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

Abstract

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.