[osg-users] PagedLOD glitches

[Robert Osfield]

Hi Andreas,

On 26 August 2016 at 12:09, Andreas Ekstrand
<andreas.ekstrand at remograph.com> wrote:
> Is there any way to avoid glitches in the PagedLOD during loading of the
> higher level after the lower level has switched out?

Are we talking just a visual glitch or a frame rate drop, or both?

> When flying over my
> quad-tree terrain the tiles are flickering and the background color is
> visible a short while before the higher level has been loaded.
>
> One can of course override and implement logic that waits to switch the
> lower level of until the higher has been loaded, but maybe I have missed
> some existing setting?

The logic in PageLOD::traverse() that decides between which LOD's to
display depends entirely on the LOD ranges used for each child, if the
ranges are distinct then no two children of a single PageLOD will be
displayed at the same time.

If you built the database such that the PageLOD's overlap a bit then
you have a case where both a lower level of detail and higher level of
detail could be visible at once.  Given your description this sounds
like it may be possibility.  I wouldn't recommend building PageLOD
databases with overlapping LOD range though - they can abut but
shouldn't overlap.

The other possibility might be display latency, or if you have some
kinds of higher level effect for visually blending between LOD levels.

Robert.