GameViewのカメラを、SceneViewのカメラと同じような操作感で動かせるスクリプト for Unity

SceneCameraController.cs

using UnityEngine;

[RequireComponent(typeof(Camera))]
public class SceneCameraController : MonoBehaviour
{
    public Vector3 targetPoint; // 注視点
    public float rotateSpeed = 10;
    public float translateSpeed = 1;
    public float zoomSpeed = 5;

    private bool _lastFocused;  
    
    private void Start()
    {
        targetPoint = transform.position + Vector3.forward * 10f;
    }
    
    private void Update()
    {
        // シーンビューにフォーカスを合わせてスクロールするとゲームビューには反映されないが
        // ゲームビューにフォーカスされたときにシーンビュー上でのスクロールがまとめて返される@Unity2022.3.3f1
        // そのため、ゲームビューにフォーカスされたときは無視する
        var focused = Application.isFocused;
        if (focused && _lastFocused)
        {
            ApplyInput();
        }

        _lastFocused = focused;
    }
    
    private void ApplyInput()
    {
        var mouseX = Input.GetAxis("Mouse X");
        var mouseY = Input.GetAxis("Mouse Y");
        var mouseWheelScroll = Input.GetAxis("Mouse ScrollWheel");

        var isControlAndCommand = Input.GetKey(KeyCode.LeftControl) || Input.GetKey(KeyCode.RightControl) || Input.GetKey(KeyCode.LeftCommand) || Input.GetKey(KeyCode.RightCommand);
        var isAlt = Input.GetKey(KeyCode.LeftAlt) || Input.GetKey(KeyCode.RightAlt);
        var isShift = Input.GetKey(KeyCode.LeftShift) || Input.GetKey(KeyCode.RightShift);

        var trans = transform;
        
        // 平行移動
        if (Input.GetMouseButton(2) || (isAlt && isControlAndCommand))
        {
            var move = new Vector3(-mouseX, -mouseY, 0f) * translateSpeed;
            var moveWorld = trans.TransformVector(move);

            // World XZ平面平行移動
            if (isShift) moveWorld.y = 0f;

            targetPoint += moveWorld;

            trans.Translate(moveWorld, Space.World);
        }

        // ズーム
        if (mouseWheelScroll != 0)
        {
            var moveWorld = trans.forward * (mouseWheelScroll * zoomSpeed);

            // World XZ平面平行移動
            if (isShift) moveWorld.y = 0f;

            trans.Translate(moveWorld, Space.World);

            var dist = Vector3.Distance(trans.position, targetPoint);
            if (dist <= 1f)
            {
                targetPoint = trans.position + trans.forward * 1f;
            }
        }


        // 回転
        if (Input.GetMouseButton(1))
        {
            var pos = trans.position;
            var dist = Vector3.Distance(pos, targetPoint);

            // trans.rotation = Quaternion.AngleAxis(rotateSpeed * -mouseY, trans.right) * trans.rotation;
            // trans.rotation = Quaternion.AngleAxis(rotateSpeed * mouseX, Vector3.up) * trans.rotation;
            trans.Rotate(Vector3.right, rotateSpeed * -mouseY);
            trans.Rotate(Vector3.up, rotateSpeed * mouseX, Space.World);

            targetPoint = pos + trans.forward * dist;
        }


        // 注視点の周りを回る
        if (Input.GetMouseButton(0) && !isControlAndCommand && isAlt)
        {
            trans.RotateAround(targetPoint, trans.right, -mouseY * rotateSpeed);
            trans.RotateAround(targetPoint, Vector3.up, mouseX * rotateSpeed);
        }
    }
}