bbox.h

任意给定三维空间的点集

/*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*
 * bbox.h -
 *     Defines an axis parallel bounding box.
 * 
 * Copyright 2000 Sariel Har-Peled ([e-mail])
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License as published by the
 * Free Software Foundation; either version 2, or (at your option) any
 * later version.
\*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*=*/

#ifndef  __BBOX__H
#define  __BBOX__H

#include  <limits.h>

template  <int DIM>
class   BBoxGeneric {
private:
    real  min_coords[ DIM ];
    real  max_coords[ DIM ];

    typedef  PointGeneric<DIM>  point_d;

public:
    void  init( const BBoxGeneric   & a,
                const BBoxGeneric   & b ) {
        for  (int  ind = 0; ind < DIM; ind++ ) {
            min_coords[ ind ] = min( a.min_coords[ ind ],
                                     b.min_coords[ ind ] );
            max_coords[ ind ] = max( a.max_coords[ ind ],
                                     b.max_coords[ ind ] );
        }

    }

    PointGeneric<DIM>  center() const {
        PointGeneric<DIM>  pnt;

        for  (int  ind = 0; ind < DIM; ind++ ) {
            pnt.setCoord( ind, ( min_coords[ ind ] 
                                  + max_coords[ ind ] ) / 2.0 );
        }

        return  pnt;
    }

    void  init() { 
        for  (int  ind = 0; ind < DIM; ind++ ) {
            min_coords[ ind ] = 1e20;
            max_coords[ ind ] = -1e20;
        }
    }

    void  dump() const {
        printf( "---(" );
        for  (int  ind = 0; ind < DIM; ind++ ) {
            printf( "[%g, %g] ",
                    min_coords[ ind ],
                    max_coords[ ind ] );
        }
        printf( ")\n" );
    }

    const real  & min_coord( int  coord ) const {
        return  min_coords[ coord ];
    }
    const real  & max_coord( int  coord ) const {
        return  max_coords[ coord ];
    }
    
    point_d   project( point_d  & pnt ) {
        point_d  out;

        for  ( int  ind = 0; ind < DIM; ind++ ) {
            if  ( pnt[ ind ] < min_coords[ ind ] )
                out[ ind ] = min_coords[ ind ];
            else
                if  ( pnt[ ind ] > max_coords[ ind ] )
                    out[ ind ] = max_coords[ ind ];
                else\
                out[ ind ] = pnt[ ind ];
        }

        return  out;
    }    

    void  bound( const point_d  & pnt ) {
        //cout << "bounding: " << pnt << "\n";
        for  ( int  ind = 0; ind < DIM; ind++ ) {
            if  ( pnt[ ind ] < min_coords[ ind ] )
                min_coords[ ind ] = pnt[ ind ];
            if  ( pnt[ ind ] > max_coords[ ind ] )
                max_coords[ ind ] = pnt[ ind ];
        }
    }

    real  length_dim( int  dim )  const {
        return  max_coords[ dim ] - min_coords[ dim ];
    }
    int  getLongestDim() const {
        int  dim = 0;
        real  len = length_dim( 0 );

        for  ( int  ind = 1; ind < DIM; ind++ ) 
            if  ( length_dim( ind ) > len ) {
                len = length_dim( ind );
                dim = ind;
            }

        return  dim;
    }
    real  getLongestEdge() const {
        return  length_dim( getLongestDim() );
    }

    

    real   get_diam() const
    {
        real  sum, val;

        sum = 0;        
        for  ( int  ind = 0; ind < DIM; ind++ ) {
            val = length_dim( ind );
            sum += val * val;
        }

        return  sqrt( sum );
    }

    real  get_min_coord( int  dim ) const {
        return  min_coords[ dim ];
    }
    real  get_max_coord( int  dim ) const {
        return  max_coords[ dim ];
    }
};

class BBox3d : public BBoxGeneric<3> {};
class BBox2d : public BBoxGeneric<2> {};

#else   /* __BBOX__H */
#error  Header file bbox.h included twice
#endif  /* __BBOX__H */

/* bbox.h - End of File ------------------------------------------*/