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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 Cobbs802March 11, 2013 10:38PM
Re: T-Junctions re-visited Tim Gould406March 11, 2013 11:31PM
Re: T-Junctions re-visited Roland Melkert375March 12, 2013 11:17AM
Re: T-Junctions re-visited Ben Supnik394March 12, 2013 11:17AM
Re: T-Junctions re-visited Roland Melkert364March 12, 2013 11:22AM
Re: T-Junctions re-visited Ben Supnik351March 12, 2013 11:32AM
Re: T-Junctions re-visited Roland Melkert341March 12, 2013 11:41AM
Re: T-Junctions re-visited Ben Supnik351March 12, 2013 11:55AM
Re: T-Junctions re-visited Roland Melkert349March 13, 2013 10:08AM
Re: T-Junctions re-visited Travis Cobbs372March 13, 2013 11:27AM
Re: T-Junctions re-visited Allen Smith381March 12, 2013 02:01PM
Re: T-Junctions re-visited Michael Heidemann367March 13, 2013 09:27AM
Re: T-Junctions re-visited Ben Supnik354March 13, 2013 10:37AM
Re: T-Junctions re-visited Tim Gould353March 13, 2013 02:31PM
Re: T-Junctions re-visited Michael Heidemann340March 13, 2013 03:42PM
Re: T-Junctions re-visited Michael Heidemann375March 17, 2013 04:35AM
Re: T-Junctions re-visited Ben Supnik309March 17, 2013 08:43AM
Re: T-Junctions re-visited Michael Heidemann311March 17, 2013 08:59AM
Re: T-Junctions re-visited Ben Supnik305March 17, 2013 09:02AM
Re: T-Junctions re-visited Magnus Forsberg328March 17, 2013 09:15AM
Re: T-Junctions re-visited Travis Cobbs384March 17, 2013 10:09PM
Re: T-Junctions re-visited Ben Supnik348March 18, 2013 07:30AM
Re: T-Junctions re-visited Travis Cobbs339March 18, 2013 10:57AM
Re: T-Junctions re-visited Ben Supnik352March 18, 2013 11:27AM
Re: T-Junctions re-visited Travis Cobbs342March 18, 2013 12:23PM
Re: T-Junctions re-visited Ben Supnik377March 18, 2013 01:41PM
Re: T-Junctions re-visited Roland Melkert396March 18, 2013 02:51PM
Re: T-Junctions re-visited Travis Cobbs366March 18, 2013 02:59PM
Re: T-Junctions re-visited Roland Melkert434March 18, 2013 03:41PM
Re: T-Junctions re-visited Ben Supnik408March 18, 2013 06:09PM
Re: T-Junctions re-visited Roland Melkert360March 19, 2013 11:38AM
Re: T-Junctions re-visited Ben Supnik383March 19, 2013 11:43AM
Re: T-Junctions re-visited Roland Melkert403March 19, 2013 07:07PM
Re: T-Junctions re-visited Travis Cobbs375March 19, 2013 10:13PM
Re: T-Junctions re-visited Tim Gould379March 20, 2013 03:56AM
Re: T-Junctions re-visited Travis Cobbs347March 20, 2013 10:13AM
Re: T-Junctions re-visited Ben Supnik340March 20, 2013 10:23AM
Re: T-Junctions re-visited Travis Cobbs370March 20, 2013 10:29AM
Re: T-Junctions re-visited Travis Cobbs347March 20, 2013 10:26AM
Re: T-Junctions re-visited Ben Supnik330March 20, 2013 11:18AM
Re: T-Junctions re-visited Ben Supnik365March 20, 2013 06:42AM
Re: T-Junctions re-visited Roland Melkert326March 20, 2013 11:36AM
Re: T-Junctions re-visited Philippe Hurbain363March 20, 2013 06:36AM
Re: T-Junctions re-visited Ben Supnik408March 20, 2013 06:58AM
Re: T-Junctions re-visited Allen Smith389March 20, 2013 09:08AM
Re: T-Junctions re-visited Roland Melkert430March 20, 2013 11:35AM
Re: T-Junctions re-visited Ben Supnik854March 20, 2013 11:50AM
Re: T-Junctions re-visited Michael Heidemann403March 18, 2013 03:54PM
Re: T-Junctions re-visited Roland Melkert354March 13, 2013 10:03AM
Re: T-Junctions re-visited Tim Gould320March 13, 2013 03:56PM
Re: T-Junctions re-visited Sergio Reano314March 13, 2013 03:51PM
Re: T-Junctions re-visited Roland Melkert390March 13, 2013 04:36PM
Re: T-Junctions re-visited Tim Gould339March 13, 2013 05:10PM
Re: T-Junctions re-visited Ben Supnik368March 14, 2013 08:17PM
Re: T-Junctions re-visited Tim Gould418March 14, 2013 08:41PM
Re: T-Junctions re-visited Ben Supnik408March 15, 2013 10:56AM
Re: T-Junctions re-visited Roland Melkert358March 15, 2013 11:36AM
Re: T-Junctions re-visited Ben Supnik309March 13, 2013 06:58PM
Re: T-Junctions re-visited Roland Melkert319March 13, 2013 07:27PM
Re: T-Junctions re-visited Ben Supnik314March 13, 2013 07:37PM
Re: T-Junctions re-visited Roland Melkert340March 13, 2013 07:59PM
Re: T-Junctions re-visited Ben Supnik342March 13, 2013 08:18PM
Re: T-Junctions re-visited Travis Cobbs407March 14, 2013 03:23PM
Re: T-Junctions re-visited Roland Melkert420March 14, 2013 03:34PM
Re: T-Junctions re-visited Tim Gould404March 14, 2013 03:41PM
Re: T-Junctions re-visited Roland Melkert405March 15, 2013 11:33AM
Re: T-Junctions re-visited Tim Gould352March 13, 2013 07:43PM
Re: T-Junctions re-visited Roland Melkert320March 13, 2013 08:08PM
Re: T-Junctions re-visited Tim Gould342March 13, 2013 08:18PM
Re: T-Junctions re-visited Ben Supnik408March 14, 2013 08:15PM
Re: T-Junctions re-visited Roland Melkert400March 15, 2013 11:29AM
Re: T-Junctions re-visited Travis Cobbs380March 15, 2013 12:27PM
Re: T-Junctions re-visited Ben Supnik366March 15, 2013 05:08PM
Re: T-Junctions re-visited Travis Cobbs390March 16, 2013 11:29PM
Re: T-Junctions re-visited Ben Supnik295March 17, 2013 08:58AM
Re: T-Junctions re-visited Roland Melkert296March 17, 2013 12:35PM
Re: T-Junctions re-visited Travis Cobbs340March 18, 2013 12:28PM
Re: T-Junctions re-visited Travis Cobbs416March 18, 2013 12:32PM
Re: T-Junctions re-visited Roland Melkert368March 18, 2013 05:00PM
Re: T-Junctions re-visited Travis Cobbs397March 18, 2013 11:05PM
Re: T-Junctions re-visited Roland Melkert450March 19, 2013 11:38AM
Re: T-Junctions re-visited Sergio Reano393March 26, 2013 02:46PM
Re: T-Junctions re-visited Roland Melkert334March 27, 2013 11:19AM
Re: T-Junctions re-visited Sergio Reano429March 27, 2013 01:48PM



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