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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
#include "vtkParametricBour.h"
#include "vtkMath.h"
#include "vtkObjectFactory.h"
VTK_ABI_NAMESPACE_BEGIN
vtkStandardNewMacro(vtkParametricBour);
//----------------------------------------------------------------------------//
vtkParametricBour::vtkParametricBour()
{
// Preset triangulation parameters
this->MinimumU = 0.;
this->MaximumU = 1.0;
this->MinimumV = 0.;
this->MaximumV = 4. * vtkMath::Pi();
this->JoinU = 0;
this->JoinV = 0;
this->TwistU = 0;
this->TwistV = 0;
this->ClockwiseOrdering = 0;
this->DerivativesAvailable = 1;
}
//----------------------------------------------------------------------------//
vtkParametricBour::~vtkParametricBour() = default;
//----------------------------------------------------------------------------//
void vtkParametricBour::Evaluate(double uvw[3], double Pt[3], double Duvw[9])
{
// Copy the parameters out of the vector, for the sake of convenience.
double u = uvw[0];
double v = uvw[1];
// We're only going to need the u and v partial derivatives.
// The w partial derivatives are not needed.
double* Du = Duvw;
double* Dv = Duvw + 3;
// Location of the point. This parametrization was taken from:
// https://en.wikipedia.org/wiki/Bour%27s_minimal_surface
const double u1_2 = std::sqrt(u);
const double u3_2 = u * u1_2;
const double cos_v = std::cos(v);
const double cos_1_5v = std::cos(1.5 * v);
const double cos_2v = std::cos(2. * v);
const double sin_v = std::sin(v);
const double sin_1_5v = std::sin(1.5 * v);
Pt[0] = u * cos_v - u * u * cos_2v / 2.;
Pt[1] = -u * sin_v * (u * cos_v + 1.);
Pt[2] = 4. / 3. * u3_2 * cos_1_5v;
// The derivative with respect to u:
Du[0] = cos_v - u * cos_2v;
Du[1] = -sin_v * (1. + 2. * u * cos_v);
Du[2] = 2 * u1_2 * cos_1_5v;
// The derivative with respect to v:
Dv[0] = u * (2. * u * cos_v - 1.) * sin_v;
Dv[1] = -u * (cos_v + u * cos_2v);
Dv[2] = -2. * u3_2 * sin_1_5v;
}
//----------------------------------------------------------------------------//
double vtkParametricBour::EvaluateScalar(double*, double*, double*)
{
return 0;
}
//----------------------------------------------------------------------------//
void vtkParametricBour::PrintSelf(ostream& os, vtkIndent indent)
{
this->Superclass::PrintSelf(os, indent);
}
VTK_ABI_NAMESPACE_END
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