How hard to migrate from Godot 3 to 4?

sent44

I want to restart the project from scratch in Godot 4 since long ago, but that critical bug is never been resolve nor Godot 4 is going to release anytime soon. I am already bored of waiting already so I think to restart in Godot 3 and migrate to Godot 4 later when release or when that bug is fix, but I also don't want to spend days hunt for broken thing after migrate.

DaveTheCoder

I'm sure the developers will provide upgrade documentation.

TwistedTwigleg

I think its a little too soon to say, as I'm not sure many developers have ported their work over to Godot 4 yet.

From my experience working with Godot 4 source code, it should be easier to port than the conversion process from Godot 2 to Godot 3, which basically required rewriting large sections of code. Godot 3 should only need minor API changes and tweaks in most cases, especially on the node renames, but some functions have different arguments (or different order, mainly physics) and this can be a touch harder to debug. Additionally, GDScript 2.0 requires much stricter typing, so if you are using the optional typing in GDScript in Godot 3.0 it should be a relatively smooth transition, but if you are not using optional typing, then it will be much harder.

It should be doable to convert projects from Godot 3 to Godot 4, but it is going to take some time, even if there is a conversion tool (which to be honest, I'm not sure if development has started on it or not...)

Calinou

@TwistedTwigleg said: Additionally, GDScript 2.0 requires much stricter typing, so if you are using the optional typing in GDScript in Godot 3.0 it should be a relatively smooth transition, but if you are not using optional typing, then it will be much harder.

GDScript will still support fully dynamic typing in 4.0. The main changes you will have to do to your scripts are with regards to annotations (export -> @export, tool -> @tool, …), replacing yield with await, and converting connect() calls to use first-class Signals and Callables.

TwistedTwigleg

@Calinou said:

@TwistedTwigleg said: Additionally, GDScript 2.0 requires much stricter typing, so if you are using the optional typing in GDScript in Godot 3.0 it should be a relatively smooth transition, but if you are not using optional typing, then it will be much harder.

GDScript will still support fully dynamic typing in 4.0. The main changes you will have to do to your scripts are with regards to annotations (export -> @export, tool -> @tool, …), replacing yield with await, and converting connect() calls to use first-class Signals and Callables.

Oh okay, good to know! When I used GDScript in Godot 4.0 the editor was having lots of issues if I didn’t do exact type scripting, but that was really early into Godot 4.0, so likely a bug or something. Glad to know dynamic typing is still supported :smile:

MasterOfNone

issues with these 2 codes from v 3.44 to 4 alpha 5, any ideas what i should change, @Calinou var velocity = Vector3() velocity = move_and_slide(velocity, Vector3.UP) oh also it had issue with onready command, does that possibly need to be @onready? it also threw issue with velocity = velocity.linear_interpolate(direction speed, acceleration delta)

cybereality

There have been a lot of changes. You might want to read the release notes on the alpha pages, and then do searches for specific keywords or functions because there are lots of little differences. The documentation is also mostly up to date. Not so much the tutorials, but all the API docs look current. You might have to switch to the stable release channel on the bottom left of the doc page (or use the in editor docs by pressing F1).

MasterOfNone

@cybereality thanks i am trying best i got is found that onready does use @, just still getting errors with my velocity stuff and cant get it to play on v4 no issues in 3.44

cybereality

This line:

velocity = move_and_slide(velocity, Vector3.UP)

Would become:

move_and_slide()

But you'll probably have a whole lot of other errors, so you'll have to check the docs.

MasterOfNone

so i am trying to import 3.44 project to v4 alpha 5 it acts like there is issue w/ these 2 lines of code var velocity = Vector3() velocity = move_and_slide(velocity, Vector3.UP) your tip on the export change was great, any ideas @Calinou

cybereality

Did you see my comment above?

MasterOfNone

@cybereality yes i just saw the one change suggestion, thanks, was checking on my phone and missed it

Megalomaniak

@cybereality said: Did you see my comment above?

TBF it was a comment stuck in moderation queue that I approved, so it might have gotten posted out of order.

Loxyrak

Depends on the size of your project really, so far the only issue I have with Godot 4 is the shaders, the code is mostly just a bunch of different annotations.

PS: devmar on youtube has really good godot 3 to 4 videos for his own project, it's worth taking a look, it helped me alot personnaly.

MasterOfNone

I understand they are optimizing and cleaning up godot script, but now im just with the people hoping for mono version of Godot 4, as I have heard good things about learning C sharp and think im just gonna learn that, as a start for being a noob, as could use in unity or Godot mono, and its an actual official language, that might become beneficial elsewhere in the future.