Godot: Node briefly appears at scene origin when instanced in _ready

[rcorre]

Godot version:

3.1.1

OS/device including version:

Linux 5.3.8-arch1-1 x86_64 GNU/Linux

Issue description:

If PackedScene is instanced during _ready and the origin is changed, it briefly appears at (0,0,0) before moving to its set position.

This is very similar to #23340, except:

1. #23340 was supposedly fixed in 3.1, this is not
2. #23340 applies to RigidBodies, this applies to a MeshInstance and possibly other types
3. This applies _only_ during _ready. If instanced during _physics_process, it doesn't seem to happen

Steps to reproduce:

extends Spatial

export(PackedScene) var scene

func _ready():
    yield(get_tree().create_timer(5.0), "timeout")
    var obj = scene.instance()
    obj.global_transform.origin = Vector3(1, 1, 1)
    add_child(obj)

Minimal reproduction project:
example.zip

[rcorre]

I came across this in a StackExchange post.

[Calinou]

This is probably not related, but does this happen with both Bullet and Godot physics? You can change the physics engine in the Project Settings.

[rcorre]

Tried both Godot and Bullet, it reproes in both.

[KoBeWi]

Does it happen if you set position after add_child?

[rcorre]

Yes, the order doesn't seem to matter. I also tried called_deferred to
set the position. Same deal.

On Thu 11/07/19 06:17PM, Tomek wrote:

Does it happen if you set position after add_child?

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[rico345100]

I also tried with using timer, but still didn't work

var asteroid_instance = asteroid_scene.instance()
asteroid_instance.transform.origin = spawn_position

yield(get_tree().create_timer(1), "timeout")
add_child(asteroid_instance)

[rico345100]

Temporarily fixed by hide mesh right after instantiated, and then used coroutine to wait very short time and show mesh back. Hope fix this soon.

[bojidar-bg]

Could reproduce on 3.1.1.stable.official, but not on 3.2.custom.build. 0e54b2d43 (master).
Note that to be able to see it clearly and reliably, I had to set debug/settings/fps/force_fps = 3.

This code does not exhibit the issue on either version, so it is clearly related to the timer:

func _ready():
    yield(get_tree().create_timer(5.0), "timeout")
    yield(get_tree(), "idle_frame") # or "physics_frame"
    var obj = scene.instance()
    obj.transform.origin = Vector3(1, 1, 1)
    add_child(obj)

Checking scene_tree.cpp's history (where SceneTreeTimer is defined), I can say that this issue has probably been fixed by #30919.

Going to close this as I think it is fixed, but feel free to reopen/comment if you have evidence to the contrary.