Event.clickCount

설명

How many consecutive mouse clicks have we received.

Used in EventType.MouseDown event; use this to differentiate between a single and double clicks.

using UnityEngine;
using System.Collections;

public class ExampleClass : MonoBehaviour {
    void OnGUI() {
        Event e = Event.current;
        if (e.isMouse)
            Debug.Log("Mouse clicks: " + e.clickCount);
        
    }
}