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Fast clipping algorithms for computer graphics Tran, Chan-Hung
Abstract
Interactive computer graphics allow achieving a high bandwidth man-machine communication only if the graphics system meets certain speed requirements. Clipping plays an important role in the viewing process, as well as in the functions zooming and panning; thus, it is desirable to develop a fast clipper. In this thesis, the intersection problem of a line segment against a convex polygonal object has been studied. Adaption of the the clip algorithms for parallel processing has also been investigated. Based on the conventional parametric clipping algorithm, two families of 2-D generalized line clipping algorithms are proposed: the t-para method and the s-para method. Depending on the implementation both run either linearly in time using a sequential tracing or logarithmically in time by applying the numerical bisection method. The intersection problem is solved after the sector locations of the endpoints of a line segment are determined by a binary search. Three-dimensional clipping with a sweep-defined object using translational sweeping or conic sweeping is also discussed. Furthermore, a mapping method is developed for rectangular clipping. The endpoints of a line segment are first mapped onto the clip boundaries by an interval-clip operation. Then a pseudo window is-defined and a set of conditions is derived for trivial acceptance and rejection. The proposed algorithms are implemented and compared with the Liang-Barsky algorithm to estimate their practical efficiency. Vectorization of the 2-D and 3-D rectangular clipping algorithms on an array processor has also been attempted.
Item Metadata
Title |
Fast clipping algorithms for computer graphics
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Creator | |
Publisher |
University of British Columbia
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Date Issued |
1986
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Description |
Interactive computer graphics allow achieving a high bandwidth man-machine communication only if the graphics system meets certain speed requirements. Clipping plays an important role in the viewing process, as well as in the functions zooming and panning; thus, it is desirable to develop a fast clipper. In this thesis, the intersection problem of a line segment against a convex polygonal object has been studied. Adaption of the the clip algorithms for parallel processing has also been investigated.
Based on the conventional parametric clipping algorithm, two families of 2-D generalized line clipping algorithms are proposed: the t-para method and the s-para method. Depending on the implementation both run either linearly in time using a sequential tracing or logarithmically in time by applying the numerical bisection method. The intersection problem is solved after the sector locations of the endpoints of a line segment are determined by a binary search. Three-dimensional clipping with a sweep-defined object using translational sweeping or conic sweeping is also discussed.
Furthermore, a mapping method is developed for rectangular clipping. The endpoints of a line segment are first mapped onto the clip boundaries by an interval-clip operation. Then a pseudo window is-defined and a set of conditions is derived for trivial acceptance and rejection.
The proposed algorithms are implemented and compared with the Liang-Barsky algorithm to estimate their practical efficiency. Vectorization of the 2-D and 3-D rectangular clipping algorithms on an array processor has also been attempted.
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Genre | |
Type | |
Language |
eng
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Date Available |
2010-07-11
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Provider |
Vancouver : University of British Columbia Library
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Rights |
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
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DOI |
10.14288/1.0096928
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URI | |
Degree | |
Program | |
Affiliation | |
Degree Grantor |
University of British Columbia
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Campus | |
Scholarly Level |
Graduate
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Aggregated Source Repository |
DSpace
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Item Citations and Data
Rights
For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.