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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 Cobbs651March 11, 2013 10:38PM
Re: T-Junctions re-visited Tim Gould303March 11, 2013 11:31PM
Re: T-Junctions re-visited Roland Melkert281March 12, 2013 11:17AM
Re: T-Junctions re-visited Ben Supnik288March 12, 2013 11:17AM
Re: T-Junctions re-visited Roland Melkert264March 12, 2013 11:22AM
Re: T-Junctions re-visited Ben Supnik277March 12, 2013 11:32AM
Re: T-Junctions re-visited Roland Melkert263March 12, 2013 11:41AM
Re: T-Junctions re-visited Ben Supnik275March 12, 2013 11:55AM
Re: T-Junctions re-visited Roland Melkert270March 13, 2013 10:08AM
Re: T-Junctions re-visited Travis Cobbs290March 13, 2013 11:27AM
Re: T-Junctions re-visited Allen Smith311March 12, 2013 02:01PM
Re: T-Junctions re-visited Michael Heidemann276March 13, 2013 09:27AM
Re: T-Junctions re-visited Ben Supnik272March 13, 2013 10:37AM
Re: T-Junctions re-visited Tim Gould262March 13, 2013 02:31PM
Re: T-Junctions re-visited Michael Heidemann264March 13, 2013 03:42PM
Re: T-Junctions re-visited Michael Heidemann264March 17, 2013 04:35AM
Re: T-Junctions re-visited Ben Supnik242March 17, 2013 08:43AM
Re: T-Junctions re-visited Michael Heidemann239March 17, 2013 08:59AM
Re: T-Junctions re-visited Ben Supnik250March 17, 2013 09:02AM
Re: T-Junctions re-visited Magnus Forsberg239March 17, 2013 09:15AM
Re: T-Junctions re-visited Travis Cobbs313March 17, 2013 10:09PM
Re: T-Junctions re-visited Ben Supnik267March 18, 2013 07:30AM
Re: T-Junctions re-visited Travis Cobbs281March 18, 2013 10:57AM
Re: T-Junctions re-visited Ben Supnik289March 18, 2013 11:27AM
Re: T-Junctions re-visited Travis Cobbs270March 18, 2013 12:23PM
Re: T-Junctions re-visited Ben Supnik291March 18, 2013 01:41PM
Re: T-Junctions re-visited Roland Melkert299March 18, 2013 02:51PM
Re: T-Junctions re-visited Travis Cobbs269March 18, 2013 02:59PM
Re: T-Junctions re-visited Roland Melkert297March 18, 2013 03:41PM
Re: T-Junctions re-visited Ben Supnik287March 18, 2013 06:09PM
Re: T-Junctions re-visited Roland Melkert292March 19, 2013 11:38AM
Re: T-Junctions re-visited Ben Supnik311March 19, 2013 11:43AM
Re: T-Junctions re-visited Roland Melkert325March 19, 2013 07:07PM
Re: T-Junctions re-visited Travis Cobbs296March 19, 2013 10:13PM
Re: T-Junctions re-visited Tim Gould280March 20, 2013 03:56AM
Re: T-Junctions re-visited Travis Cobbs270March 20, 2013 10:13AM
Re: T-Junctions re-visited Ben Supnik256March 20, 2013 10:23AM
Re: T-Junctions re-visited Travis Cobbs271March 20, 2013 10:29AM
Re: T-Junctions re-visited Travis Cobbs277March 20, 2013 10:26AM
Re: T-Junctions re-visited Ben Supnik253March 20, 2013 11:18AM
Re: T-Junctions re-visited Ben Supnik270March 20, 2013 06:42AM
Re: T-Junctions re-visited Roland Melkert264March 20, 2013 11:36AM
Re: T-Junctions re-visited Philippe Hurbain264March 20, 2013 06:36AM
Re: T-Junctions re-visited Ben Supnik275March 20, 2013 06:58AM
Re: T-Junctions re-visited Allen Smith281March 20, 2013 09:08AM
Re: T-Junctions re-visited Roland Melkert289March 20, 2013 11:35AM
Re: T-Junctions re-visited Ben Supnik677March 20, 2013 11:50AM
Re: T-Junctions re-visited Michael Heidemann288March 18, 2013 03:54PM
Re: T-Junctions re-visited Roland Melkert263March 13, 2013 10:03AM
Re: T-Junctions re-visited Tim Gould244March 13, 2013 03:56PM
Re: T-Junctions re-visited Sergio Reano251March 13, 2013 03:51PM
Re: T-Junctions re-visited Roland Melkert313March 13, 2013 04:36PM
Re: T-Junctions re-visited Tim Gould276March 13, 2013 05:10PM
Re: T-Junctions re-visited Ben Supnik257March 14, 2013 08:17PM
Re: T-Junctions re-visited Tim Gould329March 14, 2013 08:41PM
Re: T-Junctions re-visited Ben Supnik322March 15, 2013 10:56AM
Re: T-Junctions re-visited Roland Melkert274March 15, 2013 11:36AM
Re: T-Junctions re-visited Ben Supnik243March 13, 2013 06:58PM
Re: T-Junctions re-visited Roland Melkert258March 13, 2013 07:27PM
Re: T-Junctions re-visited Ben Supnik239March 13, 2013 07:37PM
Re: T-Junctions re-visited Roland Melkert257March 13, 2013 07:59PM
Re: T-Junctions re-visited Ben Supnik281March 13, 2013 08:18PM
Re: T-Junctions re-visited Travis Cobbs302March 14, 2013 03:23PM
Re: T-Junctions re-visited Roland Melkert315March 14, 2013 03:34PM
Re: T-Junctions re-visited Tim Gould327March 14, 2013 03:41PM
Re: T-Junctions re-visited Roland Melkert295March 15, 2013 11:33AM
Re: T-Junctions re-visited Tim Gould254March 13, 2013 07:43PM
Re: T-Junctions re-visited Roland Melkert251March 13, 2013 08:08PM
Re: T-Junctions re-visited Tim Gould255March 13, 2013 08:18PM
Re: T-Junctions re-visited Ben Supnik320March 14, 2013 08:15PM
Re: T-Junctions re-visited Roland Melkert312March 15, 2013 11:29AM
Re: T-Junctions re-visited Travis Cobbs282March 15, 2013 12:27PM
Re: T-Junctions re-visited Ben Supnik296March 15, 2013 05:08PM
Re: T-Junctions re-visited Travis Cobbs283March 16, 2013 11:29PM
Re: T-Junctions re-visited Ben Supnik239March 17, 2013 08:58AM
Re: T-Junctions re-visited Roland Melkert243March 17, 2013 12:35PM
Re: T-Junctions re-visited Travis Cobbs269March 18, 2013 12:28PM
Re: T-Junctions re-visited Travis Cobbs289March 18, 2013 12:32PM
Re: T-Junctions re-visited Roland Melkert278March 18, 2013 05:00PM
Re: T-Junctions re-visited Travis Cobbs311March 18, 2013 11:05PM
Re: T-Junctions re-visited Roland Melkert333March 19, 2013 11:38AM
Re: T-Junctions re-visited Sergio Reano318March 26, 2013 02:46PM
Re: T-Junctions re-visited Roland Melkert269March 27, 2013 11:19AM
Re: T-Junctions re-visited Sergio Reano320March 27, 2013 01:48PM



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