Add ability to create new difficulties in the editor

[DeviousPanda]

Currently there is no way to create a new difficulty for a beatmap other than the base edit screen for song setup (which only creates one difficulty)

adding the ability to create new difficulties similar to how stable does it would be great

[bdach]

Has since been added.

[vicky5124]

I wouldn't consider the current implementation complete enough to be able to close this issue. The original message mentions "similar to how stable does it", but currently there's no way to make a copy of an existing difficulty, you are only able to make a new difficulty from scratch that only copies over the timing points.

A lot of people that are not mappers themselves use the "create new difficulty" feature to make practice versions of a map, cutting out a specific section, modifying the stats, or flipping the map to break muscle memory. While it is possible to copy hit objects from one difficulty to another, copying hit sounds and "green timing points" for slider velocities, is quite annoying, and most of the time not feasible to do manually. Additionally, if the section that needs to be copied over is substantial, the editor can start lagging a lot with the large amount of selected objects, but the worst part is that it can even crash the game when copying them via Ctrl+C

[peppy]

This issue was specifically to track creating empty difficulties. Further work will of course be done, and tracked elsewhere.

Please open a discussion for the said crash with logs.

[bdach]

i will add that i have pending changes for adding back support for copying difficulty (and this was even foreshadowed in the PR that added new difficulty support) but i'm not entirely sure the changes are up to scratch code quality wise.

i'll link what i have later today in an issue thread/PR and maybe we can take it from there.