Importer option for permanent scaling of the scene

[SaracenOne]

This is a draft PR tied to a proposal to replace or provide an alternative to the existing importer root_scale option (https://github.com/godotengine/godot-proposals/issues/4379). The root_scale option only provides a one off modification to the root node's scale value when its instantiated, whereas this option provides a permentant modification to the underlying geometry and animations of a scene.

Left in draft while proposal is considered and the PR is being throughly tested for bugs.

Thanks to @lyuma for the original script implementation of this which I used as reference when writing this C++ version.

[fire]

Typo on the commit message. permentant -> permanent

[fire]

Want to rebase and try resolving the review comments?

[fire]

According to @lyuma this resolves the blend shape bug. Will test.

[TokageItLab]

Can this function be applied to rotations as well? I was thinking of something similar in #63662. I prefer that those transformations need to be PreProcess for retargeting.

[fire]

I want to propose to set the root transform as the default value of this importer option.

[SaracenOne]

I'm opening this up for review again based on the changes implemented by @lyuma and @fire. I shall check it again though since I haven't touched it for a while

[fire]

I'll see if I can reset the branch to avoid the big diffs.

[reduz]

Seems good for the most part, should be able to merge it

[fire]

Will revise the for loop.

[fire]

READY TO GO

1. scaled the blends shape test by 10 and then apply
2. check scaling on root and the animations play
3. done

MorphStressTest.zip

[fire]

Consider other objects types for rescaling? For example, light attenuation? camera scale/near/far?

Cameras and punctual lights are like points, so scaling a point doesn't do much. I don't know if scaling a light's light-units by distance-scale has a good formula since the physical light units is not default.

A camera is a node 3d, might work by chance.

tl;dr not a blocker.

[Calinou]

Cameras and punctual lights are like points, so scaling a point doesn't do much. I don't know if scaling a light's light-units by distance-scale has a good formula since the physical light units is not default.

Scaling a positional light by increasing its range should work well enough in some cases. Keep the same attenuation, and keep the same spot angle.

Cameras should be kept identical – don't change their FOV depending on scale.

[fire]

@reduz can you remove the merge block? The while loop has been removed.

[akien-mga]

Thanks!