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// Copyright (c) 2016 GeometryFactory (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v6.1.1/Surface_mesh_parameterization/include/CGAL/Surface_mesh_parameterization/internal/validity.h $
// $Id: include/CGAL/Surface_mesh_parameterization/internal/validity.h 08b27d3db14 $
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
// Author(s) : Mael Rouxel-Labbé
#ifndef CGAL_SURFACE_MESH_PARAMETERIZATION_INTERNAL_VALIDITY_H
#define CGAL_SURFACE_MESH_PARAMETERIZATION_INTERNAL_VALIDITY_H
#include <CGAL/license/Surface_mesh_parameterization.h>
#include <CGAL/Surface_mesh_parameterization/internal/Containers_filler.h>
#include <CGAL/Surface_mesh_parameterization/internal/kernel_traits.h>
#include <CGAL/Bbox_2.h>
#include <CGAL/box_intersection_d.h>
#include <CGAL/boost/graph/properties.h>
#include <CGAL/Kernel/global_functions.h>
#include <CGAL/intersections.h>
#include <CGAL/Polygon_mesh_processing/connected_components.h>
#include <boost/iterator/function_output_iterator.hpp>
#include <boost/range/has_range_iterator.hpp>
#include <vector>
#include <type_traits>
namespace CGAL {
namespace Surface_mesh_parameterization {
namespace internal {
template<typename TriangleMesh, typename VertexUVMap>
bool has_flips(const TriangleMesh& mesh,
typename boost::graph_traits<TriangleMesh>::halfedge_descriptor bhd,
const VertexUVMap uvmap)
{
typedef typename boost::graph_traits<TriangleMesh>::vertex_descriptor vertex_descriptor;
typedef typename boost::graph_traits<TriangleMesh>::halfedge_descriptor halfedge_descriptor;
typedef typename boost::graph_traits<TriangleMesh>::face_descriptor face_descriptor;
// Kernel subtypes:
typedef typename internal::Kernel_traits<TriangleMesh>::Kernel Kernel;
typedef typename Kernel::Point_2 Point_2;
typedef typename Kernel::Point_3 Point_3;
typedef typename Kernel::Vector_3 Vector_3;
// Fill containers
std::unordered_set<vertex_descriptor> vertices;
std::vector<face_descriptor> faces;
internal::Containers_filler<TriangleMesh> fc(mesh, vertices, &faces);
Polygon_mesh_processing::connected_component(
face(opposite(bhd, mesh), mesh),
mesh,
boost::make_function_output_iterator(fc));
Vector_3 first_triangle_normal(0., 0., 0.);
bool is_normal_set = false;
for(face_descriptor fd : faces) {
// Get 3 vertices of the facet
halfedge_descriptor hd = halfedge(fd, mesh);
vertex_descriptor vd0 = target(hd, mesh);
vertex_descriptor vd1 = target(next(hd, mesh), mesh);
vertex_descriptor vd2 = source(hd, mesh);
// Get the 3 vertices position in 2D
const Point_2& p0 = get(uvmap, vd0);
const Point_2& p1 = get(uvmap, vd1);
const Point_2& p2 = get(uvmap, vd2);
// Compute the facet normal
Point_3 p0_3D(p0.x(), p0.y(), 0.);
Point_3 p1_3D(p1.x(), p1.y(), 0.);
Point_3 p2_3D(p2.x(), p2.y(), 0.);
Vector_3 v01_3D = p1_3D - p0_3D;
Vector_3 v02_3D = p2_3D - p0_3D;
Vector_3 normal = CGAL::cross_product(v01_3D, v02_3D);
// Check that all normals are oriented the same way
if (!is_normal_set) {
first_triangle_normal = normal;
is_normal_set = true;
} else {
if (first_triangle_normal * normal < 0)
return true;
}
}
return false;
}
template <typename TriangleMesh, typename VertexUVMap>
class Intersect_facets
{
typedef typename boost::graph_traits<TriangleMesh>::vertex_descriptor vertex_descriptor;
typedef typename boost::graph_traits<TriangleMesh>::halfedge_descriptor halfedge_descriptor;
typedef typename boost::graph_traits<TriangleMesh>::face_descriptor face_descriptor;
// Kernel subtypes:
typedef typename internal::Kernel_traits<TriangleMesh>::Kernel Kernel;
typedef typename Kernel::Point_2 Point_2;
typedef typename Kernel::Segment_2 Segment_2;
typedef typename Kernel::Triangle_2 Triangle_2;
typedef typename Kernel::FT NT;
typename Kernel::Construct_segment_2 segment_functor;
typename Kernel::Construct_triangle_2 triangle_functor;
