On 05/15/2017 12:46 PM, clipka wrote:
> Folks,
>
> I'm trying out a new approach at fixing the sphere sweep issues; please
> give this version a thorough test:
>
> https://github.com/POV-Ray/povray/tree/experimental/sphere_sweep
>
> I'll build Windows binaries as soon as I find the time.
>
Absolutely a big improvement across my problem sphere_sweep problem
collection - and more or less at speed.
1) We still sometimes get noise in the end result which I think AA will
mostly clean up. The nosiest example is yours from Github #147:
https://github.com/POV-Ray/povray/issues/147
see the attached: LipkaFS81_Apr2010_Example.png image.
2) There is still too the ill formed polynomial into the solver planar
when the segment coordinates are planar and the ray is perpendicular to
the plane. See: Qfyd_Pete00_Jan19_2005.png where the scene is set up
with an orthographic camera and the b_spline is in a plane perpendicular
to all camera rays.
For such situations I was playing with the idea of checking for this
special ill formed polynomial case; finding the ray intersection with th
plane; testing if the point was this->Inside the sphere_sweep (the
inside root solver test appears to be pretty stable result wise); then
doing some magic with perturbed inside points I'd not sorted out... Code
I have isn't too long so I'll include it too as an attachment with the
thought you can probably get to a solution this faster than I can.
3) We are still exposed some to badly formed input splines. The original
FS81/GH147 is somewhat this case. Thought about adding some sanity
testing in the parser. Doing this generally is probably not possible,
but perhaps something like control point spacing > some multiple of the
max of the two radius values would make some sense. Is it worth it?
Bill P.
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Attachments:
Download 'lipkafs81_apr2010_example.png' (32 KB)
Download 'qfyd_pete00_jan19_2005.png' (12 KB)
Download 'workingcodefor2.txt' (3 KB)
Preview of image 'lipkafs81_apr2010_example.png'
Preview of image 'qfyd_pete00_jan19_2005.png'
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