// SPDX-FileCopyrightText: Copyright (c) Ken Martin, Will Schroeder, Bill Lorensen
// SPDX-FileCopyrightText: Copyright (c) 2000 - 2009, Lawrence Livermore National Security, LLC
// SPDX-License-Identifier: BSD-3-Clause

/**
 * @class   vtkTableBasedClipDataSet
 * @brief   Clip any dataset with a user-specified
 *  implicit function or an input scalar point data array.
 *
 *
 *  vtkTableBasedClipDataSet is a filter that clips any type of dataset using
 *  either any subclass of vtkImplicitFunction or an input scalar point data
 *  array. Clipping means that it actually "cuts" through the cells of the
 *  dataset, returning everything outside the specified implicit function (or
 *  greater than the scalar value) including "pieces" of a cell (Note to compare
 *  this with vtkExtractGeometry, which pulls out entire, uncut cells). The
 *  output of this filter is a vtkUnstructuredGrid data.
 *
 *  To use this filter, you need to decide whether an implicit function or an
 *  input scalar point data array is used for clipping. For the former case,
 *  1) define an implicit function
 *  2) provide it to this filter via SetClipFunction()
 *  If a clipping function is not specified, or GenerateClipScalars is off( the
 *  default), the input scalar point data array is then employed for clipping.
 *
 *  You can also specify a scalar (iso-)value, which is used to decide what is
 *  inside and outside the implicit function. You can also reverse the sense of
 *  what inside/outside is by setting the InsideOut variable. The clipping algorithm
 *  proceeds by computing an implicit function value or using the input scalar
 *  point data value for each point in the dataset. This is compared against the
 *  scalar (iso-)value to determine the inside/outside status.
 *
 *  Although this filter sometimes (but rarely) may resort to the sibling class
 *  vtkClipDataSet for handling some special grids (such as cylinders or cones
 *  with capping faces in the form of a vtkPolyData), it itself is able to deal
 *  with most grids. It is worth mentioning that vtkTableBasedClipDataSet is
 *  capable of addressing the artifacts that may occur with vtkClipDataSet due
 *  to the possibly inconsistent triangulation modes between neighboring cells.
 *  In addition, the former is much faster than the latter. Furthermore, the
 *  former produces less cells (with ratio usually being 5~6) than by the latter
 *  in the output. In other words, this filter retains the original cells (i.e.,
 *  without triangulation / tetrahedralization) wherever possible. All these
 *  advantages are gained by adopting the unique clipping and triangulation tables
 *  proposed by VisIt.
 *
 * @warning
 *  vtkTableBasedClipDataSet makes use of an hash table for edges using the
 *  vtkStaticEdgeLocatorTemplate class to detect unique edges and eliminate duplicate
 *  points. The hash-based mechanism simply compares the point Ids, without considering
 *  the actual inter-point distance (vtkClipDataSet adopts vtkMergePoints that though
 *  considers the inter-point distance for robust points merging ). As a result, some
 *  duplicate points may be present in the output. This problem occurs when some boundary
 *  (cut-through cells) happen to have faces EXACTLY aligned with the clipping plane
 *  (such as Plane, Box, or other implicit functions with planar shapes). The occurrence
 *  (though very rare) of duplicate points produces degenerate cells, which can be fixed
 *  by post-processing the output with a filter like vtkCleanGrid.
 *
 * @warning
 * This class has been threaded with vtkSMPTools. Using TBB or other
 * non-sequential type (set in the CMake variable
 * VTK_SMP_IMPLEMENTATION_TYPE) may improve performance significantly.
 *
 * @par Thanks:
 *  This filter was adapted from the VisIt clipper (vtkVisItClipper).
 *
 * @par An Accelerated Clip Algorithm for Unstructured Meshes: A Batch-Driven Approach,
 * Tsalikis, Spiros and Schroeder, Will and Szafir, Daniel and Moreland, Kenneth,
 * Eurographics Symposium on Parallel Graphics and Visualization, 2024
 *
 * @sa
 *  vtkClipDataSet vtkClipVolume vtkClipPolyData vtkCutter vtkImplicitFunction
 */

#ifndef vtkTableBasedClipDataSet_h
#define vtkTableBasedClipDataSet_h

#include "vtkFiltersGeneralModule.h"    // For export macro
#include "vtkIncrementalPointLocator.h" // For vtkIncrementalPointLocator
#include "vtkUnstructuredGridAlgorithm.h"
#include "vtkWeakPointer.h" // Needed for weak pointer to the vtkIncrementalPointLocator

