cgal/Isosurfacing_3/include/CGAL/Isosurfacing_3/Gradient_function_3.h

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// Copyright (c) 2022-2024 INRIA Sophia-Antipolis (France), 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) : Julian Stahl
// Mael Rouxel-Labbé
#ifndef CGAL_ISOSURFACING_3_GRADIENT_FUNCTION_3_H
#define CGAL_ISOSURFACING_3_GRADIENT_FUNCTION_3_H
#include <CGAL/license/Isosurfacing_3.h>
#include <CGAL/Isosurfacing_3/internal/partition_traits.h>
#include <functional>
namespace CGAL {
namespace Isosurfacing {
/**
* \ingroup IS_Fields_grp
*
* \cgalModels{IsosurfacingGradientField_3}
*
* \brief The class `Gradient_function_3` represents a field of vectors computed
* using a user-provided unary function.
*
* \tparam Partition must be a model of `IsosurfacingPartition_3`
*
* \sa `CGAL::Isosurfacing::Dual_contouring_domain_3`
*/
template <typename Partition>
class Gradient_function_3
{
public:
using Geom_traits = typename Partition::Geom_traits;
using Point_3 = typename Geom_traits::Point_3;
using Vector_3 = typename Geom_traits::Vector_3;
using PT = partition_traits<Partition>;
using vertex_descriptor = typename PT::vertex_descriptor;
private:
std::function<Vector_3(const Point_3&)> m_fn;
const Partition& m_partition;
public:
/**
* \brief constructs a field of gradients using a gradient function and a partition.
*
* \tparam Function must provide the following function signature:
* `Vector_3 operator()(const %Point_3&) const`
*
* \param fn the function providing gradients
* \param partition the space partitioning data structure
*/
template <typename Function>
Gradient_function_3(const Function& fn,
const Partition& partition)
: m_fn{fn},
m_partition{partition}
{ }
public:
/**
* \brief returns the value of the function at the point `p`.
*/
Vector_3 operator()(const Point_3& p) const
{
return m_fn(p);
}
/**
* \brief returns the value of the function at the vertex `v`.
*/
const Vector_3& operator()(const vertex_descriptor& v) const
{
return this->operator()(PT::point(v, m_partition));
}
};
} // namespace Isosurfacing
} // namespace CGAL
#endif // CGAL_ISOSURFACING_3_GRADIENT_FUNCTION_3_H