Does this question make sense in the quantum world?
Imagining a single photon (wave packet?) interacting with a single atom (its electrons etc) how do we currently describe/define the emitted photon in terms of its direction in relation to the incoming photon?
Now "scaling up" to a surface of atoms actually reflecting "light" according to the simple reflection rules like angle-in equals angle-out how do we manage to explain this effect in terms of the quantum world? How comes the probabilities work out for the out-going angle depending on the incoming-angle?