VTK_ABI_NAMESPACE_BEGIN
class vtkCallbackCommand;
class vtkDoubleArray;
class vtkImplicitFunction;
class vtkPolyData;

class VTKFILTERSGENERAL_EXPORT vtkTableBasedClipDataSet : public vtkUnstructuredGridAlgorithm
{
public:
  vtkTypeMacro(vtkTableBasedClipDataSet, vtkUnstructuredGridAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent) override;

  /**
   * Create an instance with a user-specified implicit function, turning off
   * IVARs InsideOut and GenerateClipScalars and setting IVAR Value to 0.0.
   */
  static vtkTableBasedClipDataSet* New();

  /**
   * Get the MTime for which the clip function are considered.
   */
  vtkMTimeType GetMTime() override;

  ///@{
  /**
   * Set/Get the InsideOut flag. With this flag off, a vertex is considered
   * inside (the implicit function or the isosurface) if the (function or scalar)
   * value is greater than IVAR Value. With this flag on, a vertex is considered
   * inside (the implicit function or the isosurface) if the (function or scalar)
   * value is less than or equal to IVAR Value. This flag is off by default.
   */
  vtkSetMacro(InsideOut, vtkTypeBool);
  vtkGetMacro(InsideOut, vtkTypeBool);
  vtkBooleanMacro(InsideOut, vtkTypeBool);
  ///@}

  ///@{
  /**
   * Set/Get the clipping value of the implicit function (if an implicit function
   * is applied) or scalar data array (if a scalar data array is used), with 0.0
   * as the default value. This value is ignored if flag UseValueAsOffset is true
   * AND a clip function is defined.
   */
  vtkSetMacro(Value, double);
  vtkGetMacro(Value, double);
  ///@}

  ///@{
  /**
   * Set/Get flag UseValueAsOffset, with true as the default value. With this flag
   * on, IVAR Value is used as an offset parameter to the implicit function. Value
   * is used only when clipping using a scalar array.
   */
  vtkSetMacro(UseValueAsOffset, bool);
  vtkGetMacro(UseValueAsOffset, bool);
  vtkBooleanMacro(UseValueAsOffset, bool);
  ///@}

  ///@{
  /**
   * Set/Get the implicit function with which to perform the clipping operation.
   * Unless an implicit function is defined, the specified input scalar data will
   * be used for clipping.
   */
  virtual void SetClipFunction(vtkImplicitFunction*);
  vtkGetObjectMacro(ClipFunction, vtkImplicitFunction);
  ///@}

  ///@{
  /**
   * Set/Get flag GenerateClipScalars, with 0 as the default value. With this
   * flag on, the scalar point data values obtained by evaluating the implicit
   * function will be exported to the output. Note that this flag requiries that
   * an implicit function be provided.
   */
  vtkSetMacro(GenerateClipScalars, vtkTypeBool);
  vtkGetMacro(GenerateClipScalars, vtkTypeBool);
  vtkBooleanMacro(GenerateClipScalars, vtkTypeBool);
  ///@}

  ///@{
  /**
   * Set/Get whether to generate the class of output points.
   * 0 -> input point
   * 1 -> edge point
   * 2 -> centroid point
   *
   * Default is false.
   */
  vtkSetMacro(GenerateClipPointTypes, bool);
  vtkGetMacro(GenerateClipPointTypes, bool);
  vtkBooleanMacro(GenerateClipPointTypes, bool);
  ///@}

  ///@{
  /**
   * Set/Get the tolerance used for merging duplicate points near the clipping
   * intersection cells. This tolerance may prevent the generation of degenerate
   * primitives. Note that only 3D cells actually use this IVAR when vtkClipDataSet
   * is invoked as last resort.
   */
  vtkSetClampMacro(MergeTolerance, double, 0.0001, 0.25);
  vtkGetMacro(MergeTolerance, double);
  ///@}

  ///@{
  /**
   * Set/Get whether a second output is generated. The second output contains the
   * polygonal data that is clipped away by the iso-surface.
   */
  vtkSetMacro(GenerateClippedOutput, vtkTypeBool);
  vtkGetMacro(GenerateClippedOutput, vtkTypeBool);
  vtkBooleanMacro(GenerateClippedOutput, vtkTypeBool);
  ///@}

