fix: extracting embedded texture files for materials from glTF file

[Basewq]

PR Details

Documentation on assimp texture behavior is described here:
https://assimp-docs.readthedocs.io/en/latest/API/API-Documentation.html#_CPPv49aiTexture
(Search struct aiTexture if the link doesn't jump to the correct section)

glTF materials referencing embedded textures may be denoted by * + index of the texture array, and the full file name must be determined by examining the Texture data.

Apparently it is possible to have uncompressed textures in the file (ie. the 'raw' texture is directly embedded).
I have opted to output a log error rather than implement it.

Related Issue

Used the model from #2406 (this pull does not fix the animation issue in that link)

Types of changes

• Docs change / refactoring / dependency upgrade
• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist

• My change requires a change to the documentation.
• I have added tests to cover my changes.
• All new and existing tests passed.
• I have built and run the editor to try this change out.

[Eideren]

The tuple return type for a Try[...] seems a bit awkward to work with;

var (isOk, errorMessage) = TryGetTextureFileName(elTexPath.AsString, scene, out texFileName);
if (!isOk)
{
    logger?.Error(errorMessage);
    continue; // error !
}

vs a try with another out var

if (!TryGetTextureFileName(elTexPath.AsString, scene, out texFileName, out var errorMessage))
{
    logger?.Error(errorMessage);
    continue; // error !
}

Not a big deal, but it's not standard in c#, and not sure it is any easier to read ?

[Basewq]

Yeah, I can never settle on the right way the TryGet pattern, haha.
I'll change it for returning bool and out the message since it's standard.

[Basewq]

Done, and swapped the logic in the TryGet methods so it doesn't need nested if statements.

[Eideren]

Thanks !