Godot 3.2.4 does not actually use separate textures for GLTF files exported with separate textures enabled (they're instead embedded in the materials).

[EzraT]

Godot version: v3.2.4.beta4.official, affects master as well.

OS/device including version: Linux Mint 20 x86_64

Issue description:

When exporting a blender scene to GLTF for use in Godot 3.2.4.beta4, with the export settings shown in the screenshot above, with textures exported into a folder instead of packed into the GLTF itself, Godot is supposed to use those textures in the resulting SpatialMaterial resources after importing.

beta4 currently fails to do this, even with separate textures enabled, it always ends up packing the textures directly into the SpatialMaterial, leaving the textures in the exported folder unused.

This does not happen in 3.2.3, so I'm guessing some regression may have happened at some point.

Steps to reproduce:

1. Setup a blender scene in a recent version of blender, 2.8 or 2.9.
2. Make sure textures are used in it. (ofcourse)
3. When exporting to GLTF, make sure to set it so it exports textures separately. (as shown above)
4. After exporting to Godot, right click the resulting SpatialMaterial(s), and click "Edit Dependencies".
5. Notice that there are no dependencies.

[Calinou]

cc @fire

[EzraT]

I hope this one can get fixed before 3.2.4.stable releases, my workflow relies heavily on this working correctly, since GLTF currently works the best out of all the export options available right now for me.

[fire]

Are you able to do a bisect to find the commit that change the behaviour? I have some suspects.

Like use git bisect and take your project and do a check on the bug until you find a version that doesn't error. Then tell me the version that errors and the version that doesn't error.

[EzraT]

@fire
For what its worth, all of the 3.2.4 betas suffer from this issue, so it has to be a commit from sometime before beta 1.
I found 3 commits that involve GLTF related changes for beta1, I have no way of knowing if any of them are related to this problem though.

460ab35
177d16c
9529ce4

[fire]

9529ce4#diff-391b8dac176705a7434fd9ca93ac540183658308fcb6a91cc40f6f2ecd4439baR1384 is suspicious, but I'm currently busy and in the middle of something.

[EzraT]

On an extra note, this issue affects the 4.0 master branch as well currently, but I'm guessing this will probably be resolved with the upcoming 3D asset import rework for 4.0.

[akien-mga]

Might indeed be related to #42504, I'll have a look. It would help me out if there was a minimal reproduction project that I can use right away to debug the issue.

[EzraT]

@akien-mga
mrp.zip

This includes a blender file that you can use for exporting, open it in blender, export it to GLTF using the export settings shown in the OP, export it to the import folder in the MRP to reproduce. (or anywhere in the project folder, does not really matter where)

[akien-mga]

Thanks! I exported as described with Blender 2.91.0, and it seems to work fine for me in Godot 3.2.4 beta 4 and latest 3.2 branch:

Can you still reproduce it, and which Blender version do you use?

[EzraT]

Please read the OP carefully, I'm not talking about the GLTF dependencies, this issue concerns the textures that are copied over, they do not get linked to the materials, instead they get packed inside of them, leaving the ones in the texture folder unused.

So check the dependencies of the resulting SpatialMaterials.

[akien-mga]

Thanks, I can confirm that. The .material files are indeed 3 MB of embedded data.

[akien-mga]

Indeed this change is wrong: https://github.com/godotengine/godot/pull/42504/files#diff-391b8dac176705a7434fd9ca93ac540183658308fcb6a91cc40f6f2ecd4439baR1322-R1338

This causes loading the external images as a byte array instead of a resource if it has a proper mimeType, which is wrong. I'll fix it.

[EzraT]

@akien-mga Thanks a bunch!