Hi Maxim,

It sounds like the compilation of OpenGL objects is causing the frame
drop.  The new default for the DatabasePager is for the incremental
pre compilation to be turned off, and for databases that are well
balanced this doesn't cause problems with frame drops as the number of
new objects per frame is kept modest so one doesn't get close to
breaking frame when the new objects come in.

For databases where there are lots of OpenGL objects that are
introduced at once you can switch back on the incremental pre compile,
the tells the DatabasePager to record all the OpenGL objects that need
compiling and then on each frame compile as many as it can within
specified time and number limits.  The incremental compile reduces the
overhead per frame so reduces the chances of breaking frame, however,
it also increases the amount of time it takes to prepare a scene graph
before it can be merged with the main databases - so there is higher
latency between requesting a tile and when it's served up.

To switch on the pre compile use:

   viewer.getDatabasePager()->setDoPreCompile(true);

There is a whole suite of methods relating to the fine control of pre
compile in the DatabasePager so have a look over the headers.

The other thing you could do is improve the suitability of your
databases so that it's better balanced - for instance switching
between LOD levels shouldn't introduce so much geometry/textures at
one time.  Try to create a quad tree paged database where each tile is
divided in four, and each child contains roughly the same amount of
geometry and textures as it's parent.   Such a well balanced database
won't suddenly introduce lots of geometry and textures in one go.

Robert.

On Tue, Dec 22, 2009 at 4:20 PM, Maxim Gammer <maxgam...@gmail.com> wrote:
> Hi everybody,
>
> I've got a problem - FPS falls down from 100 to 2-3 for 1-2 seconds
> during first load of "more detailed level" of PageLODs (when they're
> first seen). We suppose it's because of object "compilation" (there
> are messages about textures loading etc. on the console). FPS also
> falls down when we look at newly loaded objects.
>
> Is it possible to "compile" objects prior to their rendering? How to
> set up the PageLOD?
>
> Or maybe there are other ways to solve that?
>
>
> --
> Maxim Gammer
>
>
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> osg-users mailing list
> osg-users@lists.openscenegraph.org
> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
>
>
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