ForceUITextMask.cs

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

#if UNITY_EDITOR
using UnityEditor;
[ExecuteInEditMode]
#endif

[RequireComponent(typeof(Text), typeof(SpriteMaskingComponent))]
public class ForceUITextMask : MonoBehaviour
{
  Text text;
  SpriteMaskingComponent link;

  private Material mat;

  const string SHADER_UI_UNLIT_TEXT = "UI/Unlit/Text";
  const string STR_STENCIL_ID = "_Stencil";
  const string STR_STENCIL_COMPARISON = "_StencilComp";

  private int propertyStencilID;
  private int propertyStencilComp;

  public int curOwnerInstanceID { get; private set; }
  public int curStencilID { get; private set; }
  public int curStencilComp { get; private set; }
  public int curRenderQueue { get; private set; }

  void Reset()
  {
    mat = null;
    curOwnerInstanceID = 0;
  }

  // Use this for initialization
  void Start ()
  {
    text = GetComponent<Text>();
    link = GetComponent<SpriteMaskingComponent>();
    var temp = GetComponent<CanvasRenderer>();

    propertyStencilID = Shader.PropertyToID(STR_STENCIL_ID);
    propertyStencilComp = Shader.PropertyToID(STR_STENCIL_COMPARISON);

    updateMaterial();
  }

  public void OnRenderObject()
  {
    updateMaterial();
  }

  public void updateMaterial()
  {
    // Don't do anything if we have no SpriteMask to refer to
    if(link == null || link.owner == null)
    {
      mat = null;
      return;
    }

    // Reset if owner changed
    if(curOwnerInstanceID != link.owner.GetInstanceID())
    {
      curOwnerInstanceID = link.owner.GetInstanceID();
      mat = null;
    }

    // Make sure we have an updated material
    if (mat != text.material)
    {
      mat = new Material(Shader.Find(SHADER_UI_UNLIT_TEXT));

      mat.name += " OWNER_ID: " + curOwnerInstanceID;
      text.material = mat;
    }

    curStencilID = link.owner.stencilId;
    mat.SetInt(propertyStencilID, curStencilID);

    curStencilComp = 3;
    mat.SetInt(propertyStencilComp, curStencilComp);

    curRenderQueue = link.owner.maskRenderQueue;
    mat.renderQueue = curRenderQueue;
  }

  void Update () {
		
	}

  void OnDestroy()
  {
    if(mat == text.material)
    {
      text.material = null;
    }
  }
#if UNITY_EDITOR

#endif
}



#if UNITY_EDITOR
[CustomEditor(typeof(ForceUITextMask))]
public class ForceUITextMaskEditor : Editor
{

  public override void OnInspectorGUI()
  {
    ForceUITextMask force = (ForceUITextMask)target;
    force.updateMaterial();

    base.OnInspectorGUI();

    string msg = "Instance ID: " + force.curOwnerInstanceID + "\n"
               + "Stencil ID: " + force.curStencilID + "\n"
               + "Stencil Comp: " + force.curStencilComp + "\n"
               + "Render Queue: " + force.curRenderQueue;

    EditorGUILayout.HelpBox(msg, MessageType.None);
  }

}
#endif