48 lines
1.2 KiB
C++
48 lines
1.2 KiB
C++
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// 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 "point_triangle_squared_distance.h"
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#include <CGAL/Segment_3.h>
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template < typename Kernel>
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IGL_INLINE void point_triangle_squared_distance(
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const CGAL::Point_3<Kernel> & P1,
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const CGAL::Triangle_3<Kernel> & T2,
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CGAL::Point_3<Kernel> & P2,
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typename Kernel::FT & d)
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{
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assert(!T2.is_degenerate());
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if(T2.has_on(P1))
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{
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P2 = P1;
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d = 0;
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return;
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}
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const auto proj_1 = T2.supporting_plane().projection(P2);
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if(T2.has_on(proj_1))
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{
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P2 = proj_1;
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d = (proj_1-P1).squared_length();
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return;
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}
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// closest point must be on the boundary
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bool first = true;
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// loop over edges
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for(int i=0;i<3;i++)
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{
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CGAL::Point_3<Kernel> P2i;
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typename Kernel::FT di;
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const CGAL::Segment_3<Kernel> si( T2.vertex(i+1), T2.vertex(i+2));
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point_segment_squared_distance(P1,si,P2i,di);
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if(first || di < d)
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{
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first = false;
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d = di;
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P2 = P2i;
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}
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}
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}
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