“Temporal and Spatial Anti-Aliasing for Rendering Reflection on a Water Surface” by Podee, Iwasaki, Max and Dobashi

  • ©Namo Podee, Kei Iwasaki, Nelson L. Max, and Yoshinori Dobashi

  • ©Namo Podee, Kei Iwasaki, Nelson L. Max, and Yoshinori Dobashi


Entry Number: 50


    Temporal and Spatial Anti-Aliasing for Rendering Reflection on a Water Surface



    The ocean surface is highly dynamic. It moves rapidly and thus its shading changes rapidly as well. Usually, this doesn’t pose any problems if the shading is smooth. However, for a surface that has a strong highlight or bright reflection moving rapidly, it causes an inaccurate and unnatural flickering. In the traditional rendering algorithms, each frame is rendered independently at a discrete time, resulting in serious temporal aliasing artifacts. Particularly, for a wavy water surface, reflection vectors may not hit the light source even though they actually hit for part of the frame time. Removing such aliasing in real-time is an active research area and many methods have been proposed [Jimenez et al. 2011]. They can improve the fidelity and efficiency of the rendering method. However, their focus is on spatial anti-aliasing and most of them do not address the temporal aliasing problem, particularly the one observed in rendering a reflected image of a light source on the
    water surface.

    In this paper, we present a method that can remove the spatial and temporal aliasing simultaneously. The basic idea is to compute the intersection of the light source with a plane formed by two reflection vectors for neighboring frames. This provides us with a fraction of time when the light source is visible on the water surface. We combine this idea with a traditional spatial anti-aliasing method.


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    This work was supported by JSPS KAKENHI Grant Number JP15H05924.