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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 "Wm5IntrRay3Sphere3.h"
namespace Wm5
{
//----------------------------------------------------------------------------
template <typename Real>
IntrRay3Sphere3<Real>::IntrRay3Sphere3 (const Ray3<Real>& ray,
const Sphere3<Real>& sphere)
:
mRay(&ray),
mSphere(&sphere)
{
mQuantity = 0;
}
//----------------------------------------------------------------------------
template <typename Real>
const Ray3<Real>& IntrRay3Sphere3<Real>::GetRay () const
{
return *mRay;
}
//----------------------------------------------------------------------------
template <typename Real>
const Sphere3<Real>& IntrRay3Sphere3<Real>::GetSphere () const
{
return *mSphere;
}
//----------------------------------------------------------------------------
template <typename Real>
bool IntrRay3Sphere3<Real>::Test ()
{
Vector3<Real> diff = mRay->Origin - mSphere->Center;
Real a0 = diff.Dot(diff) - mSphere->Radius*mSphere->Radius;
if (a0 <= (Real)0)
{
// P is inside the sphere
return true;
}
// else: P is outside the sphere
Real a1 = mRay->Direction.Dot(diff);
if (a1 >= (Real)0)
{
return false;
}
// Quadratic has a real root if discriminant is nonnegative.
return a1*a1 >= a0;
}
//----------------------------------------------------------------------------
template <typename Real>
bool IntrRay3Sphere3<Real>::Find ()
{
Vector3<Real> diff = mRay->Origin - mSphere->Center;
Real a0 = diff.Dot(diff) - mSphere->Radius*mSphere->Radius;
Real a1, discr, root;
if (a0 <= (Real)0)
{
// P is inside the sphere
a1 = mRay->Direction.Dot(diff);
discr = a1*a1 - a0;
root = Math<Real>::Sqrt(discr);
mRayParameter[0] = -a1 + root;
mPoint[0] = mRay->Origin + mRayParameter[0]*mRay->Direction;
mQuantity = 1;
mIntersectionType = IT_POINT;
return true;
}
// else: P is outside the sphere
a1 = mRay->Direction.Dot(diff);
if (a1 >= (Real)0.0)
{
mQuantity = 0;
mIntersectionType = IT_EMPTY;
return false;
}
discr = a1*a1 - a0;
if (discr < (Real)0.0)
{
mQuantity = 0;
mIntersectionType = IT_EMPTY;
}
else if (discr >= Math<Real>::ZERO_TOLERANCE)
{
root = Math<Real>::Sqrt(discr);
mRayParameter[0] = -a1 - root;
mRayParameter[1] = -a1 + root;
mPoint[0] = mRay->Origin + mRayParameter[0]*mRay->Direction;
mPoint[1] = mRay->Origin + mRayParameter[1]*mRay->Direction;
mQuantity = 2;
mIntersectionType = IT_SEGMENT;
}
else
{
mRayParameter[0] = -a1;
mPoint[0] = mRay->Origin + mRayParameter[0]*mRay->Direction;
mQuantity = 1;
mIntersectionType = IT_POINT;
}
return mQuantity > 0;
}
//----------------------------------------------------------------------------
template <typename Real>
int IntrRay3Sphere3<Real>::GetQuantity () const
{
return mQuantity;
}
//----------------------------------------------------------------------------
template <typename Real>
const Vector3<Real>& IntrRay3Sphere3<Real>::GetPoint (int i) const
{
return mPoint[i];
}
//----------------------------------------------------------------------------
template <typename Real>
Real IntrRay3Sphere3<Real>::GetRayParameter (int i) const
{
return mRayParameter[i];
}
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
// Explicit instantiation.
//----------------------------------------------------------------------------
template WM5_MATHEMATICS_ITEM
class IntrRay3Sphere3<float>;
template WM5_MATHEMATICS_ITEM
class IntrRay3Sphere3<double>;
//----------------------------------------------------------------------------
}
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