Layer manager script from Shadow Play. This is used in a Unity scene to stop the player or other interactable objects from colliding with objects that aren't on their layer

ActiveLayerManager

using System;
using UnityEngine;

public class ActiveLayerManager : MonoBehaviour
{
    [SerializeField]
    int activeLayerID = 0;
    [SerializeField]
    GameObject player;
    SpriteRenderer playerSpriteRenderer;
    [SerializeField]
    //TODO: This really should just be compiste colliders 2D
    GameObject[] colliders;
    // Start is called before the first frame update
    void Start()
    {
        playerSpriteRenderer = player.GetComponent<SpriteRenderer>();
        activeLayerID = playerSpriteRenderer.sortingOrder;
        //for (int i = 0; i < colliders.Length; i++)
        //{
        //    colliders[i].SetActive(false);
        //}
        //colliders[activeLayerID].SetActive(true);

    }

    public void IncrementActiveLayer()
    {
        throw new NotImplementedException();
        colliders[activeLayerID].SetActive(false);
        activeLayerID++;
        colliders[activeLayerID].SetActive(true);
        colliders[activeLayerID].GetComponent<CompositeCollider2D>().GenerateGeometry();
        playerSpriteRenderer.sortingOrder = activeLayerID;
    }

    public void DecrementActiveLayer()
    {
        throw new NotImplementedException();

        colliders[activeLayerID].SetActive(false);
        activeLayerID--;
        colliders[activeLayerID].SetActive(true);
        colliders[activeLayerID].GetComponent<CompositeCollider2D>().GenerateGeometry();
        playerSpriteRenderer.sortingOrder =activeLayerID;
    }

    public void IgnoreCollisionsBetweenInteractableObjectAndOtherCollisionLayers(InteractableObject gameObject)
    {
        Collider2D gameObjectCollider = gameObject.GetComponent<Collider2D>();
        for (int i = 0; i < colliders.Length; i++)
        {
            if(i != gameObject.getLayer())
            {
                Physics2D.IgnoreCollision(gameObjectCollider, colliders[i].GetComponent<CompositeCollider2D>());
            }

            if(i == gameObject.getLayer())
            {
                Physics2D.IgnoreCollision(gameObjectCollider, colliders[i].GetComponent<CompositeCollider2D>(), false);            
            }
        }
    }

    public void IgnoreCollisionsBetweenCharacterAndOtherCollisionLayers(Character gameObject)
    {
        Collider2D gameObjectCollider = gameObject.GetComponent<Collider2D>();
        SpriteRenderer spriteRenderer = gameObject.GetComponent<SpriteRenderer>();

        for (int i = 0; i < colliders.Length; i++)
        {
            if(i != spriteRenderer.sortingOrder)
            {
                Physics2D.IgnoreCollision(gameObjectCollider, colliders[i].GetComponent<CompositeCollider2D>());
            }

            if(i == spriteRenderer.sortingOrder)
            {
                Physics2D.IgnoreCollision(gameObjectCollider, colliders[i].GetComponent<CompositeCollider2D>(), false);             
            }
        }

        if(spriteRenderer.sortingOrder != 0)
        {
            Physics2D.IgnoreLayerCollision(0, 8);
        }
        else
        {
            Physics2D.IgnoreLayerCollision(0, 8, false);
        }
    }

    /// <summary>
    ///Use this function if you want to block collisions between a character and colliders but using a set layer that is different than it's sorting layer
    /// </summary>
    /// <param name="gameObject"></param>
    /// <param name="customLayer"></param>
    public void IgnoreCollisionsBetweenCharacterAndOtherCollisionLayers(Character gameObject, int customLayer)
    {
        Collider2D gameObjectCollider = gameObject.GetComponent<Collider2D>();

        for (int i = 0; i < colliders.Length; i++)
        {
            if(i != customLayer)
            {
                Physics2D.IgnoreCollision(gameObjectCollider, colliders[i].GetComponent<CompositeCollider2D>());
            }

            if(i == customLayer)
            {
                Physics2D.IgnoreCollision(gameObjectCollider, colliders[i].GetComponent<CompositeCollider2D>(), false);            
            }
        }
    }

    public bool IsColliderAboveObject(int layer, CompositeCollider2D colliderToCheck)
    {
        bool foundCollider = false;
        int colliderIndex = int.MaxValue;
        //Quick sanity check to ensure we actaully have stored that collider
        for (int i = 0; i < colliders.Length; i++)
        {
            if (colliders[i].GetComponent<CompositeCollider2D>() == colliderToCheck)
            {
                foundCollider = true;
                colliderIndex = i;
                break;
            }
        }

        if(!foundCollider)
        {
            Debug.LogError("ERROR: Collider was not found in layer manager!");
        }

        if(layer == colliderIndex)
        {
            return false;
        }

        if(layer < colliderIndex)
        {
            return true;
        }

        //If we hit this the collider must be below the object (unlikely to happen)
        return false;
    }

}