Adding different material roughness parameters for easy testing to 3d/material_tests

[armanpapikyan]

The material tests scene demo has a range of materials currently on display for the demo, but it lacks a grid of abstract materials with specific increments for testing purposes of PBR.

While iterating on SSR I set up this grid that has both dielectrics and metals, and varying roughness value from 1.0 on the left to 0.0 on the right by a 0.1 step (simply duplicating the materials and setting the metal and roughness parameters on it).

No changes done to the demo itself, the new platform is outside of the camera frustum when going through the materials in the demo.

I already have this setup locally and if this can be useful I can open a PR.

[Calinou]

#809 has a setup with all roughness and metallic levels, but I think it makes sense to add this to the Material Testers demo as well.

Feel free to open a pull request for this 🙂

No changes done to the demo itself, the new platform is outside of the camera frustum when going through the materials in the demo.

It makes sense to set visible = false on those nodes in _ready(), so that you can see them in the editor but not in the running project (to improve performance on low-end systems).

[armanpapikyan]

visible = false added on a separate dedicated script, didn't want to introduce unncessary dependencies on the demo test script.

PR created #899

[Calinou]

• Implemented by Add editor-only roughness and metallic testers to Material Testers #899.