OPTIONS=dark_room uses colors, which are usually identical.

[ostrosablin]

It's been a long time since I've noticed this behavior, but I've always has assumed this to be a color scheme issue. But after #480 was brought up and turned out to be a bug, I suppose this one is a bug, too.

Here's how a room looks with OPTIONS=dark_room and "Linux Colors" color scheme.

But as it turns out, normal background color and bright color 1 can appear as same color in some of default color schemes in e.g. Konsole terminal emulator.

(Inverse is also true - bright background color is usually same as normal color 1, which is one of consequences of #480 , but it's not related to dark_room problem).

Hence, under "Solarized Dark" color scheme, dark areas of the room appear completely invisible, because background and foreground colors are identical, despite dots indicating the free space should actually be visible, otherwise it's difficult to estimate the distance precisely.

Here's color scheme definition.

It appears, that under Linux Colors color scheme, normal background and normal color 1 are same (#000000), which makes it not a viable alternative, because it would still break some color schemes.

However, dim Color 1 version appears to be visible (and pretty dim, suitable for dark_room use) over normal background in all default color schemes.

[ostrosablin]

There are also other viable (and likely better) alternatives, such as dim Color 8 or just a dim text color. They should be more contrasting and visible, while still being dimmer than regular text, which should also be fine for dark_room.