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Proceedings Paper

Curved shadow generation by ray tracing in the plane
Author(s): Alade Tokuta
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Paper Abstract

We present a method for generating shadows in a static environment represented by polygonal or parametric surfaces, and illuminated by one or more movable point light sources. Concepts of ray tracing are modified and utilized in shadow determination. Ray-patch intersection are determined by using contour integration rather than purely numerical or subdivision techniques and thus the expense of long computation is somewhat lessened. Preprocessing steps are used to ascertain that the number of such calculations are limited. Shadow pairs are detected and pairs that cannot interact to produce shadows are also detected and discarded. Coherence properties are used to limit the number of rays processed. The approach combines elements of the shadow z-buffer in the generation process and to a lesser extent, that of projected polygons in scanline rendering as a preprocessing step. The algorithm is easily integrated with scanline a z-buffer algorithm and thus retains the benefits of a z- buffer. Distributed light sources are modelled as arrays of point light sources and the method allows the computation of umbra-penumbra effects.

Paper Details

Date Published: 1 September 1990
PDF: 5 pages
Proc. SPIE 1360, Visual Communications and Image Processing '90: Fifth in a Series, (1 September 1990); doi: 10.1117/12.24165
Show Author Affiliations
Alade Tokuta, Univ. of South Florida (United States)

Published in SPIE Proceedings Vol. 1360:
Visual Communications and Image Processing '90: Fifth in a Series
Murat Kunt, Editor(s)

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