/*===========================================================================*\
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*                              OpenFlipper                                   *
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/*===========================================================================*\
*                                                                            *
*   $Revision$                                                       *
*   $LastChangedBy$                                                *
*   $Date$                     *
*                                                                            *
\*===========================================================================*/

#ifndef VIEWOBJECTMARKER_HH
#define VIEWOBJECTMARKER_HH

//== INCLUDES =================================================================
#include <ACG/Math/VectorT.hh>

//== FORWARDDECLARATIONS ======================================================

class BaseObject;

//== CLASS DEFINITION =========================================================


/** \class ViewObjectMarker ViewObjectMarker.hh <OpenFlipper/BasePlugin/ViewObjectMarker.hh>

    Abstract base class to mark objects with help of the stencil buffer

    This system allows to blend the rendered object with a color,
    to visualize different object properties/states.

    The ViewObjectMarker class can be activated for a examiner. The examiner will
    then call stencilRefForObject for each object. If stencilRefForObject returns
    "true" then the object _obj will be painted with the stencil buffer
    reference _reference (has to be != 0).

    There are 2 oparation modes

    PerNumber:
      The examiner will call blendForStencilRefNumber for each of the
      returned references of stencilRefForObject to ask for the blend values.

    PerBit:
      The examiner will call blendForStencilRefNumberBit for each of the bits
      in the returned references of stencilRefForObject to ask for the blend values.

      PerBit handling allows to blend the object multiple times with different blend
      values, to visualze multiple properties at once, but is limited to the number
      of bits avaiable in the stencil buffer (usually 8).

 **/

class DLLEXPORT ViewObjectMarker
{
//-------------------------------------------------------------- public methods
public:

  //--------------------------------------------------- destructor

  /// Blending type for this marker
  enum Type {
    /// Mark per returned reference
    PerNumber,
    /// Mark per returned reference bits
    PerBit
  };

  /// Destructor.
  virtual ~ViewObjectMarker () {};

  virtual Type type () { return PerNumber; };

  /** Get stencil reference for object
    @param _obj Object
    @param _reference stencil reference for object painting
    @return should the reference be used
  */
  virtual bool stencilRefForObject (BaseObjectData *_obj, GLuint &_reference) = 0;

  /** Per reference number blending values
    @param _reference stencil reference for blending
    @param _src sfactor parameter for glBlendFunc function
    @param _dst dfactor parameter for glBlendFunc function
    @param _color color used for blending
    @return should blending be berformed for this reference
  */
  virtual bool blendForStencilRefNumber (GLuint /*_reference*/, GLenum &/*_src*/, GLenum &/*_dst*/, ACG::Vec4f &/*_color*/) { return false; };

  /** Per reference bit blending values
    @param _refbit stencil reference bit for blending
    @param _src sfactor parameter for glBlendFunc function
    @param _dst dfactor parameter for glBlendFunc function
    @param _color color used for blending
    @return should blending be berformed for this reference
  */
  virtual bool blendForStencilRefBit (GLuint /*_refbit*/, GLenum &/*_src*/, GLenum &/*_dst*/, ACG::Vec4f &/*_color*/) { return false; };

};


#endif