Please explain this camera pan behaviour

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Godot Version

v4.2.2.stable.official [15073afe3]

Question

I have found some code on reddit for camera panning because I was struggling with the camera’s pan speed.
The code below has both my version and the reddit post’s version, selectable with the variant1 variable.

Please enlighten me why (my) variant1 does not work the same as variant2.
The only notable difference seems to be that I am using a Tween instead of directly manipulating the global_position of the Camera2D.

extends Camera2D

const ZOOM_INCREMENT = 0.05
const ZOOM_MIN = 0.5
const ZOOM_MAX = 5.0	

var panning := false
var zoom_level := 1.0
var variant1 = true
func _unhandled_input(_event:InputEvent) -> void:
	if _event is InputEventMouseButton:
		match _event.button_index:
			MOUSE_BUTTON_LEFT:
				if Input.is_key_pressed(KEY_CTRL):
					if _event.pressed:
						panning = true
					else:
						panning = false
					get_tree().get_root().set_input_as_handled()
			MOUSE_BUTTON_WHEEL_UP:
				zoom_level = clamp(zoom_level + ZOOM_INCREMENT, ZOOM_MIN, ZOOM_MAX)
				zoom = zoom_level * Vector2.ONE
				get_tree().get_root().set_input_as_handled()
			MOUSE_BUTTON_WHEEL_DOWN:
				zoom_level = clamp(zoom_level - ZOOM_INCREMENT, ZOOM_MIN, ZOOM_MAX)
				zoom = zoom_level * Vector2.ONE
				get_tree().get_root().set_input_as_handled()
	elif _event is InputEventMouseMotion and panning:
		get_tree().get_root().set_input_as_handled()
		if Input.is_mouse_button_pressed(MOUSE_BUTTON_LEFT) and Input.is_key_pressed(KEY_CTRL):
			if variant1:
				var tween = get_tree().create_tween()
				tween.tween_property(
					self,
					"global_position",	
					self.global_position - (_event.relative / zoom_level),
					0.2
					#Input.get_last_mouse_velocity().length()
				).set_trans(Tween.TRANS_LINEAR).set_ease(Tween.EASE_IN_OUT)
			else:
				global_position -= _event.relative / zoom_level
		else:
			panning = false
2

It’s definitely the tween, _event.relative is very small and a mouse movement input triggers every frame so your tweens will not have time to move. If you are aiming to have a cinematic/laggy camera pan you will need a seperate “target camera position” variable to move toward each frame.

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