| Summary: | 碩士 === 國立臺灣科技大學 === 工程技術研究所 === 81 === Line and polygon clipping is one of the important parts in 2-D
computer graphics.All of the algorithms pertaining to them need
mass MUL/DIV operations to execute , and it takes much of
microprocessor time to execute the MUL /DIV operation . As a
result , performances of these algorithms become an important
factor. To solve the problem , beside the hardware improvement,
more efficient algorithms are still to be researched for reduc-
ing the time of MUL/DIV process . SH algorithm , issued by
Sutherland-Hodgman (SH) in 1974 , uses cross product method to
distinguish the position of point which lies on the left side
or the right side of segment. This particular algorithm needs a
lot of MUL/DIV operation to carry out the polygon clipping. In
1983, Liang-Barsky(LB) introduced the parameter line equation
method,its execution time is almost half of that of SH
algorithm.However,both SH and LB algorithms have the same
restriction which can only be used to clip convex polygon. The
application is severely restricted accordingly . Based on a
structure of parameter line equation,an algorithm to clip
convex and concave polygon is proposed . The algorithm not only
improves the disadvantage of SH and LB algorithms,but also has
the same execution speed as the LB algorithm.In general , the
performance of the proposed algorithm is shown be better then a
variety of algorithms .
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