Support for #include in shaders

[Zylann]

In Godot 3.0

It would be useful to have #include functionnality in shaders for easy re-use of functions (I found this: #4505 but it only concerns built-in shaders).
I'm pretty sure this was suggested at some point when discussing on the new shader langage, but I could't find an issue about it.

[alan-j-hu]

Should the #include be handled by a preprocessor or during the compile step?

[justinluk]

This is becoming a huge issue for me. Shaders quickly become unwieldly without being able to include.

[ghost]

I want to be able to include files in Shaders. I just got permission from the author of this ShaderToy shader to use their shader in my game. I am now working on porting the shader to Godot, but I have yet to figure out how to include the "Buffer" shader that is used by the main file.

[Zylann]

@alex-evelyn I think what's in buffer in this shadertoy is sound, you probably don't need it

[Calinou]

@Hidden-Abstraction Please don't bump issues without contributing significant new information; use the 👍 reaction button on the first post instead.

[KoBeWi]

Feature and improvement proposals for the Godot Engine are now being discussed and reviewed in a dedicated Godot Improvement Proposals (GIP) (godotengine/godot-proposals) issue tracker. The GIP tracker has a detailed issue template designed so that proposals include all the relevant information to start a productive discussion and help the community assess the validity of the proposal for the engine.

The main (godotengine/godot) tracker is now solely dedicated to bug reports and Pull Requests, enabling contributors to have a better focus on bug fixing work. Therefore, we are now closing all older feature proposals on the main issue tracker.

If you are interested in this feature proposal, please open a new proposal on the GIP tracker following the given issue template (after checking that it doesn't exist already). Be sure to reference this closed issue if it includes any relevant discussion (which you are also encouraged to summarize in the new proposal). Thanks in advance!