Merge pull request #6088 from sloriot/PMP-add_discrete_curvature

Add functions to compute discrete curvatures
This commit is contained in:
Sébastien Loriot 2025-02-12 21:22:40 +01:00
commit 06b511cc65
12 changed files with 717 additions and 30 deletions

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@ -6,6 +6,11 @@
### General Changes
- The minimal supported version of Boost is now 1.74.0.
### [Polygon Mesh Processing](https://doc.cgal.org/6.1/Manual/packages.html#PkgPolygonMeshProcessing)
- Added the function `CGAL::Polygon_mesh_processing::discrete_mean_curvature` and `CGAL::Polygon_mesh_processing::discrete_Guassian_curvature` to evaluate the discrete curvature at a vertex of a mesh.
- Added the function `CGAL::Polygon_mesh_processing::angle_sum` to compute the sum of the angles around a vertex.
### [Algebraic Kernel](https://doc.cgal.org/6.1/Manual/packages.html#PkgAlgebraicKernelD)
- **Breaking change**: Classes based on the RS Library are no longer provided.

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@ -965,22 +965,14 @@ namespace CommonKernelFunctors {
typename K::Compute_scalar_product_3 scalar_product =
k.compute_scalar_product_3_object();
double product = CGAL::sqrt(to_double(scalar_product(u,u)) * to_double(scalar_product(v,v)));
double product = to_double(approximate_sqrt(scalar_product(u,u) * scalar_product(v,v)));
if(product == 0)
return 0;
// cosine
double dot = to_double(scalar_product(u,v));
double cosine = dot / product;
if(cosine > 1.){
cosine = 1.;
}
if(cosine < -1.){
cosine = -1.;
}
double cosine = std::clamp(dot / product, -1., 1.);
return std::acos(cosine) * 180./CGAL_PI;
}

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@ -23,9 +23,9 @@ compute_color_map(QColor base_color,
std::size_t nb_of_colors,
Output_color_iterator out)
{
qreal hue = base_color.hueF();
const qreal step = (static_cast<qreal>(1)) / nb_of_colors;
const qreal step = (static_cast<qreal>(0.85)) / nb_of_colors;
qreal hue = base_color.hueF();
qreal h = (hue == -1) ? 0 : hue;
for(std::size_t i=0; i<nb_of_colors; ++i)
{

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@ -22,6 +22,7 @@
#include <CGAL/Polygon_mesh_processing/compute_normal.h>
#include <CGAL/Polygon_mesh_processing/measure.h>
#include <CGAL/Polygon_mesh_processing/triangulate_faces.h>
#include <CGAL/Polygon_mesh_processing/curvature.h>
#include <CGAL/Polygon_mesh_processing/interpolated_corrected_curvatures.h>
#include <QAbstractItemView>
@ -350,11 +351,11 @@ private:
template<typename ValueType>
void displayMapLegend(const std::vector<ValueType>& values)
{
const std::size_t size = (std::min)(color_map.size(), std::size_t(1024));
const std::size_t size = (std::min)(color_map.size(), std::size_t(4096));
const int text_height = 20;
const int height = text_height * static_cast<int>(size) + text_height;
const int width = 140;
const int width = 200;
const int cell_width = width / 3;
const int top_margin = 15;
const int left_margin = 5;
@ -381,13 +382,13 @@ private:
tick_height,
color);
QRect text_rect(left_margin + cell_width + 10, drawing_height - top_margin - j, 50, text_height);
painter.drawText(text_rect, Qt::AlignCenter, QObject::tr("%1").arg(values[i], 0, 'f', 3, QLatin1Char(' ')));
QRect text_rect(left_margin + cell_width + 10, drawing_height - top_margin - j, 100, text_height);
painter.drawText(text_rect, Qt::AlignCenter, QObject::tr("%1").arg(values[i], 0, 'f', 6, QLatin1Char(' ')));
}
if(color_map.size() > size)
{
QRect text_rect(left_margin + cell_width + 10, 0, 50, text_height);
QRect text_rect(left_margin + cell_width + 10, 0, 100, text_height);
painter.drawText(text_rect, Qt::AlignCenter, QObject::tr("[...]"));
}
@ -463,6 +464,8 @@ private:
"Largest Angle Per Face",
"Scaled Jacobian",
"Face Area",
"Discrete Mean Curvature",
"Discrete Gaussian Curvature",
"Interpolated Corrected Mean Curvature",
"Interpolated Corrected Gaussian Curvature"});
property_simplex_types = { Property_simplex_type::FACE,
@ -470,6 +473,8 @@ private:
Property_simplex_type::FACE,
Property_simplex_type::FACE,
Property_simplex_type::VERTEX,
Property_simplex_type::VERTEX,
Property_simplex_type::VERTEX,
Property_simplex_type::VERTEX };
detectSMScalarProperties(*(sm_item->face_graph()));
}
@ -516,12 +521,12 @@ private Q_SLOTS:
// Curvature property-specific slider
const std::string& property_name = dock_widget->propertyBox->currentText().toStdString();
const bool is_curvature_property = (property_name == "Interpolated Corrected Mean Curvature" ||
