CGAL 4.11 beta1 released

Changelog

3D Periodic Regular Triangulations (new feature)

• Added the class Periodic_3_regular_triangulation_3, which provides functionality for 3D periodic weighted Delaunay triangulations. The construction is fully dynamic: it provides both point insertion and vertex removal.

dD Regular Triangulations (new feature)

• Added the class Regular_triangulation, which provides functionality for dD weighted Delaunay triangulations. Note that the removal of points is not yet supported.

2D and 3D Linear Geometry Kernel (breaking change)

• Breaking change: The dangerous implicit conversions between weighted points and points in the concept Kernel have been disabled. Constructors offering to build a weighted point from a point (and reversely) are still requested by the concept Kernel but must now be marked with the explicit specifier.
• Breaking change: The removal of implicit conversions between points and weighted points in the concept Kernel has incidentally created various minor breaking changes in the following packages: 2D Alpha Shapes, 2D and 3D Triangulations, and 3D Mesh Generation. See the full changelog for details.

Triangulated Surface Mesh Parameterization (breaking change)

• Breaking change: The package has been rewritten and can operate on any model of the MutableFaceGraph concept. All previous parameterization methods are still offered, although with a different, simpler API. The documentation has been updated and offers a gentle introduction to the new API. Users who wish to use the former API must use a version prior to 4.11.
• Breaking change: The adapter to add virtual seams is now the class CGAL::Seam_mesh in the package CGAL and the BGL.
• Breaking change: The package has been restructured and most headers have been moved. In a general manner, users should replace <CGAL/XXX.h> with <CGAL/Surface_mesh_parameterization/XXX.h>
• Add the As Rigid As Possible Parameterization method. This parameterization allows the user to prioritize angle preservation, shape preservation, or a balance of both.
• Add the Orbifold Tutte Embedding method. This parameterization method allows to parameterize meshes that are topological spheres.

3D Surface Subdivision Methods (breaking changes)

• The subdivision algorithms now work on any model of a MutableFaceGraph. A new API to the subdivision methods is offered, which uses optional named parameters to pass the number of iterations and a vertex property map.
• Breaking change: Removed the headers <CGAL/Subdivision_method_3.h> and <CGAL/Subdivision_mask_3.h>. The headers <CGAL/Subdivision_method_3/subdivision_methods_3.h> and <CGAL/Subdivision_method_3/subdivision_masks_3.h> should respectively be used instead.
• Sqrt3 subdivision can now handle input surfaces with a border.

Scale-Space Surface Reconstruction (breaking change)

• Breaking change: the API was rewritten to separate the smoothing and meshing algorithm and making it possible for the user to use different ones. The default algorithms used are the same as before this API change, but methods are moved to the classes Weighted_PCA_smoother and Alpha_shape_mesher.
• Alternative smoothing and meshing methods are provided: Jet_smoother and Advancing_front_mesher.

2D Alpha Shapes

• Breaking change: Mirrored the concepts of the 2D alpha shape package with those of the 3D Alpha Shapes package. Consequently, a new concept, WeightedAlphaShapeTraits_2, is introduced to provide requirements on the traits class for 2D weighted alpha shapes. All models of the concept Kernel are models of this new concept.
• The concept AlphaShapeTraits_2 now provides requirements on the traits class for 2D basic alpha shapes, and refines DelaunayTriangulationTraits_2.

