From 2fa381e2cb95abf4efd71d579973582ad1140e73 Mon Sep 17 00:00:00 2001
From: Ahmed Shariff <shariff.mfa@outlook.com>
Date: Mon, 8 Jan 2024 00:23:25 -0800
Subject: [PATCH] Add z order for HPUI Interactables

---
 Editor/HPUIBaseInteractableEditor.cs        | 4 ++++
 Runtime/Interaction/HPUIBaseInteractable.cs | 7 +++++++
 Runtime/Interaction/HPUIInteractor.cs       | 9 ++++-----
 Runtime/Interaction/IHPUIInteractable.cs    | 5 +++++
 4 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/Editor/HPUIBaseInteractableEditor.cs b/Editor/HPUIBaseInteractableEditor.cs
index 624c19d..5fc0029 100644
--- a/Editor/HPUIBaseInteractableEditor.cs
+++ b/Editor/HPUIBaseInteractableEditor.cs
@@ -54,5 +54,9 @@ protected override List<string> GetDerivedSerializedPropertyNames()
             props.AddRange(EventPropertyNames);
             return props;
         }
+
+        /// <inheritdoc />
+        protected override void DrawSelectionConfiguration()
+        {}
     }
 }
diff --git a/Runtime/Interaction/HPUIBaseInteractable.cs b/Runtime/Interaction/HPUIBaseInteractable.cs
index 97db364..78cf505 100644
--- a/Runtime/Interaction/HPUIBaseInteractable.cs
+++ b/Runtime/Interaction/HPUIBaseInteractable.cs
@@ -24,6 +24,12 @@ public Handedness Handedness
 
         public Collider boundsCollider;
 
+        [SerializeField]
+        private int _zOrder;
+
+        /// <inheritdoc />
+        public int zOrder { get => _zOrder; set => _zOrder = value; }
+
         [SerializeField]
         private HPUITapEvent tapEvent = new HPUITapEvent();
 
@@ -48,6 +54,7 @@ protected override void Awake()
         {
             base.Awake();
             getDistanceOverride = GetDistanceOverride;
+            selectMode = InteractableSelectMode.Single;
         }
 
         /// <inheritdoc />
diff --git a/Runtime/Interaction/HPUIInteractor.cs b/Runtime/Interaction/HPUIInteractor.cs
index 0771c44..d3c9ac4 100644
--- a/Runtime/Interaction/HPUIInteractor.cs
+++ b/Runtime/Interaction/HPUIInteractor.cs
@@ -1,5 +1,6 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using UnityEngine;
 using UnityEngine.Pool;
 using UnityEngine.XR.Hands;
@@ -87,12 +88,10 @@ public override void GetValidTargets(List<IXRInteractable> targets)
             List<IXRInteractable> recievedTargets = ListPool<IXRInteractable>.Get();
             recievedTargets.AddRange(targets);
 
-            foreach(IXRInteractable target in recievedTargets)
+            targets.Clear();
+            foreach(IXRInteractable target in recievedTargets.Select(t => t as IHPUIInteractable).Where(ht => ht != null).OrderBy(ht => ht.zOrder))
             {
-                if (!(target is HPUIBaseInteractable hpuiTarget) || hpuiTarget.Handedness != handedness)
-                {
-                    targets.Remove(target);
-                }
+                targets.Add(target);
             }
             ListPool<IXRInteractable>.Release(recievedTargets);
         }
diff --git a/Runtime/Interaction/IHPUIInteractable.cs b/Runtime/Interaction/IHPUIInteractable.cs
index b8499a9..f227b21 100644
--- a/Runtime/Interaction/IHPUIInteractable.cs
+++ b/Runtime/Interaction/IHPUIInteractable.cs
@@ -5,6 +5,11 @@ namespace ubco.ovilab.HPUI.Interaction
 {
     public interface IHPUIInteractable : IXRInteractable, IXRSelectInteractable
     {
+        /// <summary>
+        /// Lower z order will get higher priority.
+        /// </summary>
+        int zOrder { get; set; }
+
         /// <summary>
         /// Get the projection of the interactors position on the xz plane of this interactable, normalized.
         /// the returned Vector2 - (x, z) on the xz-plane.