Homogeneous coordinates and the principle of duality in two dimensional clipping
1989; Elsevier BV; Volume: 13; Issue: 1 Linguagem: Inglês
10.1016/0097-8493(89)90045-9
ISSN1873-7684
Autores Tópico(s)Computer Graphics and Visualization Techniques
ResumoMost of the clipping algorithms assume that the clipping window is a regular rectangular polygonal boundary with sides parallel to the coordinate axes. But in most of the applications the clipping window is not a regular polygon. Sometimes the rectangular clipping window is rotated with respect to the coordinate system. Or the window can have more than four sides. In this case the window sides may be at an angle. Hence clipping to an arbitrary window becomes essential. In the clipping process the most essential part is to find the point of intersection after making the conventional visibility tests. This paper describes how the point of intersection of the line (to be clipped) with the window edge can be determined with a single division. It uses the principle of duality based on homogeneous coordinates.
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