Changes to scent, zombies, zombie dogs, noise, and hiding in town

[Zireael]

The problem is that scent creates the "missile seeking behaviour" i2amroy described, where they find your exact position flawlessly, making hiding, evading, any sort of close-up-tension feeling impossible. I want to be able to hide from zombies and use the night to my advantage.

Wouldn’t slowing the Z down and reducing the scent radius remove the “missile seeking”?

[infectedmochi]

[quote=“Hyena Grin, post:47, topic:3591”]I think something that the game isn’t taking into account is that you can’t really tell where a scent is going to be stronger. A dog can’t ‘see’ smells ten feet away from it. It has to go to that spot and smell it to see if it’s stronger. That’s why you see dogs sniffing back and forth, backtracking, checking different spots. They are trying to find where the scent is strongest. To do that they need to physically be in that location.

The only information a zombie or any other smelling creature should have is ‘what does the tile I am on right now smell like.’

Then simply have the zombie move until the scent is weaker (and then stop and move somewhere else) or stronger. They keep moving, avoiding weaker smells while seeking stronger smells. If the code can be put together to give the zombies a search pattern, then this should result in a faaairly realistic search behavior that doesn’t lead them directly to the player.

Basically, the zombie will remain in the strongest scent area that it can. It will not move to a weaker scent area unless it has exhausted all tiles it can reach without moving to a lower scent area. The zombie would also have the tendency to follow the path that is working the best for them. So if you run in a straight line, the zombie will probably not have too much difficulty following in a straight line behind you. but if you do large zigzagging maneuvers then it might take them significantly longer as each ‘turn’ would mess up their search pattern.

This could result in some interesting behavior where, due to decay, a zombie outside a house the player is not in, might end up breaking down the door to the house because he has already searched everywhere else and the door is the only tile left to check before he moves on.

This could well get very difficult. I have very, very minimal coding skill and I suspect that efficient, reliable search patterns can be quite complicated. But I thought I’d throw it out there nonetheless.[/quote]

I like this idea, it will make smart movement more rewarding and a more tactical approach much better. Also this can potential create some interesting strategies like pile up your old clothing to make a smell distraction (similar to the proposed noise distraction) or confuse zombies with strange smell, I don’t know whether this can be very difficult to code though.

[Leper]

I think that if this mutagen can make the human body spit acid, throw electricity, and generate smoke, it is probably capable of enhancing sense of smell also.

Not 100% on acid or smoke, but I’m fairly certain the electricity is more to do with CBM stuff than mutation.

[kevin.granade]

Prototyping this now on this branch: https://github.com/CleverRaven/Cataclysm-DDA/pull/3818
So far I’ve capped the upper threshold and reduced regular sensitivity.
Making zombies without KEENNOSE hesitate a bit will be trivial, just ran out of time.
Redoing the scent diffusion for a narrower scent plume will likely take a bit longer.

[system]

Wow! When the whole stealth mechanics come together with a reworked stenchine, it will be 100 times more intense and fun to sneak through the cities!

[GlyphGryph]

Sorry it was such a slog to drag the actual requirements out of us, Kevin - glad to see you working on a solution, though.

[kevin.granade]

Btw, testing the upper threshold I got goosebumps.
Waited for night, headed into a town, debugged some vision so I could walk to within 10 squares of a zombie, then waited. (and turned off the enhanced vision)
Once my scent diffused over to the zombie, it went active and I could see ?s coming toward me, then they stoped getting closer and it just started wandering around at random. I didn’t realise how much built up tension I had about those little yellow question marks, but it was fairly nerve-wracking watching them pop right next to me.

If I stood there long enough, it would eventually wander in sight at random, but they’re fairly easy to lose now. Also if you take a step with one that close to you, it’s almost certain to find you in the next turn or two.

Let me repeat that, “they’re fairly easy to lose now”. You can lose a zombie within about 20 steps now, I think that’s an effect of the decreased sensitivity, and it makes night raiding a much more attractive prospect. (probably need to take another look at noise though)

I need to do some testing with dogs to see how they act now with the upper threshold thing. I think their scent ability will get them 2-3 steps away from you (compared to 3-4 steps with zombies), which means they have a fairly high chance of stumbling into you once they get that close. They shouldn’t be able to nip at your heels as effectively any more though, unless they manage to get a fix on you with hearing, but I think that’s going to be fairly unreliable.

Huh, they don’t have KEENOSE, probably want to change that.

Overall I think it’s a rather large improvement, I do still want to slow down their progress while tracking by scent and slow the diffusion of scent in general, but the upper and lower threshold thing is the biggest improvement IMO, as it enables actually sneaking through a town at night, albeit with a good bit of danger.