const bool is_interpolated_curvature_property = (property_name == "Interpolated Corrected Mean Curvature" ||
property_name == "Interpolated Corrected Gaussian Curvature");
dock_widget->expandingRadiusLabel->setVisible(is_curvature_property);
dock_widget->expandingRadiusSlider->setVisible(is_curvature_property);
dock_widget->expandingRadiusLabel->setEnabled(is_curvature_property);
dock_widget->expandingRadiusSlider->setEnabled(is_curvature_property);
dock_widget->expandingRadiusLabel->setVisible(is_interpolated_curvature_property);
dock_widget->expandingRadiusSlider->setVisible(is_interpolated_curvature_property);
dock_widget->expandingRadiusLabel->setEnabled(is_interpolated_curvature_property);
dock_widget->expandingRadiusSlider->setEnabled(is_interpolated_curvature_property);
}
else // no or broken property
{
@ -570,6 +575,16 @@ private:
{
displayArea(sm_item);
}
else if(property_name == "Discrete Mean Curvature")
{
displayDiscreteCurvatureMeasure(sm_item, MEAN_CURVATURE);
sm_item->setRenderingMode(Gouraud);
}
else if(property_name == "Discrete Gaussian Curvature")
{
displayDiscreteCurvatureMeasure(sm_item, GAUSSIAN_CURVATURE);
sm_item->setRenderingMode(Gouraud);
}
else if(property_name == "Interpolated Corrected Mean Curvature")
{
displayInterpolatedCurvatureMeasure(sm_item, MEAN_CURVATURE);
@ -682,6 +697,8 @@ private:
removeDisplayPluginProperty(item, "f:display_plugin_largest_angle");
removeDisplayPluginProperty(item, "f:display_plugin_scaled_jacobian");
removeDisplayPluginProperty(item, "f:display_plugin_area");
removeDisplayPluginProperty(item, "v:display_plugin_discrete_mean_curvature");
removeDisplayPluginProperty(item, "v:display_plugin_discrete_Gaussian_curvature");
removeDisplayPluginProperty(item, "v:display_plugin_interpolated_corrected_mean_curvature");
removeDisplayPluginProperty(item, "v:display_plugin_interpolated_corrected_Gaussian_curvature");
}
@ -864,6 +881,35 @@ private:
displaySMProperty<face_descriptor>("f:display_plugin_area", *sm);
}
private:
void displayDiscreteCurvatureMeasure(Scene_surface_mesh_item* sm_item,
CurvatureType mu_index)
{
SMesh* sm = sm_item->face_graph();
if(sm == nullptr)
return;
if(mu_index != MEAN_CURVATURE && mu_index != GAUSSIAN_CURVATURE)
return;
std::string vdc_name = (mu_index == MEAN_CURVATURE) ? "v:display_plugin_discrete_mean_curvature"
: "v:display_plugin_discrete_Gaussian_curvature";
bool not_initialized;
SMesh::Property_map<vertex_descriptor, double> vdc;
std::tie(vdc, not_initialized) = sm->add_property_map<vertex_descriptor, double>(vdc_name, 0);
if(not_initialized)
{
if(mu_index == MEAN_CURVATURE)
PMP::discrete_mean_curvatures(*sm, vdc);
else
PMP::discrete_Gaussian_curvatures(*sm, vdc);
}
displaySMProperty<vertex_descriptor>(vdc_name, *sm);
}
private Q_SLOTS:
void setExpandingRadius()
{
@ -1131,6 +1177,10 @@ private:
zoomToSimplexWithPropertyExtremum(faces(mesh), mesh, "f:display_plugin_scaled_jacobian", extremum);
else if(property_name == "Face Area")
zoomToSimplexWithPropertyExtremum(faces(mesh), mesh, "f:display_plugin_area", extremum);
else if(property_name == "Discrete Mean Curvature")
zoomToSimplexWithPropertyExtremum(vertices(mesh), mesh, "v:display_plugin_discrete_mean_curvature", extremum);
else if(property_name == "Discrete Gaussian Curvature")
zoomToSimplexWithPropertyExtremum(vertices(mesh), mesh, "v:display_plugin_discrete_Gaussian_curvature", extremum);
else if(property_name == "Interpolated Corrected Mean Curvature")
zoomToSimplexWithPropertyExtremum(vertices(mesh), mesh, "v:display_plugin_interpolated_corrected_mean_curvature", extremum);
else if(property_name == "Interpolated Corrected Gaussian Curvature")
@ -1470,6 +1520,8 @@ isSMPropertyScalar(const std::string& name,
name == "f:display_plugin_largest_angle" ||
name == "f:display_plugin_scaled_jacobian" ||
name == "f:display_plugin_area" ||
name == "v:display_plugin_discrete_mean_curvature" ||
name == "v:display_plugin_discrete_Gaussian_curvature" ||
name == "v:display_plugin_interpolated_corrected_mean_curvature" ||
name == "v:display_plugin_interpolated_corrected_Gaussian_curvature")
return false;

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@ -25,7 +25,7 @@
/// \ingroup PkgPolygonMeshProcessingRef
/// \defgroup PMP_measure_grp Geometric Measure Functions
/// Functions to compute lengths of edges and borders, areas of faces and patches, as well as volumes of closed meshes.
/// Functions to compute discrete curvatures, lengths of edges and borders, areas of faces and patches, volumes of closed meshes.
