Reuse the same instance of Godot for both the project manager and the editor

[AaronRecord]

See https://chat.godotengine.org/channel/editor?msg=4DRXqpP8wD3Hzqvh5

Screenshot for convenience

Describe the project you are working on

Godot

Describe the problem or limitation you are having in your project

Since the godot editor is a godot project (in a sense), I think it'd make more sense for the project manager to be a "scene", and the main editor to be another "scene", in the sense that you can switch between the 2 without a separate instance of Godot being created. Instead, the project manager would just maximize the window and "change its scene" to the editor.

Describe the feature / enhancement and how it helps to overcome the problem or limitation

Advantages of this change:

• Startup times for projects would probably be faster, so would quitting to the project manager
• C++ debugger would stay connected if you start in the project manager and open a project
• Steam time tracking would work
• etc.

  Describe how your proposal will work, with code, pseudo-code, mock-ups, and/or diagrams

  I'm not very well versed in how editor and the project manager works, but I assume it would be something along the lines of freeing the project manager, and creating a new EditorNode and making it the SceneTree root (it's probably more complicated than that, but hopefully not too much more complicated).

  If this enhancement will not be used often, can it be worked around with a few lines of script?

  No.

  Is there a reason why this should be core and not an add-on in the asset library?

  The editor is core.

[timothyqiu]

IINM, the separation of instances is due to the same reason that switching GLES3/GLES2 backend needs a restart. i.e. The project manager might be using a different backend than the project itself.

[AaronRecord]

IINM, the separation of instances is due to the same reason that switching GLES3/GLES2 backend needs a restart. i.e. The project manager might be using a different backend than the project itself.

That's a good point. Since there's currently only 2 renderer's in 3.x and 1 in master, there's a good chance that they'll be using the same renderer, but even if they aren't, if it'd be possible to change the renderer while still using the same process (I'm not very familiar with graphics api's/the specifics of processes so I don't even know if that's possible).

[Calinou]

if it'd be possible to change the renderer while still using the same process (I'm not very familiar with graphics api's/the specifics of processes so I don't even know if that's possible).

This is technically possible, but it's difficult to implement. Unlike some other engines out there, Godot doesn't have a way to fully reinitialize its renderer without quitting the process.

[ghostbutter-games]

It would be great if we could revisit thinking about this, because right now this breaks the dock functionality on macOS, effectively preventing the icon to be manually placed, because it has to be redone every time one starts the editor.

I know, it seems like a minor gripe, but it's kind of hugely frustrating as that's something every single user on macOS encounters every time they start Godot

Also, if this would improve overall startup time, that sounds like a really nice extra benefit, as well.