Soft Shadow Maps: Efficient Sampling of Light Source Visibility
Shadows, particularly soft shadows, play an important role in the
visual perception of a scene by providing visual cues about the
shape and position of objects. Several recent algorithms produce
soft shadows at interactive rates, but they do not scale well with
the number of polygons in the scene or only compute the outer
penumbra. In this paper, we present a new algorithm for computing
interactive soft shadows on the GPU. Our new approach provides both
inner- and outer-penumbra, and has a very small computational cost,
giving interactive frame-rates for models with hundreds of thousands
of polygons.
Our technique is based on a sampled image of the occluders, as in shadow map techniques. These shadow samples are used in a novel manner, computing their effect on a second projective shadow texture using fragment programs. In essence, the fraction of the light source area hidden by each sample is accumulated at each texel position of this Soft Shadow Map. We include an extensive study of the approximations caused by our algorithm, as well as its computational costs.
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Références BibTex
@Article\{AHLHHS06, author = "Atty, Lionel and Holzschuch, Nicolas and Lapierre, Marc and Hasenfratz, Jean-Marc and Hansen, Chuck and Sillion, Fran\c{c}ois", title = "Soft Shadow Maps: Efficient Sampling of Light Source Visibility", journal = "Computer Graphics Forum", number = "4", volume = "25", month = "dec", year = "2006", url = "http://artis.inrialpes.fr/Publications/2006/AHLHHS06" }