typename Kernel::Do_intersect_2 do_intersect_2_functor;
typedef CGAL::Box_intersection_d::ID_FROM_BOX_ADDRESS Box_policy;
typedef CGAL::Box_intersection_d::Box_with_info_d<NT, 2, face_descriptor, Box_policy> Box;
const TriangleMesh& mesh;
const VertexUVMap uvmap;
unsigned int& self_intersection_counter;
public:
unsigned int number_of_self_intersections() const { return self_intersection_counter; }
// callback functor that reports all truly intersecting triangles
void operator()(const Box* a, const Box* b) const
{
// Boxes intersect, need to check if there is actually an intersection
// and if it is not a subface of the faces
halfedge_descriptor h = halfedge(a->info(), mesh);
halfedge_descriptor g = halfedge(b->info(), mesh);
// check for shared edge
if(face(opposite(h, mesh), mesh) == b->info() ||
face(opposite(prev(h, mesh), mesh), mesh) == b->info() ||
face(opposite(next(h, mesh), mesh), mesh) == b->info()) {
// shared edge
// intersection if the orientations are not identical
if(CGAL::orientation(get(uvmap, target(h, mesh)),
get(uvmap, target(next(h, mesh), mesh)),
get(uvmap, source(h, mesh))) !=
CGAL::orientation(get(uvmap, target(g, mesh)),
get(uvmap, target(next(g, mesh), mesh)),
get(uvmap, source(g, mesh)))) {
++self_intersection_counter;
}
return;
}
// check for shared vertex --> possible intersection
halfedge_descriptor hd;
if(target(h, mesh) == target(g, mesh))
hd = g;
if(target(h, mesh) == target(next(g, mesh), mesh))
hd = next(g, mesh);
if(target(h, mesh) == target(next(next(g, mesh), mesh), mesh))
hd = next(next(g, mesh), mesh);
if(target(h, mesh) == target(g, mesh))
hd = g;
if(target(h, mesh) == target(next(g, mesh), mesh))
hd = next(g, mesh);
if(target(h, mesh) == target(next(next(g, mesh), mesh), mesh))
hd = next(next(g, mesh), mesh);
if(hd == halfedge_descriptor()) {
h = next(h, mesh);
if(target(h, mesh) == target(g, mesh))
hd = g;
if(target(h, mesh) == target(next(g, mesh), mesh))
hd = next(g, mesh);
if(target(h, mesh) == target(next(next(g, mesh), mesh), mesh))
hd = next(next(g, mesh), mesh);
if(hd == halfedge_descriptor()) {
h = next(h, mesh);
if(target(h, mesh) == target(g, mesh))
hd = g;
if(target(h, mesh) == target(next(g, mesh), mesh))
hd = next(g, mesh);
if(target(h, mesh) == target(next(next(g, mesh), mesh), mesh))
hd = next(next(g, mesh), mesh);
}
}
if(hd != halfedge_descriptor()) {
// shared vertex
CGAL_assertion(target(h, mesh) == target(hd, mesh));
// geometric check if the opposite segments intersect the triangles
Triangle_2 t1 = triangle_functor(get(uvmap, target(h, mesh)),
get(uvmap, target(next(h, mesh), mesh)),
get(uvmap, target(next(next(h, mesh), mesh), mesh)));
Triangle_2 t2 = triangle_functor(get(uvmap, target(hd, mesh)),
get(uvmap, target(next(hd, mesh), mesh)),
get(uvmap, target(next(next(hd, mesh), mesh), mesh)));
Segment_2 s1 = segment_functor(get(uvmap, target(next(h, mesh), mesh)),
get(uvmap, target(next(next(h, mesh), mesh), mesh)));
Segment_2 s2 = segment_functor(get(uvmap, target(next(hd, mesh), mesh)),
get(uvmap, target(next(next(hd, mesh), mesh), mesh)));
if(do_intersect_2_functor(t1, s2)) {
++self_intersection_counter;
} else if(do_intersect_2_functor(t2, s1)) {
++self_intersection_counter;
}
return;
}
// check for geometric intersection
Triangle_2 t1 = triangle_functor(get(uvmap, target(h, mesh)),
get(uvmap, target(next(h, mesh), mesh)),
get(uvmap, target(next(next(h, mesh), mesh), mesh)));
Triangle_2 t2 = triangle_functor(get(uvmap, target(g, mesh)),
get(uvmap, target(next(g, mesh), mesh)),
get(uvmap, target(next(next(g, mesh), mesh), mesh)));
if(do_intersect_2_functor(t1, t2)) {
++self_intersection_counter;
}
}
Intersect_facets(const TriangleMesh& mesh_,
const VertexUVMap uvmap_,
unsigned int& counter)
:
mesh(mesh_),
uvmap(uvmap_),
self_intersection_counter(counter)
{ }
};
/// returns whether the 3D -> 2D mapping is one-to-one.
