Sample Distribution Shadow Maps

Andrew Lauritzen Intel Corporation

Marco Salvi Intel Corporation

Aaron Lefohn Intel Corporation

ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games (I3D) 2011.

Advances in Real-Time Rendering in 3D Graphics and Games, SIGGRAPH Courses 2010.

Abstract
This paper introduces Sample Distribution Shadow Maps (SDSMs), a new algorithm for hard and soft-edged shadows that greatly reduces undersampling, oversampling, and geometric aliasing errors compared to other shadow map techniques. SDSMs fall into the space between scene-dependent, variable-performance shadow algorithms and scene-independent, fixed-performance shadow algorithms. They provide a fully automated solution to shadow map aliasing by optimizing the placement and size of a fixed number of Z-partitions using the distribution of the light space samples required by the current frame. SDSMs build on the advantages of current state of the art techniques, including predictable performance and constant memory usage, while removing tedious and ultimately suboptimal parameter tuning. We compare SDSMs to Parallel-Split Shadow Maps (PSSMs, a state of the art Z-partitioning scheme) and show that SDSMs produce higher quality shadows. Finally, we demonstrate that SDSMs outperform PSSMs in a large 2009 game scene at high resolutions, making them suitable for games and other interactive applications.

Citation: Andrew Lauritzen, Marco Salvi, Aaron Lefohn, Sample Distribution Shadow Maps, ACM SIGGRAPH Symposium on Interactive 3D Graphics and Games (I3D) 2011, February 2011.

Citation: Andrew Lauritzen, Sample Distribution Shadow Maps, Advances in Real-Time Rendering in 3D Graphics and Games, SIGGRAPH 2010, July 2010.

Paper: I3D 2011 paper

SIGGRAPH Slides: Zipped PPT, PDF (with notes)

Movie: MP4 (78 MB)

Code: sdsm.zip