vtkPolygon.h

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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
 
#ifndef vtkPolygon_h
#define vtkPolygon_h
 
#include "vtkCell.h"
#include "vtkCellStatus.h"            // For return type
#include "vtkCommonDataModelModule.h" // For export macro
 
VTK_ABI_NAMESPACE_BEGIN
class vtkDoubleArray;
class vtkIdTypeArray;
class vtkLine;
class vtkPoints;
class vtkQuad;
class vtkTriangle;
class vtkIncrementalPointLocator;
 
class VTKCOMMONDATAMODEL_EXPORT vtkPolygon : public vtkCell
{
public:
  static vtkPolygon* New();
  vtkTypeMacro(vtkPolygon, vtkCell);
  void PrintSelf(ostream& os, vtkIndent indent) override;


  int GetCellType() override { return VTK_POLYGON; }
  int GetCellDimension() override { return 2; }
  int GetNumberOfEdges() override { return this->GetNumberOfPoints(); }
  int GetNumberOfFaces() override { return 0; }
  vtkCell* GetEdge(int edgeId) override;
  vtkCell* GetFace(int) override { return nullptr; }
  int CellBoundary(int subId, const double pcoords[3], vtkIdList* pts) override;
  void Contour(double value, vtkDataArray* cellScalars, vtkIncrementalPointLocator* locator,
    vtkCellArray* verts, vtkCellArray* lines, vtkCellArray* polys, vtkPointData* inPd,
    vtkPointData* outPd, vtkCellData* inCd, vtkIdType cellId, vtkCellData* outCd) override;
  void Clip(double value, vtkDataArray* cellScalars, vtkIncrementalPointLocator* locator,
    vtkCellArray* tris, vtkPointData* inPd, vtkPointData* outPd, vtkCellData* inCd,
    vtkIdType cellId, vtkCellData* outCd, int insideOut) override;
  int EvaluatePosition(const double x[3], double closestPoint[3], int& subId, double pcoords[3],
    double& dist2, double weights[]) override;
  void EvaluateLocation(int& subId, const double pcoords[3], double x[3], double* weights) override;
  int IntersectWithLine(const double p1[3], const double p2[3], double tol, double& t, double x[3],
    double pcoords[3], int& subId) override;
  int TriangulateLocalIds(int index, vtkIdList* ptIds) override;
  void Derivatives(
    int subId, const double pcoords[3], const double* values, int dim, double* derivs) override;
  int IsPrimaryCell() VTK_FUTURE_CONST override { return 0; }

  double ComputeArea();

  void InterpolateFunctions(const double x[3], double* sf) override;


  static vtkCellStatus ComputeNormal(vtkPoints* p, int numPts, const vtkIdType* pts, double n[3]);
  static vtkCellStatus ComputeNormal(vtkPoints* p, double n[3]);
  static vtkCellStatus ComputeNormal(vtkIdTypeArray* ids, vtkPoints* pts, double n[3]);

  static vtkCellStatus ComputeNormal(int numPts, double* pts, double n[3]);

  bool IsConvex();


  static bool IsConvex(vtkPoints* p, int numPts, const vtkIdType* pts);
  static bool IsConvex(vtkIdTypeArray* ids, vtkPoints* p);
  static bool IsConvex(vtkPoints* p);


  static vtkCellStatus ComputeCentroid(
    vtkPoints* p, int numPts, const vtkIdType* pts, double centroid[3], double tolerance);
  static bool ComputeCentroid(vtkPoints* p, int numPts, const vtkIdType* pts, double centroid[3]);
  static bool ComputeCentroid(vtkIdTypeArray* ids, vtkPoints* pts, double centroid[3]);

  static bool ComputeInteriorCircle(
    vtkPoints* p, int numPts, const vtkIdType* ids, double center[3], double& radius2);

  static double ComputeArea(vtkPoints* p, vtkIdType numPts, const vtkIdType* pts, double normal[3]);

  int ParameterizePolygon(
    double p0[3], double p10[3], double& l10, double p20[3], double& l20, double n[3]);

  static int PointInPolygon(double x[3], int numPts, double* pts, double bounds[6], double n[3]);
 
  // Needed to remove warning "member function does not override any
  // base class virtual member function"
  int Triangulate(int index, vtkIdList* ptIds, vtkPoints* pts) override
  {
    return vtkCell::Triangulate(index, ptIds, pts);
  }

  int NonDegenerateTriangulate(vtkIdList* outTris);

  int BoundedTriangulate(vtkIdList* outTris, double tol);

  static double DistanceToPolygon(
    double x[3], int numPts, double* pts, double bounds[6], double closest[3]);

  static int IntersectPolygonWithPolygon(int npts, double* pts, double bounds[6], int npts2,
    double* pts2, double bounds2[6], double tol, double x[3]);

  static int IntersectConvex2DCells(
    vtkCell* cell1, vtkCell* cell2, double tol, double p0[3], double p1[3]);


  vtkGetMacro(UseMVCInterpolation, bool);
  vtkSetMacro(UseMVCInterpolation, bool);


  vtkSetClampMacro(Tolerance, double, 0.0, 1.0);
  vtkGetMacro(Tolerance, double);
 
protected:
  vtkPolygon();
  ~vtkPolygon() override;
 
  // Compute the interpolation functions using Mean Value Coordinate.
  void InterpolateFunctionsUsingMVC(const double x[3], double* weights);
 
  // variables used by instances of this class
  double Tolerance;        // Intersection tolerance set by public API
  double Tol;              // Internal tolerance set by ComputeBounds()
  void ComputeTolerance(); // Compute the internal tolerance Tol
 
  int SuccessfulTriangulation; // Stops recursive triangulation if necessary
  vtkIdList* Tris;             // Output triangulation placed here
 
  // These are used for internal computation.
  vtkTriangle* Triangle;
  vtkQuad* Quad;
  vtkDoubleArray* TriScalars;
  vtkLine* Line;
 
  // Parameter indicating whether to use Mean Value Coordinate algorithm
  // for interpolation. The parameter is false by default.
  bool UseMVCInterpolation;
 
  // Helper methods for triangulation------------------------------
  // Made public for external access
public:
  // Ear cut triangulation options. The order in which vertices are
  // removed are controlled by different measures. Changing this can
  // make subtle differences in some cases. Historically the
  // PERIMETER2_TO_AREA_RATIO has been used.
  enum EarCutMeasureTypes
  {
    PERIMETER2_TO_AREA_RATIO = 0,
    DOT_PRODUCT = 1,
    BEST_QUALITY = 2
  };


  int EarCutTriangulation(int measure = PERIMETER2_TO_AREA_RATIO);
  int EarCutTriangulation(vtkIdList* outTris, int measure = PERIMETER2_TO_AREA_RATIO);


  int UnbiasedEarCutTriangulation(int seed, int measure = PERIMETER2_TO_AREA_RATIO);
  int UnbiasedEarCutTriangulation(
    int seed, vtkIdList* outTris, int measure = PERIMETER2_TO_AREA_RATIO);
 
private:
  vtkPolygon(const vtkPolygon&) = delete;
  void operator=(const vtkPolygon&) = delete;
};
 
VTK_ABI_NAMESPACE_END
#endif