 | | Re: Inverse matrix?
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(...) I just realised something... do you want a general inverse or a specific inverse? Some inversions are simple eg. a pure rotation can be inverted by taking its transpose and reflections are their own inverses. Tim (18 years ago, 7-Apr-07, to lugnet.cad.ray, lugnet.cad)
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| | Re: how does a line ends?
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(...) Just as a proof of the value of disk caching, loading the same model using the system fgets after a fresh reboot, the same loading portion took 3300ms. Also, I switched the feof calls out for a check of the value against EOF just to see if it (...) (18 years ago, 7-Apr-07, to lugnet.cad, FTX)
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| | Re: how does a line ends?
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(...) (URL) Google to the rescue>. ROSCO (18 years ago, 7-Apr-07, to lugnet.cad, FTX)
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| | Re: how does a line ends?
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(...) Quick question. I was in a hurry, and wanted to play it safe, so I call feof instead of checking to see if char1 == EOF. Any idea what gets returned for extended ASCII characters (>= 128)? Does the int contain positive numbers greater than (...) (18 years ago, 7-Apr-07, to lugnet.cad, FTX)
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| | Re: how does a line ends?
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(...) I timed the file reading/parsing portion of the model load. It would have been more difficult to time the actual amount of time spent inside fgets/myFgets, so realistically it's likely that myFgets is even slower in comparison to fgets. The (...) (18 years ago, 7-Apr-07, to lugnet.cad, FTX)
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| | Re: Inverse matrix?
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(...) There really is no easy way to do it. Feel free to look at TCVector::invertMatrix in the LDView code if you want to see code that does it on a 4x4 matrix. To convert a 3x3 matrix into a 4x4 matrix, put the 3x3 in the top left, put a 1 in the (...) (18 years ago, 7-Apr-07, to lugnet.cad.ray, lugnet.cad)
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| | NEW VERSION! Re: Conversion file for ldraw to ldd
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(...) Mike Gallagher has very kindly uploaded his improved version of ldraw.xml to (URL) I recommend using it. Tim (18 years ago, 7-Apr-07, to lugnet.cad.ldd)
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| | Re: Conversion file for ldraw to ldd
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(...) I will do that. Thanks for all the help and the ldraw.xml file. I loaded mine as it is today. I have a bunch more I need to do and I should have those done by Tuesday or so. I made this version 1.01a for starters and will keep most up to date (...) (18 years ago, 7-Apr-07, to lugnet.cad.ldd)
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| | Re: how does a line ends?
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(...) That was quick! Thanks for taking the time to indulge me... (...) It is interesting that it was that much time difference. Are these the total load times, or just profiling of the time spent inside the fgets() routines? I see one or two things (...) (18 years ago, 7-Apr-07, to lugnet.cad, FTX)
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| | Re: Conversion file for ldraw to ldd
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--snip-- (...) Hi Mike, It's my understanding [1] that we're allowed to post our own Ldraw.xml files so perhaps you could upload yours to Brickshelf. That way people can be sure that they've got the fixes right and the XML file can grow with fixes (...) (18 years ago, 7-Apr-07, to lugnet.cad.ldd)
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| | Re: Conversion file for ldraw to ldd
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(...) I also fixed these. First 2 I just had to fix placement, 3rd one I created a “transformation” and “brick ldraw” lines, the 4th I only had to add the “transformation” line, you all ready had the “brick ldraw” line. But 3069b and 3068b I could (...) (18 years ago, 7-Apr-07, to lugnet.cad.ldd)
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| | Re: how does a line ends?
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(...) Yes, sorry that my post sounded overly defensive. I have something of a chip on my shoulder from years of working alongside programmers who want to take shortcuts at the expense of their users. Very few seem to appreciate that it is worth a (...) (18 years ago, 7-Apr-07, to lugnet.cad, FTX)
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| | Re: Conversion file for ldraw to ldd
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(...) Me too to some degree. (...) I believe the system may be (incorrectly) case sensitive when reading LDraw files. Perhaps add b and B options. It's also possible this particular aspect is not yet programmed completely. Furthermore when (...) (18 years ago, 7-Apr-07, to lugnet.cad.ldd)
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| | Re: Conversion file for ldraw to ldd
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(...) I have been trying to correct some of the errors when exporting from LDD > LDR, and not being a programmer I have come to a dead end. I have been able to correct some of the parts that would show up but not in the correct location or rotation. (...) (18 years ago, 7-Apr-07, to lugnet.cad.ldd)
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| | Re: Inverse matrix?
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(...) The inverse of <1,0,0,0,1,0,0,0,1,0,0,0> is itself. To compute the inverse of a general 3x3 matrix (essentially what you need to do) is rather complicated. You could do it in a macro using Gaussian elimination [1]. Tim [1] (URL) (18 years ago, 7-Apr-07, to lugnet.cad.ray, lugnet.cad)
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| | Re: how does a line ends?
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(...) OK, as promised, here it my fgets replacement: char *myFgets(char *buf, int bufSize, FILE *file) int i; for (i = 0; i < bufSize - 1; i++) int char1 = fgetc(file); if (feof(file)) bufi = 0; if (i > 0) return buf; else return NULL; if (char1 == (...) (18 years ago, 7-Apr-07, to lugnet.cad, FTX)
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| | Inverse matrix?
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Does anyone know how to generate an inverse matrix. By inverse I mean it will undo the rotation of the original matrix. I thought the inverse of <1,0,0,0,1,0,0,0,1,0,0,0> was <-1,0,0,0,-1,0,0,0,-1,0,0,0>. In other words, multiply every value by -1. (...) (18 years ago, 7-Apr-07, to lugnet.cad.ray, lugnet.cad)
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| | Re: how does a line ends?
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(...) You'll note that I didn't really say that there was anything wrong with your parsing routine (other than some personaly negative feelings about fgetc and ungetc). After fixing the bugs, it will do exactly what you say it will do. It's just (...) (18 years ago, 7-Apr-07, to lugnet.cad, FTX)
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| | Re: how does a line end?
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(...) Aaah, that's one of my most common mistakes. C is the third letter, so I think of it as 13 and not 12. (...) At last, someone agrees with me. :) There will still be a theoretical risk that problems will occur, "anything that can go wrong will (...) (18 years ago, 7-Apr-07, to lugnet.cad)
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| | Re: how does a line end?
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Tore Eriksson schrieb: (...) After read all this and also after I have had a look at (URL) I think that Tore is right by saying "read all and save secure". Do avoid for future discussions this should be mentioned also in the LDraw Specification. (...) (18 years ago, 7-Apr-07, to lugnet.cad)
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