dust3d/third_party/libigl/include/igl/frame_to_cross_field.cpp

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// This file is part of libigl, a simple c++ geometry processing library.
//
// Copyright (C) 2014 Daniele Panozzo <daniele.panozzo@gmail.com>
//
// This Source Code Form is subject to the terms of the Mozilla Public License
// v. 2.0. If a copy of the MPL was not distributed with this file, You can
// obtain one at http://mozilla.org/MPL/2.0/.
#include "frame_to_cross_field.h"
#include <igl/local_basis.h>
#include <igl/dot_row.h>
IGL_INLINE void igl::frame_to_cross_field(
const Eigen::MatrixXd& V,
const Eigen::MatrixXi& F,
const Eigen::MatrixXd& FF1,
const Eigen::MatrixXd& FF2,
Eigen::MatrixXd& X)
{
using namespace Eigen;
// Generate local basis
MatrixXd B1, B2, B3;
igl::local_basis(V,F,B1,B2,B3);
// Project the frame fields in the local basis
MatrixXd d1, d2;
d1.resize(F.rows(),2);
d2.resize(F.rows(),2);
d1 << igl::dot_row(B1,FF1), igl::dot_row(B2,FF1);
d2 << igl::dot_row(B1,FF2), igl::dot_row(B2,FF2);
X.resize(F.rows(), 3);
for (int i=0;i<F.rows();i++)
{
Vector2d v1 = d1.row(i);
Vector2d v2 = d2.row(i);
// define inverse map that maps the canonical axis to the given frame directions
Matrix2d A;
A << v1[0], v2[0],
v1[1], v2[1];
// find the closest rotation
Eigen::JacobiSVD<Matrix<double,2,2> > svd(A, Eigen::ComputeFullU | Eigen::ComputeFullV );
Matrix2d C = svd.matrixU() * svd.matrixV().transpose();
Vector2d v = C.col(0);
X.row(i) = v(0) * B1.row(i) + v(1) * B2.row(i);
}
}
#ifdef IGL_STATIC_LIBRARY
// Explicit template instantiation
#endif