Version: 2017.4
public bool alt ;

Description

Удерживается ли клавиша Alt/Option? (Read Only)

On Windows, this returns true if any Alt key is held down.
On Mac, this returns true if any Option key is held down.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour { void OnGUI() { Event e = Event.current; if (e.alt) if (Application.platform == RuntimePlatform.OSXEditor) Debug.Log("Option key was pressed"); else if (Application.platform == RuntimePlatform.WindowsEditor) Debug.Log("Alt Key was pressed!"); } }