vcglib/apps/sample/trimesh_fitting/trimesh_fitting.cpp

111 lines
4.8 KiB
C++

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/*! \file trimesh_fitting.cpp
\ingroup code_sample
\brief A small example about sampling and fitting
Given a mesh (an icosahedron) for each face we get a few random samples over it, and then we recover:
- the plane fitting them (that coincide with the face plane and exactly approximate all the sample points)
- the plane fitting the perturbed version of this set
- the plane fitting the perturbed version of the set but using a weighted fitting scheme.
*/
#include<vcg/complex/complex.h>
#include<vcg/complex/algorithms/create/platonic.h>
#include<vcg/complex/algorithms/point_sampling.h>
#include<wrap/io_trimesh/import_off.h>
#include<vcg/space/fitting3.h>
class MyEdge;
class MyFace;
class MyVertex;
struct MyUsedTypes : public vcg::UsedTypes< vcg::Use<MyVertex> ::AsVertexType,
vcg::Use<MyEdge> ::AsEdgeType,
vcg::Use<MyFace> ::AsFaceType>{};
class MyVertex : public vcg::Vertex<MyUsedTypes, vcg::vertex::Coord3f, vcg::vertex::Normal3f, vcg::vertex::BitFlags >{};
class MyFace : public vcg::Face< MyUsedTypes, vcg::face::FFAdj, vcg::face::VertexRef, vcg::face::Normal3f, vcg::face::BitFlags > {};
class MyEdge : public vcg::Edge<MyUsedTypes>{};
class MyMesh : public vcg::tri::TriMesh< std::vector<MyVertex>, std::vector<MyFace> , std::vector<MyEdge> > {};
float EvalPlane(vcg::Plane3f &pl, std::vector<vcg::Point3f> posVec)
{
float off=0;
for(size_t i=0;i<posVec.size();++i)
off += fabs(vcg::SignedDistancePlanePoint(pl,posVec[i]));
off/=float(posVec.size());
return off;
}
int main( )
{
MyMesh m;
vcg::tri::Icosahedron(m);
vcg::tri::UpdateNormal<MyMesh>::PerVertexNormalizedPerFaceNormalized(m);
vcg::tri::UpdateBounding<MyMesh>::Box(m);
// As a simple test just run over all the faces of a mesh
// get a few random points over it, perturb them and fit a plane on them.
vcg::Plane3f ple,plf,plw;
int cnt=0;
float scaleFac = m.bbox.Diag()/10.0f;
printf("ScaleFac %f\n\n",scaleFac);
vcg::math::MarsenneTwisterRNG rnd;
for(int i=0;i<m.FN();++i)
{
std::vector<vcg::Point3f> ExactVec;
std::vector<vcg::Point3f> PerturbVec;
std::vector<float> WeightVec;
vcg::Plane3f pl;
pl.Init(vcg::Barycenter(m.face[i]),m.face[i].N());
for(int j=0;j<200;++j)
{
vcg::Point3f p = vcg::tri::SurfaceSampling<MyMesh>::RandomPointInTriangle(m.face[i]);
ExactVec.push_back(p);
vcg::Point3f off = vcg::math::GeneratePointInUnitBallUniform<float>(rnd);
p+=off*scaleFac;
float w = std::max(0.0f, 1.0f-fabs(vcg::SignedDistancePlanePoint(pl,p))/scaleFac);
PerturbVec.push_back(p);
WeightVec.push_back(w*w); // as weight we use the square of (1-distance)
}
vcg::FitPlaneToPointSet(ExactVec,ple);
float err=EvalPlane(ple,ExactVec);
vcg::FitPlaneToPointSet(PerturbVec,plf);
float err0=EvalPlane(plf,ExactVec);
vcg::WeightedFitPlaneToPointSet(PerturbVec,WeightVec,plw);
float err1=EvalPlane(plw,ExactVec);
printf("Exact %5.3f Fit to Perturbed %5.3f Weighted fit to perturbed %5.3f\n",err,err0,err1);
if(err0>err1) cnt++;
}
printf("\nWeighted Fitting was better %i on %i\n",cnt,m.FN());
return 0;
}