A Generalized Ray Formulation For Wave-Optics Rendering


From ray optics to wave optics. In this paper we present the generalized ray: an extension of the classical ray to wave optics. The generalized ray retains the defining characteristics of the ray-optical ray: locality and linearity. These properties allow the generalized ray to serve as a ``point query'' of light's behaviour---the same purpose that the classical ray fulfils in rendering. By using such generalized rays, we enable the rendering of complex scenes, like the ones shown, under rigorous wave-optical light transport. Materials admitting diffractive optical phenomena are visible: e.g., a diffraction grated Aluminium strip dispersing light; a Bornite ore with a layer of copper oxide causing interference; a Brazilian Rainbow Boa, whose scales are biological diffraction grated surfaces; and, a Chrysomelidae beetle, whose colour arises due to naturally-occurring multilayered interference reflectors in its elytron. Our formalism serves as a link between path tracing techniques and wave optics, and admits a highly general validity domain. Therefore, we are able to apply sophisticated sampling techniques, and achieve performance that surpasses the state-of-the-art by orders-of-magnitude. We indicate resolution and samples-per-pixel (spp) count in all figures rendered using our method. While these figures showcase converged (high spp) results, our implementation also allows interactive rendering of all these scenes at 1 spp. Frame times (at 1 spp) for interactive rendering are indicated. Implementation, as well as additional renderings and videos are available in our supplemental material.