CanvasLayer's Follow Viewport doesn't translate inputs correctly

[cgbeutler]

Godot version:
3.2

OS/device including version:
Windows10

Issue description:
Turning on Follow Viewport Enable on a CanvasLayer translates child controls to the right place, but inputs are triggering in the non-follow spot

Steps to reproduce:
In a Node2D scene, add a centered Camera2D set as the current camera
Add a CanvasLayer with Follow Viewport > Enable set to true
In the CanvasLayer add a button
Hit play. The button will get hover and click events when the mouse is in the top left corner of the screen instead of when the mouse is over the button

Minimal reproduction project:
https://github.com/cgbeutler/FollowViewportBug

[chepulis]

I'm experiencing this bug, separately, in my project.

(3.2, MacOS)

[Byteron]

Same issue here, using 3.2.1

[renatodex]

@Calinou , do you think you can you help me to know where this needs to be changed? I can make a PR for that, just need some orientation.

[Calinou]

@renatodex I don't know why this bug happens, but the CanvasLayer source code is here: https://github.com/godotengine/godot/blob/master/scene/main/canvas_layer.cpp

Either way, it's not like having Control nodes in a CanvasLayer that simulates a pseudo-3D effect is exceedingly common 🙂

If you just want Control nodes to follow the camera as it moves, use a CanvasLayer without enabling Follow Viewport.

[cgbeutler]

@renatodex Disregard my deleted comment. I forgot what this was about.
Camera2D does work in a strange way. From the Camera2D docs:

This node is intended to be a simple helper to get things going quickly and it may happen that more functionality is desired to change how the camera works. To make your own custom camera node, inherit from Node2D and change the transform of the canvas by setting Viewport.canvas_transform in Viewport (you can obtain the current Viewport by using Node.get_viewport).

I think the camera2D's transform applied on the canvas seems to be the issue.
If you don't use a Camera2D at all and put in the following code:

func _ready():
	var viewport :Viewport = get_viewport()
	viewport.canvas_transform = Transform2D(0, Vector2(100,100))

You get the same error as above. Therefore, it would seem that the viewport's canvas_transform is not being applied to the input events being passed to a canvas layer? Maybe?
You may check the input event code between viewport and canvas layer. I'd guess it's something there.

[cgbeutler]

Looks like it could be related to make_input_local in CanvasItem:
https://github.com/godotengine/godot/blob/master/scene/main/canvas_item.cpp
It currently does this:

Ref<InputEvent> CanvasItem::make_input_local(const Ref<InputEvent> &p_event) const {
	ERR_FAIL_COND_V(p_event.is_null(), p_event);
	ERR_FAIL_COND_V(!is_inside_tree(), p_event);

	return p_event->xformed_by((get_canvas_transform() * get_global_transform()).affine_inverse());
}

Which, if my tired brain is correct, it shouldn't apply the canvas transform AND the global transform if it's layer is set to "follow viewport"? Maybe? I should get some sleep then come back to it...

[ghost]

I'm having the same issue in 3.2.3 :/

[kagenash1]

Still relevant in 3.3

[renatodex]

And I believe it will be for a long time, so the best option so far is to workaround Em seg., 26 de abr. de 2021 às 19:40, Gabriele Torini < ***@***.***> escreveu:

…

Still relevant in 3.3 — You are receiving this because you were mentioned. Reply to this email directly, view it on GitHub <#35965 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAAQXGZCXKZMSVPM7WYVHB3TKXTXPANCNFSM4KREVKHQ> .

[cgbeutler]

Just discovered a possible clue:
With this setup (doesn't matter if CanvasLayer has follow_viewport enabled)

When a camera is active $RootButton.get_global_mouse_position() returns the correct global position while $CLButton.get_global_mouse_position() seems to return a local mouse position. Pretty sure it shouldn't do that..?

I am definitly to naive to fix this myself. Poking around in the code has only made me more confused about how canvases and transforms work.

[Sauermann]

Here is a MRP for Godot 4: BugCanvasLayerFollow.zip

[mastrio]

I'm having this issue in 4.0.3

[Sauermann]

@mastrio I'm unable to replicate the issue in v4.0.3.stable.official [5222a99] and v4.1.beta.custom_build [01453ab].
Please provide a minimal reproduction project, so that we can verify, if this is the same issue. If this is not the same issue, then it would be best to open a new bug-report.