Basics on Godot 4 レシピ

Understanding tree order

Mon, 01 Jan 0001 00:00:00 +0000

Tip

This article is being updated from Godot 3 to Godot 4.

Problem

You need to understand in what order Godot handles nodes in the scene tree.

Solution

“Tree order” is mentioned often in the Godot docs and in tutorials. However, it is not always obvious to a beginner what is meant by this. Generally speaking, the order in which nodes are handled in the tree is in top-down fashion, starting at the root and going down each branch in turn.

Node communication (the right way)

Mon, 01 Jan 0001 00:00:00 +0000

Info

Many thanks to @TheDuriel on the Godot Discord for the original diagram that inspired this article. Save this and keep it handy.

Problem

Your project has started getting complex. You have multiple scenes, instances, and a lot of nodes. You’ve probably found yourself writing code like the following:

get_node("../../SomeNode/SomeOtherNode")
get_parent().get_parent().get_node("SomeNode")
get_tree().get_root().get_node("SomeNode/SomeOtherNode")

If you do this, you’ll soon find that node references like this break easily. As soon as you change one thing about your scene tree, none of those references may be valid anymore.

Understanding node paths

Mon, 01 Jan 0001 00:00:00 +0000

Tip

This article is being updated from Godot 3 to Godot 4.

Problem

It’s probably the most common problem seen in the Godot help channels: an invalid node reference. Most often, it appears as the following error message:

Invalid get index ‘position’ (on base: ’null instance’).

Solution

It’s that last part, the “null instance”, that’s the source of this problem, and the main source of confusion for Godot beginners.

Understanding 'delta'

Mon, 01 Jan 0001 00:00:00 +0000

Tip

This article is being updated from Godot 3 to Godot 4.

Problem

The delta or “delta time” parameter is a frequently-misunderstood concept in game development. In this tutorial, we’ll explain how it’s used, the importance of frame-rate independent movement, and practical examples of its use in Godot.

Solution

To illustrate the problem, let’s consider a Sprite node moving across the screen. If our screen is 600 pixels wide and we want the sprite to take 5 seconds to cross the screen, we can use the following calculation to find the necessary speed:

Saving/loading data

Mon, 01 Jan 0001 00:00:00 +0000

Problem

You need to save and load local data between game sessions.

Solution

Godot’s file I/O (input/output) system is based around the FileAccess object. You open a file by calling open().

var file = FileAccess.open("user://myfile.name", File.READ)

Warning

User data should only be stored in the user:// path. While res:// can be used when running from the editor, when your project is exported, the res:// path becomes read-only.

Migrating from 3.x

Mon, 01 Jan 0001 00:00:00 +0000

This is an evolving list of the main changes and “gotchas” to look out for if you’re transitioning to 4.0.

New Names

One of the biggest changes in Godot 4 is a whole bunch of renaming - of nodes, functions, and property names. Most of it is done to make things consistent or clear. Here are a few of the biggest ones to watch out for:

2D/3D nodes - In Godot 3.x, 2D nodes had the “2D” suffix, but 3D nodes had none. This has been made consistent - they all now have “2D” or “3D” suffixes. For example: RigidBody2D vs. RigidBody3D.

Circular movement

Mon, 01 Jan 0001 00:00:00 +0000

Tip

This article is being updated from Godot 3 to Godot 4.

Problem

You want an object to “orbit” (move in a circle) around another object.

Solution

This is a common beginner question, and often comes after a bunch of messy experimenting with trig functions. The answer is much simpler:

Place the orbiting sprite in a child node of the main sprite (we’re calling it “Pivot”). Give it an offset and rotate the Pivot.

Using Custom Resources

Mon, 01 Jan 0001 00:00:00 +0000

Tip

This article is being updated from Godot 3 to Godot 4.

Problem

You’re looking for a way to handle data and/or create flexible data objects in your game.

Solution

Godot’s Resource class is a powerful tool for storing and working with data. Many of the most common objects you work with in Godot extend the Resource type: animations, collision shapes, images, etc. Resources not only contain data, but can also manipulate that data (if you’re familiar with the concept of scriptable objects in Unity, the concept is similar).