Hi Chris, On Mon, Nov 2, 2009 at 4:05 PM, Chris 'Xenon' Hanson <[email protected]> wrote: > I'm kind of an old-school C-flavor programmer, so my instinctive response is > rather > C-like. I don't like bloating people's in-memory objects, so I'd lean towards > defining a > 32-bit flag member on class Node called something like > _ephemeralInternalStateFlags. This > would not be saved or restored, and the definitions of each flag bit would be > enumerated > as 1<<n enums in the Node class header. Code outside of the OSG core > distribution would be > prohibited (by policy, can't really enforce it in the compiler) from defining > and > utilizing these flag bits, but code within OSG core could. The first bit > allocated would > be used to replace the NeedToRemove indicator.
I'm not sure whether this is really needed. The NeedToRemove trick in DatabasePager is very specific to a piece of code embedded in DatabasePager it has no value outside this specific bit of code, and I believe it's not appropriate to build algorithm specific such support into the core OSG. > Also, while the read-modify-write cycle used to toggle just one bit of a > flag is not as > fast as the blind-write cycle used when you dedicate a whole boolean variable > (and consume > more memory), both the setting operation AND the testing operation should be > faster than > the current string-marking technique. > > If Robert has no objections to this solution, I'll code it up quick and > share it. I think the right thing to do is nothing in the core OSG, and look at the specific DatabasePager algorithm to retain the O(1) cost of the check that I was using, with the bugs with handling multiple viewpoints. > I'm also concerned about the amount of very similar-but-not-quite-the-same > code between > DatabasePager::capped_removeExpiredSubgraphs and > DatabasePager::expiry_removeExpiredSubgraphs. I'd like to refactor that to > DRY (Don't > Repeat Yourself) it out a bit as I'm implementing some code of my own that > needs to > cleanly dispose of some PagedLOD children. But, I don't understand why there > are > differences in the disposal technique between them (one calls > _fileRequestQueue->updateBlock() directly, one sets a local flag and calls > updateBlock() > at the end of the operation, etc). Both methods exists while we test the new capped_removeExpiredSubgraphd , once it's fully tested and debugged the old expiry_removeExpiredSubgraphs method will be removed completely this neatly avoiding the issue of similar code. Robert. _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
