Scenario Problem: Hunt the Wumpus

[Alexander SquidLord Williams]

So, right ... I've been wrestling with maps lately to try and get a few scenarios specced up, and a few things that cater to my own perverse sense of amusement in referencing ancient games of days gone by.

Voila, Hunt the Wumpus, a maze of twisty turny passage, all nearly alike, and full of room enough to drive tanks down three abreast, but not much more than that!

Unfortunately ... there seems to be a significant issue. Actually, there were a lot of significant issues, mainly due to needing to flip every bloody texture that went onto the thing by hand, for one reason or another, but that's neither here nor there.

The significant issue:

A few seconds after deployment and the bots all descend like vultures, the game begins to hitch and lag like an unruly mule. Frame rates drop to 1 per tens of seconds, though sound continues. It becomes, in short, unplayable.

My guess is the bot pathfinding algorithm is getting a bit nuts when trying to plot courses through the maze to abstract destination points I can't see. Alternately, that they're mentally crashing and burning on trying to plot courses with lots of impassible terrain intervening that may involve convoluted pathing.

That sound like I'm on the right course with my understanding, folks?

[Grappler]

I will take a look at this today, but to see if it bot path finding, just run the scenario without any bots. If everything runs just fine, it is probably the path finding.

[Alexander SquidLord Williams]

I'll do that in mere moments. Easy enough test.

(Yes, I'm awake in the daytime. Sign of the apocalypse, that is.)

[Alexander SquidLord Williams]

Yep, just me, no problems at all. Quite a fun little map to run across in a Tempest, in fact. You can get some decent air if you catch one of the alluvial erosion hills just right.

[Alexander SquidLord Williams]

Would it be possible to do a run-once "no go" extract map from a given height file that was then saved in another for use by the bot pathfinding? There has to be something that can get offloaded from the poor little guys in precomputation.

Though odds are good you're already doing what you can during that scenario load context.

[Grappler]

Oddly enough, with just two bots there seemed to be no performance drop, but as soon as I went to 10, the thing just basically stopped. Hmmm.....

The bots don't begin their path finding until they have deployed on the ground. My performance hit occurred before they were even dropped. It is more likely that the AI can't figure out where to drop.

[Grappler]

I just confirmed that the bots are getting stuck trying to drop. It will be later today before I can get into "why" that is true. The terrain here is not really worse than "Treachery" so it should work.

[Alexander SquidLord Williams]

I just tried it with one bot, and like you, it worked fine.

I do notice that the bots seem to love to drop on that bit of inaccessible terrain to the northeast of the northeast edge, in an area it won't actually let me drop. In fact, its probably an area they shouldn't be able to drop in, so it very well may be a bug with the drop selection system in general.

(Note this obsession with that area is true of both my bots and his, as I juggled them about a bit.

I also noticed that, despite setting the number of my dropships avail to 30, I ended up being told I had none left after only having ... well, none, actually ... destroyed. I think it might be counting destroyed drop pods as dropships, which would be bad.

[Alexander SquidLord Williams]

I actually just got around to trying this again after the latest round of patches.

Amusingly, the dropping events are no longer a problem. I tried 4 bots per side and myself, and the drop period was a no-brainer. Of course, my bots all dropped on the cliff-top in the far northeast of the map, and one crashed and died in the attempt because the thing landed too close to a cliff edge, but that's not the issue.

Dropping, at least, didn't bog me like it did, even if the bots were dumb about location choice.

I dropped in (and was destroyed the first time by a lousy dropship release, which makes me revisit the ray-cast for DS approach vector idea, but I digress), and could drive around for a bit, no lag.

Then I told my bot-buddies to extract en masse.

Then things blew up and turned into lag central. Not good. In fact, bloody annoying.

Extracts still drop in and pull out pretty vertical, but I suspect their guidance is trying to figure in a good drift approach, and being so close to the edge, it's just not going to happen, or at least throws a pile of failures for every success.

So, looks like the Wumpus has thrown us another pit to be dug out of.

Now, if only I could get my team-mates to stop dropping in on the walls and instead use the floor. I fear I'll need to use a DZ for that, though, with a tiny deployment radius, or some other hackery. I likewise suspect I may end up waiting for the integrated object placer simply so I don't go mad trying to figure out coordinates before I can finish this thing.

[ClaytoniousRex]

Stan, can't he simply use the MaxDropElevation thingy to completely solve this stuff with the bots and tell them to drop on the "floor"?

Alex, that's very cool. And, no, I don't only mean the intro image. You know, with a little random perturbing of the maze walls, it might even look kind of "natural", but it's more honest the way it is.

[Alexander SquidLord Williams]

There's a MaxDropElevation tag? Mein Gott, I feel ... well, I feel like I need to crack the whip over you to get the XML spec updated and the wiki filled in, but I'm well aware the WWII stuff has got to be putting boot to arse on you guys, of late.

I pretty intentionally described the environ as a virtual creation for training, knowing full well that its not a very natural looking formation. Cranking up erosion further and perturbing the edges doesn't actually look like it would be as much fun; as is, there are some silted hills and gullies along the floors that are frighteningly good at masking approaches, and corners become death zones if they're stealthed well, or a Hermes escorts some folk.

L3DT is really nice for creating terrain, but you really need to do the heightmap at 1025x1025 to get the rough design map detailed enough to do things like this. I briefly considered making huge pits of water for the true Wumpus experience, but it seemed ... redundant.

