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// Geometric Tools, LLC
// Copyright (c) 1998-2014
// Distributed under the Boost Software License, Version 1.0.
// http://www.boost.org/LICENSE_1_0.txt
// http://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
//
// File Version: 5.0.1 (2010/10/01)
#include "Wm5MathematicsPCH.h"
#include "Wm5ContPointInPolygon2.h"
namespace Wm5
{
//----------------------------------------------------------------------------
template <typename Real>
PointInPolygon2<Real>::PointInPolygon2 (int numPoints,
const Vector2<Real>* points)
:
mNumPoints(numPoints),
mPoints(points)
{
}
//----------------------------------------------------------------------------
template <typename Real>
bool PointInPolygon2<Real>::Contains (const Vector2<Real>& p) const
{
bool inside = false;
for (int i = 0, j = mNumPoints-1; i < mNumPoints; j = i++)
{
const Vector2<Real>& U0 = mPoints[i];
const Vector2<Real>& U1 = mPoints[j];
Real rhs, lhs;
if (p.Y() < U1.Y()) // U1 above ray
{
if (U0.Y() <= p.Y()) // U0 on or below ray
{
lhs = (p.Y() - U0.Y())*(U1.X() - U0.X());
rhs = (p.X() - U0.X())*(U1.Y() - U0.Y());
if (lhs > rhs)
{
inside = !inside;
}
}
}
else if (p.Y() < U0.Y()) // U1 on or below ray, U0 above ray
{
lhs = (p.Y() - U0.Y())*(U1.X() - U0.X());
rhs = (p.X() - U0.X())*(U1.Y() - U0.Y());
if (lhs < rhs)
{
inside = !inside;
}
}
}
return inside;
}
//----------------------------------------------------------------------------
template <typename Real>
bool PointInPolygon2<Real>::ContainsConvexOrderN (const Vector2<Real>& p)
const
{
for (int i1 = 0, i0 = mNumPoints-1; i1 < mNumPoints; i0 = i1++)
{
Real nx = mPoints[i1].Y() - mPoints[i0].Y();
Real ny = mPoints[i0].X() - mPoints[i1].X();
Real dx = p.X() - mPoints[i0].X();
Real dy = p.Y() - mPoints[i0].Y();
if (nx*dx + ny*dy > (Real)0)
{
return false;
}
}
return true;
}
//----------------------------------------------------------------------------
template <typename Real>
bool PointInPolygon2<Real>::ContainsConvexOrderLogN (const Vector2<Real>& p)
const
{
return SubContainsPoint(p, 0, 0);
}
//----------------------------------------------------------------------------
template <typename Real>
bool PointInPolygon2<Real>::ContainsQuadrilateral (const Vector2<Real>& p)
const
{
if (mNumPoints != 4)
{
return false;
}
Real nx = mPoints[2].Y() - mPoints[0].Y();
Real ny = mPoints[0].X() - mPoints[2].X();
Real dx = p.X() - mPoints[0].X();
Real dy = p.Y() - mPoints[0].Y();
if (nx*dx + ny*dy > (Real)0)
{
// P potentially in <V0,V1,V2>
nx = mPoints[1].Y() - mPoints[0].Y();
ny = mPoints[0].X() - mPoints[1].X();
if (nx*dx + ny*dy > (Real)0.0)
{
return false;
}
nx = mPoints[2].Y() - mPoints[1].Y();
ny = mPoints[1].X() - mPoints[2].X();
dx = p.X() - mPoints[1].X();
dy = p.Y() - mPoints[1].Y();
if (nx*dx + ny*dy > (Real)0)
{
return false;
}
}
else
{
// P potentially in <V0,V2,V3>
nx = mPoints[0].Y() - mPoints[3].Y();
ny = mPoints[3].X() - mPoints[0].X();
if (nx*dx + ny*dy > (Real)0)
{
return false;
}
nx = mPoints[3].Y() - mPoints[2].Y();
ny = mPoints[2].X() - mPoints[3].X();
dx = p.X() - mPoints[3].X();
dy = p.Y() - mPoints[3].Y();
if (nx*dx + ny*dy > (Real)0)
{
return false;
}
}
return true;
}
//----------------------------------------------------------------------------
template <typename Real>
bool PointInPolygon2<Real>::SubContainsPoint (const Vector2<Real>& p, int i0,
int i1) const
{
Real nx, ny, dx, dy;
int diff = i1 - i0;
if (diff == 1 || (diff < 0 && diff + mNumPoints == 1))
{
nx = mPoints[i1].Y() - mPoints[i0].Y();
ny = mPoints[i0].X() - mPoints[i1].X();
dx = p.X() - mPoints[i0].X();
dy = p.Y() - mPoints[i0].Y();
return nx*dx + ny*dy <= (Real)0;
}
// Bisect the index range.
int mid;
if (i0 < i1)
{
mid = (i0 + i1) >> 1;
}
else
{
mid = ((i0 + i1 + mNumPoints) >> 1);
if (mid >= mNumPoints)
{
mid -= mNumPoints;
}
}
// Determine which side of the splitting line contains the point.
nx = mPoints[mid].Y() - mPoints[i0].Y();
ny = mPoints[i0].X() - mPoints[mid].X();
dx = p.X() - mPoints[i0].X();
dy = p.Y() - mPoints[i0].Y();
if (nx*dx + ny*dy > (Real)0)
{
// P potentially in <V(i0),V(i0+1),...,V(mid-1),V(mid)>
return SubContainsPoint(p, i0, mid);
}
else
{
// P potentially in <V(mid),V(mid+1),...,V(i1-1),V(i1)>
return SubContainsPoint(p, mid, i1);
}
}
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
// Explicit instantiation.
//----------------------------------------------------------------------------
template WM5_MATHEMATICS_ITEM
class PointInPolygon2<float>;
template WM5_MATHEMATICS_ITEM
class PointInPolygon2<double>;
//----------------------------------------------------------------------------
}
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