Camera jitters/shakes violently using translate()?

Question

I have a script that allows the camera to be moved around by holding down middle mouse and dragging around the play area, but if you just hold down the middle mouse and don't move the camera will violently shake and then carry through the movement it makes when you let go of the button. This can be worked around but the outcome is still not desirable, enabling smoothing tames the shaking but if you smooth too fast the camera will violently shake again, and if you make the smoothing too slow the camera moves too slow and I don't really want any smoothing on the camera to begin with. I am using self.translate() for the camera movement because when I use self.position to move the camera it only moves mostly around a specific position.

extends Camera2D

var lastMousePos = get_global_mouse_position()
var currentMousePos = lastMousePos

func _process(delta):
    if Input.is_action_pressed("cam_drag"):
        currentMousePos = get_global_mouse_position()
        var diff = (lastMousePos - currentMousePos).normalized()
        self.translate(diff * 30)
        lastMousePos = currentMousePos #I'm assuming the jittering is because of - these variables, not sure though

thank you in advance for any and all help.

Answer 1

it's because you use globalmouseposition so when your camera moves, your 'lastMousePos' that you record when your camera is at previous position isn't correct anymore
use mouse position in viewport instead

currentMousePos = get_viewport().get_mouse_position()

and use onready at variable declaration to prevent getting null mouse position when the game starts

onready var lastMousePos = get_viewport().get_mouse_position()
onready var currentMousePos = lastMousePos

SUGGESTION:
1.reset your 'lastMousePos' every time you begin a new drag so your camera didn't move when you just click

if Input.is_action_just_pressed("cam_drag"):
    lastMousePos = get_viewport().get_mouse_position()

2.currently, all your camera drag will round to 30 even if it slightly drag. make you can't drag in small distance.
seperate the case to enable small drag with this

if lastMousePos.distance_to(currentMousePos) < 30:
    # SMALL DRAG
    self.translate(lastMousePos - currentMousePos)
else :
    var diff = (lastMousePos - currentMousePos).normalized()
    self.translate(diff * 30)

---

with all code above, we get this

extends Camera2D

onready var lastMousePos = get_viewport().get_mouse_position()
onready var currentMousePos = lastMousePos

func _process(delta):
    if Input.is_action_just_pressed("cam_drag"):
        lastMousePos = get_viewport().get_mouse_position()

    if Input.is_action_pressed("cam_drag"):
        currentMousePos = get_viewport().get_mouse_position()
        if lastMousePos.distance_to(currentMousePos) < 30:
            # SMALL DRAG
            self.translate(lastMousePos - currentMousePos)
        else :
            var diff = (lastMousePos - currentMousePos).normalized()
            self.translate(diff * 30)
        lastMousePos = currentMousePos

Comments

Thank you very much! I'll be sure to try this out!