From a23160f9f726ef070d481fa65bfff79bdcdd0aa3 Mon Sep 17 00:00:00 2001
From: Ryan Schmidt <rms@rms80.com>
Date: Sun, 24 Jun 2018 13:58:26 -0400
Subject: [PATCH] add fGameObjectPool, allows for re-use of GOs where we need a
 set of similar objects (eg like a bunch of polylines)

---
 GameObjectSet.cs            |  5 ---
 platform/fGameObjectPool.cs | 79 +++++++++++++++++++++++++++++++++++++
 2 files changed, 79 insertions(+), 5 deletions(-)
 create mode 100644 platform/fGameObjectPool.cs

diff --git a/GameObjectSet.cs b/GameObjectSet.cs
index 63ec5cd..55399fc 100644
--- a/GameObjectSet.cs
+++ b/GameObjectSet.cs
@@ -125,11 +125,6 @@ public virtual fGameObject AppendUnityPrimitiveGO(string name, PrimitiveType eTy
 		}
 
 
-        public virtual void RemoveGO(GameObject go)
-        {
-            vObjects.Remove(go);
-            go.transform.SetParent(null);
-        }
         public virtual void RemoveGO(fGameObject go)
         {
             vObjects.Remove(go);
diff --git a/platform/fGameObjectPool.cs b/platform/fGameObjectPool.cs
new file mode 100644
index 0000000..43351d6
--- /dev/null
+++ b/platform/fGameObjectPool.cs
@@ -0,0 +1,79 @@
+using System;
+using System.Collections.Generic;
+using g3;
+
+namespace f3
+{
+    /// <summary>
+    /// Pool of re-usable fGameObject instances, allocated by factory function you must provide to constructor.
+    /// Unused GOs are automatically parented to per-instance hidden parent GO, to avoid cluttering scene.
+    /// When a GO is freed, it is hidden.
+    /// When a GO is allocated from pool, it is set to have no parent, visible, and transform is cleared.
+    /// If ReinitializeF is set, this is also called on re-used GOs (*not* called on newly-allocated GOs as
+    ///    you can do that in your FactoryF)
+    /// </summary>
+    public class fGameObjectPool<T> where T : fGameObject
+    {
+        public Func<T> AllocatorFactoryF;
+        public Action<T> ReinitializeF;
+
+        fGameObject pool_parent;
+
+        List<T> Allocated;
+        List<T> Free;
+
+        public fGameObjectPool(Func<T> factoryF)
+        {
+            Allocated = new List<T>();
+            Free = new List<T>();
+
+            pool_parent = GameObjectFactory.CreateParentGO("pool_parent");
+
+            AllocatorFactoryF = factoryF;
+        }
+
+
+        public void Destroy()
+        {
+            foreach (var go in Allocated)
+                go.Destroy();
+            Allocated.Clear();
+            Free.Clear();
+            pool_parent.Destroy();
+        }
+
+
+        public T Allocate()
+        {
+            if (Free.Count > 0) {
+                T go = Free[Free.Count - 1];
+                Free.RemoveAt(Free.Count - 1);
+                go.SetParent(null);
+                go.SetVisible(true);
+                go.SetLocalFrame(Frame3f.Identity);
+                go.SetLocalScale(1.0f);
+                if (ReinitializeF != null)
+                    ReinitializeF(go);
+                return go;
+            } else {
+                T go = AllocatorFactoryF();
+                Allocated.Add(go);
+                return go;
+            }
+        }
+
+
+        public void FreeAll()
+        {
+            foreach (T go in Allocated) {
+                if (go.IsVisible()) {
+                    go.SetVisible(false);
+                    go.SetParent(pool_parent);
+                }
+            }
+            Free.Clear();
+            Free.AddRange(Allocated);
+        }
+
+    }
+}