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

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkTensorGlyph.h,v $
  Language:  C++
  Date:      $Date: 2001/10/11 13:37:18 $
  Version:   $Revision: 1.36 $


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

Redistribution and use in source and binary forms, with or without
modification, are permitted provided that the following conditions are met:

 * Redistributions of source code must retain the above copyright notice,
   this list of conditions and the following disclaimer.

 * Redistributions in binary form must reproduce the above copyright notice,
   this list of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.

 * 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.

 * Modified source versions must be plainly marked as such, and must not be
   misrepresented as being the original software.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS IS''
AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
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CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

=========================================================================*/
// .NAME vtkTensorGlyph - scale and orient glyph according to tensor eigenvalues and eigenvectors
// .SECTION Description
// vtkTensorGlyph is a filter that copies a geometric representation (specified
// as polygonal data) to every input point. The geometric representation, or 
// glyph, can be scaled and/or rotated according to the tensor at the input 
// point. Scaling and rotation is controlled by the eigenvalues/eigenvectors
// of the tensor as follows. For each tensor, the eigenvalues (and associated
// eigenvectors) are sorted to determine the major, medium, and minor 
// eigenvalues/eigenvectors. The major eigenvalue scales the glyph in the 
// x-direction, the medium in the y-direction, and the minor in the 
// z-direction. Then, the glyph is rotated so that the glyph's local x-axis 
// lies along the major eigenvector, y-axis along the medium eigenvector, and
// z-axis along the minor.
//
// A scale factor is provided to control the amount of scaling. Also, you 
// can turn off scaling completely if desired. The boolean variable 
// ClampScaling controls the maximum scaling (in conjunction with
// MaxScaleFactor.) This is useful in certain applications where 
// singularities or large order of magnitude differences exist in 
// the eigenvalues.
//
// Another instance variable, ExtractEigenvalues, has been provided to 
// control extraction of eigenvalues/eigenvectors. If this boolean is false,
// then eigenvalues/eigenvectors are not extracted, and the columns of the
// tensor are taken as the eigenvectors (norm of column is eigenvalue). 
// This allows additional capability over the vtkGlyph3D object. That is, the
// glyph can be oriented in three directions instead of one.

// .SECTION See Also
// vtkGlyph3D vtkPointLoad vtkHyperStreamline

#ifndef __vtkTensorGlyph_h
#define __vtkTensorGlyph_h

#include "vtkDataSetToPolyDataFilter.h"

class VTK_GRAPHICS_EXPORT vtkTensorGlyph : public vtkDataSetToPolyDataFilter
{
public:
  vtkTypeMacro(vtkTensorGlyph,vtkDataSetToPolyDataFilter);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description
  // Construct object with scaling on and scale factor 1.0. Eigenvalues are 
  // extracted, glyphs are colored with input scalar data, and logarithmic
  // scaling is turned off.
  static vtkTensorGlyph *New();

  // Description:
  // Specify the geometry to copy to each point.
  void SetSource(vtkPolyData *source);
  vtkPolyData *GetSource();

  // Description:
  // Turn on/off scaling of glyph with eigenvalues.
  vtkSetMacro(Scaling,int);
  vtkGetMacro(Scaling,int);
  vtkBooleanMacro(Scaling,int);

  // Description:
  // Specify scale factor to scale object by. (Scale factor always affects
  // output even if scaling is off.)
  vtkSetMacro(ScaleFactor,float);
  vtkGetMacro(ScaleFactor,float);

  // Description:
  // Turn on/off extraction of eigenvalues from tensor.
  vtkSetMacro(ExtractEigenvalues,int);
  vtkBooleanMacro(ExtractEigenvalues,int);
  vtkGetMacro(ExtractEigenvalues,int);

  // Description:
  // Turn on/off coloring of glyph with input scalar data. If false, or 
  // input scalar data not present, then the scalars from the source
  // object are passed through the filter.
  vtkSetMacro(ColorGlyphs,int);
  vtkGetMacro(ColorGlyphs,int);
  vtkBooleanMacro(ColorGlyphs,int);

  // Description:
  // Turn on/off scalar clamping. If scalar clamping is on, the ivar
  // MaxScaleFactor is used to control the maximum scale factor. (This is
  // useful to prevent uncontrolled scaling near singularities.)
  vtkSetMacro(ClampScaling,int);
  vtkGetMacro(ClampScaling,int);
  vtkBooleanMacro(ClampScaling,int);

  // Description:
  // Set/Get the maximum allowable scale factor. This value is compared to the
  // combination of the scale factor times the eigenvalue. If less, the scale
  // factor is reset to the MaxScaleFactor. The boolean ClampScaling has to 
  // be "on" for this to work.
  vtkSetMacro(MaxScaleFactor,float);
  vtkGetMacro(MaxScaleFactor,float);

protected:
  vtkTensorGlyph();
  ~vtkTensorGlyph();

  void Execute();

  int Scaling; // Determine whether scaling of geometry is performed
  float ScaleFactor; // Scale factor to use to scale geometry
  int ExtractEigenvalues; // Boolean controls eigenfunction extraction
  int ColorGlyphs; // Boolean controls coloring with input scalar data
  int ClampScaling; // Boolean controls whether scaling is clamped.
  float MaxScaleFactor; // Maximum scale factor (ScaleFactor*eigenvalue)
private:
  vtkTensorGlyph(const vtkTensorGlyph&);  // Not implemented.
  void operator=(const vtkTensorGlyph&);  // Not implemented.
};

#endif