Instant error when starting the game

Darty293 · March 10, 2026, 1:04pm

Godot Version

Godot version 4.6.1

Question

When I start the game, I get this error, I have no experience in programming, therefore, I ask you to answer in a clearer way.

tibaverus · March 10, 2026, 1:08pm

It looks like screen_size is null, which means you didn’t assign anything to it. Make sure you set that variable before you try to access it.
In your case, this can probably be achieved with the following line:

var screen_size = DisplayServer.screen_get_size()

Or simply:

screen_size = DisplayServer.screen_get_size()

if you already had the variable screen_size declared above.

I recommend starting out with some basic tutorials so you can get used to the absolute basics and see a project being made from start to finish.

Darty293 · March 10, 2026, 1:09pm

but i use it

Darty293 · March 10, 2026, 1:18pm

And by the way, even though I use it, I still can’t do anything.

tibaverus · March 10, 2026, 1:33pm

I’m not sure what you mean unfortunately. Could you show your entire script? Since the error message tells you that screen_size is null.

Darty293 · March 10, 2026, 1:48pm

extends Area2D

@export var speed = 400 # How fast the player will move (pixels/sec).
var screen_size # Size of the game window.

Called when the node enters the scene tree for the first time.

func _ready() → void:
screen_size = get_viewport_rect().size
pass # Replace with function body.

func _process(delta):
var velocity = Vector2.ZERO # The player’s movement vector.
if Input.is_action_pressed(“move_right”):
velocity.x += 1
if Input.is_action_pressed(“move_left”):
velocity.x += 1
if Input.is_action_pressed(“jump”):
velocity.y += 1
if Input.is_action_pressed(“push”):
velocity.x += 1
if Input.is_action_pressed(“run”):
velocity.y += 1
if velocity.length() > 0:
velocity = velocity.normalized() * speed
$AnimatedSprite2D.play()
else:
$AnimatedSprite2D.stop()

	position = velocity * delta
	position = position.clamp(Vector2.ZERO, screen_size)
	delta=16
	screen_size=1
	screen_size = DisplayServer.screen_get_size(1)
	
if velocity.x != 0:
	$AnimatedSprite2D.animation = "stand"
	$AnimatedSprite2D.flip_v = false
# See the note below about the following boolean assignment.
	$AnimatedSprite2D.flip_h = velocity.x < 0

tibaverus · March 10, 2026, 1:50pm

Please try to format your code properly so it’s easier to read for others.

Darty293 · March 10, 2026, 2:57pm

extends Area2D

@exportexport var speed = 400 # How fast the player will move (pixels/sec).
var screen_size # Size of the game window.

Called when the node enters the scene tree for the first time.

func _ready() → void:

>screen_size = get_viewport_rect().size

pass # Replace with function body.

> func _process(delta):

var velocity = Vector2.ZERO # The player’s movement vector.
if Input.is_action_pressed(“move_right”):

velocity.x += 1
if Input.is_action_pressed(“move_left”):
velocity.x += 1
if Input.is_action_pressed(“jump”):
velocity.y += 1
if Input.is_action_pressed(“push”):
velocity.x += 1
if Input.is_action_pressed(“run”):
velocity.y += 1
if velocity.length() > 0:
velocity = velocity.normalized() * speed
$AnimatedSprite2D.play()
else:
$AnimatedSprite2D.stop()

> > position = velocity * delta

> > position = position.clamp(Vector2.ZERO, screen_size)

delta=16
screen_size=1
screen_size = DisplayServer.screen_get_size(1)

if velocity.x != 0:

$AnimatedSprite2D.animation = “stand”
$AnimatedSprite2D.flip_v = false

See the note below about the following boolean assignment.

$AnimatedSprite2D.flip_h = velocity.x < 0

Is it clearer now?

Darty293 · March 10, 2026, 2:58pm

the two vertical bars mean “> >”

tibaverus · March 10, 2026, 3:14pm

No this is even worse. You misinterpreted the instruction given.
Please just select your code, and in the forum’s own editor, click on the “Preformatted text” buttom.

