Gaming Your Way

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New Test Level and Goon AI

Fuck funky headlines. So I said it.

Today's post is all about ... the new test level and new goon AI (mhm, maybe back to funky headlines?).

Let's start with an image:

The old test level with two elevators and some searchable objects (grey boxes).

While this worked well enough the random / percentage based goon AI it didn't look good on the new test level. One reason might have been the way I've dealt with entering/exiting the map. In short the goon wanders around until he reached the number of steps he should do and then takes the next exit he comes across. For the smaller test level this was OK, but with the much wider new level this revealed some problems. Due to the random nature, goons sometimes would just walk back and forth between a door and the elevator until it reached the required steps to exits again.

This made me rethink the way the goon walks around and I settled on the idea that it would (and does, comes to that) look better if the goon has a predefined path to follow. 


The new test level, also shown is the potential path I want the goon to follow and the new elements.

Of course this added some more things to think about, most obvious is that the goon needs a path to follow once an entry and an exit have been assigned.

As Unity comes with a nice built in NavMesh, I tried to get away with that...

... and as soon as that was in, it showed that this won't work "out of the box".

To make that story short: it works just fine as long as you can work with a continuous path, but the different floors and the elevators proved to require a lot more work than I was willing to put into. One of the "easy", but tedious solutions were using Off-Mesh Links, so the NavMesh Agent would know how to reach the different floors. As far as I found out (prove me wrong) there's currently no way to create Off-Mesh Links on the fly via code.
Creating those by hand in the editor would have made a brave man cry (I gave up after a few). For each elevator, one link between the left and the right side and for every floor AND every side, so for a 3 floor elevator: 15 Off-Mesh Links (if I counted right). 

Erm. No.

Time for plan B.

Plan B was easy, just create nodes for my a* graph based pathfinder. 

Well, creating nodes was easy, as I already had a lists of all doors, elevators and the other stuff. 

Connecting these is a different story (in a way that makes sense). Until now the map elements (which the goon could interact with) only stored the current "block" (needed later when blocks will be combined to build a bigger level) and I really didn't want to add a "connected to" list or a "floor".

So the (nasty) solution was to read out the coords and store these in a PointInt3D (my simplified int Vector3 version) by multiplying the position by 10 and reducing the y value to the floor (ie. 0, 1, ...). 

For instance an elevator creates X nodes (yellow dots, one for each floor): like [0,0,0], [0,1,0] and [0,2,0]. While I'm at it, I also connect these (so the floors are connected, too).
Then I looped over all floors and and created a temp list of the elements per floor, this list would then be sorted using the x value and viola ... all nodes per floor in order from left to right. Now simply connect Node[i] and Node[i + 1] and the floor is connected. As I had created the links between floor earlier, creating the complete graph (red lines) was a no-brainer.

Of course it isn't quite as easy as this, just look at the map and notice the green line marked "No! No! No!". I fixed this by .... well let's just say it is a dirty trick...

The path (blue line) is created by a simple "Pathfinder.GetPath(StartNode, EndNode)".

How the goons deal with that is for the next post, as this one is already long enough.

-- Olli