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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
#include "vtkParametricDini.h"
#include "vtkMath.h"
#include "vtkObjectFactory.h"
#include <cmath>
VTK_ABI_NAMESPACE_BEGIN
vtkStandardNewMacro(vtkParametricDini);
//------------------------------------------------------------------------------
vtkParametricDini::vtkParametricDini()
{
// Preset triangulation parameters
this->MinimumU = 0;
this->MaximumU = 4 * vtkMath::Pi();
this->MinimumV = 0.001;
this->MaximumV = 2.0;
this->JoinU = 0;
this->JoinV = 0;
this->TwistU = 0;
this->TwistV = 0;
this->ClockwiseOrdering = 0;
this->DerivativesAvailable = 1;
this->A = 1.0;
this->B = 0.2;
}
//------------------------------------------------------------------------------
vtkParametricDini::~vtkParametricDini() = default;
//------------------------------------------------------------------------------
void vtkParametricDini::Evaluate(double uvw[3], double Pt[3], double Duvw[9])
{
double u = uvw[0];
double v = uvw[1];
double* Du = Duvw;
double* Dv = Duvw + 3;
double cu = cos(u);
double cv = cos(v);
double su = sin(u);
double sv = sin(v);
// The point
Pt[0] = this->A * cu * sv;
Pt[1] = this->A * su * sv;
double tolerance = 0.0001;
if (std::abs(v) > tolerance)
{
Pt[2] = this->A * (cos(v) + log(tan((v / 2)))) + this->B * u;
}
else
{
// avoid log(0)=-inf result for v=0
Pt[2] = this->A * (cos(v) + log(tan((tolerance / 2)))) + this->B * u;
}
// The derivatives are:
Du[0] = -Pt[1];
Dv[0] = this->A * cu * cv;
Du[1] = Pt[0];
Dv[1] = this->A * su * cv;
Du[2] = this->B;
double tv2 = tan(0.5 * v);
if (tv2 != 0)
{
Dv[2] = this->A * (-sv + (0.5 + 0.5 * tv2 * tv2) / tv2);
}
else // Avoid division by zero at the singularity.
{
Dv[2] = this->A * (-sv + 0.00005);
}
}
//------------------------------------------------------------------------------
double vtkParametricDini::EvaluateScalar(double*, double*, double*)
{
return 0;
}
//------------------------------------------------------------------------------
void vtkParametricDini::PrintSelf(ostream& os, vtkIndent indent)
{
this->Superclass::PrintSelf(os, indent);
os << indent << "A: " << this->A << "\n";
os << indent << "B: " << this->B << "\n";
}
VTK_ABI_NAMESPACE_END
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