Proceedings: GI 2008

Exponential shadow maps

Thomas Annen, Tom Mertens, Hans-Peter Seidel, Eddy Flerackers, Jan Kautz

Proceedings of Graphics Interface 2008: Windsor, Ontario, Canada, 28 - 30 May 2008, 155-161

  • BibTex

    author = {Annen, Thomas and Mertens, Tom and Seidel, Hans-Peter and Flerackers, Eddy and Kautz, Jan},
    title = {Exponential shadow maps},
    booktitle = {Proceedings of Graphics Interface 2008},
    series = {GI 2008},
    year = {2008},
    issn = {0713-5424},
    isbn = {978-1-56881-423-0},
    location = {Windsor, Ontario, Canada},
    pages = {155--161},
    numpages = {7},
    publisher = {Canadian Human-Computer Communications Society},
    address = {Toronto, Ontario, Canada},


Rendering high-quality shadows in real-time is a challenging problem. Shadow mapping has proved to be an efficient solution, as it scales well for complex scenes. However, it suffers from aliasing problems. Filtering the shadow map alleviates aliasing, but unfortunately, native hardware-accelerated filtering cannot be applied, as the shadow test has to take place beforehand. We introduce a simple approach to shadow map filtering, by approximating the shadow test using an exponential function. This enables us to pre-filter the shadow map, which in turn allows for high quality hardware-accelerated filtering. Compared to previous filtering techniques, our technique is faster, consumes less memory and produces less artifacts.