A per-target multiplier for an area effect hitting several targets at once, stepping down
(or up) by how many targets were already resolved before this one - "full damage to the
first target hit, half to every one after" is areaFalloffMultiplier(index, [1, 0.5]).
index is the target's zero-based order among everyone the area shape hit (resolveArea's
own returned order is a natural source); an index past the end of steps repeats the last
step rather than falling back to full strength.
A per-target multiplier for an area effect hitting several targets at once, stepping down (or up) by how many targets were already resolved before this one - "full damage to the first target hit, half to every one after" is
areaFalloffMultiplier(index, [1, 0.5]).indexis the target's zero-based order among everyone the area shape hit (resolveArea's own returned order is a natural source); an index past the end ofstepsrepeats the last step rather than falling back to full strength.