Hi,
I need to project some geometry onto the surface of my database. I tried
osgSim::Overlaynode for this. Using the
OBJECT_DEPENDENT_WITH_ORTHOGRAPHIC_OVERLAY i get good results for
relatively small overlays. For testing purposes I've added a bunch of
lines to one drawable. Naturally this leads to aliasing artifacts if the
drawable contains many lines that cover a large area.
Now I've tried
VIEW_DEPENDENT_WITH_ORTHOGRAPHIC_OVERLAY/VIEW_DEPENDENT_WITH_PERSPECTIVE_OVERLAY.
Both of them didn't display anything.
So looking around in the mailing list I've discovered a discussion about
the topic in which J.P.Delport provided a "patch" for the problem.
Applying the patch more or less works in the sense, that I'm now able to
see my overlay but under certain angles it gets clipped.
Now I've got three questions:
1. Is there any benefit from grouping the geometry that is supposed to
be used as overlay (i.e. spatializing my geometry)
2. Is there anyone able to point me to some documentation/hints that my
help me debugging the code (which I deliberately don't understand a this
point)
3. How do I disable lighting for the overlay sub-graph? Setting the mode
GL_LIGHTING to false didn't work (I think for obvious reasons as the
overlaynode is using shaders that don't honor the fixed pipeline)
On the long term I think I will have to integrate the shader part into
my own shader framework, so the 3rd question is more about how to
separate the shader part from the technique. (I'm thinking of an
interface to the Overlay node which allows for a custom shader or an
interface to retrieve the shader part in order to use it inside my
shader program.
cheers
Sebastian
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