GeometricUtilities.h

// -*- tab-width: 2; indent-tabs-mode: nil; coding: utf-8-with-signature -*-
//-----------------------------------------------------------------------------
// Copyright 2000-2026 CEA (www.cea.fr) IFPEN (www.ifpenergiesnouvelles.com)
// See the top-level COPYRIGHT file for details.
// SPDX-License-Identifier: Apache-2.0
//-----------------------------------------------------------------------------
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/* GeometricUtilities.h                                        (C) 2000-2025 */
/*                                                                           */
/* Utility functions on geometry.                                            */
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#ifndef ARCANE_CORE_GEOMETRICUTILITIES_H
#define ARCANE_CORE_GEOMETRICUTILITIES_H
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#include "arcane/utils/Real3.h"
#include "arcane/utils/Real3x3.h"
 
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/*!
 * \brief Utility functions on geometry
 */
namespace Arcane::GeometricUtilities
{
 
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/*!
 * \internal
 * \brief Class allowing mapping Cartesian coordinates to
 * barycentric coordinates.
 *
 * Barycentric coordinates are between -1.0 and 1.0.
 *
 */
class ARCANE_CORE_EXPORT QuadMapping
{
 public:
 
  QuadMapping() = default;
 
 public:
 
  Real3 m_pos[4];
  Real m_precision = 1.0e-14;
 
 public:
 
  //! Calculates Cartesian coordinates from iso-barycentric coordinates
  Real3 evaluatePosition(Real3 iso) const
  {
    Real u = iso.x;
    Real v = iso.y;
 
    Real x0 = (1.0 - u) * (1.0 - v);
    Real x1 = (1.0 + u) * (1.0 - v);
    Real x2 = (1.0 + u) * (1.0 + v);
    Real x3 = (1.0 - u) * (1.0 + v);
 
    return 0.25 * (m_pos[0] * x0 + m_pos[1] * x1 + m_pos[2] * x2 + m_pos[3] * x3);
  }
  Real3x3 evaluateGradient(Real3 iso) const
  {
    Real u = iso.x;
    Real v = iso.y;
 
    Real t1 = 0.25 * (v - 1.0);
    Real t2 = 0.25 * (v + 1.0);
    Real t3 = 0.25 * (u - 1.0);
    Real t4 = 0.25 * (-u - 1.0);
 
    return Real3x3(m_pos[0] * t1 - m_pos[1] * t1 + m_pos[2] * t2 - m_pos[3] * t2,
                   m_pos[0] * t3 + m_pos[1] * t4 - m_pos[2] * t4 - m_pos[3] * t3,
                   Real3::null());
  }
  Real computeInverseJacobian(Real3 uvw, Real3x3& matrix);
  bool cartesianToIso(Real3 point, Real3& uvw, ITraceMng* tm);
  bool cartesianToIso2(Real3 point, Real3& uvw, ITraceMng* tm);
  Real3 normal();
 
 private:
 
  Real3 _normal();
};
 
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/*!
 * \internal
 * \brief Information about the projection of a point onto a segment
 * or a triangle.
 */
class ARCANE_CORE_EXPORT ProjectionInfo
{
 public:
 
  ProjectionInfo(Real distance, int region, Real alpha, Real beta, Real3 aprojection)
  : m_distance(distance)
  , m_region(region)
  , m_alpha(alpha)
  , m_beta(beta)
  , m_projection(aprojection)
  {}
  ProjectionInfo() = default;
 
 public:
 
  //! Distance of the point to its projection
  Real m_distance = FloatInfo<Real>::maxValue();
  //! Region where the projection is located (0 if inside the segment or triangle)
  int m_region = -1;
  //! Barycentric x-coordinate of the projection
  Real m_alpha = -1.0;
  //! Barycentric y-coordinate of the projection
  Real m_beta = -1.0;
  //! Position of the projection
  Real3 m_projection;
 
 public:
 
  //! Projection of point \a point onto the triangle defined by \a v1, \a v2 and \a v3.
  static ProjectionInfo projection(Real3 v1, Real3 v2, Real3 v3, Real3 point);
 
  //! Projection of point \a point onto the segment defined by \a v1, \a v2.
  static ProjectionInfo projection(Real3 v1, Real3 v2, Real3 point);
 
  /*! \brief Indicates if the projection of point \a point is inside the triangle defined
     * by \a v1, \a v2 and \a v3.
     */
  static bool isInside(Real3 v1, Real3 v2, Real3 v3, Real3 point);
  /*! \brief Indicates if the projection of point \a point is inside the segment defined
     * by \a v1 and \a v2.
     */
  static bool isInside(Real3 v1, Real3 v2, Real3 point);
};
 
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} // namespace Arcane::GeometricUtilities
 
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#endif