Fade hands when tracking confidence is lost

[goatchurchprime]

This concerns https://github.com/NeoSpark314/godot_oculus_quest_toolkit/issues/62

This stops the rubbery feel of the hand tracking when they get in the way of each other and they jump about. Give it a try.

Fading is important to show exactly what is happening. If the hand instantly disappears you don't know if it has hopped to somewhere you're not looking.

I had problems reading the materials because handmeshnode.get_surface_material(0) wasn't working from this glb file.

(I may have messed up with git as well, but I'm trying to do it with branches, which is supposed to be a better way, though I can't explain the duplicate unnecessary commits here that don't do anything)

[NeoSpark314]

This is nice. I just played around with the branch and it looks great. Any specific changes you want to make to this PR before we merge it?

[goatchurchprime]

You could merge it and hack it about afterwards.

I'd like to remove the parameters from _update_hand_model() that are class members anyway.

Can you find a better way to access the material in those hands meshes than that hack I used?

[NeoSpark314]

It works nicely; I think we can merge; I can have a look into the material access; I remember I had a similar situation some time ago; I will dig through my code. I can also do the cleanup then.

[Firepal]

The GLTF importer generates materials onto its appropriate "surface" in an ArrayMesh resource, not the MeshInstance material slot. You can get the hand model's Mesh resource and call surface_get_material(0) to get the hand's material.

Assuming handmeshnode in the code is a MeshInstance node, this would be handmeshnode.mesh.surface_get_material(0)