text: /*=========================================================================
  
    Program:   Visualization Toolkit
    Module:    vtkCompositeInterpolatedVelocityField.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   vtkCompositeInterpolatedVelocityField
   * @brief   An abstract class for
   *  obtaining the interpolated velocity values at a point
   *
   *  vtkCompositeInterpolatedVelocityField acts as a continuous velocity field
   *  by performing cell interpolation on one or more underlying vtkDataSets. That is,
   *  composite datasets are combined to create a continuous velocity field.
   *
   * @warning
   *  vtkCompositeInterpolatedVelocityField is not thread safe. A new instance
   *  should be created by each thread.
   *
   * @sa
   *  vtkInterpolatedVelocityField vtkCellLocatorInterpolatedVelocityField
   *  vtkGenericInterpolatedVelocityField vtkCachingInterpolatedVelocityField
   *  vtkTemporalInterpolatedVelocityField vtkFunctionSet vtkStreamTracer
   */
  
  #ifndef vtkCompositeInterpolatedVelocityField_h
  #define vtkCompositeInterpolatedVelocityField_h
  
  #include "vtkAbstractInterpolatedVelocityField.h"
  #include "vtkFiltersFlowPathsModule.h" // For export macro
  
  #include <vector> // STL Header; Required for vector
  
  class vtkDataSet;
  class vtkDataArray;
  class vtkPointData;
  class vtkGenericCell;
  class vtkCompositeInterpolatedVelocityFieldDataSetsType;
  
  class VTKFILTERSFLOWPATHS_EXPORT vtkCompositeInterpolatedVelocityField
    : public vtkAbstractInterpolatedVelocityField
  {
  public:
    vtkTypeMacro(vtkCompositeInterpolatedVelocityField, vtkAbstractInterpolatedVelocityField);
    void PrintSelf(ostream& os, vtkIndent indent) override;
  
    /**
     * Add a dataset for implicit velocity function evaluation. If more than
     * one dataset is added, the evaluation point is searched in all until a
     * match is found. THIS FUNCTION DOES NOT CHANGE THE REFERENCE COUNT OF
     * dataset FOR THREAD SAFETY REASONS.
     */
    virtual void AddDataSet(vtkDataSet* dataset) = 0;
  
    ///@{
    /**
     * Get the most recently visited dataset and its id. The dataset is used
     * for a guess regarding where the next point will be, without searching
     * through all datasets. When setting the last dataset, care is needed as
     * no reference counting or checks are performed. This feature is intended
     * for custom interpolators only that cache datasets independently.
     */
    vtkGetMacro(LastDataSetIndex, int);
    ///@}
  
    /**
     * Copy essential parameters between instances of this class. See
     * vtkAbstractInterpolatedVelocityField for more information.
     */
    void CopyParameters(vtkAbstractInterpolatedVelocityField* from) override;
  
  protected:
    vtkCompositeInterpolatedVelocityField();
    ~vtkCompositeInterpolatedVelocityField() override;
  
    int LastDataSetIndex;
    vtkCompositeInterpolatedVelocityFieldDataSetsType* DataSets;
  
  private:
    vtkCompositeInterpolatedVelocityField(const vtkCompositeInterpolatedVelocityField&) = delete;
    void operator=(const vtkCompositeInterpolatedVelocityField&) = delete;
  };
  
  typedef std::vector<vtkDataSet*> DataSetsTypeBase;
  class vtkCompositeInterpolatedVelocityFieldDataSetsType : public DataSetsTypeBase
  {
  };
  
  #endif
  