When crushables and crates change their Location/TopLeft, their crushability is cached, but when their CenterPosition is changed, their cached crushability is not refreshed. Since their CrushableBy functions depends on IsAtGroundLevel, which depends on the CenterPosition, this means that when the crushability is cached it will depend on the current height of the object. If the height of the object changes, the cache is not refreshed and now contains out of date information.
The Locomotor cache and the HPF both cache this same information, but at different times. HPF caches immediately, but Locomotor caches on demand which means there can be a delay. This means they can have inconsistent, differing views of the crushability information. This eventually surfaces in a "The abstract path should never be searched for an unreachable point." error from HPF when it detects the inconsistency.
The bug is that Locomotor was caching information without refreshing it when required. Fixing this to refresh the cache when the CenterPosition changes is likely to have negative performance impacts. As would removing crushability from the cache. These would both be fixes that address the underlying bug.
The high impacts of a proper fix lead us to a workaround instead. If we set the CenterPosition before setting the Location, then when the Location is set and the caches are refreshed, the new CenterPosition is available when caching the crushability information. This means logic depending on IsAtGroundLevel will get the new information and cache a more up-to-date view of things. This means when changing both the CenterPosition and Location together we now cache correct information. However calls that set only the CenterPosition and not the Location can still result in a bad cache state. Although this is imperfect it is an improvement over current affairs, and has less impact.
As far as I could tell, this was the last place that still
used 'seconds' instead of ticks, apart from
some sound notification intervals (which are better
converted to real [milli]seconds).
Also renamed ScaredyCat.PanicLength to PanicDuration for
consistency and easier finding.
While they may be only 'visual' in terms of influence/cell grid,
they all do update CenterPosition, which is essentially the
actual world position of the actor.
'Visual' would imply that it only affects the position where the
actor is drawn, which is inaccurate.
Furthermore, using the term 'Visual' here would make
naming future methods/properties related to visual interpolation
unnecessarily complicated, because that's where we might
need a real 'Visual(Only)Position'.
- Distinguish between missing sequences and missing sprites
- Lint default sequences as well as maps
- Improved performance
- Correctly handle null images
Inits that are logically singletons (e.g. actor
location or owner) should implement this interface
to avoid runtime inconsistencies.
Duplicate instances are rejected at init-time,
allowing simpler queries when they are used.
