CamOrbiting.cs

using UnityEngine;

[RequireComponent(typeof(Camera))]
public class CamOrbiting : MonoBehaviour
{
    public Transform targetMesh;
    public float distance = 10f;
    public float zoomSpeed = 2f;
    public float orbitSpeed = 100f;
    public float panSpeed = 0.01f;
    public float minZoom = 1f;
    public float maxZoom = 100f;
    Vector3 orbitCenter;
    float yaw = 0f;
    float pitch = 20f;
    Camera m_cam;
    void Start()
    {
        m_cam = GetComponent<Camera>();
        if (targetMesh != null)
        {
            orbitCenter = GetMeshBoundsCenter(targetMesh);
        }
    }

    void Update()
    {
        HandleOrbit();
        HandlePan();
        HandleZoom();
    }

    void HandleOrbit()
    {
        if (Input.GetMouseButton(0)) // rotate with left click
        {
            yaw += Input.GetAxis("Mouse X") * orbitSpeed * Time.unscaledDeltaTime;// unscaled delta time in case you're using it in a paused menu
            pitch -= Input.GetAxis("Mouse Y") * orbitSpeed * Time.unscaledDeltaTime;
            pitch = Mathf.Clamp(pitch, -89f, 89f);
        }
        Quaternion rotation = Quaternion.Euler(pitch, yaw, 0f);
        Vector3 direction = rotation * Vector3.forward;
        transform.position = orbitCenter - direction * distance;
        transform.rotation = rotation;
    }

    void HandlePan()
    {
        if (Input.GetMouseButton(2)) // pan with middle mouse button
        {
            float panX = -Input.GetAxis("Mouse X") * panSpeed * m_cam.orthographicSize;
            float panY = -Input.GetAxis("Mouse Y") * panSpeed * m_cam.orthographicSize;
            // move orbit center based on camera right and up
            Vector3 right = transform.right;
            Vector3 up = transform.up;
            orbitCenter += right * panX + up * panY;
        }
    }

    void HandleZoom()
    {
        float scroll = Input.GetAxis("Mouse ScrollWheel");
        m_cam.orthographicSize -= scroll * zoomSpeed;
        m_cam.orthographicSize = Mathf.Clamp(m_cam.orthographicSize, minZoom, maxZoom);
    }

    Vector3 GetMeshBoundsCenter(Transform target)
    {
        var renderers = target.GetComponentsInChildren<Renderer>();
        if (renderers.Length == 0) return target.position;
        Bounds combinedBounds = renderers[0].bounds;
        for (int i = 1; i < renderers.Length; i++)
        {
            combinedBounds.Encapsulate(renderers[i].bounds);
        }
        return combinedBounds.center;
    }
}