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

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


Copyright (c) 1993-2000 Ken Martin, Will Schroeder, Bill Lorensen 
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=========================================================================*/
// .NAME vtkTriangularTCoords - 2D texture coordinates based for triangles.
// .SECTION Description
// vtkTriangularTCoords is a filter that generates texture coordinates
// for triangles. Texture coordinates for each triangle are:
// (0,0), (1,0) and (.5,sqrt(3)/2). This filter assumes that the triangle
// texture map is symmetric about the center of the triangle. Thus the order
// Of the texture coordinates is not important. The procedural texture
// in vtkTriangularTexture is designed with this symmetry. For more information
// see the paper "Opacity-modulating Triangular Textures for Irregular 
// Surfaces,"  by Penny Rheingans, IEEE Visualization '96, pp. 219-225.
// .SECTION See Also
// vtkTriangularTexture vtkThresholdPoints vtkTextureMapToPlane 
// vtkTextureMapToSphere vtkTextureMapToCylinder vtkTextureMapToBox

#ifndef __vtkTriangularTCoords_h
#define __vtkTriangularTCoords_h

#include "vtkPolyDataToPolyDataFilter.h"

class VTK_EXPORT vtkTriangularTCoords : public vtkPolyDataToPolyDataFilter
{
public:
  static vtkTriangularTCoords *New();
  vtkTypeMacro(vtkTriangularTCoords,vtkPolyDataToPolyDataFilter);
  void PrintSelf(ostream& os, vtkIndent indent);

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

  // Usual data generation method
  void Execute();
};

#endif


