A Study of Efficient Algorithm For 2-D Polygon Clipping

• Main Authors: Tzung-Shing Lin, 林宗興
• Other Authors: Chu-Ming Huang
• Format: Others
• Language: zh-TW
• Published: 1993
• Online Access: http://ndltd.ncl.edu.tw/handle/05638718390605002943

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 .