What are the @export and @onready equivalents?

[Ullanar]

Is it possible to make fields in class structure which will be like gdscript @export and @onready? Maybe via struct tags?

@export var camera: Camera3D
@onready var camera_mount = $camera_mount

[Splizard]

Any exported fields in the Go struct will be exported to Godot (just like @export)
https://go.dev/ref/spec#Exported_identifiers

type MyClass struct {
    gd.Class[MyClass, Node]
    
    Camera gd.Camera3D `gd:"camera"`
}

If you add an exported node field to a node, it will be asserted as a child, so in the above example, the Camera will be added as a child node of MyClass.

[Ullanar]

So this will create child node. But godot @export does not do it. It just says what "here is 100% we have object with specified type" and gives u set it in editor on "Node" panel
I assume what there are no such functionality and this is not a very big deal, feature like "super nice to have but ok".

So maybe you can suggest correct way to do proper scene initialization?

Here for example I want to create CameraMount (Node3D) node and then create Camera3D node, save camera to struct and add it to CameraMount as child.

type Player struct {
	gd.Class[Player, gd.CharacterBody3D]
	camera      *gd.Camera3D
	CameraMount gd.Node3D `gd:"CameraMount"`
}

func (p *Player) Ready(gd.Context) {
	gd.Input(p.Temporary).SetMouseMode(gd.InputMouseModeCaptured)
	p.camera = gd.Create(p.Temporary, new(gd.Camera3D))
	gd.AddChild(p.Temporary, p.CameraMount.AsNode(), p.camera.AsNode())
	fmt.Printf("camera node name: %v", p.camera.AsNode().GetName(p.Temporary))
	p.camera.AsCamera3D().MakeCurrent()
}

And here getting error

panic: runtime.link/mmm error: use after free

goroutine 17 [running, locked to thread]:
grow.graphics/gd/internal/classdb.Node.GetName({{}, {{}, {0x0?, 0xc000882dc0?}}}, {{0x76163feb1160?, 0xc00043e540?}, 0x76163feb1160?})
        /home/lev/go/pkg/mod/grow.graphics/gd@v0.0.0-20240706100351-36c3a7c07552/internal/classdb/all.go:99484 +0x12d
git.ywa.su/rpp-team/rpp-game-client/pkg/player.(*Player).Ready(0xc0001a4360, {{0x76163efb6e20?, 0xc00043e540?}, 0x76163feb1160?})
        /home/lev/prj/ywa/rpp-game-client/pkg/player/player.go:18 +0x134
grow.graphics/gd.(*instanceImplementation).ready(0xc000012330)
        /home/lev/go/pkg/mod/grow.graphics/gd@v0.0.0-20240706100351-36c3a7c07552/register_class.go:574 +0x54a
grow.graphics/gd.(*instanceImplementation).Notification(0xc000012330, 0xd, 0x16?)
        /home/lev/go/pkg/mod/grow.graphics/gd@v0.0.0-20240706100351-36c3a7c07552/register_class.go:495 +0x37
grow.graphics/gd/gdextension.notification_func(0x0?, 0xd, 0x0)
        /home/lev/go/pkg/mod/grow.graphics/gd@v0.0.0-20240706100351-36c3a7c07552/gdextension/gdextension_interface.go:2496 +0xa3
signal: aborted (core dumped)

The reason I want to add camera into Player struct is I hate GetChild. It is nice but why do u need to find child if u can just take it from struct xD

[Splizard]

Sure, try this:

type Player struct {
    gd.Class[Player, gd.CharacterBody3D]

    CameraMount struct {
        gd.Node3D

        Camera gd.Camera3D
    } 
}

func (p *Player) Ready() { 
    gd.Input(p.Temporary).SetMouseMode(gd.InputMouseModeCaptured)
    p.CameraMount.Camera.MakeCurrent()
}

[mdevnull]

So this will create child node.

Wait, will it? I was pretty sure that it expects the node to be there in the scene tree. If an node of the given name does not exist I did run into issues as well.

[Ullanar]

So this will create child node.

Wait, will it? I was pretty sure that it expects the node to be there in the scene tree. If an node of the given name does not exist I did run into issues as well.

As I managed to understand: u add field into struct and if it is gd.Class and field is public (starting with upper case letter) then child node will be immidiately created on code build. You can even do something with it in editor :)

I truly missing godot @export functionality but not that critical.

[Ullanar]

Sure, try this:

type Player struct {
    gd.Class[Player, gd.CharacterBody3D]

    CameraMount struct {
        gd.Node3D

        Camera gd.Camera3D
    } 
}

func (p *Player) Ready() { 
    gd.Input(p.Temporary).SetMouseMode(gd.InputMouseModeCaptured)
    p.CameraMount.Camera.MakeCurrent()
}

Thank you!

[Ullanar]

@Splizard

type Player struct {
    gd.Class[Player, gd.CharacterBody3D]

    CameraMount struct {
        gd.Node3D

        Camera gd.Camera3D
    } 
}

Thank you for provided suggestion!

I see what it creates 3 separated nodes under Player node: "CameraMount" (node3d), "Node3D" (node3d) and "Camera" (camera3d).

For now it looks a bit like a bug or it is correct behavior? Also Camera is not a child of CameraMount. And I just cant understand what creating that "Node3D" node. If it is CameraMount struct representation then why "CameraMount" even was created

If it is correct behavior - I a bit misunderstand logic here, maybe you will be able to explain?

[Splizard]

Ah this is a bug, I'll check on this over the weekend.

[Ullanar]

One day I really want to help you with development. This is such amazing project for both Godot and Go ecosystems. Yet my lib knowledge is too low I will learn but one day surely will suggest some PRs :)

[Splizard]

@Ullanar thank you for your feedback! I've fixed this bug in master, please go get grow.graphics/gd@master.
You should see the following structure: