/*
* Copyright (C) 1998, 2000-2007, 2010, 2011, 2012, 2013 SINTEF ICT,
* Applied Mathematics, Norway.
*
* Contact information: E-mail: tor.dokken@sintef.no
* SINTEF ICT, Department of Applied Mathematics,
* P.O. Box 124 Blindern,
* 0314 Oslo, Norway.
*
* This file is part of TTL.
*
* TTL is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as
* published by the Free Software Foundation, either version 3 of the
* License, or (at your option) any later version.
*
* TTL is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Affero General Public License for more details.
*
* You should have received a copy of the GNU Affero General Public
* License along with TTL. If not, see
* .
*
* In accordance with Section 7(b) of the GNU Affero General Public
* License, a covered work must retain the producer line in every data
* file that is created or manipulated using TTL.
*
* Other Usage
* You can be released from the requirements of the license by purchasing
* a commercial license. Buying such a license is mandatory as soon as you
* develop commercial activities involving the TTL library without
* disclosing the source code of your own applications.
*
* This file may be used in accordance with the terms contained in a
* written agreement between you and SINTEF ICT.
*/
#ifndef _HALF_EDGE_TRAITS_
#define _HALF_EDGE_TRAITS_
#include
#include
namespace hed {
//------------------------------------------------------------------------------------------------
// Traits class for the half-edge data structure
//------------------------------------------------------------------------------------------------
/** \struct TTLtraits
* \brief \b Traits class (static struct) for the half-edge data structure.
*
* The member functions are those required by different function templates
* in the TTL. Documentation is given here to explain what actions
* should be carried out on the actual data structure as required by the functions
* in the \ref ttl namespace.
*
* The source code of \c %HeTraits.h shows how the traits class is implemented for the
* half-edge data structure.
*
* \see \ref api
*
*/
struct TTLtraits {
// The actual triangulation object
static Triangulation* triang_;
/** The floating point type used in calculations
* involving scalar products and cross products.
*/
typedef double real_type;
//----------------------------------------------------------------------------------------------
// ------------------------------- Geometric Predicates Group ---------------------------------
//----------------------------------------------------------------------------------------------
/** @name Geometric Predicates */
//@{
//----------------------------------------------------------------------------------------------
/** Scalar product between two 2D vectors represented as darts.\n
*
* ttl_util::scalarProduct2d can be used.
*/
static real_type scalarProduct2d(const Dart& v1, const Dart& v2) {
Dart v10 = v1; v10.alpha0();
Dart v20 = v2; v20.alpha0();
return ttl_util::scalarProduct2d(v10.x()-v1.x(), v10.y()-v1.y(),
v20.x()-v2.x(), v20.y()-v2.y());
}
//----------------------------------------------------------------------------------------------
/** Scalar product between two 2D vectors.
* The first vector is represented by a dart \e v, and the second
* vector has direction from the source node of \e v to the point \e p.\n
*
* ttl_util::scalarProduct2d can be used.
*/
static real_type scalarProduct2d(const Dart& v, const NodePtr& p) {
Dart d0 = v; d0.alpha0();
return ttl_util::scalarProduct2d(d0.x() - v.x(), d0.y() - v.y(),
p->GetX() - v.x(), p->GetY() - v.y());
}
//----------------------------------------------------------------------------------------------
/** Cross product between two vectors in the plane represented as darts.
* The z-component of the cross product is returned.\n
*
* ttl_util::crossProduct2d can be used.
*/
static real_type crossProduct2d(const Dart& v1, const Dart& v2) {
Dart v10 = v1; v10.alpha0();
Dart v20 = v2; v20.alpha0();
return ttl_util::crossProduct2d(v10.x()-v1.x(), v10.y()-v1.y(),
v20.x()-v2.x(), v20.y()-v2.y());
}
//----------------------------------------------------------------------------------------------
/** Cross product between two vectors in the plane.
* The first vector is represented by a dart \e v, and the second
* vector has direction from the source node of \e v to the point \e p.
* The z-component of the cross product is returned.\n
*
* ttl_util::crossProduct2d can be used.
*/
static real_type crossProduct2d(const Dart& v, const NodePtr& p) {
Dart d0 = v; d0.alpha0();
return ttl_util::crossProduct2d(d0.x() - v.x(), d0.y() - v.y(),
p->GetX() - v.x(), p->GetY() - v.y());
}
//----------------------------------------------------------------------------------------------
/** Let \e n1 and \e n2 be the nodes associated with two darts, and let \e p
* be a point in the plane. Return a positive value if \e n1, \e n2,
* and \e p occur in counterclockwise order; a negative value if they occur
* in clockwise order; and zero if they are collinear.
