Godot distance between 3d and 2d nodes

Question

Godot has the distance_to methods for Vector3 and Vector2 but what would be the best way to get the distance from a 3d node to a 2d node? For example, I'm looking to see how far away the 3d kinematic body is from a 2d text label.

Currently, I'm trying something like:

var player_global_origin = player.global_transform.origin
var player_vec2 = Vector2(player_global_origin.z, player_global_origin.x)

var distance_to_label = player_vec2.distance_to(label.get_global_transform().origin)

Which seems to work ok when just moving forwards and backwards but it feels like it's easy to break.

Answer 1

If you want the position of a 3D object on screen, you can do the following:

var position_2d = get_viewport().get_camera().unproject_position(position_3d)

That is, we use the camera projection to get the 3D position into screen coordinates with Camera.unproject_position which takes a Vector3 and returns Vector2. Why is that unproject and not project? Don't know.

However, we need a Camera to do that. Luckily Viewport.get_camera returns the current 3D Camera. Why is there not a 2D counterpart? Don't know.

And of course, to use get_camera we need a Viewport. We can get the Viewport the node belongs to with Node.get_viewport.

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Of course, once you have the 2D position on the screen, you can use distance_to to find the distance to any Control on the screen, or whatever you need.

You can also use this to have a control follow a 3D object. This example is from the official documentation:

control.visible = not get_viewport().get_camera().is_position_behind(global_transform.origin)
control.rect_position = get_viewport().get_camera().unproject_position(global_transform.origin)