34 lines
1.1 KiB
C++
34 lines
1.1 KiB
C++
// This file is part of libigl, a simple c++ geometry processing library.
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//
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// Copyright (C) 2016 Alec Jacobson <alecjacobson@gmail.com>
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//
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// This Source Code Form is subject to the terms of the Mozilla Public License
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// v. 2.0. If a copy of the MPL was not distributed with this file, You can
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// obtain one at http://mozilla.org/MPL/2.0/.
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#include "inradius.h"
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#include "edge_lengths.h"
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#include "doublearea.h"
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template <
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typename DerivedV,
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typename DerivedF,
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typename DerivedR>
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IGL_INLINE void igl::inradius(
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const Eigen::PlainObjectBase<DerivedV> & V,
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const Eigen::PlainObjectBase<DerivedF> & F,
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Eigen::PlainObjectBase<DerivedR> & r)
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{
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Eigen::Matrix<typename DerivedV::Scalar,Eigen::Dynamic,3> l;
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Eigen::Matrix<typename DerivedV::Scalar,Eigen::Dynamic,1> R;
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igl::edge_lengths(V,F,l);
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// If R is the circumradius,
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// R*r = (abc)/(2*(a+b+c))
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// R = abc/(4*area)
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// r(abc/(4*area)) = (abc)/(2*(a+b+c))
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// r/(4*area) = 1/(2*(a+b+c))
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// r = (2*area)/(a+b+c)
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DerivedR A;
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igl::doublearea(l,0.,A);
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r = A.array() /l.array().rowwise().sum();
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}
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