2D and 3D Triangulations

• Breaking change: Added a new functor requirement, Construct_point_2, to the concepts TriangulationTraits_2 and RegularTriangulationTraits_2 and a new functor requirement, Construct_point_3, to the concepts TriangulationTraits_3 and RegularTriangulationTraits_3. All models of the concept Kernel already provide these functors.
• Breaking change: Introduced the concepts RegularTriangulationVertexBase_2 and RegularTriangulationVertexBase_3. These concepts describe the requirements on classes meant to represent a vertex of a regular triangulation. Concepts that previously refined TriangulationVertexBase_2 or TriangulationVertexBase_3 but described in fact a vertex class used in a regular triangulation, such as the concept MeshVertexBase_3 in the 3D mesh generation package, now refine the corresponding new regular vertex concept.
• Breaking change: Uniformized the point type across all vertex and cell concepts. The triangulation point type name is now always Point. Note that this does not change the requirements but only the name: Point is still expected to be equal to Traits::Point_[23] for basic and Delaunay triangulations or to Traits::Weighted_point_[23] for regular triangulations. Consequently:
  • The concept RegularTriangulationVertexBase_2 now requests a Point type (equal to Traits::Weighted_point_2)
  • The concept RegularTriangulationCellBase_3 now requests a Point type instead of a Weighted_point type (but still equal to Traits::Weighted_point_3)
  • The concept DelaunayTriangulationCellBase_3 now requests a Point type instead of a Point_3 type (but still equal to Traits::Point_3).
• Introduced a new concept, RegularTriangulationCellBaseWithWeightedCircumcenter_3, which describes the requirements on a cell of a regular triangulation that caches its circumcenter. The existing class Regular_triangulation_cell_base_with_weighted_circumcenter_3 is the default model of this concept.
• Added a new 3D traits class, Robust_weighted_circumcenter_filtered_traits_3 which provides robust versions of the kernel functors Construct_weighted_circumcenter_3, Compute_squared_radius_3, and Compute_squared_radius_smallest_orthogonal_sphere_3. This class can be used as traits class in the the Mesh_3 package to efficiently yet robustly generate 3D meshes.
• Add a new type of polyhedral domain with features, Polyhedral_complex_mesh_domain_3. The domain is defined by a collection of triangulated surfaces, forming a complex.

3D Periodic Triangulations

• Added new locate and geometric access functions for 3D periodic triangulations.
• The class Periodic_3_Delaunay_triangulation_traits_3 now inherits Periodic_3_triangulation_traits_3.
• Breaking change: Some geometric access functions in Periodic_3_triangulation_3 were renamed. The introduction of Periodic_3_regular_triangulation_3 required to distinguish between functions such as segment() returning a segment of weightless points, or a segment of weighted points. As a general rule, previous geometrical access functions will return objects with point type that of the triangulation (thus, weighted objects when using weighted triangulations) and functions containing construct in the name will always return weightless geometrical objects.
• Breaking change: The concept Periodic_3TriangulationTraits_3 now requests a domain getter: get_domain().
• Introduced a new concept, RegularTriangulationCellBaseWithWeightedCircumcenter_3, which describes the requirements on a cell of a regular triangulation that caches its circumcenter. The existing class Regular_triangulation_cell_base_with_weighted_circumcenter_3 is the default model of this concept.

3D Mesh Generation

• Breaking change: The type of the surface center in the concept MeshCellBase_3 has been changed from Triangulation::Point to TriangulationTraits::Point_3 to reflect that it is a weightless point.
• Breaking change: The function invalidate_circumcenter() of the concept MeshCellBase_3 is renamed to invalidate_weighted_circumcenter_cache() and moved to the new concept RegularTriangulationCellBaseWithWeightedCircumcenter_3, which the concept MeshCellBase_3 now refines.

Poisson Surface Reconstruction

• A new global function CGAL::poisson_surface_reconstruction_delaunay() is provided in addition to the current class-based API in order to make it easier to use.

Point Set Processing

• New functions to read from and write to LAS/LAZ files (LIDAR format), with or without taking additional properties into account.
• Breaking change: The API of the PLY function to read points with properties is modified for unification with LAS (see CGAL::read_ply_points_with_properties()). A new function to write PLY with properties is provided (CGAL::write_ply_points_with_properties()).

Spatial Searching

• Added function Kd_tree::remove(Point).

CGAL and the Boost Graph Library

• Added a partial specialization for the class CGAL::Linear_cell_complex_for_combinatorial_map so that it is a model of the graph concepts BidirectionalGraph and EdgeAndVertexListGraph and of the concept MutableFaceGraph. This class can thus now be used in all BGL functions and algorithms.
• Helper functions to create an icosahedron, a regular prism and a pyramid have been added.
• Added class CGAL::Face_filtered_graph that wraps an existing graph and hide all simplices that are not in the selected connected components.
• Added the class CGAL::Seam_mesh. The Seam_mesh is a graph adaptor which allows to create virtual borders when marking edges as seam edges.
• Added the functions read_off() and write_off().