gre/3dclip.h

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/**
 * \file 3dclip.h <gre/3dclip.h>
 * \brief Clipping against unit cube [-1.0, 1.0] in homogenius coordinates
 *
 * \if NODOC
 * $Id: 3dclip.h_v 1.5 2003/09/15 13:48:59 fileserver!dwilliss Exp $
 *
 * $Log: 3dclip.h_v $
 * Revision 1.5  2003/09/15 13:48:59  fileserver!dwilliss
 * Doxygen
 *
 * Revision 1.4  2003/08/14 19:51:26  vdronov
 * added docs
 *
 * Revision 1.3  2003/07/30 13:31:19  mju
 * Add inclusion guards and ignore private section.
 *
 * Revision 1.2  2003/03/12 22:42:06  vdronov
 * added ClipPoint
 *
 * Revision 1.1  2003/03/10 15:05:04  vdronov
 * Initial revision
 * \endif
**/

#ifndef  INC_GRE_3DCLIP_H
#define  INC_GRE_3DCLIP_H

#ifndef  INC_MI32_POINT_H
   #include <mi32/point.h>
#endif

#ifndef  INC_MI32_DOUBLEAR_H
   #include <mi32/doublear.h>
#endif

namespace GRE {

//! CLIPPING3D class.
//!
//!   This class is designed to provide static clipping methods against unit cube {-1.0, 1.0] 
//! for each coordinate in homogenius coordinates.
class CLIPPING3D {
   public:

      enum PLANE {
         PLANE_X_P_W = 0,
         PLANE_X_M_W = 1,
         PLANE_Y_P_W = 2,
         PLANE_Y_M_W = 3,
         PLANE_Z_P_W = 4,
         PLANE_Z_M_W = 5,
         PLANE_Count = 6
         };

      //! Clip point
      //!
      //! @return true if point inside unit cube
      static bool ClipPoint   (
         DPOINT3DH& point
         );

      //! Clip segment with endpoints point1 and point2. If segment intersects unit cube than
      //! point1 and point2 contains endpoints of intersection in return.
      //!
      //! @return true if segment intersects unit cube 
      static bool ClipSegment (
         DPOINT3DH& point1,
         DPOINT3DH& point2
         );

      //! Clip plane polygon input. If polygon intersects unit cube than
      //! output contains polygon of intersection in return.

      //!
      //! @return true if polygon intersects unit cube 
      static bool ClipPolygon (
         const DOUBLE_ARRAY<DPOINT3DH>& input,
         DOUBLE_ARRAY<DPOINT3DH>& output
         );

   private:
      #ifndef GENERATING_DOXYGEN_OUTPUT

      static bool Check (
         const double w1,
         const double w2,
         double& tmin,
         double& tmax
         );

      static bool ClipToPlane (
         const PLANE plane,
         const DOUBLE_ARRAY<DPOINT3DH>& input,
         DOUBLE_ARRAY<DPOINT3DH>& output
         );

      static bool CheckAbove (
         const double value
         ) { return (value > 0.0); }

      static bool AbovePlane  (
         const PLANE plane,
         const DPOINT3DH& point
         );

      //! Assuming an intersection point exists always (for efficency)
      static DPOINT3DH IntersectPlane  (
         const PLANE plane,
         const DPOINT3DH& point1,
         const DPOINT3DH& point2
         );

      static bool Intersect (
         const double w1,
         const double w2,
         double& t
         );

      #endif //!< GENERATING_DOXYGEN_OUTPUT
   };

};    //! End of namespace

#endif

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