vtkIntersectionCounter.h

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// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-License-Identifier: BSD-3-Clause
 
#ifndef vtkIntersectionCounter_h
#define vtkIntersectionCounter_h
 
#include "vtkCommonDataModelModule.h" // For export macro
#include "vtkSystemIncludes.h"
#include <algorithm> // for sorting
#include <vector>    // for implementation
 
// class VTKCOMMONDATAMODEL_EXPORT vtkIntersectionCounter
 
VTK_ABI_NAMESPACE_BEGIN
class vtkIntersectionCounter
{
public:

  vtkIntersectionCounter()
    : Tolerance(0.0001)
  {
  }
  vtkIntersectionCounter(double tol, double length)
  {
    this->Tolerance = (length > 0.0 ? (tol / length) : 0.0);
  }


  void SetTolerance(double tol) { this->Tolerance = (tol < 0.0 ? 0.0001 : tol); }
  double GetTolerance() { return this->Tolerance; }

  void AddIntersection(double t) { IntsArray.push_back(t); }

  void Reset() { IntsArray.clear(); }

  int CountIntersections()
  {
    int size = static_cast<int>(IntsArray.size());
 
    // Fast check for trivial cases
    if (size <= 1)
    {
      return size; // 0 or 1
    }
 
    // Need to work harder: sort and then count the intersections
    std::sort(IntsArray.begin(), IntsArray.end());
 
    // If here, there is at least one intersection, and two inserted
    // intersection points
    int numInts = 1;
    std::vector<double>::iterator i0 = IntsArray.begin();
    std::vector<double>::iterator i1 = i0 + 1;
 
    // Now march through sorted array counting "separated" intersections
    while (i1 != IntsArray.end())
    {
      if ((*i1 - *i0) > this->Tolerance)
      {
        numInts++;
        i0 = i1;
      }
      i1++;
    }
 
    return numInts;
  }
 
protected:
  double Tolerance;
  std::vector<double> IntsArray;
 
}; // vtkIntersectionCounter
 
VTK_ABI_NAMESPACE_END
#endif
// VTK-HeaderTest-Exclude: vtkIntersectionCounter.h