 | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Steve Bliss
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| | | (...) Umm, so what? LDraw is not, and should not, be dependent on OpenGL. Having worked with transformation matrix in both formats, I find the row-major format much easier to hand-edit than column-major organization. At least for LDraw-type usage (...) (17 years ago, 21-Aug-07, to lugnet.cad)
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| | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Rob Ross
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| | | | (...) The "so-what" would be that I, as someone who will eventually read in these files to create OpenGL renderings of them, would expect the matrices to be in column-major order, unless explicitly stated otherwise. Rob (17 years ago, 21-Aug-07, to lugnet.cad)
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| | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Travis Cobbs
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| | | | (...) I think the original suggestion that we mention that it is in row-major format is valid. I agree that the fact that OpenGL (almost certainly one of the top two most used 3D APIs on the planet) uses column major format is a good reason to (...) (17 years ago, 21-Aug-07, to lugnet.cad)
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| | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Leonardo Zide
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| | | | | (...) You guys are both wrong, OpenGL is NOT column major. This is one of the biggest mistakes I keep hearing people repeat about OpenGL. The API doesn't care if you use column major or row major matrices, it just expects an array of 16 floats with (...) (17 years ago, 21-Aug-07, to lugnet.cad)
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| | | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Rob Ross
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| | | | | | | (...) The OpenGL 2.1 specification: page 23 Vertex Arrays "Matrices are loaded into these slots in column major order." page 43 Matrices LoadMatrix takes a pointer to a 4 × 4 matrix stored in column-major order as 16 consecutive floating-point (...) (17 years ago, 22-Aug-07, to lugnet.cad)
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| | | | | | | | | Re: OpenGL spec (was LDraw File Format spec) —William Howard
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| | | | | | | | (...) As this thread is for the discussion of the LDraw specification can any further debate of what the OpenGL specification may or may not say please be continued on .off-topic.debate Thanks William (17 years ago, 23-Aug-07, to lugnet.cad)
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| | | | | | | | | | Re: OpenGL spec (was LDraw File Format spec) —Leonardo Zide
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| | | | | | | | (...) Like I said before, the DOCS were written with column major notation but the API isn't column major. Please show me a place on the API where it requires a column major matrices, there isn't one. OpenGL matrices are simply an array of 16 (...) (17 years ago, 23-Aug-07, to lugnet.off-topic.debate)
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| | | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Travis Cobbs
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| | | | | | | (...) I think we'll just include two examples of how the data would go into a matrix in the two different directions and leave it at that. At this point, I think the best thing would be to add something like the following to the currently proposed (...) (17 years ago, 22-Aug-07, to lugnet.cad)
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| | | | | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Travis Cobbs
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| | | | | | | | (...) I thought I'd add a clarification to the above. A quick look at LDView's (URL) Change History> file will show that I only added support for spaces in submodel filenames in version 3.0. Furthermore, I listed it as an addition, not a bug fix, (...) (17 years ago, 22-Aug-07, to lugnet.cad, FTX)
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| | | | | | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Leonardo Zide
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| | | | | | | | | (...) My issue with spaces is not with programs supporting them or not, it's that the elements inside a line are delimited by spaces, you have 1 <space> color <space> x <space> ... <part> but then when it comes to file names that rule is broken. I (...) (17 years ago, 22-Aug-07, to lugnet.cad)
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| | | | | | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Don Heyse
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| | | | | | | | | (...) Ok, the whitespace debate has gone on long enough. It's been years now! Someone in the LSC needs to step up and really define what's an acceptable filename, whitespace and all. Personally I think since MLCad is established, popular, and pretty (...) (17 years ago, 23-Aug-07, to lugnet.cad, FTX)
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| | | | | | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Kevin L. Clague
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| | | | | | | | (...) Travis, I have *had to add* support for blanks in LPub, because so many kids expect to be able to use them. Unfortunatly, kids won't read the spec, they will just do what comes naturally. I'm an old goat, so I'm personally not a fan of blanks (...) (17 years ago, 28-Aug-07, to lugnet.cad, FTX)
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| | | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —William Howard
