Laser

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.Experimental.Rendering.Universal;

public class TestLaser : MonoBehaviour
{

    public int maxRecursions = 10;
    public float maxStepDistance = 200;

    float airIndex = 1.0f;
    public float glassIndex = 1.5f;

    public GameObject laserToSpawn;


    // Update is called once per frame
    private void OnDrawGizmos() //Update()
    {
        if (!Application.isPlaying)
        {
            return;
        }
        foreach (GameObject laser in GameObject.FindGameObjectsWithTag("Laser")) //every update redraw laser
        {
            laser.SetActive(false);
        }


        DrawPredictedReflection(this.transform.position, this.transform.up, maxRecursions);
    }

    void DrawPredictedReflection(Vector2 position, Vector2 direction, int recursionsRemaing)// int reflectionsRemaining, int splitsRemaining)
    {

        var gizmoHue = (recursionsRemaing / (this.maxRecursions + 1f));

        RaycastHit2D hit2D = Physics2D.Raycast(position, direction, maxStepDistance);

        if (hit2D) //did we hit somthing?
        {

            DrawLaser(position, hit2D.point); //draw a line to it

            if (hit2D.transform.gameObject.tag == "Lens")
            {
                //Debug.Log("Lens Hit...");
                Refract(hit2D.normal, direction, hit2D.point, hit2D.transform.gameObject, recursionsRemaing, airIndex, glassIndex);
            }
        }
        else //nothing hit
        {
            DrawLaser(position, position + direction * maxStepDistance);
        }
    }

    void DrawLaser(Vector2 start, Vector2 end)
    {

        GameObject laser = ObjectPooler.SharedInstance.GetPooledObject("Laser");
        if (laser != null)
        {

            laser.transform.position = Vector2.zero;
            laser.transform.rotation = Quaternion.identity;
            LineRenderer lr = laser.GetComponent<LineRenderer>();
            lr.SetPosition(0, start);
            lr.SetPosition(1, end);
            lr.startColor = Color.white;
            lr.endColor = Color.white;
            laser.SetActive(true);
        }
    }

    void Refract(Vector2 normal, Vector2 direction, Vector2 point, GameObject lastHit, int recursionsRemainging, float n1, float n2)
    {
        float angleOfIncidence = Vector2.Angle(normal, -direction);
        //Debug.Log("Angle of incidence = " + angleOfIncidence);
        float angleOfRefraction = Mathf.Asin((n1 * Mathf.Sin(angleOfIncidence * Mathf.Deg2Rad)) / n2) * Mathf.Rad2Deg; //snells law
        //Debug.Log("Angle of refraction = " + angleOfRefraction);


        Gizmos.color = Color.blue;
        Gizmos.DrawLine(point + normal * 0.1f, point - normal * 0.1f);


        //

        Vector2 testPoint = RotatePointByDeg(point, normal, angleOfIncidence); //laser comming before refraction
        Gizmos.color = Color.red;
        Gizmos.DrawLine(point, testPoint);

        //

        //

        testPoint = RotatePointByDeg(point, -normal, angleOfRefraction); //laser going after refraction
        Gizmos.color = Color.cyan;
        Gizmos.DrawLine(point, testPoint);

        //



    }


    Vector3 RotatePointByDeg(Vector2 origin, Vector2 normal, float angle) //rotate a point about its pivot which should be where the laser hit
    {
        Vector3 pointToRotate = origin + normal * .1f;
        Vector3 pivot = origin;
        Vector3 angles = new Vector3(0, 0, angle);
        Vector3 dir = pointToRotate - pivot;
        dir = Quaternion.Euler(angles) * dir;
        pointToRotate = dir + pivot;
        return pointToRotate;
    }
}