TL;DR the clock was being set too late, causing more transforms to be
created than necessary.
This solves the issue by way of a refactor (sorry). Overall this should
simplify handling of things as more of the logic is shared with the
known good-state `BeatmapBackgroundWithStoryboard`.
I did try without a refactor (just delaying the creation until the clock
arrives) but this version made more sense because background generally
expect to do their main load in BDL to aid in smooth transitions. And we
can't get the clock by there. (although arguably we could just use a
similar method to `BeatmapBackgroundWithStoryboard` and forego using the
editor clock).
Of note, I removed the black background overdraw hack. There are edge
cases where it will lead to weird transitions, but these are far and few
between. Basically you need a storyboard which sets the flag to hide the
beatmap background and has transparency in it. This is no longer as
flagrantly bad as things used to be (which led to the inline fix) as far
as I can tell, but feel free to prove me wrong. If this is a blocker
I'll probably just add a permanent black box (which does fix this).
Closes#36875.
- Replace the sprite with a solid black box when a storyboard requests it.
- Create a new storyboard instance and exclude the fail layer as well as strip all samples from it
- Do not attempt in creating the storyboard when it isn't needed
This avoids loading the sprite if its not needed and instead of hiding it, it is removed when the storyboard replaces the background or there is a video.
This also only initializes DrawableStoryboard if there are any elements in any layer.