109 lines
3.7 KiB
C++
109 lines
3.7 KiB
C++
/****************************************************************************
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* VCGLib o o *
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* Visual and Computer Graphics Library o o *
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* _ O _ *
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* Copyright(C) 2005 \/)\/ *
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* Visual Computing Lab /\/| *
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* ISTI - Italian National Research Council | *
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* \ *
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* All rights reserved. *
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* *
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* This program is free software; you can redistribute it and/or modify *
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* it under the terms of the GNU General Public License as published by *
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* the Free Software Foundation; either version 2 of the License, or *
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* (at your option) any later version. *
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* *
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* This program is distributed in the hope that it will be useful, *
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* but WITHOUT ANY WARRANTY; without even the implied warranty of *
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the *
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* GNU General Public License (http://www.gnu.org/licenses/gpl.txt) *
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* for more details. *
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* *
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****************************************************************************/
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/****************************************************************************
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History
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$Log: not supported by cvs2svn $
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****************************************************************************/
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#ifndef __VCGLIB_GRID_UTIL
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#define __VCGLIB_GRID_UTIL
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/** Calcolo dimensioni griglia.
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Calcola la dimensione della griglia in funzione
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della ratio del bounding box e del numero di elementi
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*/
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namespace vcg {
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template<class scalar_type>
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void BestDim( const int elems, const Point3<scalar_type> & size, Point3i & dim )
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{
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const int mincells = 1; // Numero minimo di celle
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const double GFactor = 1.0; // GridEntry = NumElem*GFactor
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double diag = size.Norm(); // Diagonale del box
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double eps = diag*1e-4; // Fattore di tolleranza
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assert(elems>0);
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assert(size[0]>=0.0);
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assert(size[1]>=0.0);
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assert(size[2]>=0.0);
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int ncell = int(elems*GFactor); // Calcolo numero di voxel
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if(ncell<mincells)
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ncell = mincells;
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dim[0] = 1;
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dim[1] = 1;
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dim[2] = 1;
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if(size[0]>eps)
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{
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if(size[1]>eps)
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{
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if(size[2]>eps)
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{
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double k = pow((double)(ncell/(size[0]*size[1]*size[2])),double(1.0/3.f));
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dim[0] = int(size[0] * k);
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dim[1] = int(size[1] * k);
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dim[2] = int(size[2] * k);
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}
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else
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{
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dim[0] = int(::sqrt(ncell*size[0]/size[1]));
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dim[1] = int(::sqrt(ncell*size[1]/size[0]));
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}
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}
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else
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{
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if(size[2]>eps)
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{
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dim[0] = int(::sqrt(ncell*size[0]/size[2]));
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dim[2] = int(::sqrt(ncell*size[2]/size[0]));
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}
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else
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dim[0] = int(ncell);
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}
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}
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else
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{
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if(size[1]>eps)
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{
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if(size[2]>eps)
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{
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dim[1] = int(::sqrt(ncell*size[1]/size[2]));
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dim[2] = int(::sqrt(ncell*size[2]/size[1]));
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}
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else
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dim[1] = int(ncell);
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}
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else if(size[2]>eps)
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dim[2] = int(ncell);
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}
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dim[0] = math::Max(dim[0],1);
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dim[1] = math::Max(dim[1],1);
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dim[2] = math::Max(dim[2],1);
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}
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}
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#endif |