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Fix DistanceToLineSquare for degenerate sections (equal ends).

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vng 2011-01-31 22:07:56 +02:00 • committed by Alex Zolotarev
parent 304827bfdc
commit f420b73f03
2 changed files with 27 additions and 5 deletions
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17
geometry/distance.hpp
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@ -1,6 +1,7 @@
#pragma once
#include "../base/base.hpp"
#include "../base/math.hpp"
#include "../std/limits.hpp"
#include "../std/static_assert.hpp"
@ -16,16 +17,24 @@ private:
STATIC_ASSERT(numeric_limits<typename PointT::value_type>::is_signed);
public:
DistanceToLineSquare(PointT p0, PointT p1)
: m_P0(p0), m_P1(p1), m_D(m_P1 - m_P0), m_D2(DotProduct(m_D, m_D)), m_InvD2(1.0 / m_D2)
DistanceToLineSquare(PointT const & p0, PointT const & p1)
: m_P0(p0), m_P1(p1), m_D(m_P1 - m_P0), m_D2(DotProduct(m_D, m_D))
{
if (my::AlmostEqual(m_D2, 0.0))
m_isZero = true;
else
{
m_InvD2 = 1.0 / m_D2;
m_isZero = false;
}
}
double operator () (PointT Y) const
{
PointT const YmP0 = Y - m_P0;
double const t = DotProduct(m_D, YmP0);
if (t <= 0)
if (m_isZero || t <= 0)
{
// Y is closest to P0.
return DotProduct(YmP0, YmP0);
@ -39,9 +48,11 @@ public:
// Closest point is interior to segment.
return DotProduct(YmP0, YmP0) - t * t * m_InvD2;
}
private:
PointT m_P0, m_P1, m_D;
double m_D2, m_InvD2;
bool m_isZero;
};
}

15
geometry/geometry_tests/distance_test.cpp
View file

@ -6,6 +6,7 @@ template <class PointT>
void FloatingPointsTest()
{
mn::DistanceToLineSquare<PointT> d(PointT(-1, 3), PointT(2, 1));
TEST_ALMOST_EQUAL(d(PointT(-1, 3)), 0.0, ());
TEST_ALMOST_EQUAL(d(PointT(2, 1)), 0.0, ());
TEST_ALMOST_EQUAL(d(PointT(-0.5, 0.5)), 3.25, ());
@ -22,12 +23,22 @@ UNIT_TEST(DistanceToLineSquare2D_Floating)
FloatingPointsTest<m2::PointF>();
}
#include "../../base/logging.hpp"
UNIT_TEST(DistanceToLineSquare2D_Integer)
{
mn::DistanceToLineSquare<m2::PointI> dI(m2::PointI(-1, 3), m2::PointI(2, 1));
TEST_ALMOST_EQUAL(dI(m2::PointI(-1, 3)), 0.0, ());
TEST_ALMOST_EQUAL(dI(m2::PointI(2, 1)), 0.0, ());
TEST_ALMOST_EQUAL(dI(m2::PointI(4, 4)), 13.0, ());
}
UNIT_TEST(DistanceToLineSquare2D_DegenerateSection)
{
typedef m2::PointD P;
mn::DistanceToLineSquare<P> d(P(5, 5), P(5, 5));
TEST_ALMOST_EQUAL(d(P(5, 5)), 0.0, ());
TEST_ALMOST_EQUAL(d(P(6, 6)), 2.0, ());
TEST_ALMOST_EQUAL(d(P(0, 0)), 50.0, ());
TEST_ALMOST_EQUAL(d(P(-1, -2)), 36.0 + 49.0, ());
}