Help with camera movement from touching the screen (Zoom and movement)

Unity Engine
,
1

Hello, I’m making a 2D map in which I can zoom and move around it, I did that, but I’m not understanding 100% how the code works and I don’t know what I should modify to be able to change the speed with which I move by touching the screen and the speed with which I zoom (the zoom speed is very slow and the movement speed is very high). I leave the code, thanks.

  public Camera cam;
    private Vector3 touchStart;
    public float maxZoom = 10;
    public float minZoom = 100;
    public float speed = 10;
    float targetZoom;
    void Start()
    {
        targetZoom = cam.orthographicSize;
    }
    void Update()
    {
        cameraController();
    }

    void zoom(float increment)
    {
        targetZoom = Mathf.Clamp(cam.orthographicSize - increment, maxZoom, minZoom);
        cam.orthographicSize = Mathf.MoveTowards(cam.orthographicSize, targetZoom, speed * Time.deltaTime);
    }

    void cameraController() {
           if (Input.GetMouseButtonDown(0))
        {
            touchStart = cam.ScreenToWorldPoint(Input.mousePosition);
        }
        if (Input.touchCount == 2)
        {
            Touch touchZero = Input.GetTouch(0);
            Touch touchOne = Input.GetTouch(1);

            Vector2 touchZeroPrevPos = touchZero.position - touchZero.deltaPosition;
            Vector2 touchOnePrevPos = touchOne.position - touchOne.deltaPosition;

            float prevMagnitude = (touchZeroPrevPos - touchOnePrevPos).magnitude;
            float currentMagnitude = (touchZero.position - touchOne.position).magnitude;

            float difference = currentMagnitude - prevMagnitude;

            zoom(difference);
        } else if (Input.GetMouseButton(0))
        {
            Vector3 direction = touchStart - cam.ScreenToWorldPoint(Input.mousePosition);
            cam.transform.position += direction;
        }
        zoom(Input.GetAxis("Mouse ScrollWheel"));
        }
}

PS: I added the Mathf.MoveTowards part because I thought that from that function I could change the speed but it didn’t work.

2

Hi!

For the zoom speed you already have a public variable that you could set in inspector: “speed”. But you are using that value to ease the zoom movement, not for making more or less zoom value. You should use that speed value in the previous line. Something like:

targetZoom = Mathf.Clamp(cam.orthographicSize - increment * speed, maxZoom, minZoom);

You could create another public variable for setting movement speed and use it here:

cam.transform.position += direction * movementSpeed;
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3

Camera stuff is pretty tricky… you may wish to consider using Cinemachine from the Unity Package Manager.

There’s even a dedicated forum: Unity Engine - Unity Discussions

4

Hello, thank you very much for your answers, regarding:

The speed part when moving the camera worked for me, I could increase or decrease it by changing a variable:

            Vector3 direction = touchStart - cam.ScreenToWorldPoint(Input.mousePosition);
            cam.transform.position += direction * movementSpeed;

However, the zoom part, I played with the speed number, both from 0.1 to 1000, but I didn’t change anything :frowning:

        targetZoom = Mathf.Clamp(cam.orthographicSize - increment * speed, maxZoom, minZoom);
        cam.orthographicSize = Mathf.MoveTowards(cam.orthographicSize, targetZoom, 2 * Time.deltaTime);
5

Welcome to debugging! Here is how to get started:

You must find a way to get the information you need in order to reason about what the problem is.

What is often happening in these cases is one of the following:

  • the code you think is executing is not actually executing at all
  • the code is executing far EARLIER or LATER than you think
  • the code is executing far LESS OFTEN than you think
  • the code is executing far MORE OFTEN than you think
  • the code is executing on another GameObject than you think it is
  • you’re getting an error or warning and you haven’t noticed it in the console window

To help gain more insight into your problem, I recommend liberally sprinkling Debug.Log() statements through your code to display information in realtime.

Doing this should help you answer these types of questions:

  • is this code even running? which parts are running? how often does it run? what order does it run in?
  • what are the values of the variables involved? Are they initialized? Are the values reasonable?
  • are you meeting ALL the requirements to receive callbacks such as triggers / colliders (review the documentation)

Knowing this information will help you reason about the behavior you are seeing.

You can also supply a second argument to Debug.Log() and when you click the message, it will highlight the object in scene, such as Debug.Log("Problem!",this);

If your problem would benefit from in-scene or in-game visualization, Debug.DrawRay() or Debug.DrawLine() can help you visualize things like rays (used in raycasting) or distances.

You can also call Debug.Break() to pause the Editor when certain interesting pieces of code run, and then study the scene manually, looking for all the parts, where they are, what scripts are on them, etc.

You can also call GameObject.CreatePrimitive() to emplace debug-marker-ish objects in the scene at runtime.

You could also just display various important quantities in UI Text elements to watch them change as you play the game.

If you are running a mobile device you can also view the console output. Google for how on your particular mobile target, such as this answer or iOS: https://discussions.unity.com/t/700551 or this answer for Android: https://discussions.unity.com/t/699654

Another useful approach is to temporarily strip out everything besides what is necessary to prove your issue. This can simplify and isolate compounding effects of other items in your scene or prefab.

Here’s an example of putting in a laser-focused Debug.Log() and how that can save you a TON of time wallowing around speculating what might be going wrong:

https://discussions.unity.com/t/839300/3

When in doubt, print it out!™

Note: the print() function is an alias for Debug.Log() provided by the MonoBehaviour class.

6

I already found my mistake, got a better understanding of the functions I was using and realized that “2 * Time.deltaTime” was limiting the maximum speed. Thanks.

1 Like