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Hi Lothar ;o)
> all determinants too small
As you mention later in your message, this is a problem related
to mesh2 and triangles that carry a texture at each vertex. This question
has been asked by Warp in this group [message of 2001-06-28] and I posted
an answer - a bit late actually.
The code was designed for interpolating 3 colors between the corners
of a triangle, as written by A. Philippsen (you might know him: author of
the DINO software). Later, Nathan Kopp improved the code to get full texture
interpolation instead of colors only. But the code is rather not optimized,
and some times you have a small problems that give this message. This most
probably happen with "degenerate" triangles (part of them include triangles
that have 2 or 3 identical vertices). IMHO this message can thus be simply
ignored, it won't affect rendering.
> In addition to that it seems very slow. I don't know whether this is a
> related error or whether mesh2 can get slow.
On my pov4grasp page I did extensive benchmarks using mesh2 and
interpolated-color-textures in mesh2 objects and did not notice particular
difference in speed (as compared to original mesh object + Chris Colefax's
macros, or my custom mesh object). I'm talking about rendering speed of
course, not parsing. See http://pov4grasp.free.fr/features/grasp_surface.php3
For more discussions, don't hesitate to contact me by normal mail
(my adress at work is prefered).
*** Nicolas Calimet
*** http://pov4grasp.free.fr
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Hi,
within the next five minutes I sent this mail off I checked the code and
found
the message in triangle.c. My guess was as you now confirmed that this is due to
an error in the triangle texture interpolation. However I could not create
manually
a situation that created this error. I have run an example with a triangle, that
worked
fine, then I made two vertices the same, still every thing okay ( no error
message ) but
of course no object was drawn, not even a line and finally I made all points the
same
:again no complaints. So I don't know what the problem actually is. But it seems
it
is save to ignore for the moment.
About my second question I found out that I suffered a tremendous performance
hit
when I use +MV3.0 switch ! Megapov is just 5-10 times slower ( rendering ). Does
any
one know why ? BTW povray 3.1 does not get slower at all - so it would seem.
( Not that is really important but puzzling if you are trying to use older style
code )
Thanks,
Lothar
Nicolas Calimet wrote:
> Hi Lothar ;o)
>
> > all determinants too small
>
> As you mention later in your message, this is a problem related
> to mesh2 and triangles that carry a texture at each vertex. This question
> has been asked by Warp in this group [message of 2001-06-28] and I posted
> an answer - a bit late actually.
> The code was designed for interpolating 3 colors between the corners
> of a triangle, as written by A. Philippsen (you might know him: author of
> the DINO software). Later, Nathan Kopp improved the code to get full texture
> interpolation instead of colors only. But the code is rather not optimized,
> and some times you have a small problems that give this message. This most
> probably happen with "degenerate" triangles (part of them include triangles
> that have 2 or 3 identical vertices). IMHO this message can thus be simply
> ignored, it won't affect rendering.
>
> > In addition to that it seems very slow. I don't know whether this is a
> > related error or whether mesh2 can get slow.
>
> On my pov4grasp page I did extensive benchmarks using mesh2 and
> interpolated-color-textures in mesh2 objects and did not notice particular
> difference in speed (as compared to original mesh object + Chris Colefax's
> macros, or my custom mesh object). I'm talking about rendering speed of
> course, not parsing. See http://pov4grasp.free.fr/features/grasp_surface.php3
>
> For more discussions, don't hesitate to contact me by normal mail
> (my adress at work is prefered).
>
> *** Nicolas Calimet
> *** http://pov4grasp.free.fr
--
Dr. Lothar Esser
NIH / NCI
Tel. 301-435-6163
email les### [at] helix nihgov
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