Godot: Expression node for visual shaders

[fire]

Issue description:

Allow custom shader code inside of the visual shaders.

I made a mockup of what the node will look like.

Edited: mockup

[CptPotato]

The inputs could be auto-generated from uniforms in the shader code.

[fire]

This is the definition of a function. You mean scan the shader code for variables?

[CptPotato]

I meant it like adding something similar to uniform vec3 Color = ...; in the shader code and the node automatically adding an input called Color which is passed to the shader using that uniform.

[Xrayez]

I've created a similar Expression node my my own noise module in:
https://github.com/Xrayez/godot-anl/commit/facbbcc59e0666c93b4a7877ec61910491eeb0f6
https://github.com/Xrayez/godot-anl/commit/299bfc61840a6bfec7f711bc8a577f1bdfae941f

I've adapted visual shader codebase to my own needs, some structures share similarities, might be useful...

[Chaosus]

I currently began to implement it. Not sure if the resulted form will be the same, but I always trying to achieve the best result. demo screenshot -