Show colliders in a build game in Unity

Question

Is there a way to show all colliders 2D in a a released game at once? I am making a 2D game in Unity and have to show all colliders to the player. Can I use Gizmos?

Answer 1

Gizmos are only visible in the Editor, so that is not a solution.

Instead, you can render the colliders or (simulate rendering them) any number of ways.

BoxCollider2D

If your 2D colliders are boxes, this is pretty simple -- use a LineRenderer to render the collider's outline.

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

[RequireComponent(typeof(BoxCollider2D))]

public class DrawBoxCollider2D : MonoBehaviour
{
    [SerializeField] private GameObject linePrefab;
    LineRenderer lineRenderer;
    BoxCollider2D boxCollider2D;

    void Start()
    {
        lineRenderer = Instantiate(linePrefab).GetComponent<LineRenderer>();
        lineRenderer.transform.SetParent(transform);
        lineRenderer.transform.localPosition = Vector3.zero;
        boxCollider2D = GetComponent<BoxCollider2D>();
       
    }

    void Update()
    {
        HiliteBox();
    }

    void HiliteBox()
    {
        Vector3[] positions = new Vector3[4];
        positions[0] = transform.TransformPoint( new Vector3(boxCollider2D.size.x / 2.0f, boxCollider2D.size.y / 2.0f,0));
        positions[1] = transform.TransformPoint(new Vector3(-boxCollider2D.size.x / 2.0f, boxCollider2D.size.y / 2.0f,0));
        positions[2] = transform.TransformPoint(new Vector3(-boxCollider2D.size.x / 2.0f, -boxCollider2D.size.y / 2.0f,0));
        positions[3] = transform.TransformPoint(new Vector3(boxCollider2D.size.x / 2.0f, -boxCollider2D.size.y / 2.0f,0));
        lineRenderer.SetPositions(positions);
    }
}

Here's the set up to get this to work:

Sprite Setup:

Line Rendererer Prefab:

In action:

PolygonCollider 2D

Polygon colliders are only a little more complex. They can consist of several paths (to allow for holes); to make the code easy to follow and sheer expediency, my example will make the dumb assumption that there is only one path in the collider:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;


[RequireComponent (typeof(PolygonCollider2D))]
public class DrawPolygonCollider2D : MonoBehaviour
{
    [SerializeField] private GameObject linePrefab;
    LineRenderer lineRenderer;
    PolygonCollider2D polygonCollider2D;

    void Start()
    {
        lineRenderer = Instantiate(linePrefab).GetComponent<LineRenderer>();
        lineRenderer.transform.SetParent(transform);
        lineRenderer.transform.localPosition = Vector3.zero;
        polygonCollider2D = GetComponent<PolygonCollider2D>();

    }

    void Update()
    {
        HiliteCollider();
    }

    void HiliteCollider()
    {

        var points = polygonCollider2D.GetPath(0); // dumb assumption for demo -- only one path

        Vector3[] positions = new Vector3[points.Length];
        for(int i = 0; i < points.Length; i++)
        {
            positions[i] = transform.TransformPoint(points[i]);
        }
        lineRenderer.positionCount = points.Length;
        lineRenderer.SetPositions(positions);
    }
}

More info on PolygonCollider2D

Setup is the same; Result are like so: