PlaneOps.h

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// GMTL is (C) Copyright 2001-2010 by Allen Bierbaum
// Distributed under the GNU Lesser General Public License 2.1 with an
// addendum covering inlined code. (See accompanying files LICENSE and
// LICENSE.addendum or http://www.gnu.org/copyleft/lesser.txt)

#ifndef _GMTL_PLANEOPS_H_
#define _GMTL_PLANEOPS_H_

#include <gmtl/Defines.h>
#include <gmtl/Plane.h>
#include <gmtl/Math.h>

namespace gmtl
{

template< class DATA_TYPE >
DATA_TYPE distance( const Plane<DATA_TYPE>& plane, const Point<DATA_TYPE, 3>& pt )
{
   return ( dot(plane.mNorm, static_cast< Vec<DATA_TYPE, 3> >(pt)) - plane.mOffset );
}

template< class DATA_TYPE >
PlaneSide whichSide( const Plane<DATA_TYPE>& plane,
                     const Point<DATA_TYPE, 3>& pt )
{
   DATA_TYPE dist = distance( plane, pt );

   if ( dist < DATA_TYPE(0) )
      return NEG_SIDE;
   else if ( dist > DATA_TYPE(0) )
      return POS_SIDE;
   else
      return ON_PLANE;
}

template< class DATA_TYPE >
PlaneSide whichSide( const Plane<DATA_TYPE>& plane,
                     const Point<DATA_TYPE, 3>& pt,
                     const DATA_TYPE& eps )
{
   DATA_TYPE dist = distance( plane, pt );

   if ( dist < eps )
      return NEG_SIDE;
   else if ( dist > eps )
      return POS_SIDE;
   else
      return ON_PLANE;
}

template< class DATA_TYPE >
DATA_TYPE findNearestPt( const Plane<DATA_TYPE>& plane,
                         const Point<DATA_TYPE, 3>& pt,
                         Point<DATA_TYPE, 3>& result )
{
   // GGI:  p297
   // GGII: p223
   gmtlASSERT( isNormalized(plane.mNorm) );   // Assert: Normalized
   DATA_TYPE dist_to_plane(0);
   dist_to_plane = plane.mOffset + dot( plane.mNorm, static_cast< Vec<DATA_TYPE, 3> >(pt) );
   result = pt - (plane.mNorm * dist_to_plane);
   return dist_to_plane;
}

template< class DATA_TYPE, unsigned SIZE>
void reflect( Point<DATA_TYPE, SIZE>& result,
              const Plane<DATA_TYPE>& plane,
              const Point<DATA_TYPE, SIZE>& point )
{
   gmtl::Point<DATA_TYPE, SIZE> point_on_plane;
   findNearestPt( plane, point, point_on_plane );
   gmtl::Vec<DATA_TYPE, SIZE> dir = point_on_plane - point;
   result = point + (dir * DATA_TYPE(2.0f));
}
template< class DATA_TYPE >
inline bool operator==( const Plane<DATA_TYPE>& p1, const Plane<DATA_TYPE>& p2 )
{
   return ( (p1.mNorm == p2.mNorm) && (p1.mOffset == p2.mOffset) );
}

template< class DATA_TYPE >
inline bool operator!=( const Plane<DATA_TYPE>& p1, const Plane<DATA_TYPE>& p2 )
{
   return (! (p1 == p2));
}

template< class DATA_TYPE >
inline bool isEqual( const Plane<DATA_TYPE>& p1, const Plane<DATA_TYPE>& p2,
                     const DATA_TYPE& eps )
{
   gmtlASSERT( eps >= 0 );
   return ( (isEqual(p1.mNorm, p2.mNorm, eps)) &&
            (Math::isEqual(p1.mOffset, p2.mOffset, eps)) );
}
} // namespace gmtl

#endif