Moved here from shadevis
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/****************************************************************************
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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) 2004 \/)\/ *
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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: gen_normal.h,v $
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****************************************************************************/
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#ifndef __VCG_GEN_NORMAL
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#define __VCG_GEN_NORMAL
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namespace vcg {
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template <class ScalarType>
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class GenNormal
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{
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public:
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typedef Point3<ScalarType> Point3x;
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static void Random(int vn, std::vector<Point3<ScalarType > > &NN)
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{
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NN.clear();
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while(NN.size()<vn)
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{
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Point3x pp(((float)rand())/RAND_MAX,
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((float)rand())/RAND_MAX,
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((float)rand())/RAND_MAX);
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pp=pp*2.0-Point3x(1,1,1);
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if(pp.SquaredNorm()<1)
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{
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Normalize(pp);
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NN.push_back(pp);
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}
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}
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}
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static void UniformCone(int vn, std::vector<Point3<ScalarType > > &NN, ScalarType AngleRad, Point3x dir=Point3x(0,1,0))
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{
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std::vector<Point3<ScalarType > > NNT;
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NN.clear();
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// per prima cosa si calcola il volume della spherical cap di angolo AngleRad
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ScalarType Height= 1.0 - cos(AngleRad); // height is measured from top...
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// Surface is the one of the tangent cylinder
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ScalarType CapArea = 2.0*M_PI*Height;
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ScalarType Ratio = CapArea / (4.0*M_PI );
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printf("----------AngleRad %f Angledeg %f ratio %f vn %i vn2 %i \n",AngleRad,math::ToDeg(AngleRad),Ratio,vn,int(vn/Ratio));
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Uniform(vn/Ratio,NNT);
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printf("asked %i got %i (expecting %i instead of %i)\n", int(vn/Ratio), NNT.size(), int(NNT.size()*Ratio), vn);
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typename std::vector<Point3<ScalarType> >::iterator vi;
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ScalarType DotProd = cos(AngleRad);
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for(vi=NNT.begin();vi!=NNT.end();++vi)
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{
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if(dir*(*vi) >= DotProd) NN.push_back(*vi);
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}
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}
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static void Uniform(int vn, std::vector<Point3<ScalarType > > &NN)
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{
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OctaLevel pp;
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int ll=10;
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while(pow(4.0f,ll)+2>vn) ll--;
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pp.Init(ll);
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sort(pp.v.begin(),pp.v.end());
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int newsize = unique(pp.v.begin(),pp.v.end())-pp.v.begin();
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pp.v.resize(newsize);
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NN=pp.v;
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Perturb(NN);
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}
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static void Perturb(std::vector<Point3<ScalarType > > &NN)
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{
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float width=0.2f/sqrt(float(NN.size()));
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typename std::vector<Point3<ScalarType> >::iterator vi;
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for(vi=NN.begin(); vi!=NN.end();++vi)
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{
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Point3x pp(((float)rand())/RAND_MAX,
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((float)rand())/RAND_MAX,
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((float)rand())/RAND_MAX);
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pp=pp*2.0-Point3x(1,1,1);
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pp*=width;
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(*vi)+=pp;
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(*vi).Normalize();
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}
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}
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private :
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class OctaLevel
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{
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public:
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std::vector<Point3x> v;
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int level;
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int sz;
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Point3f &Val(int i, int j) {
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assert(i>=0 && i<sz);
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assert(j>=0 && j<sz);
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return v[i+j*sz];
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}
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void Init(int lev)
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{
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sz=pow(2.0f,lev+1)+1;
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v.resize(sz*sz);
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if(lev==0)
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{
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Val(0,0)=Point3x( 0, 0,-1); Val(0,1)=Point3x( 0, 1, 0); Val(0,2)=Point3x( 0, 0,-1);
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Val(1,0)=Point3x(-1, 0, 0); Val(1,1)=Point3x( 0, 0, 1); Val(1,2)=Point3x( 1, 0, 0);
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Val(2,0)=Point3x( 0, 0,-1); Val(2,1)=Point3x( 0,-1, 0); Val(2,2)=Point3x( 0, 0,-1);
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}
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else
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{
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OctaLevel tmp;
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tmp.Init(lev-1);
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int i,j;
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for(i=0;i<sz;++i)
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for(j=0;j<sz;++j)
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{
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if((i%2)==0 && (j%2)==0)
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Val(i,j)=tmp.Val(i/2,j/2);
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if((i%2)!=0 && (j%2)==0)
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Val(i,j)=(tmp.Val(i/2+0,j/2)+tmp.Val(i/2+1,j/2))/2.0;
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if((i%2)==0 && (j%2)!=0)
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Val(i,j)=(tmp.Val(i/2,j/2+0)+tmp.Val(i/2,j/2+1))/2.0;
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if((i%2)!=0 && (j%2)!=0)
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Val(i,j)=(tmp.Val(i/2+0,j/2+0)+tmp.Val(i/2+0,j/2+1)+tmp.Val(i/2+1,j/2+0)+tmp.Val(i/2+1,j/2+1))/4.0;
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}
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typename std::vector<Point3<ScalarType> >::iterator vi;
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for(vi=v.begin(); vi!=v.end();++vi)
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(*vi).Normalize();
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}
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}
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};
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};
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}
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#endif
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