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Filtering Multi‐Layer Shadow Maps for Accurate Soft Shadows
Author(s) -
Selgrad K.,
Dachsbacher C.,
Meyer Q.,
Stamminger M.
Publication year - 2015
Publication title -
computer graphics forum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.578
H-Index - 120
eISSN - 1467-8659
pISSN - 0167-7055
DOI - 10.1111/cgf.12506
Subject(s) - computer science , shadow (psychology) , shadow mapping , computer vision , texel , filter (signal processing) , artificial intelligence , representation (politics) , computer graphics (images) , contrast (vision) , layer (electronics) , scalability , database , psychology , politics , political science , law , psychotherapist , chemistry , organic chemistry
In this paper, we introduce a novel technique for pre‐filtering multi‐layer shadow maps. The occluders in the scene are stored as variable‐length lists of fragments for each texel. We show how this representation can be filtered by progressively merging these lists. In contrast to previous pre‐filtering techniques, our method better captures the distribution of depth values, resulting in a much higher shadow quality for overlapping occluders and occluders with different depths. The pre‐filtered maps are generated and evaluated directly on the GPU, and provide efficient queries for shadow tests with arbitrary filter sizes. Accurate soft shadows are rendered in real‐time even for complex scenes and difficult setups. Our results demonstrate that our pre‐filtered maps are general and particularly scalable.