Experimental Code: Stop mobs hopping when pathing - FindBestZ tweaks

[Derision]

This is for those people who don't like to see mobs hopping vertically when pathing.

I've spent the past few days tweaking the 'FindBestZ' code so that mobs stay on the ground when moving. It seems to work quite well, so I thought I would put it out there for anyone interested to try it out.

(For those that don't know, the FindBestZ code attempts to use the geometry data in the zone .map file to ensure mobs stay on the ground while moving).

Diffs against the 1062 source, along with the three changed source files
(Map.cpp, waypoints.cpp and features.h) can be found here:

www.rama.demon.co.uk/BestZPatch.zip

No Windows binaries as I use Linux for playing with EQEmu.

The changes in features.h are just to enable the defines related to fixing pathing when moving, along with a new define I added, ASSIGN_BESTZ_WAYPOINTS_ON_LOAD, which, if defined, causes BestZ to be applied to waypoints as they are loaded from the database.

Notes:

What I did find while testing was that the Facelist array in the eastwastes map appears to be corrupt. This was causing a crash, so I added a check for this in FindBestZ, in the same way that is currently done in the LOS code.

Of course, this means that FindBestZ won't work for Eastern Wastes. There may be other map files that are 'corrupt' in a similar manner, although I didn't come across any others in my limited testing.

I guess this code will break pathing in underwater zones, e.g. Kedge, where mobs are actually not meant to move along the floor. I guess you could add a column to the zone table to enable/disable this code on a per zone basis. This could also be helpful to reduce CPU load for zones where the pathing correction isn't required, e.g. zones that are mostly flat or zones where the waypoints have been made by hand to avoid hopping.

[Derision]

Just in case anyone was curious what the MAP files actually contain, during my work on this I wrote a little Visual C++ 8.0 / OpenGL app so I could visualise it (3D geometry is not really my thing).

The image below shows the triangles contained in the dreadlands.map file, looking from the tunnel to Firiona Vie out across the zone (the box in the middle is Karnor Castle).

The text shows the X,Y,Z position you are viewing from, along with the Node (bounding box). The next line shows some info about the bounding box and finally the BestZ, i.e. the elevation of the ground at the X,Y position you are at.

The app is not user friendly (need to hard code the path to the zone file as well as the X,Y,Z position you want to look from, otherwise I would have posted the code for that too.

Nice work!!

[moydock]

Very nice, does this also fix mobs going under the world while attempting to path over hills? If so, you are my hero! If not, still very nice .

[Diuretic]

Aye, this is fascinating work! The problem's obviously less easy to solve than I originally thought.

Thanks again for the eye opener.

[Derision]

Originally Posted by moydock

Does this also fix mobs going under the world while attempting to path over hills?

I hope so, however I can't say for sure that it fixes all such occurrences as I only checked a limited number of mobs in a limited number of zones.

If you can give me some specific examples of where this occurs, I can check those out for you.

[Zandig]

Awesome!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!

I've wanted to see some solid work on this for quite a while.
Excellent job.

Now we need some Windows binaries

[moydock]

Working great, only problem i've noticed is when a mob goes up a steep hill or maybe it's just a certain change in his z coordinate, he goes under the world. However he does pop back up after a couple seconds. Still a huge improvement.

I may have not set it up right though, not exactly sure what the 'rule system' is.

[Zandig]

Originally Posted by moydock

I may have not set it up right though, not exactly sure what the 'rule system' is.

It has to be set up in the database.

Here is how I have mine set up (working very well):

rule_sets


rule_values


Thats all there is to it!

[moydock]

Sweet thanks, got it working, still seeing them go under when climbing steep hills. Not sure if that's fixable. I haven't upgraded to the newest build though, didn't see any fixes in the log. Btw do you know what the Map:FixPathingZatWaypoints is for?

[Derision]

Originally Posted by moydock

still seeing them go under when climbing steep hills. Not sure if that's fixable.

I've seen this happen in Dreadlands where one waypoint is on one side of a large mountain
and the next waypoint is on the other side. The movement code plots a vector between the
two waypoints which goes right through the middle of the mountain (under the world).

The BestZ code as currently implemented takes the mobs current Z position and looks downward to find the ground. If the mob is already under the world, it will either do nothing, or in the worst case, e.g. Dreadlands, which for some reason has an invisible 'floor' under the world at Z=-210, it will push the mob even further down.

I just made a quick hack to the code to make the BestZ code look up instead of down, and in the
case of the particular mob I was looking at in Dreadlands which pathed over a steep hill, it seemed
to have the desired effect of stopping it going under the world, i.e. if it was under the world, it pushed
it back up to the ground level.

The next step is to have the code look up AND down and decide which direction to push the mob.

I don't have a lot of time to play with this much at the moment, but if I find something which seems
to work reliably, I'll post a further patch.

[Derision]

Originally Posted by moydock

still seeing them go under when climbing steep hills. Not sure if that's fixable.

If you're using the PEQ Ykesha DB could you give me some test cases of mobs that path under the world, i.e. which zone they are in, then target them and do #npcstats and #wpinfo and give me the NPCID and Grid number ?

[moydock]

Originally Posted by Derision

If you're using the PEQ Ykesha DB could you give me some test cases of mobs that path under the world, i.e. which zone they are in, then target them and do #npcstats and #wpinfo and give me the NPCID and Grid number ?

I'm actually using a custom db so no help there. But I can tell you this, there seems to be a height which they reach, and they always go through the hill at that height. It also seems to be the height they would normally 'hop' up to before the fix. I'm guessing this point is the z coord of the WP they're headed to.

So what if you forced the z coord of the waypoint a mob is headed to always be the highest point in the zone. Then they wouldn't go through hills and the z-fix already in place would keep them on the ground. Would that work?