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Spatial Transformations for Rapid Scan-Line Surface Shadowing
March/April 1989 (vol. 9 no. 2)
pp. 30-38

A novel approach to surface shadowing is presented that is based on a parallel solution to the hidden-surface (visibility) problem. The approach computes visibility along scan lines of a spatial transformation of the surface height data. The transformation aligns in scan lines all potentially occluding points on the surface, allowing rapid 1-D determination of whether a point can be seen by the light source. Using this approach, arbitrarily defined surfaces can be shadowed very much more quickly than by conventional methods; a 512*512 surface image can be shadowed in less than 30 s on a MicroVAX II. The method also provides an efficient preprocessor for realistic 3-D scene synthesis, allowing the marking of shadowed pixels to eliminate unnecessary diffuse and specular reflection computations.

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Citation:
Phillip K. Robertson, "Spatial Transformations for Rapid Scan-Line Surface Shadowing," IEEE Computer Graphics and Applications, vol. 9, no. 2, pp. 30-38, March-April 1989, doi:10.1109/38.19049
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