Most optimal way to animate movement while changing parent node?

Question

Currently, I'm making a card game (think of Hearthstone) with a node oriented approach. This means, that every card is a node, and that to move a card to a designated spot (for instance, a player's hand or the combat field), I need to move the child node between parent nodes.

For example, to move a card from my hand to the combat field, I would call remove_child() on my hand and add_child() on the combat field.

Now, this works really well when it comes to having cards teleport everywhere. However, I want them to smoothly move from a parent node to another. What is the best way to achieve this? Or is there a better way to organise my scenes other than using nodes?

Answer 1

I believe the way you're doing it now is the only way to reparent nodes in Godot. The only change that you could perhaps make is to create your own reparent function, and put your current code (i.e. the remove_child() and add_child() methods) inside of it, assuming you haven't done this already. That way, you can just call the function whenever you need to reparent a node.

Answer 2

Add a Tween node to your scene and then from the code you could do something similar to:

var position_start = card.global_position
var position_end = combat_field.global_position
var duration_in_seconds = 1.0
tween.interpolate_property(card, "global_position", position_start, position_end, duration_in_seconds, Tween.TRANS_LINEAR)
tween.start()
yield(tween, "tween_completed") # wait until move animation is complete
card.get_parent().remove_child(card)
combat_field.add_child(card)
card.position = Vector2() # reset local position after re-parenting

card is your node that you want to animate.

combat_field is node you want your card to move to.

tween is your Tween node.

Demo:

Use a different approach?

I don't know why you want to change parent nodes for your cards. Perhaps, there is a simpler way?

What if instead you assign them to a different group? This way you can have different logic in your code based on groups and not parent nodes.

Another idea is that you could create a singleton class to keep track of the state of your game. Like, which cards are in player hands and which are on the combat field.