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An efficient alias-free shadow algorithm for opaque and transparent objects using per-triangle shadow volumes

Erik Sintorn (Institutionen för data- och informationsteknik, Datorteknik (Chalmers)) ; Ola Olsson (Institutionen för data- och informationsteknik, Datorteknik (Chalmers)) ; Ulf Assarsson (Institutionen för data- och informationsteknik, Datorteknik (Chalmers))
Proceedings of the 2011 SIGGRAPH Asia Conference, SA'11 (2011)
[Konferensbidrag, refereegranskat]

This paper presents a novel method for generating pixel-accurate shadows from point light-sources in real-time. The new method is able to quickly cull pixels that are not in shadow and to trivially accept large chunks of pixels thanks mainly to using the whole triangle shadow volume as a primitive, instead of rendering the shadow quads independently as in the classic Shadow-Volume algorithm. Our CUDA implementation outperforms z-fail consistently and surpasses z-pass at high resolutions, although these latter two are hardware accelerated, while inheriting none of the robustness issues associated with these methods. Another, perhaps even more important property of our algorithm, is that it requires no pre-processing or identification of silhouette edges and so robustly and efficiently handles arbitrary triangle soups. In terms of view sample test and set operations performed, we show that our algorithm can be an order of magnitude more efficient than z-pass when rendering a game-scene at multi-sampled HD resolutions. We go on to show that the algorithm can be trivially modified to support textured, semitransparent and colored semi-transparent shadow-casters and that it can be combined with either depth-peeling or stochastic transparency to also support transparent shadow receivers. Compared to recent alias-free shadow-map algorithms, our method has a very small memory footprint, does not suffer from load-balancing issues, and handles omni-directional lights without modification. It is easily incorporated into any deferred rendering pipeline and combines many of the strengths of shadow maps and shadow volumes.

Nyckelord: Alias-free, Real time, Shadows, Transparency

Denna post skapades 2012-11-16. Senast ändrad 2017-10-03.
CPL Pubid: 166244


Institutioner (Chalmers)

Institutionen för data- och informationsteknik, Datorteknik (Chalmers)


Data- och informationsvetenskap

Chalmers infrastruktur