/// \ingroup PkgPolygonMeshProcessingRef
/// \defgroup PMP_orientation_grp Orientation Functions
@ -239,6 +239,11 @@ The page \ref bgl_namedparameters "Named Parameters" describes their usage.
- `CGAL::Polygon_mesh_processing::sample_triangle_mesh()`
\cgalCRPSection{Geometric Measure Functions}
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::angle_sum()` \endlink
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::discrete_Gaussian_curvatures()` \endlink
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::discrete_Gaussian_curvature()` \endlink
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::discrete_mean_curvature()` \endlink
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::discrete_mean_curvatures()` \endlink
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::edge_length()` \endlink
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::squared_edge_length()` \endlink
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::face_area()` \endlink
@ -248,7 +253,6 @@ The page \ref bgl_namedparameters "Named Parameters" describes their usage.
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::face_border_length()` \endlink
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::longest_border()` \endlink
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::centroid()` \endlink
- \link PMP_measure_grp `CGAL::Polygon_mesh_processing::match_faces()` \endlink
\cgalCRPSection{Feature Detection Functions}
- `CGAL::Polygon_mesh_processing::sharp_edges_segmentation()`

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@ -1225,6 +1225,17 @@ compute the curvatures on a specific vertex.
\cgalExample{Polygon_mesh_processing/interpolated_corrected_curvatures_vertex.cpp}
\subsection DCurvartures Discrete Curvatures
The package also provides methods to compute the standard, non-interpolated discrete mean and Gaussian
curvatures on triangle meshes, based on the work of Meyer et al. \cgalCite{cgal:mdsb-ddgot-02}.
These curvatures are computed at each vertex of the mesh, and are based on the angles of the incident
triangles. The functions are:
- `CGAL::Polygon_mesh_processing::discrete_mean_curvature()`
- `CGAL::Polygon_mesh_processing::discrete_mean_curvatures()`
- `CGAL::Polygon_mesh_processing::discrete_Gaussian_curvature()`
- `CGAL::Polygon_mesh_processing::discrete_Gaussian_curvatures()`
****************************************
\section PMPSlicer Slicer

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@ -0,0 +1,475 @@
// Copyright (c) 2021 GeometryFactory (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL$
// $Id$
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s) : Andreas Fabri,
// Mael Rouxel-Labbé
#ifndef CGAL_PMP_CURVATURE_H
#define CGAL_PMP_CURVATURE_H
#include <CGAL/license/Polygon_mesh_processing/measure.h>
#include <CGAL/boost/graph/named_params_helper.h>
#include <CGAL/Named_function_parameters.h>
#include <CGAL/Polygon_mesh_processing/measure.h>
#include <CGAL/Weights/cotangent_weights.h>
#include <cmath>
#include <algorithm>
namespace CGAL {
namespace Polygon_mesh_processing {
/**
* \ingroup PMP_measure_grp
*
* computes the sum of the angles around a vertex.
*
* The angle sum is given in degrees.
*
* @tparam PolygonMesh a model of `FaceGraph`
* @tparam NamedParameters a sequence of \ref bgl_namedparameters "Named Parameters"
*
* @param v the vertex whose sum of angles is computed
* @param pmesh the polygon mesh to which `v` belongs
* @param np an optional sequence of \ref bgl_namedparameters "Named Parameters" among the ones listed below
*
* \cgalNamedParamsBegin
* \cgalParamNBegin{vertex_point_map}
* \cgalParamDescription{a property map associating points to the vertices of `pmesh`}
* \cgalParamType{a class model of `ReadablePropertyMap` with `boost::graph_traits<PolygonMesh>::%vertex_descriptor`
* as key type and `%Point_3` as value type}
* \cgalParamDefault{`boost::get(CGAL::vertex_point, pmesh)`}
* \cgalParamNEnd
*
* \cgalParamNBegin{geom_traits}
* \cgalParamDescription{an instance of a geometric traits class}
* \cgalParamType{The traits class must provide the nested functor `Compute_approximate_angle_3`,
* model of `Kernel::ComputeApproximateAngle_3`.}
* \cgalParamDefault{a \cgal kernel deduced from the point type, using `CGAL::Kernel_traits`}
* \cgalParamExtra{The geometric traits class must be compatible with the vertex point type.}
* \cgalParamNEnd
* \cgalNamedParamsEnd
*
* @return the sum of angles around `v`. The return type `FT` is a number type either deduced
* from the `geom_traits` \ref bgl_namedparameters "Named Parameters" if provided,
* or the geometric traits class deduced from the point property map of `pmesh`.
*
* \warning This function involves trigonometry.
