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

  Program:   Visualization Toolkit
  Module:    $RCSfile: vtkUnstructuredGridVolumeRayIntegrator.h,v $

  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 vtkUnstructuredGridVolumeRayIntegrator - a superclass for volume ray integration functions

// .SECTION Description
//
// vtkUnstructuredGridVolumeRayIntegrator is a superclass for ray
// integration functions that can be used within a
// vtkUnstructuredGridVolumeRayCastMapper.
//
// .SECTION See Also
// vtkUnstructuredGridVolumeRayCastMapper
// vtkUnstructuredGridVolumeRayCastFunction

#ifndef __vtkUnstructuredGridVolumeRayIntegrator_h
#define __vtkUnstructuredGridVolumeRayIntegrator_h

#include "vtkObject.h"

class vtkVolume;
class vtkDoubleArray;
class vtkDataArray;

class VTK_VOLUMERENDERING_EXPORT vtkUnstructuredGridVolumeRayIntegrator : public vtkObject
{
public:
  vtkTypeRevisionMacro(vtkUnstructuredGridVolumeRayIntegrator,vtkObject);
  virtual void PrintSelf(ostream& os, vtkIndent indent);

  // Description:
  // Set up the integrator with the given properties and scalars.
  virtual void Initialize(vtkVolume *volume,
                          vtkDataArray* scalars) = 0;

  // Description:
  // Given a set of intersections (defined by the three arrays), compute
  // the peicewise integration of the array in front to back order.
  // /c intersectionLengths holds the lengths of each peicewise segment.
  // /c nearIntersections and /c farIntersections hold the scalar values at
  // the front and back of each segment.  /c color should contain the RGBA
  // value of the volume in front of the segments passed in, and the result
  // will be placed back into /c color.
  virtual void Integrate(vtkDoubleArray *intersectionLengths,
                         vtkDataArray *nearIntersections,
                         vtkDataArray *farIntersections,
                         float color[4]) = 0;

protected:
  vtkUnstructuredGridVolumeRayIntegrator();
  ~vtkUnstructuredGridVolumeRayIntegrator();

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

#endif