Particles x2

[Hooray]

Just for future reference (it may be useful to preserve some of these pointers in the wiki article): search.php?st=0&sk=t&sd=d&sr=posts&keywords=particles+%2B+leaking

http://sourceforge.net/p/flightgear/mai ... /27882585/

I have been unable to run FG with particles enabled since long time due to random crashes in the particle code.

http://sourceforge.net/p/flightgear/mai ... /27884437/

I actually had it disabled for a long time. After enabling it recently,I also started having memory issues

http://sourceforge.net/p/flightgear/mai ... /27370622/

If I'm not mistaken the particles issue has been around since we got
particles, so it is apparently not that bad (leak and race
condition) in practice.

http://sourceforge.net/p/flightgear/mai ... /27353946/

IIRC each particle system is attached to the scene graph in (at least) two places: at the emitter's location in the graph and in a global vector of particle system updaters. IIRC they are never removed from the global list of updaters (a bug - but a hard one to fix due to concurrency issues). Tim knows more about this.

http://sourceforge.net/p/flightgear/mai ... sg29573519

Drawback with our current codebase: Our integration of the particle systems
need to be rethought as this contains geometry with culling disabled which
makes a pagedlod just never expire. Switching the particle systems off works
pretty good so far.

http://sourceforge.net/p/flightgear/mai ... /32925375/

Regarding precipitation - the current particles code in Simgear has major performance problems - and some outright mistakes in its implementation. Notably the animation of the particles is done in the wrong phase of OSG’s frame loop, which can prevents particle animations being unloaded - i.e can cause tiles to never be unloaded. For this reason many people have been disabling particle effects to ensure stable frame-rates. However, the complication is the Simgear particle system is effectively a fork+edit of the osgParticle system, which I think is what we use for precipitation.

Ideally we’d use the osgParticle system everywhere (since it has correct interactions with the rest of OSG) but it also has the issues about customising the rendering you mentioned. (I don’t think the Simgear particles are any better in that regard, but I may be wrong)