[osg-users] culling / bounding calculation for shader scaled geometries

[Christoph Dohmen]

Hi all,

I need to display textured items in a pixel-constant size even on zooming. For my implementation I use the position as vertices and store the size in the normals. The vertex shader handles it all corrrectly and the image is shown in a constant size.

Unfortunately these items are culled if the position is outside the viewport. That's bad :-(

I tried to use setInitialBound() with a maximum area to define the bounding box to prevent these items from being culled away. But instead of keeping the items on screen this results in scaled items!

What other way could I go to prevent the items from beeing culled? Maybe I have to read back the vertices somehow? 

Thank you!

Cheers,
Christoph

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