*/
template<typename PolygonMesh,
typename CGAL_NP_TEMPLATE_PARAMETERS>
#ifdef DOXYGEN_RUNNING
FT
#else
typename GetGeomTraits<PolygonMesh, CGAL_NP_CLASS>::type::FT
#endif
angle_sum(typename boost::graph_traits<PolygonMesh>::vertex_descriptor v,
const PolygonMesh& pmesh,
const CGAL_NP_CLASS& np = parameters::default_values())
{
using parameters::choose_parameter;
using parameters::get_parameter;
using Geom_traits = typename GetGeomTraits<PolygonMesh, CGAL_NP_CLASS>::type;
using FT = typename Geom_traits::FT;
typename GetVertexPointMap<PolygonMesh, CGAL_NP_CLASS>::const_type
vpm = choose_parameter(get_parameter(np, internal_np::vertex_point),
get_const_property_map(CGAL::vertex_point, pmesh));
Geom_traits gt = choose_parameter<Geom_traits>(get_parameter(np, internal_np::geom_traits));
CGAL_precondition(is_valid_vertex_descriptor(v, pmesh));
typename Geom_traits::Compute_approximate_angle_3 approx_angle = gt.compute_approximate_angle_3_object();
FT angle_sum = 0;
for(auto h : halfedges_around_source(v, pmesh))
{
if(is_border(h, pmesh))
continue;
angle_sum += approx_angle(get(vpm, target(h, pmesh)),
get(vpm, source(h, pmesh)),
get(vpm, source(prev(h,pmesh), pmesh)));
}
return angle_sum;
}
// Discrete Gaussian Curvature
/**
* \ingroup PMP_measure_grp
*
* computes the discrete Gaussian curvature at a vertex.
*
* We refer to Meyer et al. \cgalCite{cgal:mdsb-ddgot-02} for the definition of <i>discrete Gaussian curvature</i>.
*
* @tparam TriangleMesh a model of `FaceGraph`
* @tparam NamedParameters a sequence of \ref bgl_namedparameters "Named Parameters"
*
* @param v the vertex whose discrete Gaussian curvature is being computed
* @param tmesh the triangle mesh to which `v` belongs
* @param np an optional sequence of \ref bgl_namedparameters "Named Parameters" among the ones listed below
*
* \cgalNamedParamsBegin
* \cgalParamNBegin{vertex_point_map}
* \cgalParamDescription{a property map associating points to the vertices of `tmesh`}
* \cgalParamType{a class model of `ReadablePropertyMap` with `boost::graph_traits<TriangleMesh>::%vertex_descriptor`
* as key type and `%Point_3` as value type}
* \cgalParamDefault{`boost::get(CGAL::vertex_point, tmesh)`}
* \cgalParamNEnd
*
* \cgalParamNBegin{geom_traits}
* \cgalParamDescription{an instance of a geometric traits class}
* \cgalParamType{The traits class must be a model of `Kernel`.}
* \cgalParamDefault{a \cgal kernel deduced from the point type, using `CGAL::Kernel_traits`}
* \cgalParamExtra{The geometric traits class must be compatible with the vertex point type.}
* \cgalParamNEnd
* \cgalNamedParamsEnd
*
* @return the discrete Gaussian curvature at `v`. The return type `FT` is a number type either deduced
* from the `geom_traits` \ref bgl_namedparameters "Named Parameters" if provided,
* or the geometric traits class deduced from the point property map of `tmesh`.
*
* \warning This function involves trigonometry.
* \warning The current formulation is not well defined for border vertices.
*
* \pre `tmesh` is a triangle mesh
*/
template <typename TriangleMesh,
typename CGAL_NP_TEMPLATE_PARAMETERS>
#ifdef DOXYGEN_RUNNING
FT
#else
typename GetGeomTraits<TriangleMesh, CGAL_NP_CLASS>::type::FT
#endif
discrete_Gaussian_curvature(typename boost::graph_traits<TriangleMesh>::vertex_descriptor v,
const TriangleMesh& tmesh,
const CGAL_NP_CLASS& np = parameters::default_values())
{
using parameters::choose_parameter;
using parameters::get_parameter;
using GeomTraits = typename GetGeomTraits<TriangleMesh, CGAL_NP_CLASS>::type;
using FT = typename GeomTraits::FT;
using Vector_3 = typename GeomTraits::Vector_3;
using VertexPointMap = typename GetVertexPointMap<TriangleMesh, CGAL_NP_CLASS>::const_type;
using halfedge_descriptor = typename boost::graph_traits<TriangleMesh>::halfedge_descriptor;
GeomTraits gt = choose_parameter<GeomTraits>(get_parameter(np, internal_np::geom_traits));
VertexPointMap vpm = choose_parameter(get_parameter(np, internal_np::vertex_point),
get_const_property_map(vertex_point, tmesh));
typename GeomTraits::Construct_vector_3 vector =
gt.construct_vector_3_object();
typename GeomTraits::Construct_cross_product_vector_3 cross_product =
gt.construct_cross_product_vector_3_object();
typename GeomTraits::Compute_scalar_product_3 scalar_product =
gt.compute_scalar_product_3_object();
typename GeomTraits::Compute_squared_length_3 squared_length =
gt.compute_squared_length_3_object();
FT angle_sum = 0;
for(halfedge_descriptor h : CGAL::halfedges_around_target(v, tmesh))
{
if(is_border(h, tmesh))
continue;
const Vector_3 v0 = vector(get(vpm, v), get(vpm, target(next(h, tmesh), tmesh))); // p1p2
const Vector_3 v1 = vector(get(vpm, v), get(vpm, source(h, tmesh))); // p1p0
const FT dot = scalar_product(v0, v1);
const Vector_3 cross = cross_product(v0, v1);
const FT sqcn = squared_length(cross);
if(is_zero(dot))
{
angle_sum += CGAL_PI/FT(2);
}
else
{
if(is_zero(sqcn)) // collinear
{
if(dot < 0)
angle_sum += CGAL_PI;
// else
// angle_sum += 0;
}
else
{
angle_sum += std::atan2(CGAL::approximate_sqrt(sqcn), dot);
}
}
}
Weights::Secure_cotangent_weight_with_voronoi_area<TriangleMesh, VertexPointMap, GeomTraits> wc(tmesh, vpm, gt);
const FT gaussian_curvature = (2 * CGAL_PI - angle_sum) / wc.voronoi(v);
return gaussian_curvature;
}
/**
* \ingroup PMP_measure_grp
*
* computes the discrete Gaussian curvatures at the vertices of a mesh.
