double signeddiedralAngle(TVertex* vertexes[])
{
double di = minDiedralAngle(vertexes[0]->fPos,vertexes[1]->fPos,vertexes[2]->fPos,vertexes[3]->fPos);
double v = tetraVolume(vertexes[0]->fPos,vertexes[1]->fPos,vertexes[2]->fPos,vertexes[3]->fPos);
if (v<0)
return -di;
else
return di;
}
// http://www.mjoldfield.com/atelier/2011/03/tetra-moi.html
Matrix3r woo::Volumetric::tetraInertia_cov(const Vector3r v[4], Real& vol, bool fixSign){
Matrix3r C0=Matrix3r::Zero(); // separate parts of covariance
Vector3r C1=Vector3r::Zero();
for(int i:{0,1,2,3}){
C0+=v[i]*v[i].transpose();
C1+=v[i];
};
vol=tetraVolume(v[0],v[1],v[2],v[3]);
if(vol<0 && fixSign) vol*=-1;
Matrix3r C=(vol/20.)*(C0+C1*C1.transpose());
Matrix3r I=Matrix3r::Identity()*C.trace()-C;
// if(fixSign && I(0,0)<0) return -I;
assert(!fixSign || I(0,0)>0);
return I;
}
