Hi Manu,
I always thought update callback gets called only once. Update visitor differs
from cull visitor in this regard.
Wojtek
----- Original Message -----
From: Emmanuel Roche
To: OpenSceneGraph Users
Sent: Friday, January 29, 2010 3:01 PM
Subject: Re: [osg-users] uniform update question
Hello Wojtek,
thanks for the tips !!
I will try with getRenderStage()->getCamera() and let you know if it works
for me too.
But concerning the cull callback for uniforms, isn't it already the case for
the update callback you can put on them ? (if you use the same uniform in
multiple statesets/nodes, then the update callback is called multiple times per
frame... [or is there some kind of "security system" to prevent this I'm not
aware of ? ]
Cheers,
Manu.
2010/1/29 Wojciech Lewandowski <lewandow...@ai.com.pl>
Hi Manu,
IMHO I can offfer tips for 2 or your questions:
Why no cull calback for uniform ?
I guess there is no cull calback for state attribs/uniforms because they
could be used many times and located in many statesets/nodes. So cull visitor
can traverse them couple times per one frame.
How to obtain master camera view matrix ?
In ViewDependentShadowTechniques I used following method to obtain master
view or slave view camera:
cullVisitor->getRenderStage()->getCamera()
Depending on your setup of extra cameras it may wortk or not, but I guess
you could try it.
Cheers,
Wojtek Lewandowski
----- Original Message -----
From: Emmanuel Roche
To: OSG Users
Sent: Friday, January 29, 2010 1:08 PM
Subject: [osg-users] uniform update question
Hi everyone,
I'm facing a problem I cannot solve by myself here, I thought I could
just ask:
- I have a scene (so a scene graph)
- I use multiple View on this single scene
--> Currently I have an "homemade" mixture of customized
osgViewer::Viewer objects to deal with everything so basically, for each View,
I go through a complete (EventTraversal(), UpdateTraversal(),
RenderingTraversals() ) loop sequentially.
- Now I would like to switch to a CompositeViewer and thus go through the
event/update traversals only once per Scene (If I understand the
CompositeViewer design properly).
But I have a very specific problem to solve here:
In my scene graph I use shaders and uniforms. those uniforms have update
callbacks, and in those update callbacks, I retrieve my currently rendering
View and then the View matrix to generate eye coordinates.
--> I assume using the osg_ViewMatrix uniform is not an option for me
because I need to convert very big position vector and very big view matrix
translation, and I would clearly get a problem here if I don't have double
precision.
--> With the CompositeViewer I can't access the individual "View" anymore
in the update traversal() since this process is "View agnostic" I would say.
--> Since my views will need different settings for the uniforms, I was
thinking I would just need to do something in the cull traversal, but here I
realized something which seems strange to me: there is no such method as
uniform::setCullCallback(...)
So, the question is, how would you update your uniforms properly in that
case ?
I mean, I could still put a cullcallback on the node owning the stateset
containing the uniform for instance and "update" from here (assuming I can
retrieve the Viewmatrix I need somehow in that Cullcallback...) but is this
really the best option ??
- And generally speaking, would a uniform::setCullCallback() not make
sense for some reason I'm apparently missing for now ?
Bonus question by the way: How would I access the "master camera"
ViewMatrix in a cullcallback ? i've seen we have
osgUtil::CullVisitor::getCurrentCamera() but would this return the Master
camera of the View or just the current camera in the scene graph (as I use
DepthPartitionNode I have many sub cameras in my scene...)
Thanks in advance is someone has any tip/advise/complete solution on
those questions!
Regards,
Manu.
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