[Flightgear-devel] Deferred/Paged random object loading

[Stuart B. <stu...@gm...>]

Hi All,

As previously mentioned, I've been working on using PagedLoD to
deferred random object (buildings, trees, objects) so that they are
not generated when the tile is loaded, but only when the viewer gets
within a specific range.

This work is now checked into simgear.

There are two main impacts (example numbers taken with Bare LOD set to
100km, starting at KLAX with ufo at 30,000ft):
- Scenery memory occupancy is reduced.  Staying still, memory
occupancy stabilizes at 1.4GB rather than 2.0GB
- Startup time is reduced from 40 seconds to 15 seconds.  (Note that
about 10 seconds of that is not scenery loading, so the scenery
loading time is 30 seconds down to 5 seconds).

For the moment, the random objects are loaded when the viewer comes
within 35km of the tile center (assuming 20kmx20km tiles, that's 20km
from the tile edge).  That should probably be tied into the LOD
properties in some way.

Comments welcome as always.

-Stuart