Improved Moment Shadow Maps for Translucent Occluders, Soft Shadows and Single Scattering
Christoph Peters, Cedrick Münstermann, Nico Wetzstein, Reinhard Klein.
2017–03 in Journal of Computer Graphics Techniques (JCGT) 6, 1.
Like variance shadow maps, the recently proposed moment shadow maps can be filtered directly but they provide a substantially higher quality. We combine them with earlier approaches to enable three new applications. Shadows for translucent occluders are obtained by simply rendering to a moment shadow map with alpha blending. Soft shadows in the spirit of percentage-closer soft shadows are rendered using two queries to a summed-area table of a moment shadow map. Single scattering is rendered through one lookup per pixel in a prefiltered moment shadow map with six channels. As a foundation we also propose improvements to moment shadow mapping itself. All these techniques scale particularly well to high output resolutions and enable proper antialiasing of shadows through extensive filtering.
Keywords: filterable shadow maps, moment shadow mapping, participating media, real-time rendering, real-time shadows, single scattering, prefiltered single scattering, god rays, soft shadows, contact-hardening shadows, moment soft shadow mapping, translucent occluders, implementation, shader code
This paper is an extended version of the earlier i3D 2016 paper with various improvements to the techniques and a more detailed discussion of implementation details as well as additional comparisons.
All downloads related to this paper are freely available at the Journal of Computer Graphics Techniques. More information is available in this blog post.