[Crawl-ref-discuss] Auto-explore safety

[Odds O. <cra...@gm...>]

Hi,

I've been experimenting with options to make autoexplore safer by exploring
near upstairs. The intended change is that exploration is generally around
up-stairs, creating a safer map - because the explored area is more
circular, so the player is near more safe places, and the up-stairs are
easily accessed from the whole explored territory. The trade-off is that
exploration is likely to be slower, as it involves more backtracking across
explored territory.

Thoughts on whether something like this might get merged - either behind an
option, or as default behaviour?

The change I've tried so far is to aim for the unexplored square which
minimises:

[Distance from player] + 2*[Distance from [nearest up-stair to player]]

Experiments seem to show that this has the desired effect, and that it
slows down exploration a bit (from a *very* small sample, maybe 20%).

Prototype can be seen on
https://github.com/CrawlOdds/crawl/tree/explore_from_stairs if you want to
try it - though this is likely to have bugs and/or use the autoexplore code
in unintended ways (since I don't understand it fully).

Cheers,

Odds