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

  Program:   Visualization Toolkit
  Module:    vtkQuadric.h
  Language:  C++
  Date:      $Date$
  Version:   $Revision$


Copyright (c) 1993-2000 Ken Martin, Will Schroeder, Bill Lorensen 
All rights reserved.

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   this list of conditions and the following disclaimer.

 * Redistributions in binary form must reproduce the above copyright notice,
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 * Neither name of Ken Martin, Will Schroeder, or Bill Lorensen nor the names
   of any contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.

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=========================================================================*/
// .NAME vtkQuadric - evaluate implicit quadric function
// .SECTION Description
// vtkQuadric evaluates the quadric function F(x,y,z) = a0*x^2 + a1*y^2 + 
// a2*z^2 + a3*x*y + a4*y*z + a5*x*z + a6*x + a7*y + a8*z + a9. vtkQuadric is
// a concrete implementation of vtkImplicitFunction.

#ifndef __vtkQuadric_h
#define __vtkQuadric_h

#include "vtkImplicitFunction.h"

class VTK_EXPORT vtkQuadric : public vtkImplicitFunction
{
public:
  vtkTypeMacro(vtkQuadric,vtkImplicitFunction);
  void PrintSelf(ostream& os, vtkIndent indent);
  
  // Description
  // Construct quadric with all coefficients = 1.
  static vtkQuadric *New();

  // Description
  // Evaluate quadric equation.
  float EvaluateFunction(float x[3]);
  float EvaluateFunction(float x, float y, float z)
    {return this->vtkImplicitFunction::EvaluateFunction(x, y, z); } ;

  // Description
  // Evaluate the gradient to the quadric equation.
  void EvaluateGradient(float x[3], float g[3]);
  
  // Description
  // Set / get the 10 coefficients of the quadric equation.
  void SetCoefficients(float a[10]);
  void SetCoefficients(float a0, float a1, float a2, float a3, float a4, 
                       float a5, float a6, float a7, float a8, float a9);
  vtkGetVectorMacro(Coefficients,float,10);

protected:
  vtkQuadric();
  ~vtkQuadric() {};
  vtkQuadric(const vtkQuadric&) {};
  void operator=(const vtkQuadric&) {};

  float Coefficients[10];

};

#endif


