Mathf.SmoothDamp, damping only works "one way"

Help me understand something - am I trying to use Mathf.SmoothDamp wrong or what is going on, since the damping portion of it only seems to work when the "currentVelocity" is a positive number. If it's a negative number, then the damping doesn't work but instead currentVelocity is just instantly reset to 0 when the damping should occur.

I've been trying to google this and only found other people saying the same thing but no definite answers.

I can work around my problem by using Vector2.SmoothDamp which works the way I would expect it to, but now I'm just curious as to why Mathf.SmoothDamp seems to work differently and would need a different approach to use it like this.

So, I have a simple camera rotation code here using Mathf.SmoothDamp. I have a global variable to hold the currentVelocity for SmoothDamp.

Code (CSharp):

1. private float _refCamAxis = 0f;

Then I have this simple piece of code which rotates my camera using SmoothDamp based on which way the mouse is moved while holding down the middle button:

Code (CSharp):

1.     private void DoCameraRotation()
2.     {
3.         var currentCamAxis = _orbitTransposer.m_XAxis.Value;
4.         var desiredCamAxis = currentCamAxis;
5.  
6.         if (Input.GetMouseButton(2))
7.         {
8.             var mouseXPos = Input.mousePosition.x;
9.             var rotateBy = (_prevMouseHor < mouseXPos ? -_camRotSensitivity : (_prevMouseHor > mouseXPos ? _camRotSensitivity : 0f));
10.             desiredCamAxis = _orbitTransposer.m_XAxis.Value + rotateBy;
11.         }
12.      
13.         _orbitTransposer.m_XAxis.Value = Mathf.SmoothDamp(currentCamAxis, desiredCamAxis, ref _refCamAxis, _camRotDampTime);
14.  
15.         _prevMouseHor = Input.mousePosition.x;
16.  
17.     }

Now, when desiredCamAxis is a bigger number than currentCamAxis, resulting in a positive _refCamAxis, the damping works - the rotation comes to a smooth stop when you let go of the button (the currentVelocity ref is gradually lowered to 0).

But when desiredCamAxis is less than currentCamAxis, resulting in a negative _refCamAxis (i.e. the camera is being rotated to the other direction), there is no damping but instead it just comes to a full stop (currentVelocity, the _refCamAxis, resets instantly to 0) as soon as the button is released.

Ok so if I do the same with Vector2.SmoothDamp, it works both ways:

Code (CSharp):

1. private Vector2 _refV = new Vector2();

The rotation function using Vector2.SmoothDamp instead of Mathf.SmoothDamp:

Code (CSharp):

1.     private void DoCameraRotation()
2.     {
3.         var currentCamAxis = _orbitTransposer.m_XAxis.Value;
4.         var desiredCamAxis = currentCamAxis;
5.  
6.         if (Input.GetMouseButton(2))
7.         {
8.             var mouseXPos = Input.mousePosition.x;
9.             var rotateBy = (_prevMouseHor < mouseXPos ? -_camRotSensitivity : (_prevMouseHor > mouseXPos ? _camRotSensitivity : 0f));
10.             desiredCamAxis = _orbitTransposer.m_XAxis.Value + rotateBy;
11.         }
12.      
13.         Vector2 currentDummyVector = new Vector2(currentCamAxis, 0f);
14.         Vector2 desiredDummyVector = new Vector2(desiredCamAxis, 0f);
15.         _orbitTransposer.m_XAxis.Value = Vector2.SmoothDamp(currentDummyVector, desiredDummyVector, ref _refV, _camRotDampTime).x;
16.  
17.         _prevMouseHor = Input.mousePosition.x;
18.     }
19.  

And ta-dah, suddenly it works with both a positive and a negative currentVelocity.

So - am I trying to use Mathf.SmoothDamp wrong or does it simply just work "one way" by design? Or both? Or something else?

 

I have the exact same issue here. Mathf.SmoothDamp only works with a positive target value. (Unity v2018.3)

Thanks for workaround suggestion tho