Spatial Transformations for Rapid Scan-Line Surface Shadowing

  • Authors:
  • Phillip K. Robertson

  • Affiliations:
  • -

  • Venue:
  • IEEE Computer Graphics and Applications
  • Year:
  • 1989

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Abstract

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.