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| | | | | | | (...) So we may considered this fully, please give your reasons for this request. The file names always fall at the end of the line, so, "because it's easier to parse" has already been considered by the LSC and discarded many thanks William Howard (17 years ago, 22-Aug-07, to lugnet.cad)
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| | | | | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Leonardo Zide
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| | | | | | | | (...) I replied on another message but they are taking almost an entire day to show up. My reason is simply consistency: spaces are used to separate fields, but when it comes to file names, spaces are part of the field. If we used commas to separate (...) (17 years ago, 23-Aug-07, to lugnet.cad)
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| | | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Travis Cobbs
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| | | | | | (...) That's true. However, unless I'm badly mistaken, in addition to the xyz1 being at the end, you also need the other parameters to be in the proper direction in order to get the results that the LDraw library wants. The following two matrices (...) (17 years ago, 22-Aug-07, to lugnet.cad)
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| | | | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Leonardo Zide
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| | | | | | (...) Those matrices would be wrong in both cases (assuming xyz is the translation), you probably swapped those with the next matrices. :) (...) The first one here is a column major and the second is a row major matrix, and you are right, they are (...) (17 years ago, 22-Aug-07, to lugnet.cad)
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| | | | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Anders Isaksson
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| | | | | | (...) Are you authenticating by replying to the "Message awaiting authentication" email? If so, see my thread in lugnet.admin.general (and lugnet.-off-topic.test) about the very long delay I experience when auth-ing via email. Doing it via the web (...) (17 years ago, 23-Aug-07, to lugnet.cad)
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| | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Rob Ross
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| | | | (...) I came across the *current* LDraw file spec here: (URL) the matrix example is using column-major ordering. So now I'm really confused. Does the current spec use column-major, and the new spec is proposing to change it? Or is the current spec (...) (17 years ago, 22-Aug-07, to lugnet.cad)
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| | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Travis Cobbs
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| | | | (...) From the standpoint of OpenGL, it uses row-major ordering. There are two ways to draw a transformation matrix. OpenGL uses the following (array offsets shown after): A D G X 0 4 8 12 B E H Y 1 5 9 13 C F I Z 2 6 10 14 0 0 0 1 3 7 11 15 (...) (17 years ago, 22-Aug-07, to lugnet.cad)
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| | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Rob Ross
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| | | | (...) Hi again. What I meant was, I am confused by the (apparent) difference in what the *current* spec says on this issue, and what the new proposed spec says. If you will look at the current spec and scroll down near the end to the Line Format (...) (17 years ago, 22-Aug-07, to lugnet.cad)
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| | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Travis Cobbs
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| | | | (...) Yes, but look where the x, y, and z are. The example matrix is transposed vs the "standard" one shown in OpenGL text. If you swap the rows and columns in the above matrix, you'll get the OpenGL one. It's an alternate way of expressing a 3D (...) (17 years ago, 22-Aug-07, to lugnet.cad)
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| | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Timothy Gould
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| | | | (...) I think a full worked through example would do the specs a lot of good. If I understand right the line 1 c x y z a b c d e f g h i part.dat transforms any point by the operation (u, v, w)->(x+a*u+b*v+c*w, y+d*u+e*v+f*w, z+g*u+h*v+i*w) With it (...) (17 years ago, 22-Aug-07, to lugnet.cad)
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| | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Rob Ross
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| | | | (...) If I were new to 3D graphics (and I am ) I would be confused by this, I would have to ask someone else how to interpret the spec. I think Travis' proposal to show the two different matrices that can be built from the line of values is more (...) (17 years ago, 23-Aug-07, to lugnet.cad)
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| | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —Timothy Gould
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| | | | --snip-- (...) I'm not new to matrices and Travis' example is still a little unrigorous which is why I propose the mathematically sound form above. Note the amount of discussion already here because of what people consider 'standard' or 'given' (...) (17 years ago, 23-Aug-07, to lugnet.cad)
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| | | | | | Re: LDraw File Format Spec 1.0 DRAFT - Call for Public Comments —William Howard
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| | | | (...) I think we need to draw this particular discussion to a close. From all the comments around matrix manipulation it is clear that this part of the specification is ambiguous and so needs further consideration. Unfortunately, whatever method we (...) (17 years ago, 23-Aug-07, to lugnet.cad)
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