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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 Cobbs732March 11, 2013 10:38PM
Re: T-Junctions re-visited Tim Gould356March 11, 2013 11:31PM
Re: T-Junctions re-visited Roland Melkert336March 12, 2013 11:17AM
Re: T-Junctions re-visited Ben Supnik352March 12, 2013 11:17AM
Re: T-Junctions re-visited Roland Melkert332March 12, 2013 11:22AM
Re: T-Junctions re-visited Ben Supnik321March 12, 2013 11:32AM
Re: T-Junctions re-visited Roland Melkert311March 12, 2013 11:41AM
Re: T-Junctions re-visited Ben Supnik323March 12, 2013 11:55AM
Re: T-Junctions re-visited Roland Melkert324March 13, 2013 10:08AM
Re: T-Junctions re-visited Travis Cobbs346March 13, 2013 11:27AM
Re: T-Junctions re-visited Allen Smith346March 12, 2013 02:01PM
Re: T-Junctions re-visited Michael Heidemann332March 13, 2013 09:27AM
Re: T-Junctions re-visited Ben Supnik316March 13, 2013 10:37AM
Re: T-Junctions re-visited Tim Gould318March 13, 2013 02:31PM
Re: T-Junctions re-visited Michael Heidemann312March 13, 2013 03:42PM
Re: T-Junctions re-visited Michael Heidemann336March 17, 2013 04:35AM
Re: T-Junctions re-visited Ben Supnik281March 17, 2013 08:43AM
Re: T-Junctions re-visited Michael Heidemann278March 17, 2013 08:59AM
Re: T-Junctions re-visited Ben Supnik280March 17, 2013 09:02AM
Re: T-Junctions re-visited Magnus Forsberg304March 17, 2013 09:15AM
Re: T-Junctions re-visited Travis Cobbs355March 17, 2013 10:09PM
Re: T-Junctions re-visited Ben Supnik319March 18, 2013 07:30AM
Re: T-Junctions re-visited Travis Cobbs315March 18, 2013 10:57AM
Re: T-Junctions re-visited Ben Supnik321March 18, 2013 11:27AM
Re: T-Junctions re-visited Travis Cobbs313March 18, 2013 12:23PM
Re: T-Junctions re-visited Ben Supnik335March 18, 2013 01:41PM
Re: T-Junctions re-visited Roland Melkert353March 18, 2013 02:51PM
Re: T-Junctions re-visited Travis Cobbs323March 18, 2013 02:59PM
Re: T-Junctions re-visited Roland Melkert399March 18, 2013 03:41PM
Re: T-Junctions re-visited Ben Supnik361March 18, 2013 06:09PM
Re: T-Junctions re-visited Roland Melkert327March 19, 2013 11:38AM
Re: T-Junctions re-visited Ben Supnik343March 19, 2013 11:43AM
Re: T-Junctions re-visited Roland Melkert363March 19, 2013 07:07PM
Re: T-Junctions re-visited Travis Cobbs338March 19, 2013 10:13PM
Re: T-Junctions re-visited Tim Gould329March 20, 2013 03:56AM
Re: T-Junctions re-visited Travis Cobbs312March 20, 2013 10:13AM
Re: T-Junctions re-visited Ben Supnik304March 20, 2013 10:23AM
Re: T-Junctions re-visited Travis Cobbs329March 20, 2013 10:29AM
Re: T-Junctions re-visited Travis Cobbs315March 20, 2013 10:26AM
Re: T-Junctions re-visited Ben Supnik294March 20, 2013 11:18AM
Re: T-Junctions re-visited Ben Supnik323March 20, 2013 06:42AM
Re: T-Junctions re-visited Roland Melkert297March 20, 2013 11:36AM
Re: T-Junctions re-visited Philippe Hurbain322March 20, 2013 06:36AM
Re: T-Junctions re-visited Ben Supnik373March 20, 2013 06:58AM
Re: T-Junctions re-visited Allen Smith347March 20, 2013 09:08AM
Re: T-Junctions re-visited Roland Melkert358March 20, 2013 11:35AM
Re: T-Junctions re-visited Ben Supnik767March 20, 2013 11:50AM
Re: T-Junctions re-visited Michael Heidemann357March 18, 2013 03:54PM
Re: T-Junctions re-visited Roland Melkert322March 13, 2013 10:03AM
Re: T-Junctions re-visited Tim Gould288March 13, 2013 03:56PM
Re: T-Junctions re-visited Sergio Reano284March 13, 2013 03:51PM
Re: T-Junctions re-visited Roland Melkert358March 13, 2013 04:36PM
Re: T-Junctions re-visited Tim Gould312March 13, 2013 05:10PM
Re: T-Junctions re-visited Ben Supnik325March 14, 2013 08:17PM
Re: T-Junctions re-visited Tim Gould366March 14, 2013 08:41PM
Re: T-Junctions re-visited Ben Supnik368March 15, 2013 10:56AM
Re: T-Junctions re-visited Roland Melkert311March 15, 2013 11:36AM
Re: T-Junctions re-visited Ben Supnik279March 13, 2013 06:58PM
Re: T-Junctions re-visited Roland Melkert290March 13, 2013 07:27PM
Re: T-Junctions re-visited Ben Supnik280March 13, 2013 07:37PM
Re: T-Junctions re-visited Roland Melkert298March 13, 2013 07:59PM
Re: T-Junctions re-visited Ben Supnik314March 13, 2013 08:18PM
Re: T-Junctions re-visited Travis Cobbs353March 14, 2013 03:23PM
Re: T-Junctions re-visited Roland Melkert368March 14, 2013 03:34PM
Re: T-Junctions re-visited Tim Gould365March 14, 2013 03:41PM
Re: T-Junctions re-visited Roland Melkert354March 15, 2013 11:33AM
Re: T-Junctions re-visited Tim Gould320March 13, 2013 07:43PM
Re: T-Junctions re-visited Roland Melkert289March 13, 2013 08:08PM
Re: T-Junctions re-visited Tim Gould303March 13, 2013 08:18PM
Re: T-Junctions re-visited Ben Supnik371March 14, 2013 08:15PM
Re: T-Junctions re-visited Roland Melkert366March 15, 2013 11:29AM
Re: T-Junctions re-visited Travis Cobbs348March 15, 2013 12:27PM
Re: T-Junctions re-visited Ben Supnik338March 15, 2013 05:08PM
Re: T-Junctions re-visited Travis Cobbs351March 16, 2013 11:29PM
Re: T-Junctions re-visited Ben Supnik270March 17, 2013 08:58AM
Re: T-Junctions re-visited Roland Melkert275March 17, 2013 12:35PM
Re: T-Junctions re-visited Travis Cobbs313March 18, 2013 12:28PM
Re: T-Junctions re-visited Travis Cobbs368March 18, 2013 12:32PM
Re: T-Junctions re-visited Roland Melkert322March 18, 2013 05:00PM
Re: T-Junctions re-visited Travis Cobbs356March 18, 2013 11:05PM
Re: T-Junctions re-visited Roland Melkert399March 19, 2013 11:38AM
Re: T-Junctions re-visited Sergio Reano356March 26, 2013 02:46PM
Re: T-Junctions re-visited Roland Melkert303March 27, 2013 11:19AM
Re: T-Junctions re-visited Sergio Reano379March 27, 2013 01:48PM



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