Premium
Sample Based Visibility for Soft Shadows using Alias‐free Shadow Maps
Author(s) -
Sintorn Erik,
Eisemann Elmar,
Assarsson Ulf
Publication year - 2008
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/j.1467-8659.2008.01267.x
Subject(s) - alias , visibility , computer science , computer vision , sample (material) , shadow (psychology) , pixel , artificial intelligence , interpolation (computer graphics) , shadow mapping , computer graphics (images) , sampling (signal processing) , optics , image (mathematics) , physics , psychology , filter (signal processing) , database , psychotherapist , thermodynamics
This paper introduces an accurate real‐time soft shadow algorithm that uses sample based visibility. Initially, we present a GPU‐based alias‐free hard shadow map algorithm that typically requires only a single render pass from the light, in contrast to using depth peeling and one pass per layer. For closed objects, we also suppress the need for a bias. The method is extended to soft shadow sampling for an arbitrarily shaped area‐/volumetric light source using 128‐1024 light samples per screen pixel. The alias‐free shadow map guarantees that the visibility is accurately sampled per screen‐space pixel, even for arbitrarily shaped (e.g. non‐planar) surfaces or solid objects. Another contribution is a smooth coherent shading model to avoid common light leakage near shadow borders due to normal interpolation.