How do I make my enemy AI know that they're in a room?

Audiobellum

I just want to make my enemy AI know that they're in a particular room as oppose to another room; it this is important if I'm going to get the enemy AI to focus exclusively on reaching for cover in the room/area they're in. This seems like the biggest hurdle when it comes to me getting the enemy AI to choose cover sensibly, when I think about it. Here's a screenshot of what my test level so you can see what I'm working with right now.

So is there an elegant solution to this problem that I'm trying to solve? Hopefully, I don't have to start break up my level across multiple gridmaps to communicate to the enemy that it's in a different room or area.

xyz

Audiobellum Since you're in a grid based system, you can simply map every cell to a room id. The mapping dictionary can be automatically built at startup by traversing the cells using flood-fill like algorithm and stopping at walls.

This will eliminate any need for manual placement of areas, which may become cumbersome for more "meandering" room plans and corridors (like the green corridor on your screenshot for example)

Once you have the mapping dictionary, it's only a matter of trivial lookup into it whenever the enemy walks into a different cell.

Toxe

Audiobellum I have not used nav meshes in Godot before but that is the direction that I would be looking at.

So one option would be to have separate nav meshes for each room. Once you know the nav mesh you are on you can find the associated room.
Or if you have one giant nav mesh then try to "paint" parts of the mesh with the information of the room that it belongs to. Assign some information to the mesh to identify the associated rooms.

If the AI need to know in which room they are, they only need to "look at their feet" and get the room information via the nav mesh they are standing on.

But as I said, I have not worked with nav meshes in Godot but I assume that you can store additional properties inside a nav mesh. Or just store the information in plain old metadata of the Object class.

DaveTheCoder

Do the rooms have polygonal boundaries? It shouldn't be hard to determine whether an object's position is inside a polygon.

For efficiency, I would first check whether the position is within the room's rectangular bounding box. If it is, then do the more accurate test of whether it's in the polygon.

Audiobellum

DaveTheCoder

Is there any built-in functions that could help me do it?😅

DaveTheCoder

Audiobellum built-in functions

Yes:
https://docs.godotengine.org/en/4.5/classes/class_rect2.html#class-rect2-method-has-point
https://docs.godotengine.org/en/4.5/classes/class_aabb.html#class-aabb-method-has-point

There are also signals that could be useful here:
https://docs.godotengine.org/en/4.5/classes/class_area2d.html#signals
https://docs.godotengine.org/en/4.5/classes/class_area3d.html#signals

Audiobellum

DaveTheCoder You know. I've been thinking about using area3ds. Perhaps that's the solution I should be exploring. Thanks.

kuligs2

xyz i would just add area collider for doors, when someone enters through door you can flip a flag that this entity is in some room.. grid would fail/get complex when you start having areas that are not grid based or outside /inside mixed areas.

Doors could be instantiated object/scene and will need manual placement in the end. Doors could be typed like with doors or just door frames if you have open door holes

xyz

kuligs2 Doing it with doors is fine as well but it still requires some manual setup and possibly some connectivity data. It also needs 3d math to determine from which side you entered/exited.

Doing it the way I described is trivial once you have a system that builds grid based Dijkstra maps. And you always want to have something like that on top of your basic nav pathfinding provided by the engine. It's a relatively simple yet powerful mechanism for facilitating high level ai decision making of all sorts.

In any case, maintaining some kind of graph representation of the map with rooms/doors as graph nodes/edges is essential. Relying just on scene objects is insufficient when modeling enemy behavior.

Audiobellum

kuligs2 Oh that's what I ended up doing instead.🤣 I call them location indexes. I have to manually adjust the location indexes of the enemies and the doors. It works but, it does require more play testing or everything falls apart.

Audiobellum

xyz
"Doing it with doors is fine as well but it still requires some manual setup and possibly some connectivity data. It also needs 3d math to determine from which side you entered/exited."

My doors already use a dot produce for that. I first used the dot produce to determine what door opening animation should be used depending on what side the enemy or player is when opening the door.

I think the whole Dijkstra maps solution would make my life easier if I know how to implementing without help or copy/pasting. Truth is, I'm not very good at thinking algorithmically and I really like to understand my code.

Audiobellum

Toxe

"Or if you have one giant nav mesh then try to 'paint' parts of the mesh with the information of the room that it belongs to. Assign some information to the mesh to identify the associated rooms."

I'm not sure if that's possible in Godot or at least I don't know how to do that. That sounds like a cool idea, though.