Another way of doing this (without versors): Let u and v be the unit vectors of the initial and final click location. We want an R s.t. Ru = v. Create an ortho

Another way of doing this (without versors): Let u and v be the unit vectors of the initial and final click location. We want an R s.t. Ru = v. Create an orthonormal basis ON(u) and ON(v) (you can use the QR decomposition for the vector concatenated with I). R = ON(v) ON(u)^-1 = ON(v) ON(u)^T