*/
static real_type orient2d(const Dart& n1, const Dart& n2, const NodePtr& p) {
real_type pa[2]; real_type pb[2]; real_type pc[2];
pa[0] = n1.x(); pa[1] = n1.y();
pb[0] = n2.x(); pb[1] = n2.y();
pc[0] = p->GetX(); pc[1] = p->GetY();
return ttl_util::orient2dfast(pa, pb, pc);
}
//----------------------------------------------------------------------------------------------
/** This is the same predicate as represented with the function above,
* but with a slighty different interface:
* The last parameter is given as a dart where the source node of the dart
* represents a point in the plane.
* This function is required for constrained triangulation.
*/
static real_type orient2d(const Dart& n1, const Dart& n2, const Dart& p) {
real_type pa[2]; real_type pb[2]; real_type pc[2];
pa[0] = n1.x(); pa[1] = n1.y();
pb[0] = n2.x(); pb[1] = n2.y();
pc[0] = p.x(); pc[1] = p.y();
return ttl_util::orient2dfast(pa, pb, pc);
}
//@} // End of Geometric Predicates Group
// A rationale for directing these functions to traits is:
// e.g., constraints
//----------------------------------------------------------------------------------------------
/* Checks if the edge associated with \e dart should be swapped
* according to the Delaunay criterion.
*
* \note
* This function is also present in the TTL as ttl::swapTestDelaunay.
* Thus, the function can be implemented simply as:
* \code
* { return ttl::swapTestDelaunay(dart); }
* \endcode
*/
//static bool swapTestDelaunay(const Dart& dart) {
// return ttl::swapTestDelaunay(dart);
//}
//----------------------------------------------------------------------------------------------
/* Checks if the edge associated with \e dart can be swapped, i.e.,
* if the edge is a diagonal in a (strictly) convex quadrilateral.
* This function is also present as ttl::swappableEdge.
*/
//static bool swappableEdge(const Dart& dart) {
// return ttl::swappableEdge(dart);
//}
//----------------------------------------------------------------------------------------------
/* Checks if the edge associated with \e dart should be \e fixed, meaning
* that it should never be swapped. ??? Use when constraints.
*/
//static bool fixedEdge(const Dart& dart) {
// return dart.getEdge()->isConstrained();
//}
//----------------------------------------------------------------------------------------------
// ----------------------- Functions for Delaunay Triangulation Group -------------------------
//----------------------------------------------------------------------------------------------
/** @name Functions for Delaunay Triangulation */
//@{
//----------------------------------------------------------------------------------------------
/** Swaps the edge associated with \e dart in the actual data structure.
*
*
* \image html swapEdge.gif
*
*
* \param dart
* Some of the functions require a dart as output.
* If this is required by the actual function, the dart should be delivered
* back in a position as seen if it was glued to the edge when swapping (rotating)
* the edge CCW; see the figure.
*
* \note
* - If the edge is \e constrained, or if it should not be swapped for
* some other reason, this function need not do the actual swap of the edge.
* - Some functions in TTL require that \c swapEdge is implemented such that
* darts outside the quadrilateral are not affected by the swap.
*/
static void swapEdge(Dart& dart) {
if (!dart.getEdge()->isConstrained()) triang_->swapEdge(dart.getEdge());
}
//----------------------------------------------------------------------------------------------
/** Splits the triangle associated with \e dart in the actual data structure into
* three new triangles joining at \e point.
*
*
* \image html splitTriangle.gif
*
*
* \param dart
* Output: A CCW dart incident with the new node; see the figure.
*/
static void splitTriangle(Dart& dart, NodePtr point) {
EdgePtr edge = triang_->splitTriangle(dart.getEdge(), point);
dart.init(edge);
}
//@} // End of Functions for Delaunay Triangulation group
//----------------------------------------------------------------------------------------------
// --------------------------- Functions for removing nodes Group -----------------------------
//----------------------------------------------------------------------------------------------
/** @name Functions for removing nodes */
//@{
//----------------------------------------------------------------------------------------------
/** The reverse operation of TTLtraits::splitTriangle.
* This function is only required for functions that involve
* removal of interior nodes; see for example ttl::removeInteriorNode.
*
*
* \image html reverse_splitTriangle.gif
*
*/
static void reverse_splitTriangle(Dart& dart) {
triang_->reverse_splitTriangle(dart.getEdge());
}
//----------------------------------------------------------------------------------------------
/** Removes a triangle with an edge at the boundary of the triangulation
* in the actual data structure
*/
static void removeBoundaryTriangle(Dart& d) {
triang_->removeTriangle(d.getEdge());
}
//@} // End of Functions for removing nodes Group
};
}; // End of hed namespace
#endif