Making topdown movement work with acceleration and deceleration

[kemmustry]

Godot Version

Godot Engine v4.2.1.stable.official.b09f793f5

Question

Hey there everybody. I’m trying to make topdown movement work with acceleration and deceleration. Unfortunately I’m extremely new and even a simple mechanic for moving turned out to be a million lines long. My questions are:

1. How can I write this information in a better, shorter way?

2. Because of the way I set up the movement in the beginning, it makes the character stop instantly when I stop pressing the key. How do I get around that?

3. I want the character to slide before stopping completely. How should I approach coding that?

Thanks in advance.

func _process(delta):
	position.x -= currentSPEED * delta
	position.x += currentSPEED * delta
	
	position.y -= currentSPEED * delta
	position.y += currentSPEED * delta
	
	if Input.is_action_pressed("ui_left"):
		if velocity.length() > 1:
			velocity.normalized()
		currentSPEED += Acceleration * delta
		position.x -= currentSPEED * delta
		
		if currentSPEED > maxSPEED:
			currentSPEED = maxSPEED
		
	elif Input.is_anything_pressed() == false :
		currentSPEED -= Deceleration * delta
		if currentSPEED < 0:
			currentSPEED = 0	
	
	if Input.is_action_pressed("ui_right"):
		if velocity.length() > 1:
			velocity.normalized()
		currentSPEED += Acceleration * delta
		position.x += currentSPEED * delta
		
		if currentSPEED > maxSPEED:
			currentSPEED = maxSPEED
		
	elif Input.is_anything_pressed() == false :
		currentSPEED -= Deceleration * delta
		if currentSPEED < 0:
			currentSPEED = 0	
			
	if Input.is_action_pressed("ui_up"):
		if velocity.length() > 1:
			velocity.normalized()
		currentSPEED += Acceleration * delta
		position.y -= currentSPEED * delta
		
		if currentSPEED > maxSPEED:
			currentSPEED = maxSPEED
		
	elif Input.is_anything_pressed() == false :
		currentSPEED -= Deceleration * delta
		if currentSPEED < 0:
			currentSPEED = 0	
	
	if Input.is_action_pressed("ui_down"):
		if velocity.length() > 1:
			velocity.normalized()
		currentSPEED += Acceleration * delta
		position.y += currentSPEED * delta
		
		if currentSPEED > maxSPEED:
			currentSPEED = maxSPEED
		
	elif Input.is_anything_pressed() == false :
		currentSPEED -= Deceleration * delta
		if currentSPEED < 0:
			currentSPEED = 0	

[mimicstardust]

Are you using a CharacterBody2D? It’s recommended to use _physics_process for PhysicsBody2D nodes (like CharacterBody2D) for movement logic.

Analyzing your code I see some things that are wrong.

First, this four lines are redundant.

@kemmustry

	position.x -= currentSPEED * delta
	position.x += currentSPEED * delta
	
	position.y -= currentSPEED * delta
	position.y += currentSPEED * delta

You are substracting and adding the same values to the same variables.

Second: your are normalizing velocity in every input check and currentSPEED is being limited after adding it to position.

Third: you are checking if there are no keys pressed before applying the deceleration. That means that if I press, just for example, the space bar, that code won’t execute.

I’ll give you two ways of writing this shorter, but I recommend you to watch some tutorials on YouTube and check the documentation regularly.

Assuming your script extends CharacterBody2D (which I recommend).

func _physics_process(delta):
	var direction = Input.get_vector("ui_left", "ui_right", "ui_up", "ui_down")
	
	if direction != Vector2.ZERO:
		velocity = velocity.move_toward(direction * maxSPEED, Acceleration * delta)
	else:
		velocity = velocity.move_toward(Vector2.ZERO, Deceleration * delta)
	
	move_and_slide()

If your script is extending Node2D.

func _process(delta):
	var direction = Input.get_vector("ui_left", "ui_right", "ui_up", "ui_down")
	
	if direction != Vector2.ZERO:
		velocity = velocity.move_toward(direction * maxSPEED, Acceleration * delta)
	else:
		velocity = velocity.move_toward(Vector2.ZERO, Deceleration * delta)
	
	position += velocity * delta

Have a nice day or night!

[kemmustry]

Thanks a lot man. I’ll try to study it and check the documentation. Thank you so much for your time