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Add an example demonstrating (T)MC on octrees

This commit is contained in:
Mael Rouxel-Labbé 2025-03-24 12:16:19 +01:00
parent 9fa9150312
commit a50a7b2a30
1 changed files with 35 additions and 0 deletions
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35
Isosurfacing_3/examples/Isosurfacing_3/contouring_octree.cpp
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@ -2,6 +2,8 @@
#include <CGAL/Isosurfacing_3/dual_contouring_3.h>
#include <CGAL/Isosurfacing_3/Dual_contouring_domain_3.h>
#include <CGAL/Isosurfacing_3/marching_cubes_3.h>
#include <CGAL/Isosurfacing_3/Marching_cubes_domain_3.h>
#include <CGAL/Isosurfacing_3/Value_function_3.h>
#include <CGAL/Isosurfacing_3/Gradient_function_3.h>
#include <CGAL/Isosurfacing_3/Octree_partition.h>
@ -25,6 +27,7 @@ using Polygon_range = std::vector<std::vector<std::size_t> >;
using Octree = CGAL::Octree<Kernel, std::vector<Point> >;
using Values = CGAL::Isosurfacing::Value_function_3<Octree>;
using Gradients = CGAL::Isosurfacing::Gradient_function_3<Octree>;
using MC_Domain = CGAL::Isosurfacing::Marching_cubes_domain_3<Octree, Values>;
using Domain = CGAL::Isosurfacing::Dual_contouring_domain_3<Octree, Values, Gradients>;
namespace IS = CGAL::Isosurfacing;
@ -229,6 +232,35 @@ void run_DC_octree(const CGAL::Bbox_3 bbox,
CGAL::IO::write_polygon_soup("DC_octree_" + name + ".off", points, triangles);
}
template <typename Splitter>
void run_TMC_octree(const CGAL::Bbox_3 bbox,
const Splitter& split_predicate,
const std::function<FT(const Point&)> function,
const FT isovalue,
const std::string& name)
{
std::vector<Point> bbox_points { { bbox.xmin(), bbox.ymin(), bbox.zmin() },
{ bbox.xmax(), bbox.ymax(), bbox.zmax() } };
Octree octree(bbox_points);
octree.refine(split_predicate);
Values values { function, octree };
Point_range points;
Polygon_range triangles;
MC_Domain mcdomain { octree, values };
std::cout << "Running TMC" << std::endl;
CGAL::Isosurfacing::marching_cubes<CGAL::Parallel_if_available_tag>(mcdomain, isovalue, points, triangles);
std::cout << "Output #vertices (TMC): " << points.size() << std::endl;
std::cout << "Output #triangles (TMC): " << triangles.size() << std::endl;
CGAL::IO::write_polygon_soup("TMC_octree_" + name + ".off", points, triangles);
}
// Whether you are using MC, TMC, or DC, there is no guarantee for an octree:
// it should behave well if your nodes are split with a uniform size around the surface,
// but it is sure to produce cracks if you have varying depths around the isosurface.
@ -248,6 +280,9 @@ int main(int argc, char** argv)
Refine_around_isovalue isvalue_splitter_2(5, 5, blobby_function, isovalue);
run_DC_octree(bbox, isvalue_splitter_2, blobby_function, blobby_gradient, isovalue, "blobby_adapted");
// to illustrate cracks
run_TMC_octree(bbox, one_eight_splitter, sphere_function, isovalue, "one_eight");
std::cout << "Done" << std::endl;
return EXIT_SUCCESS;