mirror of https://github.com/CGAL/cgal
130 lines
4.3 KiB
C++
130 lines
4.3 KiB
C++
#include <CGAL/Simple_cartesian.h>
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#include <CGAL/Isosurfacing_3/Cartesian_grid_3.h>
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#include <CGAL/Isosurfacing_3/dual_contouring_3.h>
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#include <CGAL/Isosurfacing_3/Dual_contouring_domain_3.h>
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#include <CGAL/Isosurfacing_3/Interpolated_discrete_gradients_3.h>
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#include <CGAL/Isosurfacing_3/Interpolated_discrete_values_3.h>
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#include <CGAL/Isosurfacing_3/marching_cubes_3.h>
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#include <CGAL/Isosurfacing_3/Marching_cubes_domain_3.h>
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#include <CGAL/IO/polygon_soup_io.h>
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#include <vector>
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using Kernel = CGAL::Simple_cartesian<double>;
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using FT = typename Kernel::FT;
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using Point = typename Kernel::Point_3;
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using Vector = typename Kernel::Vector_3;
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using Grid = CGAL::Isosurfacing::Cartesian_grid_3<Kernel>;
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using Values = CGAL::Isosurfacing::Interpolated_discrete_values_3<Grid>;
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using Gradients = CGAL::Isosurfacing::Interpolated_discrete_gradients_3<Grid>;
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using Point_range = std::vector<Point>;
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using Polygon_range = std::vector<std::vector<std::size_t> >;
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namespace IS = CGAL::Isosurfacing;
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void run_marching_cubes(const Grid& grid,
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const FT isovalue)
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{
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using Domain = IS::Marching_cubes_domain_3<Grid, Values, IS::Linear_interpolation_edge_intersection>;
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std::cout << "\n ---- " << std::endl;
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std::cout << "Running Marching Cubes with isovalue = " << isovalue << std::endl;
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// fill up values
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Values values { grid };
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for(std::size_t i=0; i<grid.xdim(); ++i) {
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for(std::size_t j=0; j<grid.ydim(); ++j) {
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for(std::size_t k=0; k<grid.zdim(); ++k)
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{
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const Point& p = grid.point(i,j,k);
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const FT d = sqrt(CGAL::squared_distance(p, Point(CGAL::ORIGIN)));
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values(i,j,k) = d;
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}
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}
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}
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Domain domain { grid, values };
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Point_range points;
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Polygon_range triangles;
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// run marching cubes isosurfacing
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IS::marching_cubes<CGAL::Parallel_if_available_tag>(domain, isovalue, points, triangles);
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std::cout << "Output #vertices: " << points.size() << std::endl;
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std::cout << "Output #triangles: " << triangles.size() << std::endl;
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CGAL::IO::write_polygon_soup("marching_cubes_discrete.off", points, triangles);
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}
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void run_dual_contouring(const Grid& grid,
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const FT isovalue)
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{
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using Domain = IS::Dual_contouring_domain_3<Grid, Values, Gradients, IS::Linear_interpolation_edge_intersection>;
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std::cout << "\n ---- " << std::endl;
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std::cout << "Running Dual Contouring with isovalue = " << isovalue << std::endl;
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// fill up values and gradients
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Values values { grid };
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Gradients gradients { grid };
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for(std::size_t i=0; i<grid.xdim(); ++i) {
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for(std::size_t j=0; j<grid.ydim(); ++j) {
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for(std::size_t k=0; k<grid.zdim(); ++k)
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{
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const Point& p = grid.point(i,j,k);
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const FT d = sqrt(CGAL::squared_distance(p, Point(CGAL::ORIGIN)));
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values(i,j,k) = d;
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if(d != 0)
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gradients(i,j,k) = Vector(CGAL::ORIGIN, p) / d;
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else
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gradients(i,j,k) = CGAL::NULL_VECTOR;
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}
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}
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}
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// If the gradient was not known analytically, we could use:
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// - Finite_difference_gradient_3 to use finite difference to compute it from values;
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// - the function below to use finite difference _and_ store the values at the grid vertices
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// gradients.compute_discrete_gradients(values);
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Domain domain { grid, values, gradients };
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Point_range points;
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Polygon_range triangles;
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// run dual contouring isosurfacing
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IS::dual_contouring<CGAL::Parallel_if_available_tag>(domain, isovalue, points, triangles);
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std::cout << "Output #vertices: " << points.size() << std::endl;
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std::cout << "Output #triangles: " << triangles.size() << std::endl;
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CGAL::IO::write_polygon_soup("dual_contouring_discrete.off", points, triangles);
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}
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int main(int argc, char** argv)
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{
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const FT isovalue = (argc > 1) ? std::stod(argv[1]) : 0.8;
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// create bounding box and grid
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const CGAL::Bbox_3 bbox { -1., -1., -1., 1., 1., 1. };
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Grid grid { bbox, CGAL::make_array<std::size_t>(30, 30, 30) };
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std::cout << "Span: " << grid.span() << std::endl;
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std::cout << "Cell dimensions: " << grid.spacing()[0] << " " << grid.spacing()[1] << " " << grid.spacing()[2] << std::endl;
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std::cout << "Cell #: " << grid.xdim() << ", " << grid.ydim() << ", " << grid.zdim() << std::endl;
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run_marching_cubes(grid, isovalue);
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run_dual_contouring(grid, isovalue);
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std::cout << "Done" << std::endl;
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return EXIT_SUCCESS;
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}
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