New attribute DatabasePager::_expiryFrames sets number of frames a PagedLOD child is kept in memory. The attribute is set with DatabasePager::setExpiryFrames method or OSG_EXPIRY_FRAMES environmental variable.
New attribute PagedLOD::PerRangeData::_
frameNumber contains frame number of last cull traversal.
Children of PagedLOD are expired when time _AND_ number of frames since last cull traversal exceed OSG_EXPIRY_DELAY _AND_ OSG_EXPIRY_FRAMES respectively. By default OSG_EXPIRY_FRAMES = 1 which means that nodes from last cull/rendering
traversal will not be expired even if last cull time exceeds OSG_EXPIRY_DELAY. Setting OSG_EXPIRY_FRAMES = 0 revokes previous behaviour of PagedLOD.
Setting OSG_EXPIRY_FRAMES > 0 fixes problems of children reloading in lazy rendering applications. Required behaviour is achieved by manipulating OSG_EXPIRY_DELAY and OSG_EXPIRY_FRAMES together.
Two interface changes are made:
DatabasePager::updateSceneGraph(double currentFrameTime) is replaced by DatabasePager::updateSceneGraph(const osg::FrameStamp &frameStamp). The previous method is in #if 0 clause in the header file. Robert, decide if You want to include it.
PagedLOD::removeExpiredChildren(double expiryTime, NodeList &removedChildren) is deprecated (warning is printed), when subclassing use PagedLOD::removeExpiredChildren(double expiryTime, int expiryFrame, NodeList &removedChildren) instead. "
multi-threaded paging, where the Pager manages threads of reading local
and http files via seperate threads. This makes it possible to smoothly
browse large databases where parts of the data are locally cached while
others are on a remote server. Previously with this type of dataset
the pager would stall all paging while http requests were being served,
even when parts of the models are still loadable virtue of being in the
local cache.
Also as part of the refactoring the DatabaseRequest are now stored in the
ProxyNode/PagedLOD nodes to facilitate quite updating in the cull traversal,
with the new code avoiding mutex locks and searches. Previous on big
databases the overhead involved in make database requests could accumulate
to a point where it'd cause the cull traversal to break frame. The overhead
now is negligable.
Finally OSG_FILE_CACHE support has been moved from the curl plugin into
the DatabasePager. Eventually this functionality will be moved out into
osgDB for more general usage.
ReaderWriter::ReadResult now has a FILE_REQUEST enum.
ReaderWriter::Options now has a s/getAsynchronousFileReadHint() parameter methods.
libcurl based plugin now detects enabing of the AsynchronousFileReadHint, but
as yet does not handle async requests - handling everything syncronously.
DatabasePager now by default will enable AsynchronousFileReadHint for http
based file requests
as not expiring subgraphs quick enough to enable reasonable load balancing.
New version isn't perfect and will need further work, but does at least reduce
the memory footprint by as much as half on test paths on big databases.
The rewritten method no longer uses the the MaximumNumOfRemovedChildPagedLODs
and MinimumNumOfInactivePagedLODs variables so these and associated methods
for accessing them have been removed.
- /** Set the maximum number of PagedLOD child to remove per frame */
- void setMaximumNumOfRemovedChildPagedLODs(unsigned int number) { _maximumNumOfRemovedChildPagedLODs = number; }
-
- /** Get the maximum number of PagedLOD child to remove per frame */
- unsigned int getMaximumNumOfRemovedChildPagedLODs() const { return _maximumNumOfRemovedChildPagedLODs; }
-
- /** Set the minimum number of inactive PagedLOD child to keep */
- void setMinimumNumOfInactivePagedLODs(unsigned int number) { _minimumNumOfInactivePagedLODs = number; }
-
- /** Get the minimum number of inactive PagedLOD child to keep */
- unsigned int getMinimumNumOfInactivePagedLODs() const { return _minimumNumOfInactivePagedLODs; }
in the DatabasePager. The practical effects of these are to greatly reduce startup time
and the time to load an individual scenery tile in FlightGear.
- From my log message:
Minimize the number of StateSets and drawables that are compiled by checking
if they have already been compiled or will be elminated by the
SharedStateManager.
Move the sorting of the dataToCompile queue out of compileGLObjects
into the man pager run function.
Change the SharedStateManager to use maps instead of vectors."
- Get or set the target number of PagedLOD children to remove per frame.
- Get or set the minimum number of inactive PagedLOD to keep.
Corresponding environment variables have been added too.
The default values reproduce the previous DatabasePager behavior."
Created a new GraphicsThread subclass from OperationThread which allows the
GraphicsContext specific calls to be moved out of the base OperationThread class.
Updated the rest of the OSG to respect these changes.
Added and cleaned up DeleteHandler calls in osgViewer to help avoid crashes on exit.
Changed DatabasePager across to dynamically checcking osg::getCompileContext(..)
Updated wrappers.
default Registry Options object, but it would be useful to be able to
request loading with a different Options object. The attached files
allow you to do that (based off the OSG 1.2 source).
For example, I'm implementing a loader that requires context information
when it pages in subgraphs, which becomes significantly complicated when
multiple scenegraphs are requesting subgraph loads with different
contexts (the loader needs to know which context to use, and the
Registry Options needs to be carefully managed so the context settings
don't clobber each other, especially in multithreaded situations). Being
able to pass an Options instance along with the Node request resolves
this problem."
OSG_MINIMUM_COMPILE_TIME_PER_FRAME <float>
and
OSG_MAXIMUM_OBJECTS_TO_COMPILE_PER_FRAME <int>
environmental variable during the initialization of the DatabasePager
to allow apps to be tweaked for best database pager behavior.
