Improvements to the shader editor

[reduz]

• Shader editor is permanent (no longer transient).
• Can edit multiple files at the same time.

Likely fixes many usability issues (please lend me a hand Bugsquad team to identify them).

Obligatory gif

[Calinou]

I'd look into adding a button to collapse the list of shaders, similar to the one we already have at the bottom of the script editor between the list and the script:

This can be beneficial when editing shaders with long lines on narrow displays.

This button has a Toggle Scripts Panel shortcut which defaults to Ctrl + \. It probably makes sense to reuse the default binding (but with a different shortcut name, I assume).

[reduz]

@Calinou This not easy because that section is part of the shader editor itself, and the visual shader editor does not allow placing something there.

This is an initial implementation, other contributors can add small things to it and improve it afterwards.

[sztrovacsek92]

• Shader editor is permanent (no longer transient).
• Can edit multiple files at the same time.

Likely fixes many usability issues (please lend me a hand Bugsquad team to identify them).

Obligatory gif

Would it be possible, to add the Shader Editor's button next to the 2D/3D/Script buttons instead? And it would work like the regular script/visualscript window, except it could be split to 2 for previewing, like we can do it in 3D.

[reduz]

@sztrovacsek92 not really, the idea of the shader editor is that you always edit shaders while looking at the viewport to see the changes. This is what editors on the bottom dock are for. Having it on another main tab would be very annoying, because you would need to manually split it all the time. The way it is now happens on demand.

[KoBeWi]

Built-in shader names should display similar to built-in scripts, as this isn't really useful:

Also closing a scene doesn't close its built-in shaders and you can edit them on another scene, but not save.
Also also saving a built-in shader opens a save file dialog. It should save its owning scene.

[reduz]

@KoBeWi That makes sense and it will have to be added eventually, if you can work on improving it later on that would be great.

I am not as familiarized to how all that logic in the editor works nowadays and it would take me longer. In general my idea is that as I have so many things pending I need to work on, I try to get something working that does what it has to do and then rely on others to bring it up to the standards they expect.

[KoBeWi]

Guess I will just list some more problems that I found, but with an intention that they can be resolved later (unless it's something major):

• middle-click doesn't close shader
• File menu doesn't have any shortcut
• the option to open in the inspector is interesting, but not sure what can it be used for 🤔
• changing shader externally will force-reload it, even if you have unsaved changes. You can undo this though
• shaders have no modified state (no (*) appears)
• previously opened shaders aren't restored on project start

[KoBeWi]

Looks ok (aside from #61459 (comment), #61459 (comment) and some minor style stuff)

[KoBeWi]

Actually it's not ok. It doesn't fix #43635, which doesn't make sense for a permanent editor.

see above comment

[akien-mga]

Looks good to me.

As pointed out above #43635 is still not solved, this will require further work to figure it out. But we can merge this refactor as is anyway.

[akien-mga]

Thanks!