"Detect 3D" is triggered for ShaderMaterial with `shader_type canvas_item;`

[lyuma]

Godot version

4.0.dev 706dc74e

System information

Windows 10, Vulkan

Issue description

ShaderMaterial is treated as 3D for the purpose of "Detect 3D", even if the material is of type canvas_item and used in a 2D node.

Here you can see the problem. Let's take icon.png, a quality piece of artwork whose every pixel is perfectly preserved. Now we drag it into a 2D canvas_item shader, as opposed to a 2D sprite's texture slot. There could be lots of reasons for this. For example, it might be an auxiliary texture used for outline drawing, or a palette, or something else.

Now see what happened. (The import inspector doesn't refresh, so you select a different file and back.) It got VRAM Compressed!

Godot also prints the following.

res://random_texture.png: Texture detected as used in 3D. Enabling mipmap generation and setting the texture compression mode to VRAM Compressed (S3TC/ETC/BPTC).

Steps to reproduce

1. Create a new 2D scene.
2. Add a new node of type ColorRect
3. Create a new ShaderMaterial or convert to shader material.
4. Modify the shader to have the following code.

   
   shader_type canvas_item;
   render_mode blend_mix;

uniform sampler2D tex;

void fragment() { COLOR = texture(tex, UV); }

5. Find a texture, such as `icon.png`. Check the Import tab and make sure that Compress Mode is set to Lossless, and Detect 3D Compress is set to VRAM Compressed.
6. Drag this texture into the `tex` slot in the material.
7. The import inspector will still show the old settings. This is a different bug.
8. Click a different file, then select icon.png again.
9. Now the import settings will show that it has been changed to VRAM Compressed, and Detect 3D was disabled.

### Minimal reproduction project

[detect3dcanvas.zip](https://github.com/godotengine/godot/files/8914364/detect3dcanvas.zip)

Editing to add repro project from #74335 in case it helps. To repro in this project, drag `perfect.png` into the material's Evil slot.
https://github.com/godotengine/godot/files/10887280/shader.texture.distorted.reproduction.project.zip

[clayjohn]

It looks like the logic for detect 3D is to call the callback anytime textures are updated and p_use_linear_color is true

https://github.com/godotengine/godot/blob/361a401fbb1d35206f594be86dd4f5a1010c763a/servers/rendering/renderer_rd/storage_rd/material_storage.cpp#L1161-L1163

However, p_use_linear_color is always true as it is set here:

https://github.com/godotengine/godot/blob/361a401fbb1d35206f594be86dd4f5a1010c763a/servers/rendering/renderer_rd/storage_rd/material_storage.cpp#L1272

Looks like maybe we used to handle srgb differently in 2D and then we lost something during a refactoring.

Related: https://github.com/godotengine/godot/issues/61697

[clayjohn]

I can't reproduce on Beta 2! So I am going to close this issue.

At any rate, I am changing the behaviour that I described in my earlier post so this problem should be gone soon for sure.

[lyuma]

Reopening due to reproduction project in #74335 Should we close the new issue and keep this one open?

[Calinou]

Should we close the new issue and keep this one open?

Yes :slightly_smiling_face:

[RafaelVidaurre]

Any news on this, or a workaround? Super nasty issues going on for me

[Calinou]

Any news on this, or a workaround? Super nasty issues going on for me

You can change the Import Defaults for Texture2D/ImageTexture in the Project Settings. Set Detect 3D to Disable so that 3D usage detection never kicks in.