(i.e. multiloop). Most subsystems currently ignore the parameter, but
eventually, it will allow all subsystems to update by time rather than
by framerate.
Here's an unusual patch for FlightGear -- I've created .cvsignore
files for every source directory, to make CVS output more informative.
This is especially nice when using cvs-examine from (X)Emacs to look
for changes.
What was happening was that we screwed up and scheduled tiles for
(lon,lon) rather than (lon,lat) ... note the typo. This generated
bogus tile id's which the system happily accepted, put into the tile
cache system, and attempted to load. The problem was that these bogus
tile id's were negative where as all valid tile id's should be >= 0.
These negative tile id's up the logic used to remove tiles from the
cache. When identifying tiles for removal, we look for the furthest
tile away from us by starting out the furthest id at -1 and if we find
something further, we update the furthest tile id. Then at the end we
check if the furthest tile id >= 0 to see if we found anything we
could remove. However, the furthest tile id was these bogus tiles
with negative tile id's so the system always assumed there was nothing
appropriate for removal. This made it impossible to ever remove a
tile from the cache meaning it quickly filled up and no more tiles
could be loaded.
I fixed the one instance of scheduling tiles for a bogus location, and
added a sanity check so if it ever happens again we'll bomb with an
appropriate error message.
fix startup sequence problems where we initialize the FDM before we know
the desired starting altitude.
These changes delay fdm initialization until the local tile has been loaded
and we can do a real intersection and find the true ground elevation.
In order to do this, I depend more on the property manager as glue, rather
than the FGInterface.
There are some glitches still when switching to a new airport or reseting
the sim. I will work on addressing these, but I need to commit the changes
so far to keep in sync with other developers.
but no entries qualify for removal. It will keep trying to schedule the
tile(s) until an entry frees up. Entries in the cache do not qualify for
removal if they are in the process of being loaded.
a crash when relocating to a new airport. Pending work from the old
area is now just completed as normal, rather than trying to empty the various
queues in their various stages when can lead to many problems in a threaded
environment.
to have attached an ssg loaded object to this branch, then plib will remove
it and all it's states (and textures) which will call opengl api commands
which will crash the program if run from a separate thread from the main render
thread.
- model loading deferred to primary thread
- tile removal deferred to paging thread
- other tweaks and rearrangments.
Airport signs
- first stab at some support for adding taxiway and runway signs. This
is non-optimal, but I'm under the gun for a demo.
a newly loaded tile to the scene graph. Instead it puts it in a queue
for the tile manager. I've used your counter_hack to check the loaded
queue and add any tiles to the scene graph. I was playing around with
the counter_hack so there might be some commented out code, etc. I also
changed some SG_DEBUGs to SG_INFOs so I could track the tile loading.
He writes:
Here are the final changes to add threads to the tile loading. All the
thread related code is in the new FGTileLoader class.
./configure.in
./acconfig.h
Added --with-threads option and corresponding ENABLE_THREADS
definition. The default is no threads.
./src/Scenery/tilemgr
Removed load_queue and associated references. This has been replaced by
a new class FGTileLoader in FGNewCache.
Made the global variable global_tile_cache a member.
schedule_needed(): removed global_tile_cache.exists() tests since
sched_tile() effectively repeats the test.
initialize_queue(): removed code that loads tiles since this is now
performed by FGTileLoader.
update(): ditto
./src/Scenery/newcache
Added new class FGTileLoader to manage tile queuing and loading.
tile_map typedefs are private.
exists() is a const member function.
fill_in(): deleted
load_tile(): added.
./src/Scenery/FGTileLoader
The new threaded tile loader. Maintains a queue of tiles waiting to be
loaded and an array of one or more threads to load the tiles. Currently
only a single thread is created. The queue is guarded by a mutex to
synchronize access. A condition variable signals the thread when the
queue is non-empty.
CLO: I made a few tweaks to address a couple issues, hopefully what we
have is solid, but now we kick it out to the general public to see. :-)
tile has been loaded. Since this flag can be set by another thread I've
declared it "volatile bool".
Also cleaned up delete vs delete[] usage. Gcc is happy with delete[],
which is the correct usage.
