Geometrical Optics via electromagnetic wave quantization
  The basic laws of geometrical optics can be deduced from energy-momentum conservation for electromagnetic waves, without other wave concepts. However, the concept of quanta is required; it arises naturally, hence such a hypothesis could have arisen earlier than it did historically. Measurements to determine the angles of reflection and refraction demand that each incident quantum be either reflected or refracted; such a separation is central to the experimental results. 
John P. Hernandez (Department of Physics and Astronomy, University of   North Carolina, Chapel Hill)