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Am 06.09.2018 um 12:51 schrieb Bald Eagle:
>> The question you ASKED was:
>>
>> "Probably a dumb question, but can only meshes be UV mapped?"
>
>
> NOPE.
>
>
http://news.povray.org/povray.binaries.images/message/%3C5b8a7142%241%40news.povray.org%3E/#%3C5b8a7142%241%40news.povr
> ay.org%3E
Ooops, my mistake - that was indeed Mike who asked that. So your
question was - and I quote verbatim:
""
Great. How am I supposed to interpret and answer THAT?
42. There. You have your answer.
>>> Kenneth. I want Kenneth as my POV-Ray lawyer.
>>
>> Who, BTW, explicitly confirmed that /my/ reply to that thread - and I
>> quote verbatim - "was... reasonable" ;)
>
> [ Way to move the goalposts. ]
Some people accuse me of being a dick, so yes, I treasure any positive
mention ;)
> Indeed, but that particular post bordered on fisticuffs with someone else, and
> exemplified the ideology of, "You don't like it? Tough ----"
Interestingly, that person had already stepped down from any position of
authority to decide what needs fixing in POV-Ray and what doesn't.
> But the documentation is still incomplete, right where I said it was and why.
>
> Why can't you just admit it when you're WRONG?
It runs in the family. A long line of teachers and Prussian public
officials meets stubborn Westphalian farmers.
> Hrrrrmpfh. MEN.
And then there's that, yes.
:)
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Update:
I managed to work out a system by which I can calculate a 2D parametric function
to "draw" on the "global" UV-patch, determine which patch each particular point
is on, and what the uv coordinates are for that point on the patch.
Then I take those uv coordinates and use the Bernstein polynomials to map it
onto the Bezier patch on the surface of the torus.
Confused the hell out of me, took way longer than it should have, and some bugs
seem to have crept in, but all the code is there, and now I think I can go back,
refactor everything, tighten up the code a bit, and see where the errors are.
It's _supposed to be_ a noiseless torus with a coil wrapping around it 5 times -
but these things almost never work out right the first time around.
And I still need to write functions for partial derivatives to get tangent
vectors, and then cross those vectors to get the normals.
Post a reply to this message
Attachments:
Download 'bezierstitching_test_3.png' (632 KB)
Preview of image 'bezierstitching_test_3.png'
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"Bald Eagle" <cre### [at] netscape net> wrote:
> Update:
> It's _supposed to be_ a noiseless torus with a coil wrapping around it 5 times -
> but these things almost never work out right the first time around.
OHHHHhhhhhh, so much debugging.
Still a little glitch to work out, but it's super close.
> And I still need to write functions for partial derivatives to get tangent
> vectors, and then cross those vectors to get the normals.
I think this should be trivial in comparison. :D
So - here's a coil wrapping around a torus 5 times. Super easy as a sphere
weep and parametric or isosurface or polynomial... but if the torus is
deformed...
With the bicubic_patch system, everything follows the surface of the torus.
Apologies for my complete lack of artistic talent on short notice.
It's a proof-of-concept WIP.
Post a reply to this message
Attachments:
Download 'bezierstitchedtoruswithcurve.png' (997 KB)
Preview of image 'bezierstitchedtoruswithcurve.png'
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Nice trash torus!
Am 18.09.2018 um 21:11 schrieb Bald Eagle:
> [...] Super easy as a sphere weep [...]
Yeah, sometimes that's exactly what that primitive is ;)
> Apologies for my complete lack of artistic talent on short notice.
I disagreed with you previously, and I disagree with you now ;)
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On 18-9-2018 21:28, clipka wrote:
> Nice trash torus!
>
>
> Am 18.09.2018 um 21:11 schrieb Bald Eagle:
>
>> [...] Super easy as a sphere weep [...]
>
> Yeah, sometimes that's exactly what that primitive is ;)
I am out of handkerchiefs...
>
>
>> Apologies for my complete lack of artistic talent on short notice.
>
> I disagreed with you previously, and I disagree with you now ;)
>
Me too! This one is fine!
--
Thomas
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On 09/18/2018 03:11 PM, Bald Eagle wrote:
> "Bald Eagle" <cre### [at] netscapenet> wrote:
>> Update:
>
...
> So - here's a coil wrapping around a torus 5 times. Super easy as a sphere
> weep and parametric or isosurface or polynomial... but if the torus is
> deformed...
>
> With the bicubic_patch system, everything follows the surface of the torus.
> Apologies for my complete lack of artistic talent on short notice.
> It's a proof-of-concept WIP.
>
Ah, neat! Apology unnecessary - I like it.
Bill P.
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Thanks, I'm never quite sure what to use for an image map, but this one worked
out fairly well.
Technical aside:
While working on this, and reviewing the code, I noticed that the bicubic_patch
block doesn't allow trailing commas in the list of the control points.
Is this something that can be addressed without too much hassle?
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Am 19.09.2018 um 18:26 schrieb Bald Eagle:
> Thanks, I'm never quite sure what to use for an image map, but this one worked
> out fairly well.
>
>
> Technical aside:
>
> While working on this, and reviewing the code, I noticed that the bicubic_patch
> block doesn't allow trailing commas in the list of the control points.
> Is this something that can be addressed without too much hassle?
Yes, that could be done. Actually it would simplify the parser for
bicubic patch.
I'm not even sure why an extra comma explicitly forbidden - it's rather
unusual style in POV-Ray. Maybe it was implemented before commas were
made always optional, or the person implementing this piece of the
parser didn't know that.
I'm also looking at the matrix syntax while I'm at it.
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Le 18-09-18 à 15:11, Bald Eagle a écrit :
> So - here's a coil wrapping around a torus 5 times. Super easy as a sphere
> weep and parametric or isosurface or polynomial... but if the torus is
> deformed...
>
5 times around ? Then, why to I count 12 rotations ?
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Alain <kua### [at] videotronca> wrote:
> Le 18-09-18 à 15:11, Bald Eagle a écrit :
>
> > So - here's a coil wrapping around a torus 5 times. Super easy as a sphere
> > weep and parametric or isosurface or polynomial... but if the torus is
> > deformed...
> >
> 5 times around ? Then, why to I count 12 rotations ?
We use common core principles to guess at the floating-point values, and when
you do that, 5 = 12 for sufficiently large values of 5.
No really, I started off with 5, and decided it looked better with 12.
It was a counting test - you passed! :D
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