False error "Viewport Texture must be set to use it."

[rarsp]

---

Bugsquad note: This issue has been confirmed several times already. No need to confirm it further.

---

Godot version

4.0 beta 1 mono

System information

Windows 10

Issue description

Scenes with viewport shows this errors even though viewport textures are set and working in materials:

ERROR: Viewport Texture must be set to use it.
at: (scene/main/viewport.cpp:114)
ERROR: Viewport Texture must be set to use it.
at: (scene/main/viewport.cpp:109)

Steps to reproduce

Create simple scene with viewport and material that is using it as texture.

Minimal reproduction project

No response

[Rindbee]

I guess the ViewportTexture is obtained by instantiating it instead of getting it from an existing Viewport. Some properties need to be set before it can be used. The error message is really not very detailed either.

[isaaccp]

I keep getting this too (in GDscript), but otherwise my SubViewport works fine.

[PedroPareja]

I got this same situation/error. The viewport texture does not work when exporting (it does work when executing from the editor)

[PedroPareja]

I found the solution here: #55471

I set the SubViewport update mode to always to fix the problem. It seems there's a bug with "update only when visible" option and it has not been fixed yet

[Withaust]

In RC2 this error seems to be happening even with the update mode set to always... or any other mode, actually

[KettLovahr]

Yes, I'm having the same issue, no matter what configuration the SubViewport uses, it will act as if there's no Viewport set on debug or on the editor once the scene is reloaded. Spitting out the same "Viewport Texture must be set to use it." When already is set.

[1419427247]

V4.0. table. official [92bee43] Still the same

[baschermann]

Godot version

4.0.1 RC2 mono

System information

Windows 10

Issue description

Scenes with viewport as a 3D texture shows errors on game startup. Mesh materials from viewport (2D) textures do not work and show up purple ingame, even though they show up in the editor.

E 0:00:00:0832 get_height: Viewport Texture must be set to use it.
<C++ Error> Condition "!vp" is true. Returning: 0
<C++ Source> scene/main/viewport.cpp:116 @ get_height()

These appear as errors, even though they work except for the mesh material option.

Steps to reproduce

1. Create simple scene with viewport and 2D control node
2. Disable 3D in viewport
3. Use viewport as texture for material

Minimal reproduction project

ViewportTexture66247.zip

[Rindbee]

If the node tree doesn't nest multiple SubViewports, just enabling resource_local_to_scene on all resources will work, although it will produce a lot of errors.

Like in the MRP provided by @baschermann, enable resource_local_to_scene on the mesh resource in the MeshMaterial node.

Similar issues also include #68088, #72616, #74589.

If nested SubViewports are used, such as #74331 , the above solution may not work.

[baschermann]

As a workaround, set the viewport texture in the parent node of both the SubViewport and the MeshInstance3D in code:

Example in C#

public override void _Ready()
{
      RenderingServer.FramePostDraw += OnFramePostDraw;
}

private void OnFramePostDraw()
{
      SubViewport subViewport = GetNode<SubViewport>("SubViewport");
      var viewportTexture = subViewport.GetTexture();

      MeshInstance3D meshInstance = GetNode<MeshInstance3D>("Mesh");

      StandardMaterial3D mat = new()
      {
          AlbedoTexture = viewportTexture
      };

      meshInstance.SetSurfaceOverrideMaterial(0, mat);

      RenderingServer.FramePostDraw -= OnFramePostDraw;
}

[michasng]

What seems to be happening is that this depends on the order of initialization. For me, the mesh was initialized first and it holds a reference to the uninitialized viewport. That issue resolves itself after a frame or so.
As mentioned, one workaround is to remove the viewport texture in the scene tree and create it programmatically.

[Rindbee]

What seems to be happening is that this depends on the order of initialization.

This has little to do with the order of instantiation. It mainly depends on whether ViewportTexture::setup_local_to_scene() is called and when it is called.

Currently, even if a resource has local_to_scene enabled, but its parent resource does not have local_to_scene enabled, the resource will not call setup_local_to_scene().

[clemens-tolboom]

I followed along with the 3D https://docs.godotengine.org/en/stable/tutorials/animation/playing_videos.html#displaying-a-video-on-a-3d-surface on 4.0.3.rc1 ... my video plays well but errors when running from editor gives:

E 0:00:00:0580   get_width: Viewport Texture must be set to use it.
  <C++ Error>    Condition "!vp" is true. Returning: 0
  <C++ Source>   scene/main/viewport.cpp:111 @ get_width()

E 0:00:00:0580   get_height: Viewport Texture must be set to use it.
  <C++ Error>    Condition "!vp" is true. Returning: 0
  <C++ Source>   scene/main/viewport.cpp:116 @ get_height()

E 0:00:00:0623   setup_local_to_scene: Condition "proxy.is_valid()" is true.
  <C++ Source>   scene/main/viewport.cpp:89 @ setup_local_to_scene()

[ttencate]

Fixed by #75751?

[akien-mga]

Fixed by #75751?

That's likely. Please test in 4.1 dev 2 or the upcoming 4.0.3 RC 2.

