A novel scan-line algorithm for displaying bicubic surfaces is presented. Patches are decomposed on regions of constant sign of the z component of the normal before the scan process. Most of the computations are done in parametric space. The algorithm computes the intersection of the surfaces with only a restricted subset of scan planes and obtains the intersection with other scan planes by linear interpolation between exact intersections. A bound of the algorithm's error is given. The method is compared with Whitted's algorithm.Postprint (published version

Brunet Crosa, Pere

Pueyo Sánchez, Xavier

IEEE Computer Graphics and Applications

English

In recent years hidden-surface-removal algorithms have been proposed to render curved surfaces, especially bicubic (or bipolynomial) patches. Most of these algorithms use the scan-line principle to determine the scene visibility. Lane, Carpenter, Whitted, and Blinn&apos; proposed three different methods. The first algorithm is a subdivision method that stops when a desired degree of surface flatness is achieved. Then subpatches are approximated by polygons processed by a polygon-oriented algorithm. Whitted&apos;s method computes the exact intersection ofsome curves in the patch with every scan plane and approximates the patch&apos;s intersection with the plane by a polygonal line defined by these points. The exact intersection curves are the cubics defining the boundaries of the patch, isoparametri

A parametric-space-based scan-line algorithm for rendering of bicubic surfaces

Abstract

Similar works

Full text

Available Versions

CiteSeerX

UPCommons. Portal del coneixement obert de la UPC