[osg-users] Issue with Model Display in OSG with VR Juggler

Galen Faidley gfaidley at gmail.com
Thu Jul 3 11:36:52 PDT 2008


Doug,

Thanks for getting back to Abhishek on this.  I have been working with
him on the issue as well.

We had already tried alternate default lights and the custom lighting
but nothing seemed to help (we also tried them again after your post
as a sanity check).  However, seeing the working lights in your screen
shot made us do some more experimentation.  It turns out we were not
quite using the default osgNav.  We had scaled the model by a factor
0.001.  When we removed the scale the lighting behaved as expected.
We also added the scale to the osg file and the lighting in osgviewer
looked exactly like what we originally saw in juggler (the files are
both attached).

So I guess the question is how do we scale a light or at least get
equivalently lighting with the scaled model?  I tried a number of
things: attaching the light below the scale transform, scaling the
light position, and scaling all the light parameters
(constant_attenuation, linear_attenuation, etc).  So far none of these
seem to make a difference.

We'd appreciate any insight.

Regards
Galen



On Thu, Jul 3, 2008 at 11:26 AM, Doug McCorkle <mccdo at iastate.edu> wrote:
>
> On Jul 3, 2008, at 11:06 AM, Abhishek Seth wrote:
>
>> Hi !
>>
>> I am having problems with how models look when loaded in my Application. I
>> am using OSGNav Sample program from VR Juggler 2.2.1 with OSG 2.4.  Juggler
>> uses osgUtil::SceneView but does not use osgViewer::.
>>
>> When I load the file in OsgViewer it looks great; however in Juggler's
>> OSGNav it looks awful (the colors get washed out). I suspect this is related
>> to how Juggler is handling the Materials and Lighting while rendering the
>> model.  I have spent a fair amount of time working through osgviewer.exe in
>> the debuger to try to determine the what it is doing with lighting.  It
>> seems to set up multiple lights and calls into the light::apply each frame.
>>  Juggler sets up a sigle light and never calls into the light::apply after
>> the initial set up.  Before I investigate this further I thought I'd asked
>> the list since I have the suspicion that is this something simple and
>> someone might recognive the issue my just looking at a few screen shots.  I
>> have attached screenshots for both Juggler's OSGNav & OSGViewer and also the
>> osg file them self.  Furthermore, I have also included a simple model of a
>> cube that demonstrates the same effect.
>
> I imagine this has something to do with how the light is being setup. I
> would try using different settings in the:
>
> http://developer.vrjuggler.org/docs/vrjuggler/2.2/programmer.reference/classvrj_1_1OsgApp.html#1b1994aa3043cd522e749853595d4796
>
> or setup your own light:
>
> http://developer.vrjuggler.org/docs/vrjuggler/2.2/programmer.reference/classvrj_1_1OsgApp.html#e0a9dc2d8da29770af997f811df10144
>
> Here is what your data looks like in my VR Juggler / OSG app.
>
> Doug
>
>
>
>
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>
>
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