[2022] Urban Combat 7

Most likely, It's determined the same way the game determines if it should darken your screen lightwise- Which is to say conditions like "Is there a roof? Are you more than a block inside anything detectable as an entry point? Are all the walls closed up?"

Alternatively it might work the way crops determine if they can/should grow- Is there a path to sunlight within X blocks; If yes, outside, if no, inside. If it used something like this, unlike plants, it would probably consider transparent blocks as enclosed space.

I don’t know. It’s probably a quick and dirty calculation since it would need to check this constantly. But I would push back against Jost Amman’s insinuation that knowing is gaming the game. Since, as the OP points out, our intuitive sense of what is “indoors” probably doesn’t exactly apply, it’s reasonable to deduce the actual algorithm.

If it’s a ray cast up to the sky like the game uses for rain and plants, then you can be “indoors” with an unfinished or destroyed roof and not get the benefit. Or it the game uses a more sophisticated flood fill algorithm (unlikely), then the perk could not work if a door is left open or a window is broken. If “indoors” just means within the bounds of a POI, then it would be pretty broken when you consider all the space outside the building part of a POI. Or if it’s the same algorithm that determines whether to darken the screen (a feature which I hate, but I digress), then you might not get the benefit in a very large room, even if it’s enclosed, or if you’re in an attic against certain shapes of roof.

Again, none of these perfectly match a player’s intuitive understanding of what it means to be indoors or not for all situations. So the player can’t just rely on common sense unless they’re willing to accept the perk not always being on or off when it intuitively should.