Currently, we use an `UnrefQueue` which supposedly aims to transfer destruction costs to another thread. The implications of this unusual pattern can not be well understood because some allocators might free resources more efficiently if they are freed by the same thread that allocated them. In addition, `UnrefQueue` complicates the validation of thread safety in our engine. Lastly, our current usage of `UnrefQueue` triggers `ref()`, `unref()` atomic operations as objects are passed into the queue. These operations could be more expensive than the actual destruction.
With this PR we thus remove `UnrefQueue`. We can expect these changes to have a minor impact at most because we free most resources elsewhere in `ResourceSystem::updateCache`.
Fixes compile error encountered on OSX 10.9 with g++
sophie:build pineapple$ g++ --version
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/usr/include/c++/4.2.1
Apple LLVM version 6.0 (clang-600.0.56) (based on LLVM 3.5svn)
Target: x86_64-apple-darwin13.4.0
Thread model: posix
The compilation error:
[ 24%] Building CXX object apps/openmw/CMakeFiles/openmw.dir/mwrender/renderingmanager.cpp.o
In file included from /Users/pineapple/git/openmw/apps/openmw/mwrender/renderingmanager.cpp:1:
In file included from /Users/pineapple/git/openmw/apps/openmw/mwrender/renderingmanager.hpp:4:
/Users/pineapple/git/openmw/openmw-deps/include/osg/ref_ptr:35:36: error: member access into incomplete type 'SceneUtil::UnrefWorkItem'
~ref_ptr() { if (_ptr) _ptr->unref(); _ptr = 0; }
^
/Users/pineapple/git/openmw/./components/sceneutil/unrefqueue.hpp:14:11: note: in instantiation of member function
'osg::ref_ptr<SceneUtil::UnrefWorkItem>::~ref_ptr' requested here
class UnrefQueue : public osg::Referenced
^
/Users/pineapple/git/openmw/./components/sceneutil/unrefqueue.hpp:10:11: note: forward declaration of 'SceneUtil::UnrefWorkItem'
class UnrefWorkItem;