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vcglib/vcg/space/index/grid_util.h

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/****************************************************************************
* VCGLib o o *
* Visual and Computer Graphics Library o o *
* _ O _ *
* Copyright(C) 2005 \/)\/ *
* Visual Computing Lab /\/| *
* ISTI - Italian National Research Council | *
* \ *
* All rights reserved. *
* *
* 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 of the License, or *
* (at your option) any later version. *
* *
* This program is distributed in the hope that it will be useful, *
* but WITHOUT ANY WARRANTY; without even the implied warranty of *
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
* GNU General Public License (http://www.gnu.org/licenses/gpl.txt) *
* for more details. *
* *
****************************************************************************/
/****************************************************************************
History
$Log: not supported by cvs2svn $
Revision 1.8 2005/10/03 16:21:10 spinelli
erase wrong assert on boxToIbox function
Revision 1.7 2005/10/02 23:16:26 cignoni
English comment and moved typedef to public scope
Revision 1.6 2005/09/30 13:12:46 pietroni
basic grid class is derived from Indexing base class defined in base,h
Revision 1.5 2005/09/16 11:56:38 cignoni
removed wrong typename and added ending \n
Revision 1.4 2005/08/02 11:01:05 pietroni
added IPToP and IBoxToBox functions, modified BoxToIBox function in order to use PToIP function
Revision 1.3 2005/07/28 06:11:12 cignoni
corrected error in GridP (did not compile)
Revision 1.2 2005/07/01 11:33:36 cignoni
Added a class BasicGrid with some utility function that are scattered among similar classes
Revision 1.1 2005/03/15 11:43:18 cignoni
Removed BestDim function from the grid_static_ptr class and moved to a indipendent file (grid_util.h) for sake of generality.
****************************************************************************/
#ifndef __VCGLIB_GRID_UTIL
#define __VCGLIB_GRID_UTIL
#include<vcg/space/index/base.h>
#include<vcg/space/box3.h>
#include <vcg/space/index/space_iterators.h>
namespace vcg {
// Basic Class abstracting a gridded structure in a 3d space;
// Usueful for having coherent float to integer conversion in a unique place:
// Some Notes:
// - bbox is the real occupation of the box in the space;
// - siz is the number of cells for each side
// Note that PToIP(bbox.max) returns an invalid cell index (e.g. it returns siz)
template <class OBJTYPE, class SCALARTYPE>
class BasicGrid:public SpatialIndex<OBJTYPE,SCALARTYPE> {
public:
typedef SCALARTYPE ScalarType;
typedef Box3<ScalarType> Box3x;
typedef Point3<ScalarType> CoordType;
typedef OBJTYPE ObjType;
typedef OBJTYPE* ObjPtr;
typedef BasicGrid<OBJTYPE,SCALARTYPE> GridType;
Box3x bbox;
/// Dimensione spaziale (lunghezza lati) del bbox
Point3<ScalarType> dim;
/// Dimensioni griglia in celle
Point3i siz;
/// Dimensioni di una cella
Point3<ScalarType> voxel;
// Dato un punto ritorna le coordinate della cella
inline Point3i GridP( const Point3<ScalarType> & p ) const
{
Point3i pi;
PToIP(p,pi);
return pi;
}
/// Dato un punto 3d ritorna l'indice del box corrispondente
inline void PToIP(const Point3<ScalarType> & p, Point3i &pi ) const
{
Point3<ScalarType> t = p - bbox.min;
pi[0] = int( t[0]/voxel[0] );
pi[1] = int( t[1]/voxel[1] );
pi[2] = int( t[2]/voxel[2] );
}
/// Given a voxel index return the lower corner of the voxel
inline void IPToP(const Point3i & pi, Point3<ScalarType> &p ) const
{
p[0] = ((ScalarType)pi[0])*voxel[0];
p[1] = ((ScalarType)pi[1])*voxel[1];
p[2] = ((ScalarType)pi[2])*voxel[2];
p +=bbox.min;
}
/// Dato un box reale ritorna gli indici dei voxel compresi dentro un ibox
void BoxToIBox( const Box3x & b, Box3i & ib ) const
{
PToIP(b.min,ib.min);
PToIP(b.max,ib.max);
//assert(ib.max[0]>=0 && ib.max[1]>=0 && ib.max[2]>=0);
}
/// Dato un box in voxel ritorna gli estremi del box reale
void IBoxToBox( const Box3i & ib, Box3x & b ) const
{
IPtoP(ib.min,b.min);
IPtoP(ib.max,b.max);
}
};
/** Calcolo dimensioni griglia.
Calcola la dimensione della griglia in funzione
della ratio del bounding box e del numero di elementi
*/
template<class scalar_type>
void BestDim( const int elems, const Point3<scalar_type> & size, Point3i & dim )
{
const int mincells = 1; // Numero minimo di celle
const double GFactor = 1.0; // GridEntry = NumElem*GFactor
double diag = size.Norm(); // Diagonale del box
double eps = diag*1e-4; // Fattore di tolleranza
assert(elems>0);
assert(size[0]>=0.0);
assert(size[1]>=0.0);
assert(size[2]>=0.0);
int ncell = int(elems*GFactor); // Calcolo numero di voxel
if(ncell<mincells)
ncell = mincells;
dim[0] = 1;
dim[1] = 1;
dim[2] = 1;
if(size[0]>eps)
{
if(size[1]>eps)
{
if(size[2]>eps)
{
double k = pow((double)(ncell/(size[0]*size[1]*size[2])),double(1.0/3.f));
dim[0] = int(size[0] * k);
dim[1] = int(size[1] * k);
dim[2] = int(size[2] * k);
}
else
{
dim[0] = int(::sqrt(ncell*size[0]/size[1]));
dim[1] = int(::sqrt(ncell*size[1]/size[0]));
}
}
else
{
if(size[2]>eps)
{
dim[0] = int(::sqrt(ncell*size[0]/size[2]));
dim[2] = int(::sqrt(ncell*size[2]/size[0]));
}
else
dim[0] = int(ncell);
}
}
else
{
if(size[1]>eps)
{
if(size[2]>eps)
{
dim[1] = int(::sqrt(ncell*size[1]/size[2]));
dim[2] = int(::sqrt(ncell*size[2]/size[1]));
}
else
dim[1] = int(ncell);
}
else if(size[2]>eps)
dim[2] = int(ncell);
}
dim[0] = math::Max(dim[0],1);
dim[1] = math::Max(dim[1],1);
dim[2] = math::Max(dim[2],1);
}
}
#endif
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