Closes https://github.com/ppy/osu/issues/37232.
The actual fix is
https://github.com/ppy/osu/commit/e959b20517497a093d3c00a17457c5d36bf57651;
everything else is window dressing / test harness to ensure I don't try
and do a wrong change like https://github.com/ppy/osu/pull/37251 did. I
recommend reviewing commit-by-commit.
See [this desmos](https://www.desmos.com/calculator/a5yjpacvxa) for
visual explanation of change, I think it does a better job at explaining
this than any words I could type here.
Of note:
- In the end this did only affect 14K but that should never be assumed
when floating point is involved.
- Test cases generated here were generated in stable manually.
- Except for 11 / 13 / 15 / 17K which are not officially supported and
which don't work in lazer due to orthogonal reasons (see comment added
in this PR in `ManiaBeatmapConverter`), decoding in lazer was always
fine.
- My worry was that the old encoding method before this PR could
potentially cause stable to move a note from one column to another but
thankfully that is not the case. The old method of encoding columns as X
positions does not cause issues wherein lazer reads them back
differently than stable after encode.
I checked this by checking out `master`, re-encoding all of the test
stair-pattern nK beatmaps added in this PR on `master`, exporting that
as compatibility, re-importing to stable, and cross-checking that the
decoded beatmap is visually the same on lazer and on stable.
This is important to check because if this wasn't the case, we'd
potentially have cases of actual online beatmaps (remember that we have
BSS now) wherein a beatmap plays differently on stable than on lazer due
to notes moving between columns, and would need to screen for this being
the case and potentially apply corrective / reconciliatory action.
Per the request of spaceman_atlas, the No Release mod is rewritten to
avoid modifications to DrawableHoldNoteTail. The approach is based
on that of the Strict Tracking mod for the osu!(standard) ruleset,
injecting the mod behavior by replacing the normal hold note with
the mod's variant. The variant inherits most bevaior from the normal
hold note, but when creating nested hitobjects, it creates its own
hold note tail variant instead, which in turn is used to instantiate
the mod's variant of DrawableHoldNoteTail with a new behavior.
The time a judgement is awarded is changed from the end of its
Perfect window to the time of the tail itself.
The new test scene is essentially a copy of TestSceneHoldNoteInput,
modified to test the judgement changes applied by the new mod. A base
class might need to be abstracted out for them.
Bartłomiej Dach ·
Nathan Du ·