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From: hugo@gem.stack.urc.tue.nl (Hugo Lyppens)
Newsgroups: comp.graphics
Subject: checking whether 2 2D polygons overlap
Summary: ALGORITHM requested to determine whether 2 2D polygons overlap quickly.
Keywords: polygon overlap 2D
Message-ID: <111@gem.stack.urc.tue.nl>
Date: 4 Dec 90 11:17:49 GMT
Organization: Stack, Eindhoven University of Technology, The Netherlands
Lines: 17


I've partly implemented the Newell-Newell-Sancha hidden surface algorithm on the Amiga for a real-time 3D animation package I've written. This algorithm is also known as the Painter's algorithm, for it establishes a priority list and draws polygons from the back to the front.

The program allows scenes composed of planar polygons which have no holes. I 
don't however get perfect results because there's one step in the algorithm I
 don't know how to implement: to check if the projections of two polygons on 
the screen overlap or not. I haven't been able to find an article on this 
subject, not even in articles from the authors of the painter's algorithm
themselves!

So please could anyone help me with some hints or source code to determine QUICKLY whether two 2D polygons overlap or not? Then I'll be able to implement the algorithm completely.

Please E-mail your responses to

hugo@stack.urc.tue.nl

Any help is greatly appreciated!


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