*
* We refer to Meyer et al. \cgalCite{cgal:mdsb-ddgot-02} for the definition of <i>discrete Gaussian curvature</i>.
*
* @tparam TriangleMesh a model of `FaceGraph`
* @tparam VertexCurvatureMap must be a model of `WritablePropertyMap` with key type
* `boost::graph_traits<TriangleMesh>::%vertex_descriptor` and value type `FT`,
* which is either `geom_traits::FT` if this named parameter is provided,
* or `kernel::FT` with the kernel deduced from from the point property map of `tmesh`.
* @tparam NamedParameters a sequence of \ref bgl_namedparameters "Named Parameters"
*
* @param tmesh the triangle mesh to which `v` belongs
* @param vcm the property map that contains the computed discrete curvatures
* @param np an optional sequence of \ref bgl_namedparameters "Named Parameters" among the ones listed below
*
* \cgalNamedParamsBegin
* \cgalParamNBegin{vertex_point_map}
* \cgalParamDescription{a property map associating points to the vertices of `tmesh`}
* \cgalParamType{a class model of `ReadablePropertyMap` with `boost::graph_traits<TriangleMesh>::%vertex_descriptor`
* as key type and `%Point_3` as value type}
* \cgalParamDefault{`boost::get(CGAL::vertex_point, tmesh)`}
* \cgalParamNEnd
*
* \cgalParamNBegin{geom_traits}
* \cgalParamDescription{an instance of a geometric traits class}
* \cgalParamType{The traits class must be a model of `Kernel`.}
* \cgalParamDefault{a \cgal kernel deduced from the point type, using `CGAL::Kernel_traits`}
* \cgalParamExtra{The geometric traits class must be compatible with the vertex point type.}
* \cgalParamNEnd
* \cgalNamedParamsEnd
*
* \warning This function involves trigonometry.
* \warning The current formulation is not well defined for border vertices.
*
* \pre `tmesh` is a triangle mesh
*/
template <typename TriangleMesh,
typename VertexCurvatureMap,
typename CGAL_NP_TEMPLATE_PARAMETERS>
void discrete_Gaussian_curvatures(const TriangleMesh& tmesh,
VertexCurvatureMap vcm,
const CGAL_NP_CLASS& np = parameters::default_values())
{
using vertex_descriptor = typename boost::graph_traits<TriangleMesh>::vertex_descriptor;
for(vertex_descriptor v : vertices(tmesh))
{
put(vcm, v, discrete_Gaussian_curvature(v, tmesh, np));
// std::cout << "curvature: " << get(vcm, v) << std::endl;
}
}
// Discrete Mean Curvature
/**
* \ingroup PMP_measure_grp
*
* computes the discrete mean curvature at a vertex.
*
* We refer to Meyer et al. \cgalCite{cgal:mdsb-ddgot-02} for the definition of <i>discrete mean curvature</i>.
*
* @tparam TriangleMesh a model of `FaceGraph`
* @tparam NamedParameters a sequence of \ref bgl_namedparameters "Named Parameters"
*
* @param v the vertex whose discrete mean curvature is being computed
* @param tmesh the triangle mesh to which `v` belongs
* @param np an optional sequence of \ref bgl_namedparameters "Named Parameters" among the ones listed below
*
* \cgalNamedParamsBegin
* \cgalParamNBegin{vertex_point_map}
* \cgalParamDescription{a property map associating points to the vertices of `tmesh`}
* \cgalParamType{a class model of `ReadablePropertyMap` with `boost::graph_traits<TriangleMesh>::%vertex_descriptor`
* as key type and `%Point_3` as value type}
* \cgalParamDefault{`boost::get(CGAL::vertex_point, tmesh)`}
* \cgalParamNEnd
*
* \cgalParamNBegin{geom_traits}
* \cgalParamDescription{an instance of a geometric traits class}
* \cgalParamType{The traits class must be a model of `Kernel`.}
* \cgalParamDefault{a \cgal kernel deduced from the point type, using `CGAL::Kernel_traits`}
* \cgalParamExtra{The geometric traits class must be compatible with the vertex point type.}
* \cgalParamNEnd
* \cgalNamedParamsEnd
*
* @return the discrete mean curvature at `v`. The return type `FT` is a number type either deduced
* from the `geom_traits` \ref bgl_namedparameters "Named Parameters" if provided,
* or the geometric traits class deduced from the point property map of `tmesh`.
*
* \warning The current formulation is not well defined for border vertices.
