/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkParametricHenneberg.cxx

  Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
  All rights reserved.
  See Copyright.txt or http://www.kitware.com/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notice for more information.

=========================================================================*/
#include "vtkParametricHenneberg.h"
#include "vtkObjectFactory.h"
#include "vtkMath.h"

vtkStandardNewMacro(vtkParametricHenneberg);
//----------------------------------------------------------------------------//
vtkParametricHenneberg::vtkParametricHenneberg()
  {
  // Preset triangulation parameters
  this->MinimumU = -1.0;
  this->MinimumV = -vtkMath::Pi()/2.;
  this->MaximumU =  1.0;
  this->MaximumV =  vtkMath::Pi()/2.;

  this->JoinU = 0;
  this->JoinV = 0;
  this->TwistU = 0;
  this->TwistV = 0;
  this->ClockwiseOrdering = 1;
  this->DerivativesAvailable = 1;
  }

//----------------------------------------------------------------------------//
vtkParametricHenneberg::~vtkParametricHenneberg()
  {
  }

//----------------------------------------------------------------------------//
void vtkParametricHenneberg::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:
  // http://mathworld.wolfram.com/HennebergsMinimalSurface.html
  Pt[0] = 2.*sinh(u)*cos(v) - 2./3.*sinh(3.*u)*cos(3.*v);
  Pt[1] = 2.*sinh(u)*sin(v) + 2./3.*sinh(3.*u)*sin(3.*v);
  Pt[2] = 2.*cosh(2.*u)*cos(2.*v);

  // The derivative with respect to u:
  Du[0] = 2.*cosh(u)*cos(v) - 2.*cosh(3.*u)*cos(3.*v);
  Du[1] = 2.*cosh(u)*sin(v) + 2.*cosh(3.*u)*sin(3.*v);
  Du[2] = 4.*sinh(2.*u)*cos(2.*v);

  // The derivative with respect to v:
  Dv[0] = -2.*sinh(u)*sin(v) + 2.*sinh(3.*u)*sin(3.*v);
  Dv[1] =  2.*sinh(u)*cos(v) + 2.*sinh(3.*u)*cos(3.*v);
  Dv[2] = -4.*cosh(2.*u)*sin(2.*v);
  }

//----------------------------------------------------------------------------//
double vtkParametricHenneberg::EvaluateScalar(double *, double *, double *)
  {
  return 0;
  }

//----------------------------------------------------------------------------//
void vtkParametricHenneberg::PrintSelf(ostream& os, vtkIndent indent)
  {
  this->Superclass::PrintSelf(os,indent);
  }
