From: Gordon Tomlinson (gordon++at++gordon-tomlinson.com)
Date: 04/29/2005 02:37:22
I would hazard a guess that code for such as pfNode->isect is the same code
on all platforms, similar code I have written is. So if it works on one
platform it may suggest that its possibly the OS difference in handling
certain numbers and that you models may have some bad or iffy data in them
such as degenerate polygons etc.
Try taking one of your terrain tiles that fails in to your modelling package
and see if you can find any issues, Creator from Multigen has server tools
for finding degenerate polygons and or bad geometry etc..
Best Regards
Gordon
___________________________________
Gordon Tomlinson
Email : gordon++at++3dscenegraph.com
Yim/Aim : Gordon3dBrit
Msn Im : Gordon3dBrit++at++3dscenegraph.com
Forums : www.3dscenegraph.com/3dsceneBB
-----Original Message-----
From: owner-info-performer++at++performer.engr.sgi.com
[mailto:owner-info-performer++at++performer.engr.sgi.com] On Behalf Of Damien
Gerhardy
Sent: Friday, April 29, 2005 3:49 AM
To: info-performer++at++sgi.com
Subject: RE: [info-performer] RayCast bug in Performer 2.2 and 3.1.1 on IR
IX
Just letting you know it appears to be a problem with the terrain model we
are using. I've tried using a terrain model from another project and it
works fine.
Note: Using the terrain model from the other project when I raycast off the
edge of the terrain I get "no hits" returned from pfNode->isect.
Using the new terrain model when I raycast off the edge of the terrain I get
"1 hit" returned from pfNode which turns out to be (NaN, NaN, NaN).
Luckily this project requires using the old terrain models so I'm just going
to apply the "terrain code changes" a bit earlier in the schedule
(now!)
and hope this is the end of the problems.
Note: The new model looks fine on both windows and irix, but the raycasting
just doesn't work on irix, so I do believe this is a bug in the
pfNode->isect
code on irix!!
-Damien
>Still having problems with the raycasting of objects to the terrain. I
>applied the check below but it doesn't help. The check returns true but
>when I get the hit point it is still (NaN, NaN, NaN).
>
>Do I have to "wait" for the scene graph to stabalize for a few frames?
>or something else like that?
>
>This bug is a showstopper!!! and it needs to be fixed asap!!!!!!!
>
>If anyone has any ideas please help me out.
>Thanks.
>
>
>
It's been a while since I've run IRIX or Performer 2.2, but I do remember a
similar problem showing up in one of my apps, where we were doing terrain
following. This was on an Onyx RE2, and I believe we were using Performer
2.4. We ended up just working around it by checking the point to see if it
was NaN before using it anywhere. It seemed like the problem only happened
intermittently, and once we put the safeguard in, all was well. Linux has
the functions isnan(), isinf(), and finite() that help with this.
I'm not sure if IRIX has the same thing, but you could probably find
something equivalent on the web if not.
Not a great solution, I agree, but it may help you get the show on the road
until you can find a real solution.
--"J"
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