Perspective Shadow Maps

Brandon Lloyd1, Naga Govindaraju2, Cory Quammen1,
Steve Molnar3, Dinesh Manocha1
1University of North Carolina at Chapel Hill
2Microsoft Corporation
3NVIDIA Corporation

The logarithmic perspective shadow map (LogPSM) parameterization can reduce perspective aliasing artifacts for both point and directional light sources. The parameterization is a simple combination of a perspective projection with a logarithmic transformation. that produces tighter bounds on the aliasing error in the view frustum than other parameterizations. We extend three existing shadow map algorithms to use our parameterization. Compared with competing algorithms, LogPSMs produce significantly less aliasing error. Equivalently, for the same error, LogPSMs require significantly less storage and bandwidth. With hardware support, LogPSMs would have performance similar to the algorithms upon which they are based.

Practical logarithmic rasterization for low-error shadow maps (PDF) (Slides)
ACM SIGGRAPH/EUROGRAPHICS symposium on Graphics Hardware, pp.17-24, 2007

Logarithmic perspective shadow maps (PDF) (Video) (Slides)
Transactions on Graphics, vol. 27, no. 4, October 2008

My dissertation has more details not included in these papers.