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Re: T-Junctions re-visited
avatarMarch 20, 2013 10:26AM
Thinking about this some more, I think that what my current code is designed to do is reduce the number of occurences of floating point innaccuracies causing problems (with a bug of not checking the sign first). If the number is 1.03, that might end up in floating point as 1.02999999, or 1.03000001. Ideally, I'd like both of these to produce the same key value. My current code multiplies by 100 to produce 102.999999 or 103.000001, then adds .005, which produces 103.004999 or 103.005001, both of which get converted to 103. (I think this works out for negative numbers also, but the result would be -102, instead of -103 as normally expected. Given their use as keys, where the actual values don't really matter, this probably doesn't hurt anything.)

The expectation here is that LDraw files start out with fixed point coordinates, and very often, the transformed coordinate will also be very close to fixed point values (due to transformation matrices often being simple translations, or 90-degree increment rotations). So I wanted to prevent floating point innacuracies from separating two points from each other that were expected to be together.

It could well be that all of this was completely wrong-headed, and doesn't in fact do the job that it's intended to do when dealing with real-world parts.
SubjectAuthorViewsPosted
T-Junctions re-visited Travis Cobbs763March 11, 2013 10:38PM
Re: T-Junctions re-visited Tim Gould377March 11, 2013 11:31PM
Re: T-Junctions re-visited Roland Melkert357March 12, 2013 11:17AM
Re: T-Junctions re-visited Ben Supnik376March 12, 2013 11:17AM
Re: T-Junctions re-visited Roland Melkert348March 12, 2013 11:22AM
Re: T-Junctions re-visited Ben Supnik335March 12, 2013 11:32AM
Re: T-Junctions re-visited Roland Melkert327March 12, 2013 11:41AM
Re: T-Junctions re-visited Ben Supnik335March 12, 2013 11:55AM
Re: T-Junctions re-visited Roland Melkert330March 13, 2013 10:08AM
Re: T-Junctions re-visited Travis Cobbs358March 13, 2013 11:27AM
Re: T-Junctions re-visited Allen Smith363March 12, 2013 02:01PM
Re: T-Junctions re-visited Michael Heidemann352March 13, 2013 09:27AM
Re: T-Junctions re-visited Ben Supnik333March 13, 2013 10:37AM
Re: T-Junctions re-visited Tim Gould335March 13, 2013 02:31PM
Re: T-Junctions re-visited Michael Heidemann322March 13, 2013 03:42PM
Re: T-Junctions re-visited Michael Heidemann360March 17, 2013 04:35AM
Re: T-Junctions re-visited Ben Supnik295March 17, 2013 08:43AM
Re: T-Junctions re-visited Michael Heidemann286March 17, 2013 08:59AM
Re: T-Junctions re-visited Ben Supnik291March 17, 2013 09:02AM
Re: T-Junctions re-visited Magnus Forsberg316March 17, 2013 09:15AM
Re: T-Junctions re-visited Travis Cobbs367March 17, 2013 10:09PM
Re: T-Junctions re-visited Ben Supnik333March 18, 2013 07:30AM
Re: T-Junctions re-visited Travis Cobbs326March 18, 2013 10:57AM
Re: T-Junctions re-visited Ben Supnik332March 18, 2013 11:27AM
Re: T-Junctions re-visited Travis Cobbs323March 18, 2013 12:23PM
Re: T-Junctions re-visited Ben Supnik348March 18, 2013 01:41PM
Re: T-Junctions re-visited Roland Melkert373March 18, 2013 02:51PM
Re: T-Junctions re-visited Travis Cobbs346March 18, 2013 02:59PM
Re: T-Junctions re-visited Roland Melkert415March 18, 2013 03:41PM
Re: T-Junctions re-visited Ben Supnik385March 18, 2013 06:09PM
Re: T-Junctions re-visited Roland Melkert336March 19, 2013 11:38AM
