From mboxrd@z Thu Jan 1 00:00:00 1970 To: 9fans@cse.psu.edu Date: Fri, 29 Sep 2000 08:31:55 +0000 From: "Douglas A. Gwyn" Message-ID: <39D39586.E1AB3224@arl.army.mil> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit References: <39D23579.265E60B8@arl.army.mil>, Subject: Re: [9fans] Re: moving things in a window Topicbox-Message-UUID: 1233c794-eac9-11e9-9e20-41e7f4b1d025 Theo Honohan wrote: > In message <39D23579.265E60B8@arl.army.mil>, "Douglas A. Gwyn" writes: > > I know of no way to do this right without taking into account all > > potentially visible objects. I should note that for moving a relatively small object, quite often one doesn't have to look at *every* other object, just those that *could* overlap. So if one maintains some "bounding box" coordinates for each object, a faster scan looking for potentially affected objects is possible. (Typically one then assumes that if an object is potentially affected according to this test, it *is* affected, a conservative approach that usually saves time.) E.g. in my implementation of "crabs" for the DMD/MTG I used "syndrome" words to keep track of the crabs and handled crab-crab interactions.