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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: 5.0.3 (2013/11/12)
#include "Wm5MathematicsPCH.h"
#include "Wm5IntrLine2Line2.h"
namespace Wm5
{
//----------------------------------------------------------------------------
template <typename Real>
IntrLine2Line2<Real>::IntrLine2Line2 (const Line2<Real>& line0,
const Line2<Real>& line1)
:
mLine0(&line0),
mLine1(&line1),
mDotThreshold(Math<Real>::ZERO_TOLERANCE)
{
}
//----------------------------------------------------------------------------
template <typename Real>
const Line2<Real>& IntrLine2Line2<Real>::GetLine0 () const
{
return *mLine0;
}
//----------------------------------------------------------------------------
template <typename Real>
const Line2<Real>& IntrLine2Line2<Real>::GetLine1 () const
{
return *mLine1;
}
//----------------------------------------------------------------------------
template <typename Real>
bool IntrLine2Line2<Real>::Test ()
{
mIntersectionType = Classify(mLine0->Origin, mLine0->Direction,
mLine1->Origin, mLine1->Direction, mDotThreshold);
if (mIntersectionType == IT_POINT)
{
mQuantity = 1;
}
else if (mIntersectionType == IT_LINE)
{
mQuantity = INT_MAX;
}
else
{
mQuantity = 0;
}
return mIntersectionType != IT_EMPTY;
}
//----------------------------------------------------------------------------
template <typename Real>
bool IntrLine2Line2<Real>::Find ()
{
Real s[2];
mIntersectionType = Classify(mLine0->Origin, mLine0->Direction,
mLine1->Origin, mLine1->Direction, mDotThreshold, s);
if (mIntersectionType == IT_POINT)
{
mQuantity = 1;
mPoint = mLine0->Origin + s[0]*mLine0->Direction;
}
else if (mIntersectionType == IT_LINE)
{
mQuantity = INT_MAX;
}
else
{
mQuantity = 0;
}
return mIntersectionType != IT_EMPTY;
}
//----------------------------------------------------------------------------
template <typename Real>
int IntrLine2Line2<Real>::Classify (const Vector2<Real>& P0,
const Vector2<Real>& D0, const Vector2<Real>& P1, const Vector2<Real>& D1,
Real dotThreshold, Real* s)
{
// Ensure dotThreshold is nonnegative.
dotThreshold = std::max(dotThreshold, (Real)0);
// The intersection of two lines is a solution to P0+s0*D0 = P1+s1*D1.
// Rewrite this as s0*D0 - s1*D1 = P1 - P0 = Q. If D0.Dot(Perp(D1)) = 0,
// the lines are parallel. Additionally, if Q.Dot(Perp(D1)) = 0, the
// lines are the same. If D0.Dot(Perp(D1)) is not zero, then
// s0 = Q.Dot(Perp(D1))/D0.Dot(Perp(D1))
// produces the point of intersection. Also,
// s1 = Q.Dot(Perp(D0))/D0.Dot(Perp(D1))
Vector2<Real> diff = P1 - P0;
Real D0DotPerpD1 = D0.DotPerp(D1);
if (Math<Real>::FAbs(D0DotPerpD1) > dotThreshold)
{
// Lines intersect in a single point.
if (s)
{
Real invD0DotPerpD1 = ((Real)1)/D0DotPerpD1;
Real diffDotPerpD0 = diff.DotPerp(D0);
Real diffDotPerpD1 = diff.DotPerp(D1);
s[0] = diffDotPerpD1*invD0DotPerpD1;
s[1] = diffDotPerpD0*invD0DotPerpD1;
}
return IT_POINT;
}
// Lines are parallel.
diff.Normalize();
Real diffNDotPerpD1 = diff.DotPerp(D1);
if (Math<Real>::FAbs(diffNDotPerpD1) <= dotThreshold)
{
// Lines are colinear.
return IT_LINE;
}
// Lines are parallel, but distinct.
return IT_EMPTY;
}
//----------------------------------------------------------------------------
template <typename Real>
void IntrLine2Line2<Real>::SetDotThreshold (Real dotThreshold)
{
if (dotThreshold >= (Real)0)
{
mDotThreshold = dotThreshold;
return;
}
assertion(false, "Dot threshold must be nonnegative.");
}
//----------------------------------------------------------------------------
template <typename Real>
Real IntrLine2Line2<Real>::GetDotThreshold () const
{
return mDotThreshold;
}
//----------------------------------------------------------------------------
template <typename Real>
int IntrLine2Line2<Real>::GetQuantity () const
{
return mQuantity;
}
//----------------------------------------------------------------------------
template <typename Real>
const Vector2<Real>& IntrLine2Line2<Real>::GetPoint () const
{
return mPoint;
}
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
// Explicit instantiation.
//----------------------------------------------------------------------------
template WM5_MATHEMATICS_ITEM
class IntrLine2Line2<float>;
template WM5_MATHEMATICS_ITEM
class IntrLine2Line2<double>;
//----------------------------------------------------------------------------
}
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