Darty293 · March 10, 2026, 3:17pm

that’s what i did

Darty293 · March 10, 2026, 3:20pm

extends Area2D

@export var speed = 400 # How fast the player will move (pixels/sec).
var screen_size # Size of the game window.

#Called when the node enters the scene tree for the first time.

func _ready() → void:
> screen_size = get_viewport_rect().size
> pass # Replace with function body.

func _process(delta):
> var velocity = Vector2.ZERO # The player’s movement vector.
> if Input.is_action_pressed(“move_right”):
> > velocity.x += 1
> if Input.is_action_pressed(“move_left”):
> > velocity.x += 1
> if Input.is_action_pressed(“jump”):
> > velocity.y += 1
> if Input.is_action_pressed(“push”):
> > velocity.x += 1
> if Input.is_action_pressed(“run”):
> > velocity.y += 1
> if velocity.length() > 0:
> > velocity = velocity.normalized() * speed
> > $AnimatedSprite2D.play()
> else:
> > $AnimatedSprite2D.stop()

> >	position = velocity * delta
> >	position = position.clamp(Vector2.ZERO, screen_size)
> >	delta=16
> >	screen_size=1
> >	screen_size = DisplayServer.screen_get_size(1)
	
> if velocity.x != 0:
> >	$AnimatedSprite2D.animation = "stand"
> >	$AnimatedSprite2D.flip_v = false
# See the note below about the following boolean assignment.
> >	$AnimatedSprite2D.flip_h = velocity.x < 0

Darty293 · March 10, 2026, 3:20pm

like this?

tibaverus · March 10, 2026, 3:25pm

Please remove all the > > symbols you added. Simply copy your code from your editor, paste it in, and use the preformatted text button.

Darty293 · March 10, 2026, 3:25pm

extends Area2D

@export var speed = 400 # How fast the player will move (pixels/sec).
var screen_size # Size of the game window.

Called when the node enters the scene tree for the first time.

func _ready() → void:
screen_size = get_viewport_rect().size
pass # Replace with function body.

func _process(delta):
var velocity = Vector2.ZERO # The player’s movement vector.
if Input.is_action_pressed(“move_right”):
velocity.x += 1
if Input.is_action_pressed(“move_left”):
velocity.x += 1
if Input.is_action_pressed(“jump”):
velocity.y += 1
if Input.is_action_pressed(“push”):
velocity.x += 1
if Input.is_action_pressed(“run”):
velocity.y += 1
if velocity.length() > 0:
velocity = velocity.normalized() * speed
$AnimatedSprite2D.play()
else:
$AnimatedSprite2D.stop()

	position = velocity * delta
	position = position.clamp(Vector2.ZERO, screen_size)
	delta=16
	screen_size=1
	screen_size = DisplayServer.screen_get_size(1)
	
if velocity.x != 0:
	$AnimatedSprite2D.animation = "stand"
	$AnimatedSprite2D.flip_v = false
# See the note below about the following boolean assignment.
	$AnimatedSprite2D.flip_h = velocity.x < 0

Darty293 · March 10, 2026, 3:31pm

and yet, when I start the game, my character cannot move, although I have assigned keys, I have written a script, but it does not move. (you don’t need to send me links to training, I’m already using them to make a game)

gertkeno · March 11, 2026, 4:21am

This line sets the position based on velocity, it doesn’t add to the position, try using
position += velocity * delta

To write code blocks use three back ticks ``` by pressing the tilde key ~ without holding shift. Then paste your code.

```
func _ready() -> void:
print("This is my code")
```

converts to

func _ready() -> void:
    print("This is my code")

sancho2 · March 11, 2026, 6:31am

You have not given screen_size a type so when it gets to screen_size = 1 it is of type variant/int.
You should probably get rid of that line.
Then when it gets to the next line you give DisplayServer.screen_get_size(1). The parameter 1 is probably invalid.
The documentation notes some constants you can use for a parameter and for most cases it should be -1

SCREEN_OF_MAIN_WINDOW = -1

Since the 1 as the screen parameter is likely invalid screen_get_size() will return Vector2i.ZERO (0,0)
position will then be clamped to Vector2i(0,0)
That is going to contribute to the problem.