vcglib/vcg/space/index/grid_util2d.h

222 lines
7.2 KiB
C++

/****************************************************************************
* 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. *
* *
****************************************************************************/
/****************************************************************************
****************************************************************************/
#ifndef __VCGLIB_GRID_UTIL_2D
#define __VCGLIB_GRID_UTIL_2D
#include<vcg/space/index/base2d.h>
#include<vcg/space/box2.h>
#ifndef WIN32
#define __int64 long long
#define __cdecl
#endif
namespace vcg {
/** BasicGrid2D
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
OBJTYPE: Type of the indexed objects.
SCALARTYPE: Scalars type for structure's internal data (may differ from
object's scalar type).
*/
template <class SCALARTYPE>
class BasicGrid2D
{
public:
typedef SCALARTYPE ScalarType;
typedef Box2<ScalarType> Box2x;
typedef Point2<ScalarType> CoordType;
typedef BasicGrid2D<SCALARTYPE> GridType;
Box2x bbox;
CoordType dim; /// Spatial Dimention (edge legth) of the bounding box
Point2i siz; /// Number of cells forming the grid
CoordType voxel; /// Dimensions of a single cell
/*
Derives the right values of Dim and voxel starting
from the current values of siz and bbox
*/
void ComputeDimAndVoxel()
{
this->dim = this->bbox.max - this->bbox.min;
this->voxel[0] = this->dim[0]/this->siz[0];
this->voxel[1] = this->dim[1]/this->siz[1];
}
/* Given a 3D point, returns the coordinates of the cell where the point is
* @param p is a 3D point
* @return integer coordinates of the cell
*/
inline Point2i GridP( const Point2<ScalarType> & p ) const
{
Point2i pi;
PToIP(p, pi);
return pi;
}
/* Given a 3D point p, returns the index of the corresponding cell
* @param p is a 3D point in the space
* @return integer coordinates pi of the cell
*/
inline void PToIP(const CoordType & p, Point2i &pi ) const
{
CoordType t = p - bbox.min;
pi[0] = int( t[0] / voxel[0] );
pi[1] = int( t[1] / voxel[1] );
}
/* Given a cell index return the lower corner of the cell
* @param integer coordinates pi of the cell
* @return p is a 3D point representing the lower corner of the cell
*/
inline void IPiToPf(const Point2i & pi, CoordType &p ) const
{
p[0] = ((ScalarType)pi[0])*voxel[0];
p[1] = ((ScalarType)pi[1])*voxel[1];
p += bbox.min;
}
/* Given a cell index return the corresponding box
* @param integer coordinates pi of the cell
* @return b is the corresponding box in <ScalarType> coordinates
*/
inline void IPiToBox(const Point2i & pi, Box2x & b ) const
{
CoordType p;
p[0] = ((ScalarType)pi[0])*voxel[0];
p[1] = ((ScalarType)pi[1])*voxel[1];
p += bbox.min;
b.min = p;
b.max = (p + voxel);
}
/* Given a cell index return the center of the cell itself
* @param integer coordinates pi of the cell
* @return b is the corresponding box in <ScalarType> coordinates
*/inline void IPiToBoxCenter(const Point2i & pi, CoordType & c ) const
{
CoordType p;
IPiToPf(pi,p);
c = p + voxel/ScalarType(2.0);
}
// Same of IPiToPf but for the case that you just want to transform
// from a space to the other.
inline void IPfToPf(const CoordType & pi, CoordType &p ) const
{
p[0] = ((ScalarType)pi[0])*voxel[0];
p[1] = ((ScalarType)pi[1])*voxel[1];
p += bbox.min;
}
/* Given a cell in <ScalarType> coordinates, compute the corresponding cell in integer coordinates
* @param b is the cell in <ScalarType> coordinates
* @return ib is the correspondent box in integer coordinates
*/
inline void BoxToIBox( const Box2x & b, Box2i & 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);
}
/* Given a cell in integer coordinates, compute the corresponding cell in <ScalarType> coordinates
* @param ib is the cell in integer coordinates
* @return b is the correspondent box in <ScalarType> coordinates
*/
/// Dato un box in voxel ritorna gli estremi del box reale
void IBoxToBox( const Box2i & ib, Box2x & b ) const
{
IPiToPf(ib.min,b.min);
IPiToPf(ib.max+Point2i(1,1),b.max);
}
};
template<class scalar_type>
void BestDim2D( const Box2<scalar_type> box, const scalar_type voxel_size, Point2i & dim )
{
Point2<scalar_type> box_size = box.max-box.min;
__int64 elem_num = (__int64)(box_size[0]/voxel_size +0.5) *( __int64)(box_size[1]/voxel_size +0.5);
BestDim2D(elem_num,box_size,dim);
}
/** 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 BestDim2D( const __int64 elems, const Point2<scalar_type> & size, Point2i & dim )
{
const __int64 mincells = 1; // Numero minimo di celle
const double GFactor = 1; // 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);
__int64 ncell = (__int64)(elems*GFactor); // Calcolo numero di voxel
if(ncell<mincells)
ncell = mincells;
dim[0] = 1;
dim[1] = 1;
if ((size[0]>eps)&&(size[1]>eps))
{
scalar_type Area=size[0]*size[1];
double k = pow((double)(ncell/Area),double(1.0/2.f));
dim[0] = int(size[0] * k);
dim[1] = int(size[1] * k);
}
else
{
if(size[0]>eps)
dim[0] = int(ncell);
else
dim[1] = int(ncell);
}
dim[0] = std::max(dim[0],1);
dim[1] = std::max(dim[1],1);
}
}///end namespace
#endif