Frustum.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_FRUSTUM_H_
#define _GMTL_FRUSTUM_H_

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


namespace gmtl
{

template<typename DATA_TYPE>
class Frustum
{
public:
   typedef DATA_TYPE DataType;
   typedef Frustum<DATA_TYPE> FrustumType;

   enum PlaneNames
   {
      PLANE_LEFT = 0,      
      PLANE_RIGHT = 1,   
      PLANE_BOTTOM = 2,   
      PLANE_TOP = 3,      
      PLANE_NEAR = 4,      
      PLANE_FAR = 5      
   };

   Frustum()
   {
   
   }

   Frustum(const gmtl::Matrix<DATA_TYPE, 4, 4>& projMatrix)
   {
      extractPlanes(projMatrix);
   }

   Frustum(const gmtl::Matrix<DATA_TYPE, 4, 4>& modelviewMatrix,
           const gmtl::Matrix<DATA_TYPE, 4, 4>& projMatrix)
   {
      extractPlanes(modelviewMatrix, projMatrix);
   }

   void extractPlanes(const gmtl::Matrix<DATA_TYPE, 4, 4>& modelviewMatrix,
                      const gmtl::Matrix<DATA_TYPE, 4, 4>& projMatrix)
   {
      extractPlanes(projMatrix * modelviewMatrix);
   }

   void extractPlanes(const gmtl::Matrix<DATA_TYPE, 4, 4>& projMatrix)
   {
      const gmtl::Matrix<DATA_TYPE, 4, 4>& m = projMatrix;

      //left
      mPlanes[PLANE_LEFT].setNormal(gmtl::Vec<DATA_TYPE, 3>(m[3][0] + m[0][0],
                                                            m[3][1] + m[0][1],
                                                            m[3][2] + m[0][2]));
      mPlanes[PLANE_LEFT].setOffset(m[3][3] + m[0][3]);
      //right
      mPlanes[PLANE_RIGHT].setNormal(gmtl::Vec<DATA_TYPE, 3>(m[3][0] - m[0][0],
                                                             m[3][1] - m[0][1],
                                                             m[3][2] - m[0][2]));
      mPlanes[PLANE_RIGHT].setOffset(m[3][3] - m[0][3]);
      //bottom
      mPlanes[PLANE_BOTTOM].setNormal(gmtl::Vec<DATA_TYPE, 3>(m[3][0] + m[1][0],
                                                              m[3][1] + m[1][1],
                                                              m[3][2] + m[1][2]));
      mPlanes[PLANE_BOTTOM].setOffset(m[3][3] + m[1][3]);
      //top
      mPlanes[PLANE_TOP].setNormal(gmtl::Vec<DATA_TYPE, 3>(m[3][0] - m[1][0],
                                                           m[3][1] - m[1][1],
                                                           m[3][2] - m[1][2]));
      mPlanes[PLANE_TOP].setOffset(m[3][3] - m[1][3]);
      //near
      mPlanes[PLANE_NEAR].setNormal(gmtl::Vec<DATA_TYPE, 3>(m[3][0] + m[2][0],
                                                            m[3][1] + m[2][1],
                                                            m[3][2] + m[2][2]));
      mPlanes[PLANE_NEAR].setOffset(m[2][3] + m[3][3]);
      //far
      mPlanes[PLANE_FAR].setNormal(gmtl::Vec<DATA_TYPE, 3>(m[3][0] - m[2][0],
                                                           m[3][1] - m[2][1],
                                                           m[3][2] - m[2][2]));
      mPlanes[PLANE_FAR].setOffset(m[3][3] - m[2][3]);
   }

   gmtl::Plane<DATA_TYPE> mPlanes[6];
};

typedef Frustum<float> Frustumf;
typedef Frustum<double> Frustumd;

}


#endif /* _GMTL_FRUSTUM_H_ */