Smooth zoom for 2D game

Unity Engine
,
1

Hi there! I’m making a 2D top down game and I just started using CInemachine for the firs time.

I’m trying to get a smooth zoom effect working and I’m having issues.

So, right now I’m using the following code:

private void Update()
    {
        if (active)
        {
            float horizontalInput = Input.GetAxisRaw("Horizontal");
            float verticalInput = Input.GetAxisRaw("Vertical");

            direction.x = horizontalInput;
            direction.y = verticalInput;
            direction = direction.normalized;
          
            velocity = direction * camSpeed * 15f;
            movement = velocity * Time.deltaTime;

            mapCam.transform.position = new Vector3(mapCam.transform.position.x + movement.x, mapCam.transform.position.y + movement.y, mapCam.transform.position.z);

            float zoom = Input.mouseScrollDelta.y * zoomMagnitude;
            mapCam.m_Lens.OrthographicSize = Mathf.Lerp(mapCam.m_Lens.OrthographicSize, mapCam.m_Lens.OrthographicSize + zoom, zoomSpeed * Time.deltaTime);
        }
    }

The zoom works (though it needs some major work) but it just snaps to the orthographic size and I wanted it to sort of smoothly transition. I have another virtual camera on the scene with a different orthographic size and when going from one camera to the other it zooms smoothly so I’m sure it can be done but I just can’t figure it out.

Not sure

2

This zooms in nicely:

private void Update()
{
        float zoom = Input.mouseScrollDelta.y;
        vcam.m_Lens.OrthographicSize = Mathf.Lerp(vcam.m_Lens.OrthographicSize, vcam.m_Lens.OrthographicSize + zoom, Time.deltaTime);
}

I don’t know what zoomSpeed is in your code, but it may scale up Time.deltaTime too much. Lerp expect a t value between 0 and 1.

3

@gaborkb

Hey, thanks for the reply! Sorry I should have specified what the variables are.

zoomMagnitude and zoomSpeed are just floats meant to control the rate at which each scroll on the mouse wheel zooms. I guess I really don’t need both, I changed my code to the following based on your suggestion:

private void Update()
    {
        if (active)
        {
            float zoom = -Input.mouseScrollDelta.y;
            mapCam.m_Lens.OrthographicSize = Mathf.Lerp(mapCam.m_Lens.OrthographicSize, mapCam.m_Lens.OrthographicSize + zoom * zoomMagnitude, Time.deltaTime);
            mapCam.m_Lens.OrthographicSize = Mathf.Clamp(mapCam.m_Lens.OrthographicSize, minZoom, maxZoom);
        }
    }

It’s still not smooth except for very small values of zoomMagnitude. Also when I look at the Orthographic size in the inspector it seems to be changing imminently and I thought Lerp was supposed to change the value over time.

Maybe it can’t be done using this method?

4

For me, it is smooth (tried zoomMagnitude from 0.1 to 100). Could you send a video recording showing what happens in your case exactly?