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

  Program:   Visualization Toolkit
  Module:    vtkHomogeneousTransform.h
  Language:  C++
  Date:      $Date$
  Version:   $Revision$
  Thanks:    Thanks to David G. Gobbi who developed this class.

Copyright (c) 1993-2001 Ken Martin, Will Schroeder, Bill Lorensen 
All rights reserved.

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   misrepresented as being the original software.

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=========================================================================*/
// .NAME vtkHomogeneousTransform - superclass for homogeneous transformations
// .SECTION Description
// vtkHomogeneousTransform provides a generic interface for homogeneous 
// transformations, i.e. transformations which can be represented by 
// multiplying a 4x4 matrix with a homogeneous coordinate. 
// .SECTION see also
// vtkPerspectiveTransform vtkLinearTransform vtkIdentityTransform


#ifndef __vtkHomogeneousTransform_h
#define __vtkHomogeneousTransform_h

#include "vtkAbstractTransform.h"
#include "vtkMatrix4x4.h"

class VTK_COMMON_EXPORT vtkHomogeneousTransform : public vtkAbstractTransform
{
public:

  vtkTypeMacro(vtkHomogeneousTransform,vtkAbstractTransform);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Apply the transformation to a series of points, and append the
  // results to outPts.  
  void TransformPoints(vtkPoints *inPts, vtkPoints *outPts);

  // Description:
  // Apply the transformation to a combination of points, normals
  // and vectors.  
  virtual void TransformPointsNormalsVectors(vtkPoints *inPts, 
					     vtkPoints *outPts, 
					     vtkNormals *inNms, 
					     vtkNormals *outNms,
					     vtkVectors *inVrs, 
					     vtkVectors *outVrs)
    {
      this->TransformPointsNormalsVectors(inPts, outPts,
					  inNms->GetData(), outNms->GetData(),
					  inVrs->GetData(), outVrs->GetData());
    }

  virtual void TransformPointsNormalsVectors(vtkPoints *inPts, 
					     vtkPoints *outPts, 
					     vtkDataArray *inNms, 
					     vtkDataArray *outNms,
					     vtkDataArray *inVrs, 
					     vtkDataArray *outVrs);

  // Description:
  // Get a copy of the internal transformation matrix.  The
  // transform is Updated first, to guarantee that the matrix
  // is valid.
  void GetMatrix(vtkMatrix4x4 *m);

  // Description:
  // Get a pointer to an internal vtkMatrix4x4 that represents
  // the transformation.  An Update() is called on the transform
  // to ensure that the matrix is up-to-date when you get it.
  // You should not store the matrix pointer anywhere because it
  // might become stale.
  vtkMatrix4x4 *GetMatrix() { this->Update(); return this->Matrix; };

  // Description:
  // Just like GetInverse(), but includes typecast to vtkHomogeneousTransform.
  vtkHomogeneousTransform *GetHomogeneousInverse() {
    return (vtkHomogeneousTransform *)this->GetInverse(); };

  // Description:
  // This will calculate the transformation without calling Update.
  // Meant for use only within other VTK classes.
  void InternalTransformPoint(const float in[3], float out[3]);
  void InternalTransformPoint(const double in[3], double out[3]);

  // Description:
  // This will calculate the transformation as well as its derivative
  // without calling Update.  Meant for use only within other VTK
  // classes.
  void InternalTransformDerivative(const float in[3], float out[3],
				   float derivative[3][3]);
  void InternalTransformDerivative(const double in[3], double out[3],
				   double derivative[3][3]);

protected:
  vtkHomogeneousTransform();
  ~vtkHomogeneousTransform();

  void InternalDeepCopy(vtkAbstractTransform *transform);

  vtkMatrix4x4 *Matrix;
private:
  vtkHomogeneousTransform(const vtkHomogeneousTransform&);  // Not implemented.
  void operator=(const vtkHomogeneousTransform&);  // Not implemented.
};

#endif





