// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
/* vtkSuperQuadric originally written by Michael Halle,
   Brigham and Women's Hospital, July 1998.

   Based on "Rigid physically based superquadrics", A. H. Barr,
   in "Graphics Gems III", David Kirk, ed., Academic Press, 1992.
*/

#include "vtkSuperquadric.h"
#include "vtkObjectFactory.h"

#include <cmath>

VTK_ABI_NAMESPACE_BEGIN
vtkStandardNewMacro(vtkSuperquadric);

// Construct with superquadric radius of 0.5, toroidal off, center at 0.0,
// scale (1,1,1), size 0.5, phi roundness 1.0, and theta roundness 0.0.
vtkSuperquadric::vtkSuperquadric()
{
  this->Toroidal = 0;
  this->Thickness = 0.3333;
  this->PhiRoundness = 0.0;
  this->SetPhiRoundness(1.0);
  this->ThetaRoundness = 0.0;
  this->SetThetaRoundness(1.0);
  this->Center[0] = this->Center[1] = this->Center[2] = 0.0;
  this->Scale[0] = this->Scale[1] = this->Scale[2] = 1.0;
  this->Size = .5;
}

static constexpr double MAX_FVAL = 1e12;
static double VTK_MIN_SUPERQUADRIC_ROUNDNESS = 1e-24;

void vtkSuperquadric::SetThetaRoundness(double e)
{
  e = std::max(e, VTK_MIN_SUPERQUADRIC_ROUNDNESS);

  if (this->ThetaRoundness != e)
  {
    this->ThetaRoundness = e;
    this->Modified();
  }
}

void vtkSuperquadric::SetPhiRoundness(double e)
{
  e = std::max(e, VTK_MIN_SUPERQUADRIC_ROUNDNESS);

  if (this->PhiRoundness != e)
  {
    this->PhiRoundness = e;
    this->Modified();
  }
}

// Evaluate Superquadric equation
double vtkSuperquadric::EvaluateFunction(double xyz[3])
{
  double e = this->ThetaRoundness;
  double n = this->PhiRoundness;
  double p[3], s[3];
  double val;

  s[0] = this->Scale[0] * this->Size;
  s[1] = this->Scale[1] * this->Size;
  s[2] = this->Scale[2] * this->Size;

  if (this->Toroidal)
  {
    double tval;
    double alpha;

    alpha = (1.0 / this->Thickness);
    s[0] /= (alpha + 1.0);
    s[1] /= (alpha + 1.0);
    s[2] /= (alpha + 1.0);

    p[0] = (xyz[0] - this->Center[0]) / s[0];
    p[1] = (xyz[1] - this->Center[1]) / s[1];
    p[2] = (xyz[2] - this->Center[2]) / s[2];

    tval = pow((pow(fabs(p[2]), 2.0 / e) + pow(fabs(p[0]), 2.0 / e)), e / 2.0);
    val = pow(fabs(tval - alpha), 2.0 / n) + pow(fabs(p[1]), 2.0 / n) - 1.0;
  }
  else
  { // Ellipsoidal
    p[0] = (xyz[0] - this->Center[0]) / s[0];
    p[1] = (xyz[1] - this->Center[1]) / s[1];
    p[2] = (xyz[2] - this->Center[2]) / s[2];

    val = pow((pow(fabs(p[2]), 2.0 / e) + pow(fabs(p[0]), 2.0 / e)), e / n) +
      pow(fabs(p[1]), 2.0 / n) - 1.0;
  }

  if (val > MAX_FVAL)
  {
    val = MAX_FVAL;
  }
  else if (val < -MAX_FVAL)
  {
    val = -MAX_FVAL;
  }

  return val;
}

// Description
// Evaluate Superquadric function gradient.
void vtkSuperquadric::EvaluateGradient(double vtkNotUsed(xyz)[3], double g[3])
{
  // bogus! lazy!
  // if someone wants to figure these out, they are each the
  // partial of x, then y, then z with respect to f as shown above.
  // Careful for the fabs().

  g[0] = g[1] = g[2] = 0.0;
}

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

  os << indent << "Toroidal: " << (this->Toroidal ? "On\n" : "Off\n");
  os << indent << "Size: " << this->Size << "\n";
  os << indent << "Thickness: " << this->Thickness << "\n";
  os << indent << "ThetaRoundness: " << this->ThetaRoundness << "\n";
  os << indent << "PhiRoundness: " << this->PhiRoundness << "\n";
  os << indent << "Center: (" << this->Center[0] << ", " << this->Center[1] << ", "
     << this->Center[2] << ")\n";
  os << indent << "Scale: (" << this->Scale[0] << ", " << this->Scale[1] << ", " << this->Scale[2]
     << ")\n";
}
VTK_ABI_NAMESPACE_END