*   geom = YADE_CAST<ScGeom*>(I->geom.get());
			vtkIdType       pid[1];
			Vector3r        pos(geom->contactPoint);
			pid[0] = pbContactPoint->InsertNextPoint(pos);
			pbCellsContact->InsertNextCell(1, pid);
			//intrBodyPos->InsertNextPoint(geom->contactPoint[0],geom->contactPoint[1],geom->contactPoint[2]);
			// gives _signed_ scalar of normal force, following the convention used in the respective constitutive law
			float fn[3] = { (float)phys->normalForce[0], (float)phys->normalForce[1], (float)phys->normalForce[2] };
			float fs[3] = { (float)phys->shearForce[0], (float)phys->shearForce[1], (float)phys->shearForce[2] };
			pbNormalForce->INSERT_NEXT_TUPLE(fn);
			pbShearForce->INSERT_NEXT_TUPLE(fs);
			count++;
		}
		if (count > 0) {
			auto pbUgCP = vtkSmartPointer<vtkUnstructuredGrid>::New();
			pbUgCP->SetPoints(pbContactPoint);
			pbUgCP->SetCells(VTK_VERTEX, pbCellsContact);
			pbUgCP->GetPointData()->AddArray(pbNormalForce);
			pbUgCP->GetPointData()->AddArray(pbShearForce);
			auto writerB = vtkSmartPointer<vtkXMLUnstructuredGridWriter>::New();
			writerB->SetDataModeToAscii();
			string fcontact = fileName + "contactPoint." + std::to_string(scene->iter) + ".vtu";
			writerB->SetFileName(fcontact.c_str());
			writerB->SetInputData(pbUgCP);
			writerB->Write();
		}
	}

	// ################ contact point ###########################


	auto writer = vtkSmartPointer<vtkXMLPolyDataWriter>::New();
	writer->SetDataModeToAscii();
	string fn = fileName + "-pb." + std::to_string(scene->iter) + ".vtp";
	writer->SetFileName(fn.c_str());
	writer->SetInputConnection(appendFilter->GetOutputPort());
	writer->Write();

	//intrBodyPos->Delete();
	//intrForceN->Delete();
	//intrAbsForceT->Delete();
	//pbContactPoint->Delete();
	//pbCellsContact->Delete();
	//pbNormalForce->Delete();
	//pbShearForce->Delete();
	//pbCells->Delete();
	//pbLinVelVec->Delete();
	//pbLinVelLen->Delete();
	//pbAngVelVec->Delete();
	//pbAngVelLen->Delete();
}

YADE_PLUGIN((PotentialParticleVTKRecorder));

#endif // YADE_VTK
} // namespace yade

#endif // YADE_POTENTIAL_PARTICLES