Raycast 2D ricochet in Unity? - unity3d

Question

I'm new to Raycasting so I might be going about this in a bad way, but I would to send a raycast outward to direction a gameobject is facing, bounce off the first object it hits and go a short distance before disappearing.
As far as I can tell there is no built in function for reflecting raycasts in Unity, so I have been trying to generate a another raycast where the first one hits but my luck hasn't been going well. Here's what I have so far:
public Gameobject firePoint; // I have an object attached to my main object that I use as a point of origin
void DrawLazer()
{
Vector2 origin = new Vector2(firePoint.transform.position.x, firePoint.transform.position.y);
Vector2 direction = transform.TransformDirection(Vector2.up);
RaycastHit2D hit = Physics2D.Raycast(origin, direction, 10f);
Debug.DrawLine(origin, direction *10000, Color.black);
if (hit)
{
Debug.Log("Hit: " + hit.collider.name);
var whatWeHit = new Vector2(hit.transform.position.x, hit.transform.position.y);
var offset = whatWeHit + hit.point;
offset.y = 0;
RaycastHit2D hit2 = Physics2D.Raycast(offset, Vector3.Reflect(direction, hit.normal) * -10000);
if (hit2)
{
Debug.DrawLine(offset, -Vector3.Reflect(direction, hit.normal) * -10000);
}
}
}
I call DrawLaxer(); in update.
This current script is sort of able to generate a 2nd raycast, however as you can see, the first raycast still does not stop when it hits something, and more importantly while this solution works well when it hits a flat object on a horizontal plane. But if it hits on object on a vertical or diagonal plane it applys several calculations to the wrong axis:
Any help would be greatly appreciated.

Answer 1

Here is a complete example monobehavior that uses Vector2.Reflect and SphereCast.
using System.Collections;
using System.Collections.Generic;
using UnityEngine;
public class ReflectionExample : MonoBehaviour
{
public GameObject firePoint;
// Start is called before the first frame update
void Start()
{
}
// Update is called once per frame
void Update()
{
DrawPredictionDisplay();
}
private void DrawPredictionDisplay()
{
Vector2 origin = firePoint.transform.position; //unity has a built in type converter that converts vector3 to vector2 by dropping the z component
Vector2 direction = firePoint.transform.up;
float radius = 1.0f;
RaycastHit2D distanceCheck = Physics2D.Raycast(origin, direction);
RaycastHit2D hit = Physics2D.CircleCast(origin, radius, direction);
Debug.DrawLine(origin, direction * 10000, UnityEngine.Color.black);
DrawCircle(origin, 1.0f, UnityEngine.Color.black);
if (hit)
{
origin = hit.point + (hit.normal * radius);
direction = Vector2.Reflect(direction, hit.normal);
hit = Physics2D.CircleCast(origin, radius, direction);
Debug.DrawLine(origin, direction * 10000, UnityEngine.Color.blue);
DrawCircle(origin, 1.0f, UnityEngine.Color.blue);
}
}
private void DrawCircle(Vector2 center, float radius, UnityEngine.Color color)
{
Vector2 prevPoint = new Vector2(Mathf.Sin(0f), Mathf.Cos(0f));
for (float t = 0.1f; t < 2 * Mathf.PI; t = t + 0.1f)
{
var nextPoint = new Vector2(Mathf.Sin(t), Mathf.Cos(t));
Debug.DrawLine(center + prevPoint, center + nextPoint, color);
prevPoint = nextPoint;
}
}
}