IGL_INLINE Eigen::Quaternion<Scalar> igl::random_quaternion() { // http://mathproofs.blogspot.com/2005/05/uniformly-distributed-random-unit.html const auto & unit_rand = []()->Scalar { return ((Scalar)rand() / (Scalar)RAND_MAX); }; const Scalar t0 = 2.*M_PI*unit_rand(); const Scalar t1 = acos(1.-2.*unit_rand()); const Scalar t2 = 0.5*(M_PI*unit_rand() + acos(unit_rand())); return Eigen::Quaternion<Scalar>( 1.*sin(t0)*sin(t1)*sin(t2), 1.*cos(t0)*sin(t1)*sin(t2), 1.*cos(t1)*sin(t2), 1.*cos(t2)); }
Vec rand_vec(){ return {unit_rand()-0.5, unit_rand()-0.5}; }