示例#1
0
// The Real Core Function doing the actual mesh processing.
bool FilterHarmonicPlugin::applyFilter(QAction * action, MeshDocument & md, RichParameterSet & par, vcg::CallBackPos * cb)
{
	switch(ID(action))
	{
	case FP_SCALAR_HARMONIC_FIELD :
	{
		typedef vcg::GridStaticPtr<CMeshO::VertexType, CMeshO::ScalarType> VertexGrid;

		typedef double                           CoeffScalar; // TODO, when moving the code to a class make it a template (CoeffScalar = double)

		typedef CMeshO::ScalarType               ScalarType;
		typedef CMeshO::CoordType                CoordType;
		typedef CMeshO::VertexType               VertexType;
		typedef CMeshO::FaceType                 FaceType;

		typedef Eigen::Triplet<CoeffScalar>      T;
		typedef Eigen::SparseMatrix<CoeffScalar> SpMat; //sparse matrix type of double


		CMeshO & m = md.mm()->cm;

		vcg::tri::Allocator<CMeshO>::CompactFaceVector(m);
		vcg::tri::Allocator<CMeshO>::CompactVertexVector(m);

		md.mm()->updateDataMask(MeshModel::MM_FACEFACETOPO | MeshModel::MM_VERTMARK);
		vcg::tri::UpdateBounding<CMeshO>::Box(m);
		vcg::tri::UpdateTopology<CMeshO>::FaceFace(m);

		int n  = m.VN();
		int fn = m.FN();

		std::vector<T>             coeffs; // coefficients of the system
		std::map<size_t,CoeffScalar> sums; // row sum of the coefficient

		SpMat laplaceMat; // the system to be solved
		laplaceMat.resize(n, n);

		Log("Generating coefficients.`");
		cb(0, "Generating coefficients...");
		vcg::tri::UpdateFlags<CMeshO>::FaceClearV(m);
		// Iterate over the faces
		for (size_t i = 0; i < m.face.size(); ++i)
		{
			CMeshO::FaceType & f = m.face[i];

			if (f.IsD())
			{
				assert(int(i) == fn);
				break; // TODO FIX the indexing of vertices
			}

			assert(!f.IsV());
			f.SetV();

			// Generate coefficients for each edge
			for (int idx = 0; idx < 3; ++idx)
			{
				CoeffScalar weight;
				WeightInfo res = ComputeWeight<FaceType, CoeffScalar>(f, idx, weight);

				switch (res)
				{
				case EdgeAlreadyVisited : continue;
				case Success            : break;
				case BorderEdge         :
					this->errorMessage = "Mesh not closed, cannot compute harmonic field on mesh containing holes or borders";
					return false;
				default: assert(0);
				}

//				if (weight < 0) weight = 0; // TODO check if negative weight may be an issue

				// Add the weight to the coefficients vector for both the vertices of the considered edge
				size_t v0_idx = vcg::tri::Index(m, f.V0(idx));
				size_t v1_idx = vcg::tri::Index(m, f.V1(idx));

				coeffs.push_back(T(v0_idx, v1_idx, -weight));
				coeffs.push_back(T(v1_idx, v0_idx, -weight));

				// Add the weight to the row sum
				sums[v0_idx] += weight;
				sums[v1_idx] += weight;
			}

			f.SetV();
		}

		// Fill the system matrix
		Log("Fill the system matrix");
		cb(10, "Filling the system matrix...");
		laplaceMat.reserve(coeffs.size());
		for (std::map<size_t,CoeffScalar>::const_iterator it = sums.begin(); it != sums.end(); ++it)
		{
			coeffs.push_back(T(it->first, it->first, it->second));
		}
		laplaceMat.setFromTriplets(coeffs.begin(), coeffs.end());

		// Get the two vertices with value set
		VertexGrid vg;
		vg.Set(m.vert.begin(), m.vert.end());

		vcg::vertex::PointDistanceFunctor<ScalarType> pd;
		vcg::tri::Tmark<CMeshO, VertexType> mv;
		mv.SetMesh(&m);
		mv.UnMarkAll();
		CoordType  closestP;
		ScalarType minDist = 0;
		VertexType * vp0 = vcg::GridClosest(vg, pd, mv, par.getPoint3f("point1"), m.bbox.Diag(), minDist, closestP);
		VertexType * vp1 = vcg::GridClosest(vg, pd, mv, par.getPoint3f("point2"), m.bbox.Diag(), minDist, closestP);
		if (vp0 == NULL || vp1 == NULL || vp0 == vp1)
		{
			this->errorMessage = "Error occurred for selected points.";
			return false;
		}

		size_t v0_idx = vcg::tri::Index(m, vp0);
		size_t v1_idx = vcg::tri::Index(m, vp1);

		// Add penalty factor alpha
		Log("Setting up the system matrix");
		const CoeffScalar alpha = pow(10, 8);

		Eigen::Matrix<CoeffScalar, Eigen::Dynamic, 1> b, x; // Unknown and known terms vectors
		b.setZero(n);
		b(v0_idx) = alpha * par.getFloat("value1");
		b(v1_idx) = alpha * par.getFloat("value2");

		laplaceMat.coeffRef(v0_idx, v0_idx) += alpha;
		laplaceMat.coeffRef(v1_idx, v1_idx) += alpha;

		// Solve system laplacianMat x = b
		Log("System matrix decomposition...");
		cb(20, "System matrix decomposition...");
		Eigen::SimplicialLDLT<Eigen::SparseMatrix<CoeffScalar> > solver; // TODO eventually use another solver
		solver.compute(laplaceMat);
		if(solver.info() != Eigen::Success)
		{
			// decomposition failed
			this->errorMessage = "System matrix decomposition failed: ";
			if (solver.info() == Eigen::NumericalIssue)
				this->errorMessage += "numerical issue.";
			else if (solver.info() == Eigen::NoConvergence)
				this->errorMessage += "no convergence.";
			else if (solver.info() == Eigen::InvalidInput)
				this->errorMessage += "invalid input.";

			return false;
		}

		Log("Solving the system...");
		cb(85, "Solving the system...");
		x = solver.solve(b);
		if(solver.info() != Eigen::Success)
		{
			// solving failed
			this->errorMessage = "System solving failed.";
			return false;
		}

		// Colorize bands for the 0-1 interval
		if (par.getBool("colorize"))
		{
			float steps = 20.0f;
			for (size_t i = 0; int(i) < n; ++i)
			{
				bool on = (int)(x[i]*steps)%2 == 1;
				if (on)
				{
					m.vert[i].C() = vcg::Color4b::ColorRamp(0,2,x[i]);
				}
				else
				{
					m.vert[i].C() = vcg::Color4b::White;
				}
			}
		}

		// Set field value into vertex quality attribute
		for (size_t i = 0; int(i) < n; ++i)
		{
			m.vert[i].Q() = x[i];
		}

		cb(100, "Done.");

		return true;
	}
	default : assert(0);
	}
	return false;
}