Whew, time to look at every `int` variable we ever declared! The best
moment to do this would have been a year ago, but well, better late
than never. No need to communicate that in comments anymore.
These shouldn't be used for widths, heights, or sprite-space
coordinates. Maybe we'll cover that another time, this commit is
already large enough.
Part of P0111, funded by [Anonymous] and Blue Bolt.
One fewer magic number. And one more deliberate dependency on a
PC-98-specific hardware constant, to further drive home just how
unportable these games are, even once decompilation will be complete.
Part of P0105, funded by Yanga.
I tried `brge` for the latter, but that had *the* most horrible
ergonomics, and I misspelled it as `bgre` 100% of the times I typed it
manually. Turns out that `dots` is also consistent with master.lib's
naming scheme, leaving `planar` to *actually* refer to types storing
multiple planes worth of pixels. These types are showing up more and
more, and deserve something better than their previous long-winded and
misleading name.
Part of P0081, funded by Ember2528.