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// Boost.Geometry (aka GGL, Generic Geometry Library)
// Copyright (c) 2007-2015 Barend Gehrels, Amsterdam, the Netherlands.
// Copyright (c) 2008-2015 Bruno Lalande, Paris, France.
// Copyright (c) 2009-2015 Mateusz Loskot, London, UK.
// Copyright (c) 2013-2015 Adam Wulkiewicz, Lodz, Poland.
// This file was modified by Oracle on 2015, 2017, 2019.
// Modifications copyright (c) 2015-2019 Oracle and/or its affiliates.
// Contributed and/or modified by Menelaos Karavelas, on behalf of Oracle
// Contributed and/or modified by Adam Wulkiewicz, on behalf of Oracle
// Use, modification and distribution is subject to the Boost Software License,
// Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
#ifndef BOOST_GEOMETRY_ALGORITHMS_DETAIL_POINT_IS_EQUAL_OR_SPIKE_HPP
#define BOOST_GEOMETRY_ALGORITHMS_DETAIL_POINT_IS_EQUAL_OR_SPIKE_HPP
#include <boost/geometry/algorithms/detail/direction_code.hpp>
#include <boost/geometry/algorithms/detail/recalculate.hpp>
#include <boost/geometry/core/cs.hpp>
#include <boost/geometry/policies/robustness/robust_point_type.hpp>
#include <boost/geometry/strategies/side.hpp>
#include <boost/geometry/util/condition.hpp>
#include <boost/geometry/util/math.hpp>
namespace boost { namespace geometry
{
#ifndef DOXYGEN_NO_DETAIL
namespace detail
{
template <typename Point1, typename Point2, typename Point3>
inline bool collinear_point_is_spike_or_equal(Point1 const& last_point,
Point2 const& segment_a,
Point3 const& segment_b)
{
// Check if segment is equal
int const sgn_x1 = sign_of_difference<0>(last_point, segment_b);
int const sgn_y1 = sign_of_difference<1>(last_point, segment_b);
if (sgn_x1 == 0 && sgn_y1 == 0)
{
return true;
}
// Check if segment moves forward
int const sgn_x2 = sign_of_difference<0>(segment_b, segment_a);
int const sgn_y2 = sign_of_difference<1>(segment_b, segment_a);
return sgn_x1 != sgn_x2 || sgn_y1 != sgn_y2;
}
// Checks if a point ("last_point") causes a spike w.r.t.
// the specified two other points (segment_a, segment_b)
//
// x-------x------x
// a lp b
//
// Above, lp generates a spike w.r.t. segment(a,b)
// So specify last point first, then (a,b)
// The segment's orientation does matter: if lp is to the right of b
// no spike is reported
template
<
typename Point1, typename Point2, typename Point3,
typename SideStrategy
>
inline bool point_is_spike_or_equal(Point1 const& last_point, // prev | back
Point2 const& segment_a, // next | back - 2
Point3 const& segment_b, // curr | back - 1 | spike's vertex
SideStrategy const& strategy)
{
typedef typename SideStrategy::cs_tag cs_tag;
int const side = strategy.apply(segment_a, segment_b, last_point);
if (side == 0)
{
// Last point is collinear w.r.t previous segment.
#ifdef BOOST_GEOMETRY_ENABLE_POINT_IS_SPIKE_OR_EQUAL_TEST
bool r1 = collinear_point_is_spike_or_equal(last_point, segment_a, segment_b);
bool r2 = direction_code(segment_a, segment_b, last_point) < 1;
if (r1 != r2)
std::cout << "spike detection failure with: " << r1 << " " << r2 << std::endl;
return r2;
#else
return direction_code<cs_tag>(segment_a, segment_b, last_point) < 1;
#endif
}
return false;
}
template
<
typename Point1,
typename Point2,
typename Point3,
typename SideStrategy,
typename RobustPolicy
>
inline bool point_is_spike_or_equal(Point1 const& last_point,
Point2 const& segment_a,
Point3 const& segment_b,
SideStrategy const& strategy,
RobustPolicy const& robust_policy)
{
if (point_is_spike_or_equal(last_point, segment_a, segment_b, strategy))
{
return true;
}
if (BOOST_GEOMETRY_CONDITION(! RobustPolicy::enabled))
{
return false;
}
// Try using specified robust policy
typedef typename geometry::robust_point_type
<
Point1,
RobustPolicy
>::type robust_point_type;
robust_point_type last_point_rob, segment_a_rob, segment_b_rob;
geometry::recalculate(last_point_rob, last_point, robust_policy);
geometry::recalculate(segment_a_rob, segment_a, robust_policy);
geometry::recalculate(segment_b_rob, segment_b, robust_policy);
return point_is_spike_or_equal
(
last_point_rob,
segment_a_rob,
segment_b_rob,
strategy
);
}
template
<
typename Point1,
typename Point2,
typename Point3,
typename SideStrategy,
typename RobustPolicy
>
inline bool point_is_collinear(Point1 const& last_point,
Point2 const& segment_a,
Point3 const& segment_b,
SideStrategy const& strategy,
RobustPolicy const& robust_policy)
{
int const side = strategy.apply(segment_a, segment_b, last_point);
if (side == 0)
{
return true;
}
// This part (or whole method, because it is then trivial)
// will be removed after rescaling
if (BOOST_GEOMETRY_CONDITION(! RobustPolicy::enabled))
{
return false;
}
// Redo, using specified robust policy
typedef typename geometry::robust_point_type
<
Point1,
RobustPolicy
>::type robust_point_type;
robust_point_type last_point_rob, segment_a_rob, segment_b_rob;
geometry::recalculate(last_point_rob, last_point, robust_policy);
geometry::recalculate(segment_a_rob, segment_a, robust_policy);
geometry::recalculate(segment_b_rob, segment_b, robust_policy);
int const side_rob = strategy.apply(segment_a_rob, segment_b_rob, last_point_rob);
return side_rob == 0;
}
//! Version with intuitive order (A, B, C). The original order was
//! unclear (C, A, B). It was used in a different way in has_spikes.
//! On longer term the C,A,B version can be deprecated
template
<
typename Point1,
typename Point2,
typename Point3,
typename SideStrategy
>
inline bool is_spike_or_equal(Point1 const& a,
Point2 const& b,
Point3 const& c,
SideStrategy const& strategy)
{
return point_is_spike_or_equal(c, a, b, strategy);
}
} // namespace detail
#endif
}} // namespace boost::geometry
#endif // BOOST_GEOMETRY_ALGORITHMS_DETAIL_POINT_IS_EQUAL_OR_SPIKE_HPP
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