[Flightgear-scenery] [Flightgear-devel] Scenery manager

[Adrian Musceac]

Hi Adrian,

I am presenting an experimental (WIP) method to reduce memory consumption
by scenery with 30%, while increasing the visibility distance 4 times.
This method relies on some kind of LOD system, without mesh
simplification. People smarter than me can come up with a safe algorithm
to do that, but I'm afraid it requires changes to Terragear. Right now
mesh simplification was not

Could you explain how your system works?
Presumably you are making some change to the tiles for the low
resolution version?
-Stuart

Hi Stuart,
It' basically very simple. Far tiles no longer compute anything other than
it's own geometry, and also use a very low resolution texture set, obtained by
running a batch resize on the regular texture set.
This allows me to have 2.5 times larger view distance in high detail (SRTM)
terrain with same memory consumption. There is of course a slight increase in
disk IO, but I have only tested this with multithreading enabled on a dual
core CPU.
Load times for far tiles are actually smaller, since no calculations other
than geometry and effects are performed on them.
Inner tiles close to the viewer position are normal tiles, nothing changed.
That's basically it.
I need to refactor the code a bit before I can show it, I wrote it fast and
while half asleep.

Now, the really big stuff would be load-time mesh simplification, and I have
read a couple of papers that seem to suggest that's possibile, but would
require some changes to the BTG format. I leave that up to the Terragear guys,
I am not very familiar with the way their mesh construction works.

Cheers,
Adrian