Filtering Multi‐Layer Shadow Maps for Accurate Soft Shadows. (27th October 2014)

• Record Type: Journal Article
• Authors: Selgrad, K.; Dachsbacher, C.; Meyer, Q.; Stamminger, M.
• Is Part Of: Computer graphics forum. Volume 34:Number 1(2015)
• Page Start: 205
• Page End: 215
• Publication Date: 2014-10-27
• Subjects: soft shadow -- shadow mapping -- filtering -- rendering -- I.3.7 [Computer Graphics]: Three‐Dimensional Graphics and Realism Color -- shading -- shadowing -- and texture; Computer graphics -- Periodicals; 006.605
• DOI: 10.1111/cgf.12506
• Languages: English
• ISSNs: 0167-7055

Abstract

Abstract : 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. Abstract: 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.