*
* \pre `tmesh` is a triangle mesh
*/
template <typename TriangleMesh,
typename CGAL_NP_TEMPLATE_PARAMETERS>
#ifdef DOXYGEN_RUNNING
FT
#else
typename GetGeomTraits<TriangleMesh, CGAL_NP_CLASS>::type::FT
#endif
discrete_mean_curvature(typename boost::graph_traits<TriangleMesh>::vertex_descriptor v,
const TriangleMesh& tmesh,
const CGAL_NP_CLASS& np = parameters::default_values())
{
using parameters::choose_parameter;
using parameters::get_parameter;
using GeomTraits = typename GetGeomTraits<TriangleMesh, CGAL_NP_CLASS>::type;
using FT = typename GeomTraits::FT;
using Vector_3 = typename GeomTraits::Vector_3;
using VertexPointMap = typename GetVertexPointMap<TriangleMesh, CGAL_NP_CLASS>::const_type;
using Point_ref = typename boost::property_traits<VertexPointMap>::reference;
using vertex_descriptor = typename boost::graph_traits<TriangleMesh>::vertex_descriptor;
using halfedge_descriptor = typename boost::graph_traits<TriangleMesh>::halfedge_descriptor;
GeomTraits gt = choose_parameter<GeomTraits>(get_parameter(np, internal_np::geom_traits));
VertexPointMap vpm = choose_parameter(get_parameter(np, internal_np::vertex_point),
get_const_property_map(vertex_point, tmesh));
#if 0
typename GeomTraits::Compute_squared_distance_3 squared_distance =
gt.compute_squared_distance_3_object();
typename GeomTraits::Compute_approximate_dihedral_angle_3 dihedral_angle =
gt.compute_approximate_dihedral_angle_3_object();
const FT two_pi = 2 * CGAL_PI;
FT hi = 0;
for(halfedge_descriptor h : CGAL::halfedges_around_target(v, tmesh))
{
const Point_3& p = get(vpm, source(h, tmesh));
const Point_3& q = get(vpm, target(h, tmesh));
const Point_3& r = get(vpm, target(next(h, tmesh), tmesh));
const Point_3& s = get(vpm, target(next(opposite(h, tmesh), tmesh), tmesh));
const FT l = squared_distance(p,q);
FT phi = CGAL_PI * dihedral_angle(p, q, r, s) / FT(180);
if(phi < 0)
phi += two_pi;
if(phi > two_pi)
phi = two_pi;
hi += FT(0.5) * l * (CGAL_PI - phi);
}
return FT(0.5) * hi;
#else
typename GeomTraits::Construct_vector_3 vector =
gt.construct_vector_3_object();
typename GeomTraits::Construct_sum_of_vectors_3 vector_sum =
gt.construct_sum_of_vectors_3_object();
typename GeomTraits::Construct_scaled_vector_3 scaled_vector =
gt.construct_scaled_vector_3_object();
typename GeomTraits::Compute_squared_length_3 squared_length =
gt.compute_squared_length_3_object();
Weights::Secure_cotangent_weight_with_voronoi_area<TriangleMesh, VertexPointMap, GeomTraits> wc(tmesh, vpm, gt);
Vector_3 kh = vector(CGAL::NULL_VECTOR);
for(halfedge_descriptor h : CGAL::halfedges_around_target(v, tmesh))
{
const vertex_descriptor v1 = source(h, tmesh);
const Point_ref p0 = get(vpm, v);
const Point_ref p1 = get(vpm, v1);
FT local_c = 0;
if(!is_border(h, tmesh))
{
const vertex_descriptor v2 = target(next(h, tmesh), tmesh);
const Point_ref p2 = get(vpm, v2);
local_c += Weights::cotangent_3_clamped(p0, p2, p1, gt);
}
if(!is_border(opposite(h, tmesh), tmesh))
{
const vertex_descriptor v3 = target(next(opposite(h, tmesh), tmesh), tmesh);
const Point_ref p3 = get(vpm, v3);
local_c += Weights::cotangent_3_clamped(p1, p3, p0, gt);
}
kh = vector_sum(kh, scaled_vector(vector(p0, p1), local_c));
}
const FT khn = CGAL::approximate_sqrt(squared_length(kh));
const FT va = wc.voronoi(v);
CGAL_assertion(!is_zero(va));
const FT mean_curvature = khn / (FT(4) * va);
return mean_curvature;
#endif
}
/**
* \ingroup PMP_measure_grp
*
* computes the discrete mean curvatures at the vertices of a mesh.
*
* We refer to Meyer et al. \cgalCite{cgal:mdsb-ddgot-02} for the definition of <i>discrete mean curvature</i>.
*
* @tparam TriangleMesh a model of `FaceGraph`
* @tparam VertexCurvatureMap must be a model of `WritablePropertyMap` with key type
* `boost::graph_traits<TriangleMesh>::%vertex_descriptor` and value type `FT`,
* which is either `geom_traits::FT` if this named parameter is provided,
* or `kernel::FT` with the kernel deduced from from the point property map of `tmesh`.
