Visible wandering hordes

[ghost]

Make wandering hordes visible on overmap. (Code pulled from Reaper42's abandoned PR #6827)

[bug-sniper]

Are the hordes visible from a greater distance with binoculars?

[ghost]

@bug-sniper Yeah, hord sight range is calculated using overmap_sight_range(), which takes into account binoculars, rifle scopes, as well as the eagleeyed and bird_eye traits

[KA101]

Sounds good.

[KA101]

Tested, works, merging.

[ghost]

Thanks, KA101

[KA101]

No problem.

[Nandorianen]

Midnight: everything's fine.
Morning: zombie horde is closing on my house and can be seen on the map. And map is lagging heavily. Pretty sure these two are connected.
Build 1317, SDL, windows.

Also some kind of hint is in order, I think. Right now it shows Z on map, but doesn't explain what it is anywhere close.

[ghost]

@Nandorianen, thanks for the feedback. Are you sure the lag is not resulting from the horde itself being nearby (i.e. a crap-ton of baddies spawning nearby)? I haven't experienced any lag resulting from this PR, and from going over the code, I don't see any way it can cause lag from nearby hordes. The cost of displaying a horde on the overmap should be the same regardless of how close the horde is to the player.

[ghost]

@Nandorianen, also regarding the map symbol, I think it's fairly intuitive as-is. (At least in the context of the rest of the game ;) ) Though, I guess it couldn't hurt to add a line of text on the right side of the overmap screen - probably a trivial change for someone more familar with the code than me.

[Nandorianen]

Are you sure the lag is not resulting from the horde itself being nearby (i.e. a crap-ton of baddies spawning nearby)?

I can't be sure since I have no effective methods to thoroughly scientifically test it, but my limited experience suggests that this is the case. No lag anywhere except overmap. And now that the horde is gone / killed, no lag on overmap again.

[KA101]

Yeah, I think the map moves a little slower now. Can't say it's the horde display BUT it does move at a similar (maybe slower? possible confirmation bias) rate when I hit horde-debug.

So I'd believe that the large amount of flashing characters might be a culprit. Can't prove it though.

[Nandorianen]

To clarify: by map lag I mean slow scrolling if you hold down direction button.

Don't know what it is now. No hordes around, all map levels lagging when I am on ground level. Rain was a suspect, but turned out innocent.

When I am in the basement, everything is quick and smooth. Any levels of overmap. But going upstairs introduces lag back.

Should I make a separate issue then?

[KA101]

Feel free, but I think that may have been mentioned already.

[ghost]

I've confirmed there is definitely a significant slow-down to overmap scrolling caused by this PR, but it doesn't seem related to how close hordes are to the player or even if there are any hordes at all. It looks like the problem is that Reaper42's code is checking for player line-of-sight to every square of the overmap, with every draw.

I'll look into it further and open a new PR with a solution.

[kevingranade]

Please be careful, there's a reason his stuff wasn't getting merged, it had
large flaws like this. Unless a very immediate solution presents itself
the fix is reverting the PR.