Up to date

This page is up to date for Godot 4.0. If you still find outdated information, please open an issue.

Random number generation¶

Many games rely on randomness to implement core game mechanics. This page guides you through common types of randomness and how to implement them in Godot.

After giving you a brief overview of useful functions that generate random numbers, you will learn how to get random elements from arrays, dictionaries, and how to use a noise generator in GDScript.

Note

Computers cannot generate "true" random numbers. Instead, they rely on pseudorandom number generators (PRNGs).

Global scope versus RandomNumberGenerator class¶

Godot exposes two ways to generate random numbers: via global scope methods or using the RandomNumberGenerator class.

Global scope methods are easier to set up, but they don't offer as much control.

RandomNumberGenerator requires more code to use, but allows creating multiple instances, each with their own seed and state.

This tutorial uses global scope methods, except when the method only exists in the RandomNumberGenerator class.

The randomize() method¶

In global scope, you can find a randomize() method. This method should be called only once when your project starts to initialize the random seed. Calling it multiple times is unnecessary and may impact performance negatively.

Putting it in your main scene script's _ready() method is a good choice:

func _ready():
    randomize()

public override void _Ready()
{
    GD.Randomize();
}

You can also set a fixed random seed instead using seed(). Doing so will give you deterministic results across runs:

func _ready():
    seed(12345)
    # To use a string as a seed, you can hash it to a number.
    seed("Hello world".hash())

public