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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 Cobbs924March 11, 2013 10:38PM
Re: T-Junctions re-visited Tim Gould487March 11, 2013 11:31PM
Re: T-Junctions re-visited Roland Melkert425March 12, 2013 11:17AM
Re: T-Junctions re-visited Ben Supnik440March 12, 2013 11:17AM
Re: T-Junctions re-visited Roland Melkert413March 12, 2013 11:22AM
Re: T-Junctions re-visited Ben Supnik398March 12, 2013 11:32AM
Re: T-Junctions re-visited Roland Melkert387March 12, 2013 11:41AM
Re: T-Junctions re-visited Ben Supnik399March 12, 2013 11:55AM
Re: T-Junctions re-visited Roland Melkert393March 13, 2013 10:08AM
Re: T-Junctions re-visited Travis Cobbs418March 13, 2013 11:27AM
Re: T-Junctions re-visited Allen Smith428March 12, 2013 02:01PM
Re: T-Junctions re-visited Michael Heidemann413March 13, 2013 09:27AM
Re: T-Junctions re-visited Ben Supnik390March 13, 2013 10:37AM
Re: T-Junctions re-visited Tim Gould399March 13, 2013 02:31PM
Re: T-Junctions re-visited Michael Heidemann382March 13, 2013 03:42PM
Re: T-Junctions re-visited Michael Heidemann411March 17, 2013 04:35AM
Re: T-Junctions re-visited Ben Supnik357March 17, 2013 08:43AM
Re: T-Junctions re-visited Michael Heidemann354March 17, 2013 08:59AM
Re: T-Junctions re-visited Ben Supnik343March 17, 2013 09:02AM
Re: T-Junctions re-visited Magnus Forsberg367March 17, 2013 09:15AM
Re: T-Junctions re-visited Travis Cobbs431March 17, 2013 10:09PM
Re: T-Junctions re-visited Ben Supnik399March 18, 2013 07:30AM
Re: T-Junctions re-visited Travis Cobbs394March 18, 2013 10:57AM
Re: T-Junctions re-visited Ben Supnik403March 18, 2013 11:27AM
Re: T-Junctions re-visited Travis Cobbs375March 18, 2013 12:23PM
Re: T-Junctions re-visited Ben Supnik448March 18, 2013 01:41PM
Re: T-Junctions re-visited Roland Melkert461March 18, 2013 02:51PM
Re: T-Junctions re-visited Travis Cobbs436March 18, 2013 02:59PM
Re: T-Junctions re-visited Roland Melkert503March 18, 2013 03:41PM
Re: T-Junctions re-visited Ben Supnik489March 18, 2013 06:09PM
Re: T-Junctions re-visited Roland Melkert431March 19, 2013 11:38AM
Re: T-Junctions re-visited Ben Supnik442March 19, 2013 11:43AM
Re: T-Junctions re-visited Roland Melkert467March 19, 2013 07:07PM
Re: T-Junctions re-visited Travis Cobbs443March 19, 2013 10:13PM
Re: T-Junctions re-visited Tim Gould448March 20, 2013 03:56AM
Re: T-Junctions re-visited Travis Cobbs409March 20, 2013 10:13AM
Re: T-Junctions re-visited Ben Supnik406March 20, 2013 10:23AM
Re: T-Junctions re-visited Travis Cobbs436March 20, 2013 10:29AM
Re: T-Junctions re-visited Travis Cobbs411March 20, 2013 10:26AM
Re: T-Junctions re-visited Ben Supnik390March 20, 2013 11:18AM
Re: T-Junctions re-visited Ben Supnik411March 20, 2013 06:42AM
Re: T-Junctions re-visited Roland Melkert389March 20, 2013 11:36AM
Re: T-Junctions re-visited Philippe Hurbain409March 20, 2013 06:36AM
Re: T-Junctions re-visited Ben Supnik451March 20, 2013 06:58AM
Re: T-Junctions re-visited Allen Smith461March 20, 2013 09:08AM
Re: T-Junctions re-visited Roland Melkert524March 20, 2013 11:35AM
Re: T-Junctions re-visited Ben Supnik934March 20, 2013 11:50AM
Re: T-Junctions re-visited Michael Heidemann475March 18, 2013 03:54PM
Re: T-Junctions re-visited Roland Melkert395March 13, 2013 10:03AM
Re: T-Junctions re-visited Tim Gould362March 13, 2013 03:56PM
Re: T-Junctions re-visited Sergio Reano350March 13, 2013 03:51PM
Re: T-Junctions re-visited Roland Melkert439March 13, 2013 04:36PM
Re: T-Junctions re-visited Tim Gould384March 13, 2013 05:10PM
Re: T-Junctions re-visited Ben Supnik431March 14, 2013 08:17PM
Re: T-Junctions re-visited Tim Gould485March 14, 2013 08:41PM
Re: T-Junctions re-visited Ben Supnik449March 15, 2013 10:56AM
Re: T-Junctions re-visited Roland Melkert396March 15, 2013 11:36AM
Re: T-Junctions re-visited Ben Supnik349March 13, 2013 06:58PM
Re: T-Junctions re-visited Roland Melkert368March 13, 2013 07:27PM
Re: T-Junctions re-visited Ben Supnik350March 13, 2013 07:37PM
Re: T-Junctions re-visited Roland Melkert407March 13, 2013 07:59PM
Re: T-Junctions re-visited Ben Supnik410March 13, 2013 08:18PM
Re: T-Junctions re-visited Travis Cobbs477March 14, 2013 03:23PM
Re: T-Junctions re-visited Roland Melkert491March 14, 2013 03:34PM
Re: T-Junctions re-visited Tim Gould474March 14, 2013 03:41PM
Re: T-Junctions re-visited Roland Melkert448March 15, 2013 11:33AM
Re: T-Junctions re-visited Tim Gould385March 13, 2013 07:43PM
Re: T-Junctions re-visited Roland Melkert384March 13, 2013 08:08PM
Re: T-Junctions re-visited Tim Gould405March 13, 2013 08:18PM
Re: T-Junctions re-visited Ben Supnik478March 14, 2013 08:15PM
Re: T-Junctions re-visited Roland Melkert446March 15, 2013 11:29AM
Re: T-Junctions re-visited Travis Cobbs427March 15, 2013 12:27PM
Re: T-Junctions re-visited Ben Supnik414March 15, 2013 05:08PM
Re: T-Junctions re-visited Travis Cobbs437March 16, 2013 11:29PM
Re: T-Junctions re-visited Ben Supnik351March 17, 2013 08:58AM
Re: T-Junctions re-visited Roland Melkert341March 17, 2013 12:35PM
Re: T-Junctions re-visited Travis Cobbs380March 18, 2013 12:28PM
Re: T-Junctions re-visited Travis Cobbs480March 18, 2013 12:32PM
Re: T-Junctions re-visited Roland Melkert434March 18, 2013 05:00PM
Re: T-Junctions re-visited Travis Cobbs459March 18, 2013 11:05PM
Re: T-Junctions re-visited Roland Melkert521March 19, 2013 11:38AM
Re: T-Junctions re-visited Sergio Reano464March 26, 2013 02:46PM
Re: T-Junctions re-visited Roland Melkert384March 27, 2013 11:19AM
Re: T-Junctions re-visited Sergio Reano494March 27, 2013 01:48PM



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