pastk/organicmaps
1
Fork 0
forked from organicmaps/organicmaps
Code Pull requests Activity

Better distance calculation. Add more tests for distance to section.

Browse source
This commit is contained in:
vng 2011-02-01 22:46:46 +02:00 • committed by Alex Zolotarev
parent 541e1561f7
commit 6e09c5a8b8
2 changed files with 19 additions and 10 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

25
geometry/distance.hpp
View file

@ -1,6 +1,6 @@
#pragma once
#include "point2d.hpp"
#include "../base/base.hpp"
#include "../base/math.hpp"
#include "../std/limits.hpp"
@ -20,21 +20,25 @@ public:
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))
{
m_D2 = sqrt(m_D2);
if (my::AlmostEqual(m_D2, 0.0))
m_isZero = true;
{
// make zero vector - then all DotProduct will be equal to zero
m_D = m2::PointD(0, 0);
}
else
{
m_InvD2 = 1.0 / m_D2;
m_isZero = false;
// normalize vector
m_D = m_D / m_D2;
}
}
double operator () (PointT Y) const
{
PointT const YmP0 = Y - m_P0;
m2::PointD const YmP0 = Y - m_P0;
double const t = DotProduct(m_D, YmP0);
if (m_isZero || t <= 0)
if (t <= 0)
{
// Y is closest to P0.
return DotProduct(YmP0, YmP0);
@ -45,14 +49,15 @@ public:
PointT const YmP1 = Y - m_P1;
return DotProduct(YmP1, YmP1);
}
// Closest point is interior to segment.
return DotProduct(YmP0, YmP0) - t * t * m_InvD2;
return my::sq(CrossProduct(YmP0, m_D));
}
private:
PointT m_P0, m_P1, m_D;
double m_D2, m_InvD2;
bool m_isZero;
PointT m_P0, m_P1;
m2::PointD m_D;
double m_D2;
};
}

4
geometry/geometry_tests/distance_test.cpp
View file

@ -30,6 +30,10 @@ UNIT_TEST(DistanceToLineSquare2D_Integer)
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, ());
double const sqSin = 4.0 / m2::PointI(-1, 3).SquareLength(m2::PointI(2, 1));
TEST_ALMOST_EQUAL(dI(m2::PointI(0, 1)), 4.0*sqSin, ());
TEST_ALMOST_EQUAL(dI(m2::PointI(-1, 1)), 9.0*sqSin, ());
}
UNIT_TEST(DistanceToLineSquare2D_DegenerateSection)