[BUG] Checkpoint doesn't work when using world map

[LoveBodhi]

Describe the issue

In the latest development build, checkpoint doesn't work when using world map, but works fine if not use world map.

Example Case

002.zip (Requires Nostalgic Paradise asset!)
TheXTech_log_2022_08_07_14_33_27.txt

Recording

Vanilla Recording

None

Additional context

None

[Wohlstand]

Confirmed just now, even on normal assets, this is a bug of engine itself:

[Wohlstand]

I also confirm, they works normally on 1.3.5.3 version.

[0lhi]

Could this be related to #371 and #152 ?

[ds-sloth]

I'd strongly suspect it's related to #371. There was an issue where some of the FileName variables weren't being restored to the world's variables when returning to the world. But, I'd guess that the checkpoints system relied on not restoring those variables. We could either (1) save the most recently visited level separately so that clearing checkpoints works (this makes the game's internals cleaner, but adds ~80 more bytes of RAM -- this is practically nothing on our target platforms), or (2) revert the fix for #371 and make another fix that more narrowly targets the issue, saving this RAM but making the internal code more convoluted.

[Alucard648]

I prefer 1). 80 bytes of RAM is not that meaningful on modern platforms.

[ds-sloth]

As I suspected, it's this incorrect line here: https://github.com/Wohlstand/TheXTech/blob/f913d6b0/src/player.cpp#L106-L108

I'm going to fix it by adding a check to not clear checkpoints if LevelSelect is set on line 108.

Sorry for not catching this when fixing #371.

[ds-sloth]

@LoveBodhi, can you check whether the issue still occurs?

@Wohlstand, does this look like a good solution? Do you remember any other checks that relied on FullFileName being incorrect?

[LoveBodhi]

Problem fixed❤

[Wohlstand]

I also confirm the bug has gone! :)

[Wohlstand]

P.S. Please remove the "NEED A TEST" label from cases that were tested and confirmed as solved.