[GlyphGryph]

Wow. It sounds exactly like I had hoped it would, and has created almost exactly the sort of situation I was picturing that the current system was failing to live up to, and why it bothered me so much - the sort of tension you’re describing is exactly what I was hoping for.

Awesome.

[infectedmochi]

Here’s hoping this change will bring a much needed atmosphere for the game, the atmosphere of playing hide and seek with zombies and trying to figure out whether they actually have picked up your scent and heading toward your position.

Imagine the tension!

[GrizzlyAdamz]

Pst, make dogs bark when they find you? Maybe shriekers as well?

[kevin.granade]

Yea that’s the plan, shriekers do it already, and REALLY loud. oof, running into a shrieker at night in a town, that’d be a BAD time. Dogs could howl when they start tracking you… heh heh.

[GrizzlyAdamz]

Will this be in a new experimental or are you guys going to be tweaking it before merging it?

[i2amroy]

Will this be in a new experimental or are you guys going to be tweaking it before merging it?

It’ll most likely follow the exact same progression as any other large PR; first an enterprising coder makes it and places it into a [WIP] pull request so it can begin being tested/reviewed while being worked on. Then eventually it will be deemed “ready” and merged into the mainline experimental builds just like anything else.

[vultures]

Please consider the upper treshold for Hardcore mode, but it should however be a kick in the nuts if you intentionally fail to sneak like you obviously should.

[kevin.granade]

I want to add the hesitation feature and probably the slower diffusion change, then people can throw rocks at it and tell me what a terrible person I am (not really, you can’t throw rocks on the internet). Other stuff we’ve brought up can probably wait for another PR, expecially since we’re trying to hammer out a bunch of bugs in the next week or so to make a haloween release. There IS an automatically built linux/SDL image at http://ci.narc.ro/job/Cataclysm-PullRequests/1971/artifact/cataclysmdda-0.8.tar.gz if you want to try out the current state of it.

Please consider the upper treshold for Hardcore mode, but it should however be a kick in the nuts if you intentionally fail to sneak like you obviously should.

I’m not sure I understand, do you mean if you’re not being sneaky you should attract more attention? Once there’s a sneaky gait you can use to actually sneak, I think running at the current speed will cause more noise, so there’ll be that.

[Zireael]

I think something that the game isn't taking into account is that you can't really tell where a scent is going to be stronger. A dog can't 'see' smells ten feet away from it. It has to go to that spot and smell it to see if it's stronger. That's why you see dogs sniffing back and forth, backtracking, checking different spots. They are trying to find where the scent is strongest. To do that they need to physically be in that location.

The only information a zombie or any other smelling creature should have is ‘what does the tile I am on right now smell like.’

Then simply have the zombie move until the scent is weaker (and then stop and move somewhere else) or stronger. They keep moving, avoiding weaker smells while seeking stronger smells. If the code can be put together to give the zombies a search pattern, then this should result in a faaairly realistic search behavior that doesn’t lead them directly to the player.

Basically, the zombie will remain in the strongest scent area that it can. It will not move to a weaker scent area unless it has exhausted all tiles it can reach without moving to a lower scent area. The zombie would also have the tendency to follow the path that is working the best for them. So if you run in a straight line, the zombie will probably not have too much difficulty following in a straight line behind you. but if you do large zigzagging maneuvers then it might take them significantly longer as each ‘turn’ would mess up their search pattern.

This could result in some interesting behavior where, due to decay, a zombie outside a house the player is not in, might end up breaking down the door to the house because he has already searched everywhere else and the door is the only tile left to check before he moves on.

This could well get very difficult. I have very, very minimal coding skill and I suspect that efficient, reliable search patterns can be quite complicated. But I thought I’d throw it out there nonetheless.

This sounds very similar to A* pathfinding, you know.

[youtoo]

if we are going to make sound more important, we could add ‘flatulents’ as a negative trait and ‘beans’ as a food that can make you rather noisy?

[infectedmochi]

if we are going to make sound more important, we could add ‘flatulents’ as a negative trait and ‘beans’ as a food that can make you rather noisy?

Now the apocalypse is complete!

On a more serious note: There are a ton of things which can make noise and give your position away (footstep!), a flatulent is the probably last thing I’d worry about in a zombie apocalypse.

[kevin.granade]

So I accidentally merged my WIP branch, so the sensitivity thresholds are in the latest experimental. Just FYI.

[i2amroy]

So I accidentally merged my WIP branch, so the sensitivity thresholds are in the latest experimental. Just FYI.

Kevin, there’s a reason we use WIP tags you know! (It’s obviously so some other dev doesn’t merge our works in progress :P).