using UnityEngine;
using System.Collections;

public class RotateMe : MonoBehaviour
{

    public float speed = 0.5f;
    public Transform rotorY;
    public Transform rotorX;

    private Vector3 dragStart;
    private Vector3 dragDelta;
    private Vector3 initialEulers;

    void Start()
    {
        dragDelta = Vector3.zero;
    }

    void Update()
    {
        //start mouse drag
        if (Input.GetMouseButtonDown(0))
        {
            dragStart = Input.mousePosition;
            initialEulers = new Vector3(rotorX.localEulerAngles.x, rotorY.localEulerAngles.y, 0f);
        }
        //drag process
        else if (Input.GetMouseButton(0))
        {
            //find amount of drag
            dragDelta = Input.mousePosition - dragStart;

            //apply y rotation
            Vector3 eulers = rotorY.localEulerAngles;
            eulers.y = initialEulers.y - dragDelta.x * speed;
            rotorY.localEulerAngles = eulers;

            //apply x rotation
            eulers = rotorX.localEulerAngles;
            eulers.x = initialEulers.x + dragDelta.y * speed;

            //Unity 5.5.0: bring rotation range to [-180, 180] interval, instead of default [0, 360]
            if (eulers.x > 180f)
                eulers.x -= 360f;

            eulers.x = Mathf.Clamp(eulers.x, -89.9f, 89.9f);    //so that rotation does not go on vertical flip
            rotorX.localEulerAngles = eulers;
        }
    }
}