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/*=========================================================================
Program: Visualization Toolkit
Module: vtkContourTriangulator.h
Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
All rights reserved.
See Copyright.txt or http://www.kitware.com/Copyright.htm for details.
This software is distributed WITHOUT ANY WARRANTY; without even
the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
PURPOSE. See the above copyright notice for more information.
=========================================================================*/
/**
* @class vtkContourTriangulator
* @brief Fill all 2D contours to create polygons
*
* vtkContourTriangulator will generate triangles to fill all of the 2D
* contours in its input. The contours may be concave, and may even
* contain holes i.e. a contour may contain an internal contour that
* is wound in the opposite direction to indicate that it is a hole.
* @warning
* The triangulation of is done in O(n) time for simple convex
* inputs, but for non-convex inputs the worst-case time is O(n^2*m^2)
* where n is the number of points and m is the number of holes.
* The best triangulation algorithms, in contrast, are O(n log n).
* The resulting triangles may be quite narrow, the algorithm does
* not attempt to produce high-quality triangles.
* @par Thanks:
* Thanks to David Gobbi for contributing this class to VTK.
*/
#ifndef vtkContourTriangulator_h
#define vtkContourTriangulator_h
#include "vtkFiltersGeneralModule.h" // For export macro
#include "vtkPolyDataAlgorithm.h"
class vtkCellArray;
class vtkIdList;
class VTKFILTERSGENERAL_EXPORT vtkContourTriangulator : public vtkPolyDataAlgorithm
{
public:
static vtkContourTriangulator* New();
vtkTypeMacro(vtkContourTriangulator, vtkPolyDataAlgorithm);
void PrintSelf(ostream& os, vtkIndent indent) override;
//@{
/**
* Check if there was a triangulation failure in the last update.
*/
vtkGetMacro(TriangulationError, int);
//@}
//@{
/**
* Generate errors when the triangulation fails.
* Note that triangulation failures are often minor, because they involve
* tiny triangles that are too small to see.
*/
vtkSetMacro(TriangulationErrorDisplay, vtkTypeBool);
vtkBooleanMacro(TriangulationErrorDisplay, vtkTypeBool);
vtkGetMacro(TriangulationErrorDisplay, vtkTypeBool);
//@}
/**
* A robust method for triangulating a polygon.
* It cleans up the polygon and then applies the ear-cut triangulation.
* A zero return value indicates that triangulation failed.
*/
static int TriangulatePolygon(vtkIdList* polygon, vtkPoints* points, vtkCellArray* triangles);
/**
* Given some closed contour lines, create a triangle mesh that
* fills those lines. The input lines must be single-segment lines,
* not polylines. The input lines do not have to be in order.
* Only numLines starting from firstLine will be used.
*/
static int TriangulateContours(vtkPolyData* data, vtkIdType firstLine, vtkIdType numLines,
vtkCellArray* outputPolys, const double normal[3]);
protected:
vtkContourTriangulator();
~vtkContourTriangulator() override;
int RequestData(vtkInformation* request, vtkInformationVector** inputVector,
vtkInformationVector* outputVector) override;
int TriangulationError;
vtkTypeBool TriangulationErrorDisplay;
private:
vtkContourTriangulator(const vtkContourTriangulator&) = delete;
void operator=(const vtkContourTriangulator&) = delete;
};
#endif