The cache in Locomotor that is populated via the UpdateCellBlocking method disagreed with the non-cached logic of IsBlockedBy when dealing with Mobile actors. The cache determined an actor to be moving if it was both movable and had horizontal movement types. IsBlockedBy determined an actor to be moving if it had horizontal movement types, but did not check if it was movable. This difference in checks could allow a mobile trait that was disabled or paused and which had horizontal movement to be treated differently be the two methods. UpdateCellBlocking would consider it not moving due to the disabled/paused trait. IsBlockedBy would consider it moving as it didn't care about the disabled/paused state of the trait.
Now, we unify the two methods to consider a mobile trait that is disabled/paused as not moving. This prevents HierarchicalPathFinder from crashing on the inconsistent state, i.e. when asked to path search through a cell of a mobile unit which has disabled or paused movement, but which has horizontal movement types from prior movement.
These make it possible to write more advanced update
rules that query state across multiple actors, or
based on resolved state.
(cherry picked from commit 129db98a2f)
An event is added to Map to indicate when the cell projection is changed. This is important as this can mean Map.Contains(CPos) could now return different results for the cell. The HierarchicalPathFinder is made aware of these changes so it can rebuild any out-of-date information. This fixes prevent a crash if a cell that was previously outside the map changes height and becomes inside the map. The local path search will explore the cell as it is inside the map - but if the HPF was unaware if had been updated, it will still consider the cell to be outside the map and unreachable, resulting in a crash.
If a path search is performed by the HierarchicalPathFinder when the source cell is unreachable location, a path is still allowed and starts from one of the cells adjacent to the location. If moving into one of these cells results in the actor moving into an isolated area that cannot reach the target this would previously crash as no abstract path could be found. Now we handle such locations by giving them a unreachable cost so the path search will not attempt to explore them.
Imagine a map split into two by a one tile wide line of impassable cliffs. If an actor is on top of these cliffs it is allowed to path because it can "jump off" the cliff and move into the cell immediately either side of it. However it is important which side it chooses to jump into, as one it has moved off the cliff it loses access to the other side. The previous error came about because the path might try and search on the side that couldn't reach the target location. Now we avoid that being considered.
The Locomotor IsMoving check was allowing us to consider another actor that moving as not a blocker. However for some reason it also considered the actor trying to path being mobile as sufficient for this check to pass which did not make sense. We remove that extra check and inline the method.
This was a regression from 4a609bbee8 which changed the method from IsMovingInMyDirection (which required the lookup of the mobile trait) to just IsMoving. It should have removed the lookup as not required.
This fixes a crash in HPF which was considered the location as blocked when Locomotor considered it unblocked because the logic was not aligned. Removing this check aligns the logic and resolves the crash.
Using the local pathfinder, you could not find a path to an unreachable destination cell, but it was possible to find a path from an unreachable source cell if there was a reachable cells adjacent to it.
The hierarchical pathfinder did not have this behaviour and considering an unreachable source cell to block attempts to find a path.
Now, we unify the pathfinders to use a consistent behaviour, allowing paths from unreachable source cells to be found.
