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  // ************************************************************************* //
  //                              avtRayCompositer.h                           //
  // ************************************************************************* //
  
  #ifndef AVT_RAY_COMPOSITER_H
  #define AVT_RAY_COMPOSITER_H
  
  #include <filters_exports.h>
  
  #include <avtSamplePointsToImageFilter.h>
  
  #define BACKGROUND_SOLID           0
  #define BACKGROUND_GRADIENT_TB     1
  #define BACKGROUND_GRADIENT_BT     2
  #define BACKGROUND_GRADIENT_LR     3
  #define BACKGROUND_GRADIENT_RL     4
  #define BACKGROUND_GRADIENT_RADIAL 5
  
  class  avtRayFunction;
  class  avtPixelizer;
  
  
  // ****************************************************************************
  //  Class: avtRayCompositer
  //
  //  Purpose:
  //      Composites rays from sample points.  The output is an avtImage.
  //
  //  Programmer: Hank Childs
  //  Creation:   December 4, 2000
  //
  //  Modifications:
  //
  //    Hank Childs, Sat Feb  3 20:17:20 PST 2001
  //    Remove dependence on pixelizers.
  //
  //    Hank Childs, Tue Feb 13 15:15:50 PST 2001
  //    Allowed for opaque images to be inserted in to volume rendering.
  //
  //    Brad Whitlock, Wed Dec 5 10:32:35 PDT 2001
  //    Added methods to draw the background.
  //
  // ****************************************************************************
  
  class AVTFILTERS_API avtRayCompositer : public avtSamplePointsToImageFilter
  {
    public:
                            avtRayCompositer(avtRayFunction *);
  
      virtual const char   *GetType(void) { return "avtRayCompositer"; };
      virtual const char   *GetDescription(void) 
                                               { return "Compositing samples"; };
      void                  SetBackgroundColor(const unsigned char [3]);
      void                  SetBackgroundMode(int mode);
      void                  SetGradientBackgroundColors(const double [3],
                                                        const double [3]);
      void                  InsertOpaqueImage(avtImage_p);
      void                  UpdateCompositeProgress(int, int);
  
    protected:
      avtRayFunction       *rayfoo;
      int                   backgroundMode;
      unsigned char         background[3];
      double                gradBG1[3];
      double                gradBG2[3];
      avtImage_p            opaqueImage;
  
      virtual void          Execute(void);
      void                  FillBackground(unsigned char *, int, int);
      void                  DrawRadialGradient(unsigned char *, int, int);
  };
  
  
  #endif
  
  
  