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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 Cobbs879March 11, 2013 10:38PM
Re: T-Junctions re-visited Tim Gould464March 11, 2013 11:31PM
Re: T-Junctions re-visited Roland Melkert410March 12, 2013 11:17AM
Re: T-Junctions re-visited Ben Supnik422March 12, 2013 11:17AM
Re: T-Junctions re-visited Roland Melkert395March 12, 2013 11:22AM
Re: T-Junctions re-visited Ben Supnik377March 12, 2013 11:32AM
Re: T-Junctions re-visited Roland Melkert371March 12, 2013 11:41AM
Re: T-Junctions re-visited Ben Supnik381March 12, 2013 11:55AM
Re: T-Junctions re-visited Roland Melkert378March 13, 2013 10:08AM
Re: T-Junctions re-visited Travis Cobbs403March 13, 2013 11:27AM
Re: T-Junctions re-visited Allen Smith411March 12, 2013 02:01PM
Re: T-Junctions re-visited Michael Heidemann397March 13, 2013 09:27AM
Re: T-Junctions re-visited Ben Supnik380March 13, 2013 10:37AM
Re: T-Junctions re-visited Tim Gould388March 13, 2013 02:31PM
Re: T-Junctions re-visited Michael Heidemann370March 13, 2013 03:42PM
Re: T-Junctions re-visited Michael Heidemann400March 17, 2013 04:35AM
Re: T-Junctions re-visited Ben Supnik341March 17, 2013 08:43AM
Re: T-Junctions re-visited Michael Heidemann337March 17, 2013 08:59AM
Re: T-Junctions re-visited Ben Supnik332March 17, 2013 09:02AM
Re: T-Junctions re-visited Magnus Forsberg354March 17, 2013 09:15AM
Re: T-Junctions re-visited Travis Cobbs417March 17, 2013 10:09PM
Re: T-Junctions re-visited Ben Supnik380March 18, 2013 07:30AM
Re: T-Junctions re-visited Travis Cobbs377March 18, 2013 10:57AM
Re: T-Junctions re-visited Ben Supnik389March 18, 2013 11:27AM
Re: T-Junctions re-visited Travis Cobbs365March 18, 2013 12:23PM
Re: T-Junctions re-visited Ben Supnik425March 18, 2013 01:41PM
Re: T-Junctions re-visited Roland Melkert440March 18, 2013 02:51PM
Re: T-Junctions re-visited Travis Cobbs409March 18, 2013 02:59PM
Re: T-Junctions re-visited Roland Melkert475March 18, 2013 03:41PM
Re: T-Junctions re-visited Ben Supnik464March 18, 2013 06:09PM
Re: T-Junctions re-visited Roland Melkert410March 19, 2013 11:38AM
Re: T-Junctions re-visited Ben Supnik427March 19, 2013 11:43AM
Re: T-Junctions re-visited Roland Melkert450March 19, 2013 07:07PM
Re: T-Junctions re-visited Travis Cobbs419March 19, 2013 10:13PM
Re: T-Junctions re-visited Tim Gould426March 20, 2013 03:56AM
Re: T-Junctions re-visited Travis Cobbs388March 20, 2013 10:13AM
Re: T-Junctions re-visited Ben Supnik387March 20, 2013 10:23AM
Re: T-Junctions re-visited Travis Cobbs419March 20, 2013 10:29AM
Re: T-Junctions re-visited Travis Cobbs390March 20, 2013 10:26AM
Re: T-Junctions re-visited Ben Supnik371March 20, 2013 11:18AM
Re: T-Junctions re-visited Ben Supnik395March 20, 2013 06:42AM
Re: T-Junctions re-visited Roland Melkert373March 20, 2013 11:36AM
Re: T-Junctions re-visited Philippe Hurbain400March 20, 2013 06:36AM
Re: T-Junctions re-visited Ben Supnik437March 20, 2013 06:58AM
Re: T-Junctions re-visited Allen Smith438March 20, 2013 09:08AM
Re: T-Junctions re-visited Roland Melkert489March 20, 2013 11:35AM
Re: T-Junctions re-visited Ben Supnik913March 20, 2013 11:50AM
Re: T-Junctions re-visited Michael Heidemann449March 18, 2013 03:54PM
Re: T-Junctions re-visited Roland Melkert380March 13, 2013 10:03AM
Re: T-Junctions re-visited Tim Gould345March 13, 2013 03:56PM
Re: T-Junctions re-visited Sergio Reano338March 13, 2013 03:51PM
Re: T-Junctions re-visited Roland Melkert414March 13, 2013 04:36PM
Re: T-Junctions re-visited Tim Gould371March 13, 2013 05:10PM
Re: T-Junctions re-visited Ben Supnik413March 14, 2013 08:17PM
Re: T-Junctions re-visited Tim Gould468March 14, 2013 08:41PM
Re: T-Junctions re-visited Ben Supnik438March 15, 2013 10:56AM
Re: T-Junctions re-visited Roland Melkert383March 15, 2013 11:36AM
Re: T-Junctions re-visited Ben Supnik336March 13, 2013 06:58PM
Re: T-Junctions re-visited Roland Melkert348March 13, 2013 07:27PM
Re: T-Junctions re-visited Ben Supnik337March 13, 2013 07:37PM
Re: T-Junctions re-visited Roland Melkert386March 13, 2013 07:59PM
Re: T-Junctions re-visited Ben Supnik387March 13, 2013 08:18PM
Re: T-Junctions re-visited Travis Cobbs455March 14, 2013 03:23PM
Re: T-Junctions re-visited Roland Melkert466March 14, 2013 03:34PM
Re: T-Junctions re-visited Tim Gould455March 14, 2013 03:41PM
Re: T-Junctions re-visited Roland Melkert434March 15, 2013 11:33AM
Re: T-Junctions re-visited Tim Gould375March 13, 2013 07:43PM
Re: T-Junctions re-visited Roland Melkert366March 13, 2013 08:08PM
Re: T-Junctions re-visited Tim Gould383March 13, 2013 08:18PM
Re: T-Junctions re-visited Ben Supnik460March 14, 2013 08:15PM
Re: T-Junctions re-visited Roland Melkert436March 15, 2013 11:29AM
Re: T-Junctions re-visited Travis Cobbs411March 15, 2013 12:27PM
Re: T-Junctions re-visited Ben Supnik399March 15, 2013 05:08PM
Re: T-Junctions re-visited Travis Cobbs418March 16, 2013 11:29PM
Re: T-Junctions re-visited Ben Supnik338March 17, 2013 08:58AM
Re: T-Junctions re-visited Roland Melkert328March 17, 2013 12:35PM
Re: T-Junctions re-visited Travis Cobbs369March 18, 2013 12:28PM
Re: T-Junctions re-visited Travis Cobbs455March 18, 2013 12:32PM
Re: T-Junctions re-visited Roland Melkert413March 18, 2013 05:00PM
Re: T-Junctions re-visited Travis Cobbs440March 18, 2013 11:05PM
Re: T-Junctions re-visited Roland Melkert498March 19, 2013 11:38AM
Re: T-Junctions re-visited Sergio Reano443March 26, 2013 02:46PM
Re: T-Junctions re-visited Roland Melkert369March 27, 2013 11:19AM
Re: T-Junctions re-visited Sergio Reano469March 27, 2013 01:48PM



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