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

  Program:   Visualization Toolkit
  Module:    vtkVolumeRayCastCompositeFunction.h
  Language:  C++
  Date:      $Date$
  Version:   $Revision$


Copyright (c) 1993-2000 Ken Martin, Will Schroeder, Bill Lorensen 
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 * Neither name of Ken Martin, Will Schroeder, or Bill Lorensen nor the names
   of any contributors may be used to endorse or promote products derived
   from this software without specific prior written permission.

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=========================================================================*/
// .NAME vtkVolumeRayCastCompositeFunction - a ray function for compositing

// .SECTION Description
// vtkVolumeRayCastCompositeFunction is a ray function that can be used
// within a vtkVolumeRayCastMapper. This function performs compositing along
// the ray according to the properties stored in the vtkVolumeProperty for
// the volume. 

// .SECTION See Also
// vtkVolumeRayCastMapper vtkVolumeProperty vtkVolume

#ifndef __vtkVolumeRayCastCompositeFunction_h
#define __vtkVolumeRayCastCompositeFunction_h

#include "vtkVolumeRayCastFunction.h"

#define VTK_COMPOSITE_CLASSIFY_FIRST 0
#define VTK_COMPOSITE_INTERPOLATE_FIRST 1

class VTK_EXPORT vtkVolumeRayCastCompositeFunction : public vtkVolumeRayCastFunction
{
public:
  static vtkVolumeRayCastCompositeFunction *New();
  vtkTypeMacro(vtkVolumeRayCastCompositeFunction,vtkVolumeRayCastFunction);
  void PrintSelf( ostream& os, vtkIndent index );

  // Description:
  // Set the CompositeMethod to either Classify First or Interpolate First
  vtkSetClampMacro( CompositeMethod, int,
        VTK_COMPOSITE_CLASSIFY_FIRST, VTK_COMPOSITE_INTERPOLATE_FIRST );
  vtkGetMacro(CompositeMethod,int);
  void SetCompositeMethodToInterpolateFirst()
    {this->SetCompositeMethod(VTK_COMPOSITE_INTERPOLATE_FIRST);}
  void SetCompositeMethodToClassifyFirst() 
    {this->SetCompositeMethod(VTK_COMPOSITE_CLASSIFY_FIRST);}
  char *GetCompositeMethodAsString(void);

//BTX
  void CastRay( VTKRayCastRayInfo *rayInfo,
		VTKRayCastVolumeInfo *volumeInfo);

  float GetZeroOpacityThreshold( vtkVolume *vol );
//ETX

protected:
  vtkVolumeRayCastCompositeFunction();
  ~vtkVolumeRayCastCompositeFunction();
  vtkVolumeRayCastCompositeFunction(const vtkVolumeRayCastCompositeFunction&) {};
  void operator=(const vtkVolumeRayCastCompositeFunction&) {};

//BTX
  void SpecificFunctionInitialize( vtkRenderer *ren,
				   vtkVolume   *vol,
				   VTKRayCastVolumeInfo *volumeInfo,
				   vtkVolumeRayCastMapper *mapper );
//ETX
  
  int           CompositeMethod;
};


#endif
