How to connect _on_body_entered function from an instanced bullet scene to an instanced asteroid scene?

Question

Hi, I'm making an Asteroids clone with Godot. The MainScene generates a number of asteroids, making new ones appear when another one gets out of screen, and the Player script generates bullet when the shoot key is pressed. I've been trying to use signals to connect the onbodyentered on the Bullet script, but the only workable function I found uses getchild(0) which doesn't return the right instance. I also don't really know where to emit the signal from!
So far I have :

if Input.is_action_just_pressed("shoot"):
        b = Bullet.instance()
        owner.add_child(b)
        b.add_to_group("Bullets")
        b.transform = $Muzzle.global_transform
        get_parent().get_child(0).emit()

and on the Bullet scene :

func emit():
    emit_signal("bullet_collision")
    print("emission")

func _on_Bullet_body_entered(body):
    if body.is_in_group("Asteroids"):
        print("bullet collision")
        body.queue_free()
        queue_free()

and in the ready of Bullet :

connect("bullet_collision", self, "_on_Bullet_body_entered")

Oh and the collisions work fine when they're not instances. Thanks!

Answer 1

There are builtin signals in Godot, and "body_entered" is one of them. It is always emitted by default, whenever collision object collides with a body. You have to connect it, but You don't need to emit it.
What I see in your code - You created custom signal "bulletcollision". You can't expect it to trigger by itself. Just use "body_entered" signal, connect it instead.
You can see a list of built in signals in node documentation, as well as in editor signals tab.

Comments

It's working thanks!! I've been racking my brain over this!