/// This function is stronger than "has_flips()" because the parameterized
/// surface can loop over itself without creating any flips.
template <typename TriangleMesh,
typename Faces_Container,
typename VertexUVMap>
bool is_one_to_one_mapping(const TriangleMesh& mesh,
const Faces_Container& faces,
const VertexUVMap uvmap,
std::enable_if_t<
boost::has_range_iterator<Faces_Container>::value
>* = nullptr)
{
typedef typename boost::graph_traits<TriangleMesh>::vertex_descriptor vertex_descriptor;
typedef typename boost::graph_traits<TriangleMesh>::halfedge_descriptor halfedge_descriptor;
typedef typename boost::graph_traits<TriangleMesh>::face_descriptor face_descriptor;
// Kernel subtypes:
typedef typename internal::Kernel_traits<TriangleMesh>::Kernel Kernel;
typedef typename Kernel::FT NT;
typedef typename Kernel::Point_2 Point_2;
typedef CGAL::Box_intersection_d::ID_FROM_BOX_ADDRESS Box_policy;
typedef CGAL::Box_intersection_d::Box_with_info_d<NT, 2, face_descriptor, Box_policy> Box;
// Create the corresponding vector of bounding boxes
std::vector<Box> boxes;
for(face_descriptor fd : faces) {
halfedge_descriptor hd = halfedge(fd, mesh);
vertex_descriptor vd0 = target(hd, mesh);
vertex_descriptor vd1 = target(next(hd, mesh), mesh);
vertex_descriptor vd2 = source(hd, mesh);
// Get the 3 vertices position in 2D
const Point_2& p0 = get(uvmap, vd0);
const Point_2& p1 = get(uvmap, vd1);
const Point_2& p2 = get(uvmap, vd2);
NT bx[2] = { (std::min)(p0[0], (std::min)(p1[0], p2[0])),
(std::min)(p0[1], (std::min)(p1[1], p2[1])) };
NT by[2] = { (std::max)(p0[0], (std::max)(p1[0], p2[0])),
(std::max)(p0[1], (std::max)(p1[1], p2[1])) };
boxes.emplace_back(bx, by, fd);
}
std::vector<const Box*> boxes_ptr;
boxes_ptr.reserve(boxes.size());
for(Box& b : boxes)
boxes_ptr.push_back(&b);
// Run the self intersection algorithm with all defaults
unsigned int counter = 0;
Intersect_facets<TriangleMesh, VertexUVMap> intersect_facets(mesh, uvmap, counter);
std::ptrdiff_t cutoff = 2000;
CGAL::box_self_intersection_d(boxes_ptr.begin(), boxes_ptr.end(), intersect_facets, cutoff);
return (counter == 0);
}
template <typename TriangleMesh,
typename VertexUVMap>
bool is_one_to_one_mapping(const TriangleMesh& mesh,
typename boost::graph_traits<TriangleMesh>::halfedge_descriptor bhd,
const VertexUVMap uvmap)
{
typedef typename boost::graph_traits<TriangleMesh>::vertex_descriptor vertex_descriptor;
typedef typename boost::graph_traits<TriangleMesh>::face_descriptor face_descriptor;
std::unordered_set<vertex_descriptor> vertices;
std::vector<face_descriptor> faces;
internal::Containers_filler<TriangleMesh> fc(mesh, vertices, &faces);
Polygon_mesh_processing::connected_component(
face(opposite(bhd, mesh), mesh),
mesh,
boost::make_function_output_iterator(fc));
return is_one_to_one_mapping(mesh, faces, uvmap);
}
} // namespace internal
} // namespace Surface_mesh_parameterization
} // namespace CGAL
#endif // CGAL_SURFACE_MESH_PARAMETERIZATION_INTERNAL_VALIDITY_H
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