`ciCompareLen(a, b, b.size()) == 0` expression is an equivalent of checking for
equality of `a` prefix with size `b.size()` with `b`.
`ciCompareLen(a, b, a.size()) == 0` is also the same thing but `a` is a prefix
`b` should start with.
This PR fixes a crash caused by the improperly ensured lifetime of RigGeometry::mSourceGeometry. mSourceGeometry was not adequate to ensure mSourceGeometry would outlive mGeometry because we extend mGeometrys lifetime beyond this lifetime by passing mGeometry to the draw traversal instead of this.
In addition,
We add important comments.
We detect and prevent generally unsafe operations in high level code.
We add a sprinkling of const to help clarify intentions.
Make sure it copies all relevant drawable parent nodes (e.g. including the node with the environment map effect)
Make sure it doesn't copy nodes multiple times
The double buffering is an implementation detail so it should be handled as such, rather than mandating the scene graph to be structured in a certain way.
Override accept(NodeVisitor&) instead of using callbacks.
This resulted in a crash/corruption because the KeyframeController, for performance reasons, does not check that the expected user data is there and of correct type.
(Fixes#3829)
A Warning indicates a potential problem in the content file(s) that the user told OpenMW to load. E.g. this might cause an object to not display at all or as intended, however the rest of the game will run fine.
An Error, however, is more likely to be a bug with the engine itself - it means that basic assumptions have been violated and the engine might not run correctly anymore.
The above mostly applies to errors/warnings during game-play; startup issues are handled differently: when a file is completely invalid/corrupted to the point that the engine can not start, that might cause messages that are worded as Error due to the severity of the issue but are not necessarily the engine's fault.
Hopefully, being a little more consistent here will alleviate confusion among users as to when a log message should be reported and to whom.
