Units in formation sometimes appear to slide

[zoot]

Sometimes, one or more units in a formation fail to play its walking animation when moving:

See also: http://www.wildfiregames.com/forum/index.php?showtopic=16969

[zoot]

Savegame (and map) with a 'sliding' formation member.

[zoot]

Attached above (unitslide.tar.gz) is a savegame (and its corresponding map) in which a unit will begin 'sliding' a few seconds after loading. The unit has entity ID '46'.

Just before the unit begins sliding, ​OnMotionChanged is invoked on its UnitAI, and this subsequently leads to the unit entering a "FORMATIONMEMBER.IDLE" state prematurely (while it is still moving), which in turn disables the walking animation.

Why OnMotionChanged is invoked, I don't know, but it appears to be due to some kind of failure in UnitMotion because of the unit's path 'colliding' with a house.

[leper]

In 13079:

Stop formation members from sliding. Fixes #1823. Thanks to zoot for the test case!

[leper]

Thanks for the great test case!

[zoot]

The first case is fixed for me too, but apparently here is another one (sliding2.0adsave). About 15 seconds after loading the game, the unit with entity ID '1522' will begin sliding. (The unit is a packed ballista in the north-eastern part of the map.)

[leper]

In 13112:

Only call FinishOrder on MoveCompleted if we didn't get an error. Fix #1823.

[leper]

Replying to zoot:

The first case is fixed for me too, but apparently here is another one (sliding2.0adsave).

Thanks for providing another test case! I overlooked another case that triggered the OnMotionChanged hook, but it should be fixed now.