OpenSceneGraph/include/osg/ClippingVolume

//C++ header - Open Scene Graph - Copyright (C) 1998-2001 Robert Osfield
//Distributed under the terms of the GNU Library General Public License (LGPL)
//as published by the Free Software Foundation.

#ifndef OSG_CLIPPINGVOLUME
#define OSG_CLIPPINGVOLUME 1

#include <osg/Plane>

#include <vector>

namespace osg {

/** A ClippingVolume class for representing convex clipping volumes made up.*/
class SG_EXPORT ClippingVolume
{

    public:

        typedef std::vector<osg::Plane> PlaneList;

        inline ClippingVolume() {setupMask();}

        inline ClippingVolume(const ClippingVolume& cv) : _localMask(cv._localMask), _planeList(cv._planeList)  {}
        
        inline ClippingVolume(const PlaneList& pl) : _planeList(pl) {setupMask();}

        inline ~ClippingVolume() {}

        inline void clear() { _planeList.clear(); setupMask(); }

        inline ClippingVolume& operator = (const ClippingVolume& cv)
        {
            if (&cv==this) return *this;
           _localMask = cv._localMask;
           _planeList = cv._planeList;
           return *this;
        }
        
        /** Create a ClippingVolume with is cube, centered at 0,0,0, with sides of 2 units.*/
        void setToUnitFrustum()
        {
            _planeList.clear();
            _planeList.push_back(Plane(1.0f,0.0f,0.0f,1.0f)); // left plane.
            _planeList.push_back(Plane(-1.0f,0.0f,0.0f,1.0f)); // right plane.
            _planeList.push_back(Plane(0.0f,1.0f,0.0f,1.0f)); // bottom plane.
            _planeList.push_back(Plane(0.0f,-1.0f,0.0f,1.0f)); // top plane.
            _planeList.push_back(Plane(0.0f,0.0f,-1.0f,1.0f)); // near plane
            _planeList.push_back(Plane(0.0f,0.0f,1.0f,1.0f)); // far plane
            setupMask();
        }

        void setToUnitFrustumWithoutNearFar()
        {
            _planeList.clear();
            _planeList.push_back(Plane(1.0f,0.0f,0.0f,1.0f)); // left plane.
            _planeList.push_back(Plane(-1.0f,0.0f,0.0f,1.0f)); // right plane.
            _planeList.push_back(Plane(0.0f,1.0f,0.0f,1.0f)); // bottom plane.
            _planeList.push_back(Plane(0.0f,-1.0f,0.0f,1.0f)); // top plane.
            setupMask();
        }

        inline void set(const ClippingVolume& cs) { _planeList = cs._planeList; setupMask(); }

        inline void set(const PlaneList& pl) { _planeList = pl; setupMask(); }
        
        inline void add(const osg::Plane& pl) { _planeList.push_back(pl); setupMask(); }

        inline PlaneList& getPlaneList() { return _planeList; }

        inline const PlaneList& getPlaneList() const { return _planeList; }

        inline void setupMask()
        {
            _localMask = 0;
            for(unsigned int i=0;i<_planeList.size();++i)
            {
                _localMask = (_localMask<<1) | 1;
            }
        }


        /** Check whether a vertex is contained with clipping set.*/
        inline const bool contains(const osg::Vec3& v) const
        {
            for(PlaneList::const_iterator itr=_planeList.begin();
                itr!=_planeList.end();
                ++itr)
            {
                if (itr->distance(v)<0.0f) return false;
            }
            return true;
        }

        /** Check whether any part of a bounding sphere is contained within clipping set.
            Using a mask to determine which planes should be used for the check, and
            modifying the mask to turn off planes which wouldn't contribute to clipping
            of any internal objects.  This feature is used in osgUtil::CullVisitor
            to prevent redundant plane checking.*/
        inline const bool contains(const osg::BoundingSphere& bs,unsigned int& mask) const
        {
            if (!(mask & _localMask)) return true;

            unsigned int selector_mask = 0x1;
            for(PlaneList::const_iterator itr=_planeList.begin();
                itr!=_planeList.end();
                ++itr)
            {
                if (mask&selector_mask)
                {
                    int res=itr->intersect(bs);
                    if (res<0) return false; // outside clipping set.
                    else if (res>0) mask ^= selector_mask; // subsequent checks against this plane not required.
                }
                selector_mask <<= 1; 
            }
            return true;
        }
        
        /** Check whether any part of a bounding sphere is contained within clipping set.*/
        inline const bool contains(const osg::BoundingSphere& bs) const
        {
            for(PlaneList::const_iterator itr=_planeList.begin();
                itr!=_planeList.end();
                ++itr)
            {
                if (itr->intersect(bs)<0) return false; // outside clipping set.
            }
            return true;
        }

        /** Check whether any part of a bounding box is contained within clipping set.
            Using a mask to determine which planes should be used for the check, and
            modifying the mask to turn off planes which wouldn't contribute to clipping
            of any internal objects.  This feature is used in osgUtil::CullVisitor
            to prevent redundant plane checking.*/
        inline const bool contains(const osg::BoundingBox& bb,unsigned int& mask) const
        {
            if (!(mask & _localMask)) return true;

            unsigned int selector_mask = 0x1;
            for(PlaneList::const_iterator itr=_planeList.begin();
                itr!=_planeList.end();
                ++itr)
            {
                if (mask&selector_mask)
                {
                    int res=itr->intersect(bb);
                    if (res<0) return false; // outside clipping set.
                    else if (res>0) mask ^= selector_mask; // subsequent checks against this plane not required.
                }
                selector_mask <<= 1; 
            }
            return true;
        }

        /** Check whether any part of a bounding box is contained within clipping set.*/
        inline const bool contains(const osg::BoundingBox& bb) const
        {
            for(PlaneList::const_iterator itr=_planeList.begin();
                itr!=_planeList.end();
                ++itr)
            {
                if (itr->intersect(bb)<0) return false; // outside clipping set.
            }
            return true;
        }


        /** Transform the clipping set by matrix.  Note, this operations carries out
          * the calculation of the inverse of the matrix since to transforms
          * planes must be multiplied my the inverse transposed. This
          * make this operation expensive.  If the inverse has been already
          * calculated elsewhere then use transformProvidingInverse() instead.
          * See http://www.worldserver.com/turk/computergraphics/NormalTransformations.pdf*/
        inline void transform(const osg::Matrix& matrix)
        {
            osg::Matrix inverse;
            inverse.invert(matrix);
            transformProvidingInverse(inverse);
        }
        
        /** Transform the clipping set by provide a pre inverted matrix.
          * see transform for details. */
        inline void transformProvidingInverse(const osg::Matrix& matrix)
        {
            for(PlaneList::iterator itr=_planeList.begin();
                itr!=_planeList.end();
                ++itr)
            {
                itr->transformProvidingInverse(matrix);
            }
        }
        
    protected:


        unsigned int _localMask;
        PlaneList _planeList;

};

}	// end of namespace

#endif