Doomsday Engine

Something that'd be useful is an automatic
brightness/contrast adjustment system. It seems we
all like to play jDoom pretty dark, but there are some
levels which are almost unplayable at such settings,
whereas other levels still seem too bright. What if
jDoom considered all indoor sectors on-screen,
compared their light levels, and automatically
adjusted brightness/contrast on the fly? The effect
would be similar to, in real life, walking from a bright
room to a dark, or vice versa... After a few seconds,
your eyesight adjusts.

"It would still need some kind of a 'master setting',
because people's monitors have different brightness
settings." - Skyjake

Yes, I'd realized that, omitted to mention it.

The best way I could think to implement user
configuration is to keep all existing
Brightness/Contrast/Gamma controls as-is, and add
an "Auto-Adjust" slider to the control panel.

The possible values would be 0-10.
0 = Off
1 = Minimal
...
10 = Aggressive

Perhaps it'd be cool to add some sort of time option,
to determine how long it takes lighting to adjust, but
that would be to control the realism of the effect, a
matter of preference and probably unnecessary.