[Withaust]

4.1 dev 2 still has the issue with get_height() and get_width()

Project.zip

[Withaust]

Also, reopening the project attached above in 4.1 dev 2 greets you with Viewport Texture must be set to use it., so it is not fixed at all

[Rindbee]

Resources are instantiated before nodes during scene instantiation. At this point get_local_scene() returns null. vp_pending is not switching to true as expected.

godot/scene/main/viewport.cpp

Lines 107 to 111 in 8cfa19a

	if (get_local_scene() && !path.is_empty()) {
	setup_local_to_scene();
	} else {
	emit_changed();
	}

These error messages are printed when setting the material's texture.

godot/scene/resources/material.cpp

Lines 1895 to 1896 in 8cfa19a

	RS::get_singleton()->material_set_param(_get_material(), shader_names->albedo_texture_size,
	Vector2i(p_texture->get_width(), p_texture->get_height()));

[canb227]

Can confirm that this is still an issue in 4.1 dev 2.

[RichardR01]

This is still an issue in 4.02 stable. Having multiple errors, even though it technically works. In my case, the explosion scene is preloaded on start. It is instantiated in code. Though that doesn't make any difference. I put a camera in the explosion scene, and get the same errors when I run the scene itself.
Edit: please fix this issue. or give us something new that can do a similar thing in 3D (animated sprite texture on a 3d mesh imported).

[kesocos]

Getting the same error on 4.1 stable

[fire]

I hasty un-merged this in our fork. https://github.com/V-Sekai/godot/tree/viewport-path-update-fix.

The screen is pink and after the fix it works as it did in 4.0.

In 4.1 and 4.2 the screen is pink and the desktop copy of the vr viewport does not work. It's a blocker for us, so this is rush job fix.

[kapaseker]

Same Error 4.1.1

[PITR-DEV]

Still present for me in 4.2 dev5

[SlashScreen]

regarding the workaround
This works in 4.1.1. Gerre's a GDScript approximation:

extends MeshInstance3D


@export var viewport:SubViewport # Could instead get a child with an @onready


func _ready() -> void:
	RenderingServer.frame_post_draw.connect(on_draw.bind())


func on_draw() -> void:
	var tex = viewport.get_texture()
	var mat = StandardMaterial3D.new()
	mat.albedo_texture = tex
	set_surface_override_material(0, mat)
	RenderingServer.frame_post_draw.disconnect(on_draw.bind())

[2fd5]

Still present in 4.2 beta 1

[chrisl8]

I built Godot from source using master today and I still get the error, so even in 4.2 Beta 3+

It all works fine in game though, so I guess it is a timing issue?

I will try some of the workarounds, as the error is distracting when I'm looking for real problems.

[mdarius31]

Are there plans to backport the fix to godot lts?

[Calinou]

Are there plans to backport the fix to godot lts?

The issue isn't fully resolved in 4.x yet as per the above comments, so that needs to be done first before it can be backported to 3.x.

[nicemicro]

The issue isn't fuilly resolved in 4.x yet as per the above comments, so that needs to be done first before it can be backported to 3.x.

Thank you! I confirm that a similar issue exists in 3.5.3.

[SoapSpangledGames]

I found the solution here: #55471

I set the SubViewport update mode to always to fix the problem. It seems there's a bug with "update only when visible" option and it has not been fixed yet

My SubViewport update mode is set to Always, and I still get the error message when trying to duplicate the texture. I get no error when debugging in the editor, but it happens in the exported program (in my case, the Quest 3).

I'm using Godot 4.2 stable.

[SrColoma]

I found a solution while attempting to bypass that check, and it seems to be working fine. I want to recreate Prey's screens, and this is how it's turning out:

https://twitter.com/GalacticLake/status/1769937516889616637

Before, I was getting pink screens every time I started the project. This is my solution:

It seems the trick lies in creating an exported variable that stores a packed scene of what the subviewport will display. Inside the _ready function, assign it as a child of the subviewport, then make the necessary configurations, such as assigning the material and calling setup_local_to_scene(). Disabling the process mode isn't necessary; that's part of my multi-screen system. With this method, I no longer encounter errors because it's created and configured after the nodes are ready.

In the editor, the screens won't be visible, but they will appear in the game; that's the only issue.

[GeorgeS2019]

A demo to test the latest status of the Viewport in Godot4

MASSHUU12/godot-control-3d#3

[chrisl8]

FWIW, the error, Viewport Texture must be set to use it. occurs in

• v4.2.stable.official [46dc277] (4.2.1 Stable release)
  and
• v4.3.dev.custom_build [9d6bdbc] (latest build from Master at the moment)

When running the following Godot Demo projects:

Procedural Materials
GUI in 3D

So both of those demo projects can be used to test fixes for this issue in current and future versions.

[timkrief]

I'm using 4.2.2, my project is working fine but I have those issues, should we just ignore those warnings and errors for the time being?

[Calinou]

I'm using 4.2.2, my project is working fine but I have those issues, should we just ignore those warnings and errors for the time being?

Yes, I'd just ignore these for now.

[Withaust]

4.3 stable, still happening :(

[NervenCid]

I am using the 4.3 stable version, but i get the same error:

This is the structure of my nodes:

And i am defining the HUD as my texture on "MeshInstance3D" but i get the same errors:

How can i set a texture of a viewport? I can't see the option

[AThousandShips]

Please see the thread above for an explanation, but please don't bump issues without adding significant new information