mirror of https://github.com/CGAL/cgal
111 lines
3.8 KiB
C++
111 lines
3.8 KiB
C++
//! \file examples/Envelope_3/ex_envelope_triangles.cpp
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// Constructing the lower and the upper envelope of a set of triangles.
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#include <CGAL/Gmpq.h>
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#include <CGAL/Cartesian.h>
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#include <CGAL/Env_triangle_traits_3.h>
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#include <CGAL/Env_surface_data_traits_3.h>
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#include <CGAL/envelope_3.h>
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#include <iostream>
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#include <list>
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typedef CGAL::Gmpq Number_type;
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typedef CGAL::Cartesian<Number_type> Kernel;
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typedef CGAL::Env_triangle_traits_3<Kernel> Traits_3;
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typedef Kernel::Point_3 Point_3;
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typedef Traits_3::Surface_3 Triangle_3;
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typedef CGAL::Env_surface_data_traits_3<Traits_3, char> Data_traits_3;
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typedef Data_traits_3::Surface_3 Data_triangle_3;
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typedef CGAL::Envelope_diagram_2<Data_traits_3> Envelope_diagram_2;
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/* Auxiliary function - print the features of the given envelope diagram. */
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void print_diagram (const Envelope_diagram_2& diag)
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{
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// Go over all arrangement faces.
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Envelope_diagram_2::Face_const_iterator fit;
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Envelope_diagram_2::Ccb_halfedge_const_circulator ccb;
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Envelope_diagram_2::Surface_const_iterator sit;
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for (fit = diag.faces_begin(); fit != diag.faces_end(); ++fit)
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{
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// Print the face boundary.
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if (fit->is_unbounded())
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{
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std::cout << "[Unbounded face]";
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}
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else
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{
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// Print the vertices along the outer boundary of the face.
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ccb = fit->outer_ccb();
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std::cout << "[Face] ";
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do
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{
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std::cout << '(' << ccb->target()->point() << ") ";
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++ccb;
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} while (ccb != fit->outer_ccb());
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}
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// Print the labels of the triangles that induce the envelope on this face.
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std::cout << "--> " << fit->number_of_surfaces()
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<< " triangles:";
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for (sit = fit->surfaces_begin(); sit != fit->surfaces_end(); ++sit)
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std::cout << ' ' << sit->data();
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std::cout << std::endl;
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}
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// Go over all arrangement edges.
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Envelope_diagram_2::Edge_const_iterator eit;
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for (eit = diag.edges_begin(); eit != diag.edges_end(); ++eit)
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{
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// Print the labels of the triangles that induce the envelope on this edge.
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std::cout << "[Edge] (" << eit->source()->point()
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<< ") (" << eit->target()->point()
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<< ") --> " << eit->number_of_surfaces()
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<< " triangles:";
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for (sit = eit->surfaces_begin(); sit != eit->surfaces_end(); ++sit)
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std::cout << ' ' << sit->data();
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std::cout << std::endl;
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}
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return;
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}
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/* The main program: */
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int main ()
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{
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// Construct the input triangles, makred A and B.
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std::list<Data_triangle_3> triangles;
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triangles.push_back (Data_triangle_3 (Triangle_3 (Point_3 (0, 0, 0),
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Point_3 (0, 6, 0),
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Point_3 (5, 3, 4)),
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'A'));
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triangles.push_back (Data_triangle_3 (Triangle_3 (Point_3 (6, 0, 0),
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Point_3 (6, 6, 0),
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Point_3 (1, 3, 4)),
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'B'));
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// Compute and print the minimization diagram.
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Envelope_diagram_2 min_diag;
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CGAL::lower_envelope_3 (triangles.begin(), triangles.end(),
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min_diag);
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std::cout << std::endl << "The minimization diagram:" << std::endl;
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print_diagram (min_diag);
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// Compute and print the maximization diagram.
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Envelope_diagram_2 max_diag;
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CGAL::upper_envelope_3 (triangles.begin(), triangles.end(),
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max_diag);
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std::cout << std::endl << "The maximization diagram:" << std::endl;
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print_diagram (max_diag);
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return (0);
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}
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