Need to occlude NavigationPolygon set in TileSet at runtime

[TotCac]

NavigationPolygon can be added to a Tileset to mark a tile to be used by Navigation2d to find a path.
While building your Tilemap, each tile have static data of navigation to be considered by pathfinding.

Problem: If you an extra layer of object that have to be avoided by Navigation2d pathfinding, how can you do?

Is it possible to have this improvment to 2d pathfinding?

[akien-mga]

I can confirm the need for something like this, unless I'm misusing Navigation2D.

In DynaDungeons, I had tried using Navigation2D (not committed) for pathfinding, but my problem is that I use two tilemaps:

• One for ground and wall tiles, which have NavigationPolygons to make them either allowed or not for pathfinding (e.g. wall is not allowed, ground is allowed).
• One for "obstacles" that can be destroyed and thus reveal the ground tile behind them. Typically they are not allowed for pathfinding, but the ground tile behind them is.

With the implementation I had tried, the "allowed" status of the ground tile would take precedence over the "not allowed" status of the obstacle, thus pathfinding would ignore all obstacles.

[jackmakesthings]

Yesss. This would be an extremely good thing to have, I've been wrestling with the same problem @akien-mga described above.

[ProbDenis]

Yes, having some kind of "NavigationOccluder" object would be extremely useful.

[Anarchid]

Having a way to punch holes into navmeshes would be prim, too :P

[Zylann]

I have the same issue as akien-mga, and I can even have non-tile objects on top of it, that need to be avoided as well. Actually, in some cases it would be easier to build navigation only with occluders instead of nav. polys.

[akien-mga]

Given how popular this issue is, I'll make sure it's fixed sometime before 2.1 is released :)

[PixelWizzard]

That would be great!

[genete]

I also need that for my games.
Currently the Navigation2D only takes in consideration the first NavigationPolygon found in the children list. If I have two NavigationPolygon as children and change the position of them, then the Navigation2D consider the first of its children.
It would be great to have this:

1. Change Navigation2D to consider all the NavigationPolygon children's the result of a boolean combination of all them.
2. Add one new parameter to the NavigationPolygon to make one boolean operation with the next NavigationPolygon in the children list
3. Add one new parameter to the NavigationPolygon node to enable or disable its effect.
4. As said, new navigation occluder. I imagine this would be a bit difficult to implement if the occluder object is not a children of the Navigation2D

With 1) and 2) would be very easy to create moving walls or opening doors. With 3) it would be great to make bodies to do not allow mutual crossing if they are occluding the path.

I have one question:
@TotCac : When you said: "While building your Tilemap, each tile have static data of navigation to be considered by pathfinding." What are you referring to? Is that documented anywhere?
Thanks!

[kakoeimon]

I think this is in the TODO list but not in the 2.1 as it looks like.
By the way it's called Detour / Recast.
Recast is for creating the navamesh from the polygons of the a 3d model (this is a technique introduced in 3d)
and Detour is the way to navigate on the navigation mesh.
Right now we have only Detour in Godot, a tool for creating NavMesh for 2D and a way to import a 3D navmesh created by the Recast in Blender for example.
We do not have obstacle avoidance and for this reason we do not have the ability to block passages of the navigation mesh, we also we do not have crowd control and for this reason agents eventually get in line when they want to get to the same location.

Edit: Sorry my mistake. This is in the todo list for 2.1
https://trello.com/c/vfEeGOIc/35-local-obstacle-avoidance-in-navigationpoly-mesh

[TotCac]

Don't know if this trello is really used by developpers

[TotCac]

@kakoeimon when you build your tileset, you define a navigation polygon for each tile. Then, if you set a tilemap as a children of a Navigation2D, each tile will be linked to your navigation2d, and you build a full level of navigation. I said static data because you can't modify it at runtime as it's a tile information. Check this: https://www.youtube.com/watch?v=S-zEA_Ce1mk

[batmanasb]

To add to this, you can actually use the "set_cell()" in the Tilemap node to switch cells with a NavigationPolygon to cells without them. Which is a way to cut off paths for doors and other roadblocks.