/*=========================================================================

  Program:   Visualization Toolkit
  Module:    vtkFlyingEdges3D.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.

=========================================================================*/
// .NAME vtkFlyingEdges3D - generate isosurface from 3D image data (volume)
// .SECTION Description
// vtkFlyingEdges3D is a reference implementation of the 3D version of the
// flying edges algorithm. It is designed to be highly scalable (i.e.,
// parallelizable) for large data. It implements certain performance
// optimizations including computational trimming to rapidly eliminate
// processing of data regions, packed bit representation of case table
// values, single edge intersection, elimination of point merging, and
// elimination of any reallocs (due to dynamic data insertion). Note that
// computational trimming is a method to reduce total computational cost in
// which partial computational results can be used to eliminate future
// computations.
//
// This is a four-pass algorithm. The first pass processes all x-edges and
// builds x-edge case values (which, when the four x-edges defining a voxel
// are combined, are equivalent to vertex-based case table except edge-based
// approaches are separable in support of parallel computing). Next x-voxel
// rows are processed to gather information from yz-edges (basically to count
// the number of y-z edge intersections and triangles generated). In the third
// pass a prefix sum is used to count and allocate memory for the output
// primitives. Finally in the fourth pass output primitives are generated into
// pre-allocated arrays. This implementation uses voxel cell axes (a x-y-z
// triad located at the voxel origin) to ensure that each edge is intersected
// at most one time. Note that this implementation also reuses the VTK
// Marching Cubes case table, although the vertex-based MC table is
// transformed into an edge-based table on object instantiation.
//
// See the paper "Flying Edges: A High-Performance Scalable Isocontouring
// Algorithm" by Schroeder, Maynard, Geveci. Proc. of LDAV 2015. Chicago, IL.

// .SECTION Caveats
// This filter is specialized to 3D volumes. This implementation can produce
// degenerate triangles (i.e., zero-area triangles).
//
// 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.

// .SECTION See Also
// vtkContourFilter vtkFlyingEdges2D vtkSynchronizedTemplates3D
// vtkMarchingCubes vtkSMPFlyingEdges3D

#ifndef vtkFlyingEdges3D_h
#define vtkFlyingEdges3D_h

#include "vtkFiltersCoreModule.h" // For export macro
#include "vtkPolyDataAlgorithm.h"
#include "vtkContourValues.h" // Passes calls through

class vtkImageData;

class VTKFILTERSCORE_EXPORT vtkFlyingEdges3D : public vtkPolyDataAlgorithm
{
public:
  static vtkFlyingEdges3D *New();
  vtkTypeMacro(vtkFlyingEdges3D,vtkPolyDataAlgorithm);
  void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Because we delegate to vtkContourValues.
  unsigned long int GetMTime();

  // Description:
  // Set/Get the computation of normals. Normal computation is fairly
  // expensive in both time and storage. If the output data will be processed
  // by filters that modify topology or geometry, it may be wise to turn
  // Normals and Gradients off.
  vtkSetMacro(ComputeNormals,int);
  vtkGetMacro(ComputeNormals,int);
  vtkBooleanMacro(ComputeNormals,int);

  // Description:
  // Set/Get the computation of gradients. Gradient computation is fairly
  // expensive in both time and storage. Note that if ComputeNormals is on,
  // gradients will have to be calculated, but will not be stored in the
  // output dataset. If the output data will be processed by filters that
  // modify topology or geometry, it may be wise to turn Normals and
  // Gradients off.
  vtkSetMacro(ComputeGradients,int);
  vtkGetMacro(ComputeGradients,int);
  vtkBooleanMacro(ComputeGradients,int);

  // Description:
  // Set/Get the computation of scalars.
  vtkSetMacro(ComputeScalars,int);
  vtkGetMacro(ComputeScalars,int);
  vtkBooleanMacro(ComputeScalars,int);

  // Description:
  // Set a particular contour value at contour number i. The index i ranges
  // between 0<=i<NumberOfContours.
  void SetValue(int i, double value) {this->ContourValues->SetValue(i,value);}

  // Description:
  // Get the ith contour value.
  double GetValue(int i) {return this->ContourValues->GetValue(i);}

  // Description:
  // Get a pointer to an array of contour values. There will be
  // GetNumberOfContours() values in the list.
  double *GetValues() {return this->ContourValues->GetValues();}

  // Description:
  // Fill a supplied list with contour values. There will be
  // GetNumberOfContours() values in the list. Make sure you allocate
  // enough memory to hold the list.
  void GetValues(double *contourValues) {
    this->ContourValues->GetValues(contourValues);}

  // Description:
  // Set the number of contours to place into the list. You only really
  // need to use this method to reduce list size. The method SetValue()
  // will automatically increase list size as needed.
  void SetNumberOfContours(int number) {
    this->ContourValues->SetNumberOfContours(number);}

  // Description:
  // Get the number of contours in the list of contour values.
  int GetNumberOfContours() {
    return this->ContourValues->GetNumberOfContours();}

  // Description:
  // Generate numContours equally spaced contour values between specified
  // range. Contour values will include min/max range values.
  void GenerateValues(int numContours, double range[2]) {
    this->ContourValues->GenerateValues(numContours, range);}

  // Description:
  // Generate numContours equally spaced contour values between specified
  // range. Contour values will include min/max range values.
  void GenerateValues(int numContours, double rangeStart, double rangeEnd)
    {this->ContourValues->GenerateValues(numContours, rangeStart, rangeEnd);}

  // Description:
  // Set/get which component of the scalar array to contour on; defaults to 0.
  vtkSetMacro(ArrayComponent, int);
  vtkGetMacro(ArrayComponent, int);

protected:
  vtkFlyingEdges3D();
  ~vtkFlyingEdges3D();

  int ComputeNormals;
  int ComputeGradients;
  int ComputeScalars;
  int ArrayComponent;
  vtkContourValues *ContourValues;

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

private:
  vtkFlyingEdges3D(const vtkFlyingEdges3D&);  // Not implemented.
  void operator=(const vtkFlyingEdges3D&);  // Not implemented.
};

#endif