  /**
   * Return the clipped output.
   */
  vtkUnstructuredGrid* GetClippedOutput();

  ///@{
  /**
   * Set/get the desired precision for the output types. See the documentation
   * for the vtkAlgorithm::Precision enum for an explanation of the available
   * precision settings.
   */
  vtkSetClampMacro(OutputPointsPrecision, int, SINGLE_PRECISION, DEFAULT_PRECISION);
  vtkGetMacro(OutputPointsPrecision, int);
  ///@}

  ///@{
  /**
   * Specify the number of input cells in a batch, where a batch defines
   * a subset of the input cells operated on during threaded
   * execution. Generally this is only used for debugging or performance
   * studies (since batch size affects the thread workload).
   *
   * Default is 1000.
   */
  vtkSetClampMacro(BatchSize, unsigned int, 1, VTK_INT_MAX);
  vtkGetMacro(BatchSize, unsigned int);
  ///@}

  ///@{
  /**
   * Specify a spatial locator for merging points.
   * Forwarded to vtkClipDataSet.
   */
  void SetLocator(vtkIncrementalPointLocator* locator);
  vtkGetObjectMacro(Locator, vtkIncrementalPointLocator);
  ///@}

protected:
  vtkTableBasedClipDataSet(vtkImplicitFunction* cf = nullptr);
  ~vtkTableBasedClipDataSet() override;

  int RequestData(vtkInformation*, vtkInformationVector**, vtkInformationVector*) override;
  int FillInputPortInformation(int port, vtkInformation* info) override;

private:
  /**
   * This function resorts to the sibling class vtkClipDataSet to handle
   * special grids (such as cylinders or cones with capping faces in the
   * form a vtkPolyData).
   */
  void ClipDataSet(vtkDataSet* pDataSet, vtkUnstructuredGrid* outputUG);

  /**
   * This function clips a vtkPolyData object based on a specified iso-value
   * (isoValue) using a scalar point data array that is either just an
   * input scalar point data array or the result of evaluating an implicit function
   * (provided via SetClipFunction()). The clipping result is exported to outputUG.
   */
  void ClipPolyData(vtkPolyData* inputGrid, vtkImplicitFunction* implicitFunction,
    vtkDoubleArray* scalars, double isoValue, vtkUnstructuredGrid* outputUG);

  /**
   * This function clips a DataSet based on a specified iso-value
   * (isoValue) using a scalar point data array that is either just an
   * input scalar point data array or the result of evaluating an implicit function
   * (provided via SetClipFunction()). The clipping result is exported to outputUG.
   */
  template <class TGrid>
  void ClipTDataSet(TGrid* inputGrid, vtkImplicitFunction* implicitFunction,
    vtkDoubleArray* scalars, double isoValue, vtkUnstructuredGrid* outputUG);

  /**
   * This function handles the actual steps of the clipping operation.
   */
  template <typename TGrid, typename TInputIdType, bool InsideOut>
  vtkSmartPointer<vtkUnstructuredGrid> ClipTDataSet(
    TGrid* input, vtkImplicitFunction* implicitFunction, vtkDoubleArray* scalars, double isoValue);

  /**
   * Register a callback function with the InternalProgressObserver.
   */
  static void InternalProgressCallbackFunction(vtkObject*, unsigned long, void* clientdata, void*);

  /**
   * The actual operation executed by the callback function.
   */
  void InternalProgressCallback(vtkAlgorithm* algorithm);

protected:
  vtkTypeBool InsideOut;
  vtkTypeBool GenerateClipScalars;
  vtkTypeBool GenerateClippedOutput;
  bool UseValueAsOffset;
  double Value;
  double MergeTolerance;
  vtkCallbackCommand* InternalProgressObserver;
  vtkImplicitFunction* ClipFunction;
  unsigned int BatchSize;

  int OutputPointsPrecision;

  vtkWeakPointer<vtkIncrementalPointLocator> Locator;

private:
  vtkTableBasedClipDataSet(const vtkTableBasedClipDataSet&) = delete;
  void operator=(const vtkTableBasedClipDataSet&) = delete;

  bool GenerateClipPointTypes;
};

VTK_ABI_NAMESPACE_END
#endif
