inria-00281388, version 1
A survey of Real-Time Soft Shadows Algorithms
Jean-Marc Hasenfratz
a, 1, 2Marc Lapierre 1Nicolas Holzschuch
b, 1François X. Sillion
b, 1
Computer Graphics Forum 22, 4 (2003) 753-774
Résumé : Recent advances in GPU technology have produced a shift in focus for real-time rendering applications, whereby improvements in image quality are sought in addition to raw polygon display performance. Rendering effects such as antialiasing, motion blur and shadow casting are becoming commonplace and will likely be considered indispensable in the near future. The last complete and famous survey on shadow algorithms -Woo, 1990- has to be updated in particular in view of recent improvements in graphics hardware, which make new algorithms possible. This STAR covers all current methods for real-time shadow rendering, without venturing into slower, high quality techniques based on ray casting or radiosity. Shadows are useful for a variety of reasons: first, they help understand relative object placement in a 3D scene by providing visual cues. Second, they dramatically improve image realism and allow the creation of complex lighting ambiances. Depending on the application, the emphasis is placed on a guaranteed framerate, or on the visual quality of the shadows including penumbra effects or ``soft shadows''. Obviously no single method can render physically correct soft shadows in real-time for any dynamic scene! However our survey aims at providing an exhaustive study allowing a programmer to choose the best compromise for his/her needs. In particular we discuss the advantages, limitations, rendering quality and cost of each algorithm. Recommendations are included based on simple characteristics of the application such as static/moving lights, single or multiple light sources, static/dynamic geometry, geometric complexity, directed or omnidirectional lights, etc. Finally we indicate which methods can efficiently exploit the most recent graphics hardware facilities.
- a – Université Pierre Mendès-France - Grenoble II
- b – INRIA
- 1 : ARTIS (IMAG-INRIA Rhône-Alpes / GRAVIR)
- CNRS : FR71 – CNRS : UMR5527 – INRIA – Université Joseph Fourier - Grenoble I – Institut National Polytechnique de Grenoble (INPG)
- 2 : IUP Commerce et Vente (IUP-CV)
- Université Pierre Mendès-France - Grenoble II
- Domaine : Informatique/Synthèse d'image et réalité virtuelle
- Mots-clés : shadow algorithms – soft shadows – real-time – shadow mapping – shadow volume algorithm
- inria-00281388, version 1
- http://hal.inria.fr/inria-00281388
- oai:hal.inria.fr:inria-00281388
- Contributeur : Jean-Marc Hasenfratz
- Soumis le : Jeudi 22 Mai 2008, 11:03:36
- Dernière modification le : Mercredi 28 Avril 2010, 16:31:34






















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