* @tparam NamedParameters a sequence of \ref bgl_namedparameters "Named Parameters"
*
* @param tmesh the triangle mesh to which `v` belongs
* @param vcm the property map that contains the computed discrete curvatures
* @param np an optional sequence of \ref bgl_namedparameters "Named Parameters" among the ones listed below
*
* \cgalNamedParamsBegin
* \cgalParamNBegin{vertex_point_map}
* \cgalParamDescription{a property map associating points to the vertices of `tmesh`}
* \cgalParamType{a class model of `ReadablePropertyMap` with `boost::graph_traits<TriangleMesh>::%vertex_descriptor`
* as key type and `%Point_3` as value type}
* \cgalParamDefault{`boost::get(CGAL::vertex_point, tmesh)`}
* \cgalParamNEnd
*
* \cgalParamNBegin{geom_traits}
* \cgalParamDescription{an instance of a geometric traits class}
* \cgalParamType{The traits class must be a model of `Kernel`.}
* \cgalParamDefault{a \cgal kernel deduced from the point type, using `CGAL::Kernel_traits`}
* \cgalParamExtra{The geometric traits class must be compatible with the vertex point type.}
* \cgalParamNEnd
* \cgalNamedParamsEnd
*
* \warning The current formulation is not well defined for border vertices.
*
* \pre `tmesh` is a triangle mesh
*/
template <typename TriangleMesh,
typename VertexCurvatureMap,
typename CGAL_NP_TEMPLATE_PARAMETERS>
void discrete_mean_curvatures(const TriangleMesh& tmesh,
VertexCurvatureMap vcm,
const CGAL_NP_CLASS& np = parameters::default_values())
{
using vertex_descriptor = typename boost::graph_traits<TriangleMesh>::vertex_descriptor;
for(vertex_descriptor v : vertices(tmesh))
put(vcm, v, discrete_mean_curvature(v, tmesh, np));
}
} // namespace Polygon_mesh_processing
} // namespace CGAL
#endif //CGAL_PMP_CURVATURE_H

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@ -28,6 +28,7 @@ create_single_source_cgal_program("test_stitching.cpp")
create_single_source_cgal_program("remeshing_test.cpp")
create_single_source_cgal_program("remeshing_with_isolated_constraints_test.cpp" )
create_single_source_cgal_program("measures_test.cpp")
create_single_source_cgal_program("test_discrete_curvatures.cpp")
create_single_source_cgal_program("triangulate_faces_test.cpp")
create_single_source_cgal_program("triangulate_faces_hole_filling_dt3_test.cpp")
create_single_source_cgal_program("triangulate_faces_hole_filling_all_search_test.cpp")

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@ -0,0 +1,146 @@
#include <CGAL/Exact_predicates_inexact_constructions_kernel.h>
#include <CGAL/Surface_mesh.h>
#include <CGAL/Polyhedron_3.h>
#include <CGAL/Polygon_mesh_processing/curvature.h>
#include <boost/graph/graph_traits.hpp>
#include <iostream>
#include <string>
#define ABS_ERROR 1e-6
namespace PMP = CGAL::Polygon_mesh_processing;
typedef CGAL::Exact_predicates_inexact_constructions_kernel K;
typedef K::FT FT;
typedef CGAL::Surface_mesh<K::Point_3> SMesh;
typedef CGAL::Polyhedron_3<K> Polyhedron;
struct Average_test_info
{
FT mean_curvature_avg;
FT gaussian_curvature_avg;
FT tolerance = 0.9;
Average_test_info(FT mean_curvature_avg,
FT gaussian_curvature_avg)
: mean_curvature_avg(mean_curvature_avg),
gaussian_curvature_avg(gaussian_curvature_avg)
{ }
};
bool passes_comparison(FT result, FT expected, FT tolerance)
{
std::cout << "result: " << result << std::endl;
std::cout << "expected: " << expected << std::endl;
if(abs(expected) < ABS_ERROR && abs(result) < ABS_ERROR)
return true; // expected 0, got 0
else if (abs(expected) < ABS_ERROR)
return false; // expected 0, got non-0
return (std::min)(result, expected) / (std::max)(result, expected) > tolerance;
}
template <typename TriangleMesh>
void test_curvatures(std::string mesh_path,
Average_test_info test_info)
{
std::cout << "test discrete curvatures of " << mesh_path << std::endl;
std::cout << "mesh type: " << typeid(mesh_path).name() << std::endl;
typedef typename boost::graph_traits<TriangleMesh>::vertex_descriptor vertex_descriptor;
TriangleMesh tmesh;
const std::string filename = CGAL::data_file_path(mesh_path);
if(!CGAL::IO::read_polygon_mesh(filename, tmesh) || faces(tmesh).size() == 0)
{
std::cerr << "Invalid input file." << std::endl;
std::exit(1);
}
typename boost::property_map<TriangleMesh, CGAL::dynamic_vertex_property_t<FT>>::type
mean_curvature_map = get(CGAL::dynamic_vertex_property_t<FT>(), tmesh),
gaussian_curvature_map = get(CGAL::dynamic_vertex_property_t<FT>(), tmesh);
PMP::discrete_mean_curvatures(tmesh, mean_curvature_map);
PMP::discrete_Gaussian_curvatures(tmesh, gaussian_curvature_map);
FT mean_curvature_avg = 0, gaussian_curvature_avg = 0;
for(vertex_descriptor v : vertices(tmesh))
{
