.new() method?

mr_moon

In the code below, what does the .new() method do and why is it necessary for random number generation?

var rng = RandomNumberGenerator.new()
func _ready():
    rng.randomize()
    var my_random_number = rng.randf_range(-10.0, 10.0)

SIsilicon28

new is a function that all object classes in Godot have. They're used to create an instance of an object class. In the code above, RandomNumberGenerator is a class, while rng is an object instanced from that class.

Object instances can hold properties of their own, separate from their class, and inherit the functions in said class.

mr_moon

Thank you.

So, when we reference an object in our node tree we don't need to do this .new() because the nodes in our tree are already instanciated?

Kequc

Everything is an instance except primitives like strings and integers vector3's and so on. Sometimes you need a new instance of something and that's when new is used. For example if you have a class.

class MyClass:
	func hi():
		print("hello")

var my_class = MyClass.new()
my_class.hi()

Instancing nodes instead of scripts is a bit different since you're creating instances of a PackedScene, so you use .instance() instead of .new() bit of a gotcha but not much of one.

SIsilicon28

@mr_moon said: Thank you.

So, when we reference an object in our node tree we don't need to do this .new() because the nodes in our tree are already instanciated?

That's correct. The nodes in the scene tree are objects instanced from their respective classes (a viewport node is an object instanced from the Viewport class for example), so they don't have nor need a new method.

SIsilicon28

@Kequc said: Instancing nodes instead of scripts is a bit different since you're creating instances of a PackedScene, so you use .instance() instead of .new() bit of a gotcha but not much of one.

Actually, creating i.e. instancing nodes from their class still uses the new method; the same goes for PackedScene. You can create one with new, but already existing PackedScene objects have an instance method to create the node tree they contain. So the new method still applies here.

Kequc

Why would you want to instance a node without the tree that's saved under it?

SIsilicon28

@Kequc said: Why would you want to instance a node without the tree that's saved under it?

Could you structure your sentence a little differently? I'm not sure what you're asking about.

Kequc

Maybe I didn't understand your post above mine. It sounds like you're saying PackedScene is in fact already a class instance which makes sense. But why would that class instance have a .new method and if it did what would be the purpose?

If an instance of PackedScene doesn't have a .new method then disregard. My confusion makes sense because when I preload a .tscn file in order to instance it, I didn't expect the preload method to generate an instance of anything.

You can't do that with scripts for example. So it must be some magic going on in the background of the gdscript language.

SIsilicon28

A PackedScene object is an object just like any other resource, so its class would also have a new method; not the object itself. While Godot calls this method when loading packed scenes (It needs to create one to put data in it), there's little no reason why the user would need to do it manually, since they'd have to manually put data into it. The class has new to create objects. The object (with data inside of it) has instance to parse said data into a node tree.

Kequc

Yep so when you preload a scene file the engine generates a packedscene instance that can then be used to instance a tree of nodes. I thought a PackedScene was analogous to a class.

Always wondered why the difference between .new and .instance, thanks.