Re: T-Junctions re-visited Ben Supnik355March 19, 2013 11:43AM
Re: T-Junctions re-visited Roland Melkert383March 19, 2013 07:07PM
Re: T-Junctions re-visited Travis Cobbs352March 19, 2013 10:13PM
Re: T-Junctions re-visited Tim Gould344March 20, 2013 03:56AM
Re: T-Junctions re-visited Travis Cobbs329March 20, 2013 10:13AM
Re: T-Junctions re-visited Ben Supnik315March 20, 2013 10:23AM
Re: T-Junctions re-visited Travis Cobbs353March 20, 2013 10:29AM
Re: T-Junctions re-visited Travis Cobbs325March 20, 2013 10:26AM
Re: T-Junctions re-visited Ben Supnik310March 20, 2013 11:18AM
Re: T-Junctions re-visited Ben Supnik346March 20, 2013 06:42AM
Re: T-Junctions re-visited Roland Melkert307March 20, 2013 11:36AM
Re: T-Junctions re-visited Philippe Hurbain345March 20, 2013 06:36AM
Re: T-Junctions re-visited Ben Supnik392March 20, 2013 06:58AM
Re: T-Junctions re-visited Allen Smith366March 20, 2013 09:08AM
Re: T-Junctions re-visited Roland Melkert395March 20, 2013 11:35AM
Re: T-Junctions re-visited Ben Supnik808March 20, 2013 11:50AM
Re: T-Junctions re-visited Michael Heidemann384March 18, 2013 03:54PM
Re: T-Junctions re-visited Roland Melkert337March 13, 2013 10:03AM
Re: T-Junctions re-visited Tim Gould305March 13, 2013 03:56PM
Re: T-Junctions re-visited Sergio Reano295March 13, 2013 03:51PM
Re: T-Junctions re-visited Roland Melkert375March 13, 2013 04:36PM
Re: T-Junctions re-visited Tim Gould324March 13, 2013 05:10PM
Re: T-Junctions re-visited Ben Supnik349March 14, 2013 08:17PM
Re: T-Junctions re-visited Tim Gould394March 14, 2013 08:41PM
Re: T-Junctions re-visited Ben Supnik392March 15, 2013 10:56AM
Re: T-Junctions re-visited Roland Melkert334March 15, 2013 11:36AM
Re: T-Junctions re-visited Ben Supnik292March 13, 2013 06:58PM
Re: T-Junctions re-visited Roland Melkert302March 13, 2013 07:27PM
Re: T-Junctions re-visited Ben Supnik296March 13, 2013 07:37PM
Re: T-Junctions re-visited Roland Melkert322March 13, 2013 07:59PM
Re: T-Junctions re-visited Ben Supnik324March 13, 2013 08:18PM
Re: T-Junctions re-visited Travis Cobbs393March 14, 2013 03:23PM
Re: T-Junctions re-visited Roland Melkert400March 14, 2013 03:34PM
Re: T-Junctions re-visited Tim Gould378March 14, 2013 03:41PM
Re: T-Junctions re-visited Roland Melkert381March 15, 2013 11:33AM
Re: T-Junctions re-visited Tim Gould338March 13, 2013 07:43PM
Re: T-Junctions re-visited Roland Melkert300March 13, 2013 08:08PM
Re: T-Junctions re-visited Tim Gould324March 13, 2013 08:18PM
Re: T-Junctions re-visited Ben Supnik388March 14, 2013 08:15PM
Re: T-Junctions re-visited Roland Melkert386March 15, 2013 11:29AM
Re: T-Junctions re-visited Travis Cobbs364March 15, 2013 12:27PM
Re: T-Junctions re-visited Ben Supnik351March 15, 2013 05:08PM
Re: T-Junctions re-visited Travis Cobbs372March 16, 2013 11:29PM
Re: T-Junctions re-visited Ben Supnik282March 17, 2013 08:58AM
Re: T-Junctions re-visited Roland Melkert284March 17, 2013 12:35PM
Re: T-Junctions re-visited Travis Cobbs325March 18, 2013 12:28PM
Re: T-Junctions re-visited Travis Cobbs394March 18, 2013 12:32PM
Re: T-Junctions re-visited Roland Melkert351March 18, 2013 05:00PM
Re: T-Junctions re-visited Travis Cobbs373March 18, 2013 11:05PM
Re: T-Junctions re-visited Roland Melkert426March 19, 2013 11:38AM
Re: T-Junctions re-visited Sergio Reano366March 26, 2013 02:46PM
Re: T-Junctions re-visited Roland Melkert315March 27, 2013 11:19AM
Re: T-Junctions re-visited Sergio Reano405March 27, 2013 01:48PM



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