Alias-Free Shadow Maps using Graphics Hardware

Jukka Arvo
University of Turku and Turku Centre for Computer Science

This paper appears in issue Volume 12, Number 1.
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Abstract

The alias-free shadow maps technique is the first shadow map-based algorithm that computes shadows at floating-point accuracy and handles transparent surfaces elegantly. However, its major disadvantage is that it is a specialized software rendering technique, because shadow computations are performed by using irregular sampling point locations. We present a new algorithm that inherits the strengths of alias-free shadow maps and has an efficient hardware-accelerated implementation. With our method, the sampling points are transformed into multiple layers of regular pixel boundaries with a point sprite rendering technique, and the rasterized geometry is modified to include the necessary information for computing accurate shadow terms. We also present novel acceleration techniques and propose a few hardware modifications to enable real-time implementations.

Author Information

Jukka Arvo, ATI Technologies, Rauhalammintie 1, 29600 Noormarkku, Finland jukka.arvo@amd.com

BibTeX Entry

@article{Arvo07,
  author = "Jukka Arvo",
  title = "Alias-Free Shadow Maps using Graphics Hardware",
  journal = "journal of graphics tools",
  volume = "12",
  number = "1",
  pages = "47-59",
  year = "2007",
}