Hi all,

I'd like to ask for feedback about something concerning osgOcean. We've been using it in multiple views for a while now, only activating the reflection effect, and it has worked well. We knew that one view would control the LOD of the ocean tiles (seems to be the last one rendered, so the last one added to the viewer). That's not a problem for us since the views' viewpoints are generally close to each other. Surprisingly, the reflection works correctly in all views.

A larger problem now occurs because we need to start using the transparency effect, which depends on a refraction MRT pass. It seems that this MRT, as opposed to the reflection, but similarly to LOD, only takes effect in the last view in the viewer.

I've put some details on this in this issue on the osgOcean bug tracker.

http://code.google.com/p/osgocean/issues/detail?id=37

Our main problem stems from the fact that in all cases of viewer setup we've seen, the main view is always added first, and the inset view(s) are added after. That means that the inset views get the transparency/refraction effects, which is not what we want.

These effects should not depend on the order of views in the viewer. But the solution is not straightforward, and so I'm asking for comments. Would the correct solution be to do something like in the ViewDependentShadow classes in osgShadow, and have a ViewData class that would store separate target textures for each view, and when rendering the MRT camera we would switch these so they render to the right textures for the current view? Or is there a better / simpler solution?

The oceanExample that comes with osgOcean has new options to demonstrate this, these are explained in the issue linked above, and you can check out the trunk if you want to tinker with it.

http://osgocean.googlecode.com/svn/trunk/

I'll be thankful for any comments / suggestions.

J-S
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______________________________________________________
Jean-Sebastien Guay    [email protected]
                               http://www.cm-labs.com/
                    http://whitestar02.dyndns-web.com/
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