When gamemode(teleporter) gets run in a script, it brings up a read-only
version of the teleporter screen, intended only for displaying rooms on
the minimap.
However, ever since 2.3 allowed bringing up the map screen during
cutscenes (in order to prevent softlocks), bringing up the map screen
during this mode would (1) do an unnecessary animation of suddenly
switching back to the game and bringing up the menu screen again (even
though the menu screen has already been brought up), and (2) would let
you close the menu entirely and go back to GAMEMODE, thus
unintentionally closing the teleporter screen and kind of ruining the
cutscene.
To fix this, when you bring up the map screen, it will instead instantly
transition to the map screen. And when you bring it down, it will also
instantly transition back to the teleporter screen.
But that's not all. The previous behavior was actually kind of a nice
failsafe, in that if you somehow got stuck in a state where a script ran
gamemode(teleporter), but stopped running before it could take you out
of that mode by running gamemode(game), then you could return to
GAMEMODE yourself by bringing up the map screen and then bringing it
back down. So I've made sure to keep that failsafe behavior, only as
long as there isn't a script running.
As part of fixing #464, I'll need to move these pieces of code around
easily. In #220 I just kind of shoved them awkwardly in whatever
fixed function would be last called in the gamestate loop, which I
shouldn't have done as I've now had to make formal fixed-render
functions anyway. Because these fixed functions need to be called
directly before a render function, and I'm fixing the order to put
render functions in their proper place, so I need to be able to move
these around easily, and making them function calls instead of inlined
makes them easier to manipulate.