// Calculate the reflection of a "laser beam" off a clicked object.
    
    // The object from which the beam is fired. The incoming beam will
    // not be visible if the camera is used for this!
    var gunObj: Transform;
    
    
    function Update () {
        if (Input.GetMouseButton(0)) {
            var hit: RaycastHit;
            var ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            
            if (Physics.Raycast(ray, hit)) {
                // Find the line from the gun to the point that was clicked.
                var incomingVec = hit.point - gunObj.position;
                
                // Use the point's normal to calculate the reflection vector.
                var reflectVec = Vector3.Reflect(incomingVec, hit.normal);
                
                // Draw lines to show the incoming "beam" and the reflection.
                Debug.DrawLine(gunObj.position, hit.point, Color.red);
                Debug.DrawRay(hit.point, reflectVec, Color.green);
            }
        }
    }

using UnityEngine;
using System.Collections;

public class example : MonoBehaviour {
    public Transform gunObj;
    void Update() {
        if (Input.GetMouseButton(0)) {
            RaycastHit hit;
            Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
            if (Physics.Raycast(ray, out hit)) {
                Vector3 incomingVec = hit.point - gunObj.position;
                Vector3 reflectVec = Vector3.Reflect(incomingVec, hit.normal);
                Debug.DrawLine(gunObj.position, hit.point, Color.red);
                Debug.DrawRay(hit.point, reflectVec, Color.green);
            }
        }
    }
}

import UnityEngine
import System.Collections

class example(MonoBehaviour):

    public gunObj as Transform

    def Update():
        if Input.GetMouseButton(0):
            hit as RaycastHit
            ray as Ray = Camera.main.ScreenPointToRay(Input.mousePosition)
            if Physics.Raycast(ray, hit):
                incomingVec as Vector3 = (hit.point - gunObj.position)
                reflectVec as Vector3 = Vector3.Reflect(incomingVec, hit.normal)
                Debug.DrawLine(gunObj.position, hit.point, Color.red)
                Debug.DrawRay(hit.point, reflectVec, Color.green)