How to create a gd.StringName?

[ardawan]

i cannot pass the string to the AddResource method. even I tried to cast it to gd.StringName but still it was unsuccessful.

func (w *World) Ready(ctx gd.Context) {             
    w.Class.Super().SetEnvironment(gd.Environment{})             

    env.AddResource("world1", "res://world1.tres")                      
}

error:

env.AddResource undefined (type "grow.graphics/gd/internal/classdb".Environment has no field or method AddResource) 

even I've tried to make StringName var but there is no way to add string to it

    var name gd.StringName
    var path gd.Resource 

[Splizard]

It doesn't look like the Godot Environment class has an add_resource method?
https://docs.godotengine.org/en/4.2/classes/class_environment.html

I regards to StringName, this is a Godot defined reference type, it can be initialised via an available gd.Lifetime. The value will be valid for the lifetime of the context.

func (w *World) Ready() {
    var name = w.Temporary.StringName("Go string that will become a StringName")

    // do something with name
}

Note that for any godot reference types (including string names & classes), the zero value is not valid, ie. it is essentially nil. So passing gd.Environment{} does not create a new Environment as you may be expecting. Use gd.Create for this.

The gd.Lifetime may be a bit confusing. You can imagine it as an interface to Godot's RAM, it can be used to create new Godot reference values and has a lifetime that can be ended which is when all of the values attached to it will be freed ie. garbage collected.

The reason why there's this awkward way to create StringName values and why the memory for Godot reference types are managed more manually is because of performance reasons, you don't want to be allocating new strings everywhere and copying them between Go and Godot every frame as this will put pressure on the Go garbage collector and may lead to unavoidable frame drops.

[ardawan]

Thanks for the explanation.
What I'm trying to do is to add new_environment.tres to the class and see it on the editor.

as you suggested, I've created this struct and trying to use the reference doc to find out how can I add my environment resource at res://new-environment.tres to the placeholder.
But there is no way for me to find anything that can make this happen.

It would be good if we have some kind of snippet/example for it.

type World struct {                                       
    gd.Class[World, gd.WorldEnvironment] `gd:"World"`     
    Environment                          gd.WorldEnvronment
}

func (w *World) Ready(ctx gd.Context) {
    w.Environment.SetEnvironment(??)
}

[Splizard]

It's certainly easier to manage resources in this way from the Godot Editor, unless you need to change the environment dynamically.

In such a case you could load the .tres file using the ResourceLoader and cast it into the correct type using gd.As so it can be passed to the function.