Hi Paul,
PagedLOD are expired automatically when they go out of the view
frustum as well as on LOD ranges. What the DatabasePager/PagedLOD
does is increment the frame count of when the PagedLOD's children are
traversed during the cull traversal to know which ones are still
active - this means it works for all types of culling.
What you are probably seeing is that the DatabasePager doesn't expire
subgraphs unless it exceeds the a maximum number of PagedLOD in use at
once, if you request more PagedLOD than this maximum the pager will go
a reclaim the PagedLOD that are no longer active i.e are out of the
view frustum. This on-demand expiry results in the best performance
and load balancing. You can tune the max number of PagedLOD via the
osgDB::DatabasePager method:
/** Set the target maximum number of PagedLOD to maintain in memory.
* Note, if more than the target number are required for
rendering of a frame then these active PagedLOD are excempt from being
expiried.
* But once the number of active drops back below the target
the inactive PagedLOD will be trimmed back to the target number.*/
void setTargetMaximumNumberOfPageLOD(unsigned int target) {
_targetMaximumNumberOfPageLOD = target; }
So set it to a low number and the pager will expiry subgraphs rapidly,
increase the value and it'll leave them around until the load goes up.
Robert,
On 2 October 2013 15:17, Paul Leopard <[email protected]> wrote:
> I've been experimenting with PagedLOD for use in loading/unloading terrain
> tiles in my application. I need my tiles to be unloaded/removed from the
> scene graph when they are outside of the field of view. Apparently PagedLOD
> works off the range from the eyepoint only and does not page out tiles that
> are behind the viewer or to the side.
>
> Anyone have any alternative methods? I'd sure like to use DatabasePager if
> possible ... Is there a way to subclass PagedLOD and override the paging
> decision to include FOV metrics?
>
> Thanks,
> Paul
>
> ------------------------
> things are more like they are now than they have ever been before
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=56593#56593
>
>
>
>
>
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