A simple Unity C# script for orbital movement around a target gameobject

CameraOrbit.cs

//  A simple Unity C# script for orbital movement around a target gameobject
//  Author: Ashkan Ashtiani
//  Gist on Github: https://gist.github.com/3dln/c16d000b174f7ccf6df9a1cb0cef7f80

using System;
using UnityEngine;

namespace TDLN.CameraControllers
{
    public class CameraOrbit : MonoBehaviour
    {
        public GameObject target;
        public float distance = 10.0f;

        public float xSpeed = 250.0f;
        public float ySpeed = 120.0f;

        public float yMinLimit = -20;
        public float yMaxLimit = 80;

        float x = 0.0f;
        float y = 0.0f;

        void Start()
        {
            var angles = transform.eulerAngles;
            x = angles.y;
            y = angles.x;
        }

        float prevDistance;

        void LateUpdate()
        {
            if (distance < 2) distance = 2;
            distance -= Input.GetAxis("Mouse ScrollWheel") * 2;
            if (target && (Input.GetMouseButton(0) || Input.GetMouseButton(1)))
            {
                var pos = Input.mousePosition;
                var dpiScale = 1f;
                if (Screen.dpi < 1) dpiScale = 1;
                if (Screen.dpi < 200) dpiScale = 1;
                else dpiScale = Screen.dpi / 200f;

                if (pos.x < 380 * dpiScale && Screen.height - pos.y < 250 * dpiScale) return;

                // comment out these two lines if you don't want to hide mouse curser or you have a UI button 
                Cursor.visible = false;
                Cursor.lockState = CursorLockMode.Locked;

                x += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
                y -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;

                y = ClampAngle(y, yMinLimit, yMaxLimit);
                var rotation = Quaternion.Euler(y, x, 0);
                var position = rotation * new Vector3(0.0f, 0.0f, -distance) + target.transform.position;
                transform.rotation = rotation;
                transform.position = position;

            }
            else
            {
                // comment out these two lines if you don't want to hide mouse curser or you have a UI button 
                Cursor.visible = true;
                Cursor.lockState = CursorLockMode.None;
            }

            if (Math.Abs(prevDistance - distance) > 0.001f)
            {
                prevDistance = distance;
                var rot = Quaternion.Euler(y, x, 0);
                var po = rot * new Vector3(0.0f, 0.0f, -distance) + target.transform.position;
                transform.rotation = rot;
                transform.position = po;
            }
        }

        static float ClampAngle(float angle, float min, float max)
        {
            if (angle < -360)
                angle += 360;
            if (angle > 360)
                angle -= 360;
            return Mathf.Clamp(angle, min, max);
        }
    }
}

Put the script on your camera and specify a target

Thank you kind sir, works like a charm!

Nice, this is exactly what I was looking for.

Not sure but should this:

                if (Screen.dpi < 1) dpiScale = 1;
                if (Screen.dpi < 200) dpiScale = 1;
                else dpiScale = Screen.dpi / 200f;

be this?

                if (Screen.dpi < 1) dpiScale = 1;
                else if (Screen.dpi >= 200) dpiScale = 1;
                else dpiScale = Screen.dpi / 200f;

Thanks so much for this 3dIn!
I have a quick question...
I'm still learning coding so I wasn't able to see the answer as quick as you would. I need to clamp the distance the camera can zoom out from the scroll wheel. Something like just 8m. Maybe some kind of return.mathfClamp? Not sure where it would go or be implemented. Any thoughts here would be greatly appreciated!
Cheers
Jeff

Thanks so much for this 3dIn! I have a quick question... I'm still learning coding so I wasn't able to see the answer as quick as you would. I need to clamp the distance the camera can zoom out from the scroll wheel. Something like just 8m. Maybe some kind of return.mathfClamp? Not sure where it would go or be implemented. Any thoughts here would be greatly appreciated! Cheers Jeff

Add 2 variables (as well as a step per scroll) and switch the placement so you don't get the camera bumping when scrolling:

distance -= Input.GetAxis("Mouse ScrollWheel") * distanceStep; if (distance < minDistance) distance = minDistance; if (distance > maxDistance) distance = maxDistance;