Unity 2D Trail Renderer Collision

Question

I making 2D unity game but I am facing a major issue which my game depends on.

I attached a trail renderer component to my player and what I need is to make the renderer be a collider act as a MeshCollider I just didn't figure out if it is possible to make a collider to take the shape of a 2D trail renderer.

I've searched over google but didn't have a well performing solution:

• Some say create an empty gameobject attach the trail renderer component then add a collider to it. But doesn't work neither.
• I tried to follow this WIKI and My Trail Renderer collides but is not nice but I need to assign the tag to the trail too.

Is there some script I can write to achieve my goal Or UnityEngine has a render solution.Thanks in advance.

EDIT1:

After I copied the script and run it The trail collides but it acts goofy when player is not moving.

EDIT2:

The game basically is a player that has transform.position equal to the mouse position.So the trail doesn't have a specific length.

Answer 1

The way I would do it is the following:

Create a script and attach it to the object that the trail follows.

Create a prefab of empty gameObject with collider the size of your trail and attach it to the script.

public TrailRenderer trail; //the trail
public GameObject TrailFollower;
public GameObject ColliderPrefab;

Create a pool of the collider prefab (the more you use the more expensive it is, but more accurate.)

public int poolSize=5;
GameObject[] pool;

void Start()
{
    trail = GetComponent<TrailRenderer>();
    pool = new GameObject[poolSize];
    for (int i = 0; i < pool.Length; i++)
    {
        pool[i] = Instantiate(ColliderPrefab);
    }
}

now while updating the game you should do the following:

 void Update () {
    if (!trail.isVisible)
    {
        for (int i = 0; i < pool.Length; i++)
        {
            pool[i].gameObject.SetActive(false);

        }
    }
    else
    {
        TrailCollission();
    }

}

void TrailCollission()
{
    for (int i = 0; i < pool.Length; i++)
    {
        if (pool[i].gameObject.activeSelf == false)
        {
            pool[i].gameObject.SetActive(true);
            pool[i].gameObject.transform.position = TrailFollower.gameObject.transform.position;
            return;
        }
    }
}

1. check if trail is being drawn on screen, if not, hide all colliders.

2. else, run on the pool and search for hidden collider.

3. when found hidden collider make it visible on the position of the trail gameObject.

(if not all the trail disappear at once you can also add iEnumerator that will hide it after the required time).

By making the pool bigger the chance for missing colliders will be lowered, play around with it until you find something that suits your needs.

edit:

To make Colliders hide after some time do this:

private IEnumerator hide(float waitTime, GameObject p)
{
    while (true)
    {
        yield return new WaitForSeconds(waitTime);
        p.SetActive(false);

        yield break;
    }
    yield break;
}

call this after setting their position

hide(time,pool[i].gameObject);
StartCoroutine(hide);

Answer 2

Here is another trick make a script that creates circle colliders (Maybee not the perfect, but a well solution);

The script will instantiate circle collider gameObject that sticks to its initial instantiated position(doesn't change position), enlarge and shrink the circle collider gameObject according to the TrailRenderer width graph in the inspector, and the circle collider will destroy it self when its lifetime is equal to the TrailRenderer's lifetime.