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// David Eberly, Geometric Tools, Redmond WA 98052
// Copyright (c) 1998-2021
// Distributed under the Boost Software License, Version 1.0.
// https://www.boost.org/LICENSE_1_0.txt
// https://www.geometrictools.com/License/Boost/LICENSE_1_0.txt
// Version: 4.0.2019.08.13
#pragma once
#include <Mathematics/RiemannianGeodesic.h>
#include <Mathematics/BSplineSurface.h>
namespace gte
{
template <typename Real>
class BSplineGeodesic : public RiemannianGeodesic<Real>
{
public:
BSplineGeodesic(BSplineSurface<3, Real> const& spline)
:
RiemannianGeodesic<Real>(2),
mSpline(&spline)
{
}
virtual ~BSplineGeodesic()
{
}
private:
virtual void ComputeMetric(const GVector<Real>& point) override
{
mSpline->Evaluate(point[0], point[1], 2, mJet);
Vector<3, Real> const& der0 = mJet[1];
Vector<3, Real> const& der1 = mJet[2];
this->mMetric(0, 0) = Dot(der0, der0);
this->mMetric(0, 1) = Dot(der0, der1);
this->mMetric(1, 0) = this->mMetric(0, 1);
this->mMetric(1, 1) = Dot(der1, der1);
}
virtual void ComputeChristoffel1(const GVector<Real>&) override
{
Vector<3, Real> const& der0 = mJet[1];
Vector<3, Real> const& der1 = mJet[2];
Vector<3, Real> const& der00 = mJet[3];
Vector<3, Real> const& der01 = mJet[4];
Vector<3, Real> const& der11 = mJet[5];
this->mChristoffel1[0](0, 0) = Dot(der00, der0);
this->mChristoffel1[0](0, 1) = Dot(der01, der0);
this->mChristoffel1[0](1, 0) = this->mChristoffel1[0](0, 1);
this->mChristoffel1[0](1, 1) = Dot(der11, der0);
this->mChristoffel1[1](0, 0) = Dot(der00, der1);
this->mChristoffel1[1](0, 1) = Dot(der01, der1);
this->mChristoffel1[1](1, 0) = this->mChristoffel1[1](0, 1);
this->mChristoffel1[1](1, 1) = Dot(der11, der1);
}
BSplineSurface<3, Real> const* mSpline;
// We are guaranteed that RiemannianGeodesic calls ComputeMetric
// before ComputeChristoffel1. Thus, we can compute the B-spline
// first- and second-order derivatives in ComputeMetric and cache
// the results for use in ComputeChristoffel1.
Vector<3, Real> mJet[6];
};
}