Unity Layer Utility

ULayer.cs

using System.Collections.Generic;
using UnityEngine;

/**
 * LAYER UTIL - ONE SCRIPT TO HOUSE EVERY LAYER MASK, ETC.
 *
 * USAGE:
 *
 * - Add all of your layers to the ULayerType enum
 * - Update static getters to include all of your layers
 *
 * ```
 * ULayer.init(); // initialize the ULayer in Awake() or Start()
 * ULayer.Water.mask(); // get mask for Water layer
 * ULayer.Ground.value(); // get layer number for Ground layer
 * ```
 *
 * PROS:
 *
 * - one-time setup
 * - update single file when adding/updating layers
 * - warns if a layer does not exist
 * - allows for intellisense autosuggest for layers (e.g. start typing "Layer.Gr" to get the ground layer)
 *
 * CONS:
 *
 * - must initialize upon app start
 */

// -- ADD YOUR LAYERS HERE --
enum ULayerType {
    Ground,
    Water,
    UI,
}

public static class ULayer
{
    // -- ADD YOUR LAYERS HERE --
    public static ULayerMaskItem Ground => layerMaskItems[ULayerType.Ground.ToString()];
    public static ULayerMaskItem Water => layerMaskItems[ULayerType.Water.ToString()];
    public static ULayerMaskItem UI => layerMaskItems[ULayerType.UI.ToString()];

    static Dictionary<string, ULayerMaskItem> layerMaskItems = new Dictionary<string, ULayerMaskItem>();
    static bool initialized = false;

    /// <summary>Initialize layers (call in Awake or Start)</summary>
    public static void Init()
    {
        if (initialized) return;

        foreach(string name in System.Enum.GetNames(typeof(ULayerType))) {
            layerMaskItems.Add(name, new ULayerMaskItem(name) );
        }

        initialized = true;
    }
}

public struct ULayerMaskItem {
    public ULayerMaskItem(string layerName) {
        _name = layerName;
        _mask = LayerMask.GetMask(layerName);
        if (_mask == 0 && layerName != "Default") Debug.LogWarning("Warning: layer \"" + layerName + "\" may not exist");
    }
    string _name;
    int _mask;
    public string name => _name;
    public int mask => _mask;
    public int value => ULayerUtils.ToLayer(_mask);
    public bool ContainsLayer(int layer) { return ULayerUtils.LayerMaskContainsLayer(_mask, layer); }
    public override string ToString() { return _name + " | " + value + " | " + _mask; }
}

public static class ULayerUtils {
    // check to see whether a LayerMask contains a layer
    // see: https://answers.unity.com/questions/50279/check-if-layer-is-in-layermask.html
    public static bool LayerMaskContainsLayer(int mask, int layer) {
        bool contains = ((mask & (1 << layer)) != 0);
        return contains;
    }

    // get the layer num from a layermask
    // see: https://forum.unity.com/threads/get-the-layernumber-from-a-layermask.114553/#post-3021162
    public static int ToLayer(int layerMask) {
        int result = layerMask > 0 ? 0 : 31;
        while( layerMask > 1 ) {
            layerMask = layerMask >> 1;
            result++;
        }
        return result;
    }
}