Keep stack leniency consistent throughout all mod combinations on the same map

[peppy]

Discussed in https://github.com/ppy/osu/discussions/13144

^{Originally posted by **Kingling664** August 12, 2020} Currently with how osu! stable works, putting on mods like HR can change how circles are stacked. This means circles that the mapper intended to be stacked normally can become perfect stacks which impacts the playability of the map. Perfect stacks only really work when the mapper explicitly intended them to be perfect stacks, as they can often cause some maps to be unreadable and notes stacked seemingly randomly when not intended. My proposal is for all note stacking to be the same as how notes are stacked on nomod, regardless of mods added.

Bumping this to an issue as I think it should get more visibility, and likely treated as a bug we fix everywhere.

[doginuu]

It does this often but HR also flips the stacks creating small jumps where there weren't any originally in some 1/4 rhythms worst case scenario. Changing this would make the 'issue' of vertical mirror but keeping the stacks in the direction of the top left a more apparent gameplay change. Easily able to be bandaged by also changing the stack direction though plus mappers sometime manually make stacks which are less affected by HR.

I do like how stacks are uniform to the top left and the overlaps aren't particularly new if you've played like any djpop map but either way both making mirror mods perfectly reflect the map or allowing mods to fuck up maps by making stacks overlaps are both acceptable, just the idea of getting rid of overlaps but leaving the stacks' uniform top left direction in HR might make some unintended jerky jumps in maps intended to be fluid much more often than you see currently. It'd be a large change to many older maps in particular if I'm not mistaken.

[BdBrian]

It's specifically Approach Rate that is the deciding factor, so this applies to Difficulty Adjust too. For instance on this map https://osu.ppy.sh/beatmapsets/788847#osu/2244390 which has a Stack Leniency of 0.2. 1/4 interval stacks will get turned into perfect stacks at AR10.3 and above.

It does this often but HR also flips the stacks creating small jumps where there weren't any originally in some 1/4 rhythms worst case scenario. Changing this would make the 'issue' of vertical mirror but keeping the stacks in the direction of the top left a more apparent gameplay change. Easily able to be bandaged by also changing the stack direction though plus mappers sometime manually make stacks which are less affected by HR.

I do like how stacks are uniform to the top left and the overlaps aren't particularly new if you've played like any djpop map but either way both making mirror mods perfectly reflect the map or allowing mods to fuck up maps by making stacks overlaps are both acceptable, just the idea of getting rid of overlaps but leaving the stacks' uniform top left direction in HR might make some unintended jerky jumps in maps intended to be fluid much more often than you see currently. It'd be a large change to many older maps in particular if I'm not mistaken.

This is a separate topic/discussion, tangential to this bug that should be fixed.