CustomMaterialEditor - Unity

CustomMaterialEditor.cs

//Copyright(c) 2015 Phil Lira - phil.rlira [at] gmail [dot] com

//Permission is hereby granted, free of charge, to any person obtaining a copy
//of this software and associated documentation files (the "Software"), to deal
//in the Software without restriction, including without limitation the rights
//to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
//copies of the Software, and to permit persons to whom the Software is
//furnished to do so, subject to the following conditions:

//The above copyright notice and this permission notice shall be included in all
//copies or substantial portions of the Software.

using UnityEngine;
using UnityEditor;

// Custom Material Inspector to allow manual rendering sorting per material
// In order to use it add the following line in the shader you want a custom inspector:
// CustomEditor "CustomMaterialEditor"

// for more info on custom inspectors see the following link:
// http://docs.unity3d.com/460/Documentation/Manual/SL-CustomMaterialEditors.html
public class CustomMaterialEditor : MaterialEditor
{
    private bool _OverrideSorting;
    private Material _Material;
    private string[] _LayerOptions = {"Background", "Opaque", "Transparent", "Overlay"};

    private int _LayerID;
    private int _LayerOrder;

    public override void OnEnable()
    {
        base.OnEnable();
        _Material = (target as Material);

        if (_Material.renderQueue > -1)
        {
            _LayerID = (_Material.renderQueue / 1000) - 1;
            _LayerOrder = _Material.renderQueue % 1000;

            // There's no means to query if the current settings is equal to shader. So we check if 
            // order in layer is 0 and assume no override is wanted in that case.
            _OverrideSorting = (_LayerOrder > 0);
        }
        else
        {
            _OverrideSorting = false;
        }
    }

    public override void OnInspectorGUI()
    {
        if (_Material != null)
        {
            // Setting Material.renderQueue to -1 tells Unity to use value from shader.
            int _RenderQueue = -1;
            int layerID = _LayerID;
            int layerOrder = _LayerOrder;

            _OverrideSorting = EditorGUILayout.Toggle("Override Sorting", _OverrideSorting);
            if (_OverrideSorting)
            {
                layerID = EditorGUILayout.Popup("Layer", _LayerID, _LayerOptions);
                layerOrder = Mathf.Max(0, EditorGUILayout.IntField("Order", _LayerOrder));
                _RenderQueue = ((layerID + 1) * 1000) + layerOrder;
            }

            if (GUI.changed)
            {
                if (_OverrideSorting == false || layerID != _LayerID || layerOrder != _LayerOrder)
                {
                    _LayerID = layerID;
                    _LayerOrder = layerOrder;

                    Undo.RecordObject(_Material, "SortOrder");
                    _Material.renderQueue = _RenderQueue;
                    EditorUtility.SetDirty(_Material);
                }
            }
        }
        base.OnInspectorGUI();
    }
}