[Grappler]

There is an optional MaxDropElevation and a MinDropElevation tag in the scenario file. These are used by the bots to keep them from choosing drop locations in the gulch in DeadGulch and on the top of mountains in other scenarios.

[Chilibird]

Why not add an additional mask image to scenarios, one to designate to the AI where dropships can't drop? Just a simple Red/Green map, Red= No Drop, Green= Drop, and in between = more/less likely of success.

That way, they'd stop with dropping on buildings, on hillsides, ect. which just ends in AFV destruction.

[ClaytoniousRex]

That is a really good idea, Iceman!

[Alexander SquidLord Williams]

Hmmm, making that map would be a right PitA, for the record, since buildings don't necessarily appear in all scenarios. Map-making is already kind of dodgy in some cases. I still don't know exactly what ShadowMap is supposed to be for, for example.

[Jalinth]

Of course with the scenario editing software that is coming out some time, it could well be easier.

Perhaps a mask for each game type or some such.

[Alexander SquidLord Williams]

The scenario-editing bits will be handy for all sorts of reasons, not least being that it'll make it way easier to get the vertical flipping right given the inputs. Oi, what a pain ...

Anyway, for things like drop-acceptible areas, and if they decide to go to a multi-texture terrain maps (beyond the current 3/4), we'll probably just want to go to B&W images for each layer/descriptor. That gives the 65k range without the complications of unused channels. That is, if white is described as "always OK to drop" or "complete coverage of this texture" and black as the opposite, the usage becomes fairly easy.

[ClaytoniousRex]

Did MaxDropElevation get the Wumpus fixed for you, Alex?

[Alexander SquidLord Williams]

Originally posted by ClaytoniousRex:

Did MaxDropElevation get the Wumpus fixed for you, Alex?

Sadly, no.

Interestingly, when I put MaxDropElevation 500 in the scenario file, I get the <i>original</i> behaviour that I had issues with, the bots grind in a hard cycle, bogging the entire server down ... and even then, I believe I saw one trying to land on the NE ridge.

Ultimately, kind of frustrating.

[ClaytoniousRex]

Here's the issue that was making the bots' brains explode on Hunt the Wumpus:

The entire terrain is only 8,192 meters across. However, the objective is at the following location: 14528,14628. The objective is several kilometers to the northeast of the edge of the map. The bots are dutifully trying their level best to drop near that objective, but it's not legal to drop out in no-man's land.

Moving the objective onto the actual playing area seems to fix this problem.

As an aside, setting MaxDropElevation to about 200.0 works really well on this map (500.0 is still 1/2 way up the walls).

[Alexander SquidLord Williams]

OK, that's an odd place for the objective to be ... I'm trying to remember why in Hades' name I set the TargetLocation to somewhere out in hyperspace. Probably a side-effect of not knowing the unit the coordinate for it was supposed to be in (pixels vs metres).

Luckily, however, it's an easy fix.

It'll help a lot once we have an integrated scenario design aide, of course; the automatic coordinate and radius setting will be a huge boon to getting things "just so."

[Alexander SquidLord Williams]

I've been tinkering with the scenario a bit before bed, putting the Possession right in the dead center of the map (perversely, atop a mountain, but ...), and with MaxDrop set to 200. Things go extrordinarially well ... except for the fact that somehow, at some times, things still manage to drop on the slopes or even tops of the mountains, despite the setting for height.

Moreover, and possibly as perversely, I've seen dropships, particularly on extract, hit a mountain and go cartwheeling up into the sky until they hit ceiling, then flatten, drift a bit, and finalize the extract.

If nothing else, the tightness of the terrain is a solid test of the dropship patchfinding, I'll say that. And watching bots try to drive up the side of a nearly vertical slope is perversely satisfying, if bug-finding.

[Toby Haynes]

Originally posted by Alexander SquidLord Williams:

OK, that's an odd place for the objective to be ... I'm trying to remember why in Hades' name I set the TargetLocation to somewhere out in hyperspace. Probably a side-effect of not knowing the unit the coordinate for it was supposed to be in (pixels vs metres).

I have assumed that all the coordinates in the scenario files are in "Real World" coordinates, i.e. centers for procedural objects, team positions, etc.

How does that work out for heights? I'm working on the assumption that given the following (taken from VolcanicDeposits.scenario)

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;"><VertexSpacing>20.0</VertexSpacing>

<ElevationScale>0.03</ElevationScale></pre>

[ClaytoniousRex]

Yes, Toby, that's correct.

Alex, one of the improvements in 1.1.6 is that dropship pilots automatically seek out flatter, safer, landing areas near the designation drop point when the drop point is dangerously steep or rough. They should do a much better job on Wumpus with this update.

[Alexander SquidLord Williams]

Originally posted by ClaytoniousRex:

Alex, one of the improvements in 1.1.6 is that dropship pilots automatically seek out flatter, safer, landing areas near the designation drop point when the drop point is dangerously steep or rough. They should do a much better job on Wumpus with this update.

Schuper! At some point, once this stuff gets worked out, I'll actually gain enough clue to put things like facilities and other useful things on the terrain. Wouldn't that be swell?

Speaking of swell, it'd be nice to have there be some kind of switch I could throw so that the system displays my current vehicular coordinates in three-space while driving around in the terrain. If nothing else, it'd allow some kind of translation for deciding where to put objects on the map without needing the integrated placer or guesstimating ...