added options for tetrahedral remeshing

#include <CGAL/Polyhedral_mesh_domain_with_features_3.h>

#include <CGAL/make_mesh_3.h>

#include <CGAL/refine_mesh_3.h>

#include <CGAL/tetrahedral_remeshing.h>

#include <CGAL/IO/output_to_vtu.h>

#include "lyra/lyra.hpp"

	// degrees) of mesh cells.

	double exude_sliver_bound = 0;

// Multi-Material Isotropic Tetrahedral Remeshing

// - https://doc.cgal.org/latest/Tetrahedral_remeshing/index.html

// - https://doc.cgal.org/latest/Tetrahedral_remeshing/group__PkgTetrahedralRemeshingRef.html

	// remesh_iterations: The number of iterations for the remeshing algorithm.

	// Value of 0 disables remeshing.

	std::size_t remesh_iterations = 0;

	// remesh_target_edge_length: This parameter provides a uniform mesh

	// density target for the remeshing algorithm.

	double remesh_target_edge_length = 0;

	// remesh_boundaries: If false, none of the input volume boundaries can be

	// modified. Otherwise, the topology is preserved, but atomic operations

	// can be performed on the surfaces, and along feature polylines, such that

	// boundaries are remeshed.

	bool remesh_boundaries = true;

	void set_cli_options(lyra::cli & cli)

	{

		// pipeline options

				["--exude-sliver-bound"]

				("A targeted lower bound on dihedral angles (in degrees) of mesh "

				 "cells." + fmt_default(exude_sliver_bound));

		// remeshing parameters

		cli |= lyra::opt(remesh_iterations, "N")

				["--remesh-iterations"]

				("The number of iterations for the Multi-Material Isotropic "

				 "Tetrahedral Remeshing algorithm. Value of 0 disables "

				 "remeshing." + fmt_default(remesh_iterations));

		cli |= lyra::opt(remesh_target_edge_length, "SCALAR")

				["--remesh-target-edge-length"]

				("This parameter provides a uniform mesh density target for the "

				 "remeshing algorithm." + fmt_default(remesh_target_edge_length));

		cli |= lyra::opt(remesh_boundaries, "BOOL")

				["--remesh-boundaries"]

				("If false, none of the input volume boundaries can be "

				 "modified. Otherwise, the topology is preserved, but atomic "

				 "operations can be performed on the surfaces, and along feature "

				 "polylines, such that boundaries are remeshed."

				 + fmt_default(exude_time_limit));

	}

	void print_options(std::ostream & str)

			str << "  - Time limit: " << exude_time_limit << " seconds\n";

			str << "  - Sliver bound: " << exude_sliver_bound << "°\n";

		}

		str << "- Number of remeshing iterations: " << remesh_iterations << "\n";

		if (remesh_iterations > 0) {

			str << "  - Remeshing target edge length: " << remesh_target_edge_length << "\n";

			str << "  - Remesh boundaries: " << remesh_boundaries << "\n";

		}

		str.flush();

	}

};

	if (args.cell_size < 0) throw std::invalid_argument("cell_size cannot be negative");

	if (args.detect_features && args.edge_size == 0)

		throw std::invalid_argument("edge_size must be positive when detection of sharp features is enabled");

	if (args.remesh_iterations > 0 && args.remesh_target_edge_length <= 0)

		throw std::invalid_argument("remesh_iterations is positive, but remesh_target_edge_length is not positive");

	Polyhedron casePoly;

	readPolyhedron(casePoly, input_file);

			);

	}

	// Remeshing

	if (args.remesh_iterations > 0) {

		std::cout << "Remeshing..." << std::endl;

		// Extract triangulation from c3t3 and discard the c3t3 object

		using Triangulation_3 = CGAL::Triangulation_3<typename Tr::Geom_traits, typename Tr::Triangulation_data_structure>;

		Triangulation_3 t3 = CGAL::convert_to_triangulation_3(std::move(c3t3));

		// Remesh

		CGAL::tetrahedral_isotropic_remeshing(t3,

			args.remesh_target_edge_length,

			CGAL::parameters::number_of_iterations(args.remesh_iterations)

			.remesh_boundaries(args.remesh_boundaries)

		);

		// Create another c3t3 for output (but of different type)

		CGAL::Mesh_complex_3_in_triangulation_3<Triangulation_3, int, int> c3t3;

		c3t3.triangulation() = std::move(t3);

		c3t3.rescan_after_load_of_triangulation();

		// Output

		std::ofstream out(output_file);

		output_to_vtu(out, c3t3);

		out.close();

	}

	else {

		// Output

		std::ofstream out(output_file);

		output_to_vtu(out, c3t3);

		out.close();

	}

}

int main(int argc, char * argv[])

{