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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 "Wm5ContScribeCircle2.h"
namespace Wm5
{
//----------------------------------------------------------------------------
template <typename Real>
bool Circumscribe (const Vector2<Real>& v0, const Vector2<Real>& v1,
const Vector2<Real>& v2, Circle2<Real>& circle)
{
Vector2<Real> e10 = v1 - v0;
Vector2<Real> e20 = v2 - v0;
Real A[2][2] =
{
{e10[0], e10[1]},
{e20[0], e20[1]}
};
Real B[2] =
{
((Real)0.5)*e10.SquaredLength(),
((Real)0.5)*e20.SquaredLength()
};
Vector2<Real> solution;
if (LinearSystem<Real>().Solve2(A, B, (Real*)&solution))
{
circle.Center = v0 + solution;
circle.Radius = solution.Length();
return true;
}
return false;
}
//----------------------------------------------------------------------------
template <typename Real>
bool Inscribe (const Vector2<Real>& v0, const Vector2<Real>& v1,
const Vector2<Real>& v2, Circle2<Real>& circle)
{
Vector2<Real> d10 = v1 - v0;
Vector2<Real> d20 = v2 - v0;
Vector2<Real> d21 = v2 - v1;
Real len10 = d10.Length();
Real len20 = d20.Length();
Real len21 = d21.Length();
Real perimeter = len10 + len20 + len21;
if (perimeter > Math<Real>::ZERO_TOLERANCE)
{
Real inv = ((Real)1)/perimeter;
len10 *= inv;
len20 *= inv;
len21 *= inv;
circle.Center = len21*v0 + len20*v1 + len10*v2;
circle.Radius = inv*Math<Real>::FAbs(d10.DotPerp(d20));
return true;
}
return false;
}
//----------------------------------------------------------------------------
//----------------------------------------------------------------------------
// Explicit instantiation.
//----------------------------------------------------------------------------
template WM5_MATHEMATICS_ITEM
bool Circumscribe<float> (const Vector2<float>&, const Vector2<float>&,
const Vector2<float>&, Circle2<float>&);
template WM5_MATHEMATICS_ITEM
bool Inscribe<float> (const Vector2<float>&, const Vector2<float>&,
const Vector2<float>&, Circle2<float>&);
template WM5_MATHEMATICS_ITEM
bool Circumscribe<double> (const Vector2<double>&, const Vector2<double>&,
const Vector2<double>&, Circle2<double>&);
template WM5_MATHEMATICS_ITEM
bool Inscribe<double> (const Vector2<double>&, const Vector2<double>&,
const Vector2<double>&, Circle2<double>&);
//----------------------------------------------------------------------------
}
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