mean_curvature_avg += get(mean_curvature_map, v);
gaussian_curvature_avg += get(gaussian_curvature_map, v);
}
mean_curvature_avg /= vertices(tmesh).size();
gaussian_curvature_avg /= vertices(tmesh).size();
std::cout << "checking mean curvature..." << std::endl;
assert(passes_comparison(mean_curvature_avg, test_info.mean_curvature_avg, test_info.tolerance));
std::cout << "checking Gaussian curvature..." << std::endl;
assert(passes_comparison(gaussian_curvature_avg, test_info.gaussian_curvature_avg, test_info.tolerance));
}
template <typename PolygonMesh>
void test_angle_sums(const std::string mesh_path,
const std::vector<FT>& expected_values)
{
typedef typename boost::graph_traits<PolygonMesh>::vertex_descriptor vertex_descriptor;
PolygonMesh pmesh;
const std::string filename = CGAL::data_file_path(mesh_path);
if(!CGAL::IO::read_polygon_mesh(filename, pmesh) || faces(pmesh).size() == 0)
{
std::cerr << "Invalid input file." << std::endl;
std::exit(1);
}
std::size_t pos = 0;
for(vertex_descriptor v : vertices(pmesh))
{
FT angle_sum = PMP::angle_sum(v, pmesh,
CGAL::parameters::geom_traits(K())
.vertex_point_map(get(CGAL::vertex_point, pmesh)));
assert(passes_comparison(angle_sum, expected_values[pos++], 0.9));
}
}
int main(int, char**)
{
// testing on a simple sphere(r = 0.5), on both Polyhedron & SurfaceMesh:
// Expected: Mean Curvature = 2, Gaussian Curvature = 4
test_curvatures<Polyhedron>("meshes/sphere.off", Average_test_info(2, 4));
test_curvatures<SMesh>("meshes/sphere.off", Average_test_info(2, 4));
// testing on a simple sphere(r = 10), on both Polyhedron & SurfaceMesh:
// Expected: Mean Curvature = 0.1, Gaussian Curvature = 0.01
test_curvatures<Polyhedron>("meshes/sphere966.off", Average_test_info(0.1, 0.01));
test_curvatures<SMesh>("meshes/sphere966.off", Average_test_info(0.1, 0.01));
// testing on a simple half cylinder(r = 1), on both Polyhedron & SurfaceMesh:
// Expected: Mean Curvature = 0.5, Gaussian Curvature = 0
// To be tested once the discrete curvatures are well defined for boundary vertices
// test_curvatures<Polyhedron>("meshes/cylinder.off", Average_test_info(0.5, 0));
// test_curvatures<SMesh>("meshes/cylinder.off", Average_test_info(0.5, 0));
test_angle_sums<Polyhedron>("meshes/quad.off", std::vector<FT>(4, 90));
test_angle_sums<SMesh>("meshes/quad.off", std::vector<FT>(4, 90));
test_angle_sums<Polyhedron>("meshes/regular_tetrahedron.off", std::vector<FT>(4, 180));
test_angle_sums<SMesh>("meshes/regular_tetrahedron.off", std::vector<FT>(4, 180));
test_angle_sums<Polyhedron>("meshes/cube_quad.off", std::vector<FT>(8, 270));
test_angle_sums<SMesh>("meshes/cube_quad.off", std::vector<FT>(8, 270));
test_angle_sums<Polyhedron>("meshes/cube_poly.off", std::vector<FT>(8, 270));
test_angle_sums<SMesh>("meshes/cube_poly.off", std::vector<FT>(8, 270));
std::cout << "Done." << std::endl;
return EXIT_SUCCESS;
}

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@ -9,8 +9,9 @@
#include <boost/graph/graph_traits.hpp>
#include <functional>
#include <iostream>
#include <unordered_map>
#include <string>
#define ABS_ERROR 1e-6
@ -181,7 +182,7 @@ void test_average_curvatures(std::string mesh_path,
int main()
{
// testing on a simple sphere(r = 0.5), on both Polyhedron & SurfaceMesh:
// For this mesh, ina addition to the whole mesh functions, we also compare against the single vertex
// For this mesh, in addition to the whole mesh functions, we also compare against the single vertex
// curvature functions to make sure the produce the same results
// Expected: Mean Curvature = 2, Gaussian Curvature = 4, Principal Curvatures = 2 & 2 so 2 on avg.
test_average_curvatures<Polyhedron>("meshes/sphere.off", Average_test_info(2, 4, 2), true);

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@ -344,7 +344,6 @@ public:
return cotangent_weight_calculator(he);
}
private:
FT voronoi(const vertex_descriptor v0) const
{
auto squared_length_3 = m_traits.compute_squared_length_3_object();
@ -354,11 +353,12 @@ private:
for (const halfedge_descriptor he : halfedges_around_target(halfedge(v0, m_pmesh), m_pmesh))
{
CGAL_assertion(v0 == target(he, m_pmesh));
CGAL_assertion(CGAL::is_triangle(he, m_pmesh));
if (is_border(he, m_pmesh))
continue;
CGAL_assertion(CGAL::is_triangle(he, m_pmesh));
const vertex_descriptor v1 = source(he, m_pmesh);
const vertex_descriptor v2 = target(next(he, m_pmesh), m_pmesh);

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@ -44,7 +44,7 @@ private:
public:
FT operator()(const FT value) const
{
return static_cast<FT>(CGAL::sqrt(CGAL::to_double(CGAL::abs(value))));
return CGAL::approximate_sqrt(CGAL::abs(value));
}
};