vector4 sample_orientation_uniform(vector u)
Three numbers between 0 and 1.
Returns a unit vector4, i.e. a vector4 of length 1, based on
Given uniform random
u vectors of three values in [0,1), the returned unit vectors will be
uniform random and continuous with respect to
u on the surface of the unit hypersphere.
In other words, they will be uniform random orientation quaternions.