Needs documentation: NavigationServer will only update after 1 physics frame

[Xyotic]

Godot version

Godot 3.5-beta1_mono

System information

Windows 10, GLES3, RTX2080

Issue description

Edit: @smix8 noticed the issue was me not waiting for the physics frame to end.
See the solution in the comments. Changing the subject to "Needs documentation".

Setting a NavigationServer map to active via .MapSetActive() does not have any effect.
.MapIsActive() will always return false.

I used a pretty simple setup using C#:

    NavigationMesh navmesh;
    public override void _Ready()
    {
        navmesh = new NavigationMesh();
        navmesh.Vertices = new Vector3[]
        {
            new Vector3(0,0,0),
            new Vector3(9,0,0),
            new Vector3(0,0,9),
        };
        navmesh.AddPolygon(new int[] { 0, 1, 2 });

        NavigationServer.SetActive(true);
        var map = NavigationServer.MapCreate();
        var region1 = NavigationServer.RegionCreate();
        NavigationServer.MapSetUp(map, Vector3.Up);
        NavigationServer.RegionSetTransform(region1, Transform.Identity);
        NavigationServer.RegionSetNavmesh(region1, navmesh);
        NavigationServer.RegionSetMap(region1, map);
        NavigationServer.MapSetActive(map, true);

        GD.Print("Is active: " + NavigationServer.MapIsActive(map)); //Will return false

        var result = NavigationServer.MapGetPath(map, new Vector3(0.1f, 0, 0.1f), new Vector3(1f, 0, 1f), true);

        GD.Print("Found waypoints: " + result.Length);
    }

Steps to reproduce

Run the MRP in Godot 3.5 beta mono build.

Minimal reproduction project

NavigationServerTest.zip

[smix8]

@Xyotic

Can't run and test mono builds but here are a few things.

The NavigationServer is active by default as soon as it is created by Godot, no need to set it active again.

If a Map is created through NavigationServer API alone it needs to be created / registered and set activated afterward.

Any change like registering a map, a region or an agent, changing their transform ... takes time to sync as the NavigationServer runs on a different thread. Don't expect changes to be in effect immediately or a path to return on the same frame you setup all the regions and maps. You need to wait at least 1 physics tick for the NavigationServer sync and queue flush before changes can take place.

If possible please test again and verify. I think it is not a bug but a setup, documentation and expectation issue.

[Xyotic]

Thx for the reply!
Do you have a example how to set this up in gdscript?

[smix8]

@Xyotic

var navmesh : NavigationMesh
func _ready():
	# use call deferred to make sure the entire SceneTree Nodes are setup
	# else if yield on 'physics_frame' in a _ready() sceneload might get stuck
	call_deferred("setup")


func setup():
	
	navmesh = NavigationMesh.new()
	var vertices : PoolVector3Array = PoolVector3Array([Vector3(0,0,0), Vector3(9.0,0,0), Vector3(0,0,9.0)])
	navmesh.set_vertices(vertices)
	var polygon : PoolIntArray = PoolIntArray([0, 1, 2])
	navmesh.add_polygon(polygon)
	
	var map : RID = NavigationServer.map_create()
	var region : RID = NavigationServer.region_create()
	
	NavigationServer.map_set_up(map, Vector3.UP)
	NavigationServer.map_set_active(map, true)
	
	NavigationServer.region_set_transform(region, Transform())
	NavigationServer.region_set_navmesh(region, navmesh)
	NavigationServer.region_set_map(region, map)
	
	# wait for NavigationServer sync to adapt to changes made
	yield(get_tree(),"physics_frame")
	
	var is_active : bool = NavigationServer.map_is_active(map)
	print("Is active: %s" % is_active)
	
	var path : PoolVector3Array = NavigationServer.map_get_path(map, Vector3(0.1, 0.0, 0.1), Vector3(1.0, 0.0, 1.0), true)
	
	print("Found waypoints:")
	print(path)

[smix8]

@Xyotic
Could that solve the issue?

[Xyotic]

Will try it this weekend

[Xyotic]

@smix8 waiting for the physics frame to end did the trick!

For anyone curious, this it how it would look in C#

    NavigationMesh navmesh;
    public override void _Ready()
    {
        CallDeferred(nameof(Setup));
    }

    private async void Setup() 
    {
        navmesh = new NavigationMesh();
        navmesh.Vertices = new Vector3[]
        {
            new Vector3(0,0,0),
            new Vector3(9,0,0),
            new Vector3(0,0,9),
        };
        navmesh.AddPolygon(new int[] { 0, 1, 2 });

        var map = NavigationServer.MapCreate();
        var region1 = NavigationServer.RegionCreate();

        NavigationServer.MapSetUp(map, Vector3.Up);
        NavigationServer.MapSetActive(map, true);

        NavigationServer.RegionSetTransform(region1, Transform.Identity);
        NavigationServer.RegionSetNavmesh(region1, navmesh);
        NavigationServer.RegionSetMap(region1, map);

        await ToSignal(GetTree(), "physics_frame");

        var result = NavigationServer.MapGetPath(map, new Vector3(0.1f, 0, 0.1f), new Vector3(1f, 0, 1f), true);

        GD.Print("Found waypoints: " + result.Length);
        foreach (var r in result) GD.Print(r);
    }

[Zireael07]

If this is a documentation issue, it shouldn't be closed before documentation is updated.