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Hi Werner,<br>
<br>
I do not know if I have found the code that you are suggesting. I
see that CullVisitor could help to find the near and far plane,
however with Z I meant the world vertical axis, not the axis of the
view frustum.<br>
<br>
Regards,<br>
Renzo<br>
<br>
<div class="moz-cite-prefix">On 15-Oct-20 11:25 AM, OpenSceneGraph
Users wrote:<br>
</div>
<blockquote type="cite" cite="mid:mailman.21793.1602753923.3538.osg-users-openscenegraph.org@lists.openscenegraph.org">
<p dir="ltr">Hi Renzo,<br>
Maybe a node visitor with z-near and z-far as parameter is a
possible approach.<br>
Werner</p>
<br>
<br>
<div class="gmail_quote">On 15. Oktober 2020 09:46:57 MESZ,
OpenSceneGraph Users <a class="moz-txt-link-rfc2396E" href="mailto:osg-users@lists.openscenegraph.org"><osg-users@lists.openscenegraph.org></a>
wrote:
<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt
0.8ex; border-left: 1px solid rgb(204, 204, 204);
padding-left: 1ex;"> <br>
Hi Robert,<br>
<br>
<div class="moz-cite-prefix">On 14-Oct-20 3:56 PM,
OpenSceneGraph Users wrote:<br>
</div>
<blockquote type="cite" cite="mid:mailman.21167.1602683796.3540.osg-users-openscenegraph.org@lists.openscenegraph.org">
<div dir="ltr">
<div dir="ltr">Hi Renzo,<br>
</div>
<br>
<div class="gmail_quote">
<div dir="ltr" class="gmail_attr">On Wed, 14 Oct 2020 at
12:00, OpenSceneGraph Users <<a href="mailto:osg-users@lists.openscenegraph.org" moz-do-not-send="true">osg-users@lists.openscenegraph.org</a>>
wrote:<br>
</div>
<blockquote class="gmail_quote" style="margin:0px 0px
0px 0.8ex;border-left:1px solid
rgb(204,204,204);padding-left:1ex">
<div><font size="-1">I am using
osg::Drawable::getBoundingBox() to retrieve the
bounding box around the whole geometry. Is there a
similar short way to get the equivalent box for
just the culled geometry or do I need to write my
own procedure?</font></div>
</blockquote>
<div><br>
</div>
<div>Culling isn't related to the nodes directly, but to
a traversersal of the scene graph that compares the
bounding shere's of internal nodes of the scene graph
and the bounding boxes of the drawable leaves.
Culling can happen at any point in the hierarchy - it
can cull right up at the top node in the scene graph
if the scene is outside the view frustum.</div>
<div><br>
</div>
<div>Within the cull traversal there is no tracking of
culled or non culling bounding boxes, a cull test is
done and the bool result used directly. There isn't a
"bounding box" or "bounding sphere" for culled or non
culled objects. All the cull traversal cares about is
building a list of drawables leaves that pass the view
frustum test, there is no tracking of any objects that
are culled - this would be a crazy waste of CPU
resources.<br>
</div>
<div><br>
</div>
<div>I have to ask, why do you want a bounding box of
culled objects - what is the high level problem you
are trying to solve? It may well be that you are
asking the wrong question thinking about the task you
have in the wrong way.<br>
</div>
<div><br>
</div>
<div>Robert.<br>
</div>
</div>
</div>
</blockquote>
<br>
thanks for pointing out how cull traversal operates.<br>
<br>
Yes, it might be I am searching in the wrong direction. I need
to get the minimum and the maximum Z coordinate of the
geometry vertices in order to apply a color range. This is
quite easy to do for the whole geometry but I would know if
there is a way just for the vertices inside the view frustum.<br>
<br>
Regards,<br>
Renzo<br>
<br>
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