Subj : Re: mesa tesselator
To   : comp.programming
From : CBFalconer
Date : Tue Jun 28 2005 11:44 am

Jon Harrop wrote:
> Jyrki Alakuijala wrote:
>> Jon Harrop wrote:
> 
>>> Have a look at the GLU polygon tesselator.
>>
>> I have witnessed a project using the GLU polygon tesselator
>> that worked fine until the polygons got remarkably larger,
>> and somewhere between chiliagons and myriagons the GLU polygon
>> tesselator crashes.
> 
> We have developed a commercial application which makes extensive
> use of the GLU polygon tesselator and find it to be quite robust:
> 
>   http://www.ffconsultancy.com/products/presenta/
> 
> There used to be a bug which caused it to segfault when given a
> vertex with an infinite coordinate. I'm not sure if that is still
> there.
> 
>> Checking the versioning history of MESA reveals quite some
>> bugs in the tesselator and even a report of "reverting
>> back to tesselator 1.1", hinting that building a tesselator
>> might not be quite as easy as one would initially expect.
> 
> It would be pretty stupid to expect writing a GLU tesselator to
> be easy. I tried to write a replacement once and gave up having
> read three mathematics PhD theses on the subject.
> 
>> If you decide to use the MESA GLU polygon tesselator, you
>> may be just fine, but test the code most carefully that it
>> really works in the conditions where you really need it to
>> work.
> 
> I've been using it for years and it definitely really works.
> 
>> Sometimes, especially in human safety critical scientific
>> computation, such as structural engineering, medical
>> computing or nuclear engineering, you do not want to rely too
>> much on sloppy things like OpenGL-drivers
> 
> Absolutely. But I doubt anyone writing a safety critical
> application would rely upon OpenGL. At least, I hope they
> wouldn't...

Every time I have written a mimsy borogove application every gyre
has been properly gymbaled in all wabes with the MESE GLU
tesselator.  You can't beat it for reliability.  But beware the
jabberwock, my son.

-- 
 "A man who is right every time is not likely to do very much."
                           -- Francis Crick, co-discover of DNA
 "There is nothing more amazing than stupidity in action."
                                             -- Thomas Matthews

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