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

  Program:   Visualization Toolkit
  Module:    vtkUnstructuredGridHomogeneousRayIntegrator.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.

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

/*
 * Copyright 2004 Sandia Corporation.
 * Under the terms of Contract DE-AC04-94AL85000, there is a non-exclusive
 * license for use of this work by or on behalf of the
 * U.S. Government. Redistribution and use in source and binary forms, with
 * or without modification, are permitted provided that this Notice and any
 * statement of authorship are reproduced on all copies.
 */

/**
 * @class   vtkUnstructuredGridHomogeneousRayIntegrator
 * @brief   performs piecewise constant ray integration.
 *
 *
 *
 * vtkUnstructuredGridHomogeneousRayIntegrator performs homogeneous ray
 * integration.  This is a good method to use when volume rendering scalars
 * that are defined on cells.
 *
 */

#ifndef vtkUnstructuredGridHomogeneousRayIntegrator_h
#define vtkUnstructuredGridHomogeneousRayIntegrator_h

#include "vtkRenderingVolumeModule.h" // For export macro
#include "vtkUnstructuredGridVolumeRayIntegrator.h"

class vtkVolumeProperty;

class VTKRENDERINGVOLUME_EXPORT vtkUnstructuredGridHomogeneousRayIntegrator
  : public vtkUnstructuredGridVolumeRayIntegrator
{
public:
  vtkTypeMacro(vtkUnstructuredGridHomogeneousRayIntegrator, vtkUnstructuredGridVolumeRayIntegrator);
  static vtkUnstructuredGridHomogeneousRayIntegrator* New();
  void PrintSelf(ostream& os, vtkIndent indent) override;

  void Initialize(vtkVolume* volume, vtkDataArray* scalars) override;

  void Integrate(vtkDoubleArray* intersectionLengths, vtkDataArray* nearIntersections,
    vtkDataArray* farIntersections, float color[4]) override;

  ///@{
  /**
   * For quick lookup, the transfer function is sampled into a table.
   * This parameter sets how big of a table to use.  By default, 1024
   * entries are used.
   */
  vtkSetMacro(TransferFunctionTableSize, int);
  vtkGetMacro(TransferFunctionTableSize, int);
  ///@}

protected:
  vtkUnstructuredGridHomogeneousRayIntegrator();
  ~vtkUnstructuredGridHomogeneousRayIntegrator() override;

  vtkVolume* Volume;
  vtkVolumeProperty* Property;

  int NumComponents;
  float** ColorTable;
  float** AttenuationTable;
  double* TableShift;
  double* TableScale;
  vtkTimeStamp TablesBuilt;

  int UseAverageColor;
  int TransferFunctionTableSize;

  virtual void GetTransferFunctionTables(vtkDataArray* scalars);

private:
  vtkUnstructuredGridHomogeneousRayIntegrator(
    const vtkUnstructuredGridHomogeneousRayIntegrator&) = delete;
  void operator=(const vtkUnstructuredGridHomogeneousRayIntegrator&) = delete;
};

#endif // vtkUnstructuredGridHomogeneousRayIntegrator_h
