Hello,
Thanks for your answer. I think, using the bounding volume of the whole
scene won't help much. We want to use the scene graph to render objects
into terrain, which is drawn by our own renderer. So most of the time
the user will probably be within the scene graphs bounding volume.
We considered using a fixed near plane, but would prefer to use a
dynamically calculated one, since the terrain mesh is quite big and we
would like to use the available z-resolution as optimal as possible.
But if there is no other way, we will possibly use a fixed near plane.
The two other options, I see at the moment is either writing my own
visitor to find the near plane or using an really ugly hack to change
the projection matrix after the culling step.
State seems to be ok at the moment, though I got the problem, that OSG
stops with an GL_ERROR, when an VertexBuffer is bound before its draw is
called. Possibly a bug?
Best Regards,
Roland
Paul Martz schrieb:
Do you need to have OSG recompute the near/far planes? If not, I would
disable it if I were you, and instead use the top-level bounding volume in
your computation of the global projection matrix.
I used to maintain an application that had OSG as well as other renderers. I
did as described above: I created a projection matrix used by all renderers
based on the bounding volumes of all geometry in all renderers, and I told
the osgUtil::SceneView to not compute the near/far planes.
(The bigger problem I ran into was managing state between all the renderers,
but that's another thread.)
Best of luck with this,
-Paul
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED] On Behalf Of
[EMAIL PROTECTED]
Sent: Tuesday, September 26, 2006 1:15 AM
To: [email protected]
Subject: [osg-users] Near/Far Clipping Plane when integrating
OSG withexternal renderers
Hello,
we would like to combine OSG with other renderers, which are
called independent from OpenScene Graph. The Problem is, that
for this to work, all renderers have to use the same near and
far clipping planes.
To do this, we collect the near and far clipping planes,
required by the different renderers, before we start
rendering and combine them to an projection mMatrix, which is
then used by all renderers.
At the moment I'm using osgUtil::SceneView to render the Scene Graph.
The problem is, that the clipping planes are calculated in
SceneView::cull. But after calling cull it seems to be
impossible to change the projection matrix again, as it is
already stored in the renderLeaf objects and a change has no
effect, before cull is called a second time.
Is it possible to get the clipping planes independent from
the culling?
Or is it somehow possible, to change the projection matrix
after culling? Or would you generally recommend a completely
different approach to combine OSG with other renderers?
We already considered integrating the other renderers in
Scene Graph nodes, but would prefer, to keep them apart to
reduce the dependence on each other.
Best Regards,
Roland
_______________________________________________
osg-users mailing list
[email protected]
http://openscenegraph.net/mailman/listinfo/osg-users
http://www.openscenegraph.org/
_______________________________________________
osg-users mailing list
[email protected]
http://openscenegraph.net/mailman/listinfo/osg-users
http://www.openscenegraph.org/
_______________________________________________
osg-users mailing list
[email protected]
http://openscenegraph.net/mailman/listinfo/osg-users
http://www.openscenegraph.org/
