From 786f057971468ea4dd187c402a49f47a3fa90d82 Mon Sep 17 00:00:00 2001
From: Wojtek Figat <wojtek@figat.pl>
Date: Sun, 3 Jan 2021 23:18:53 +0100
Subject: [PATCH] Fix crash on scripting reload when using Anim Graph with
 custom nodes

---
 Source/Engine/Animations/Graph/AnimGraph.cpp | 16 +++++++++++++++-
 Source/Engine/Animations/Graph/AnimGraph.h   |  5 ++++-
 2 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/Source/Engine/Animations/Graph/AnimGraph.cpp b/Source/Engine/Animations/Graph/AnimGraph.cpp
index c02161a07..2abbb3ff3 100644
--- a/Source/Engine/Animations/Graph/AnimGraph.cpp
+++ b/Source/Engine/Animations/Graph/AnimGraph.cpp
@@ -119,8 +119,9 @@ bool AnimGraph::Load(ReadStream* stream, bool loadMeta)
 
     // Register for scripts reloading events (only if using any custom nodes)
     // Handle load event always because anim graph asset may be loaded before game scripts
-    if (_customNodes.HasItems())
+    if (_customNodes.HasItems() && !_isRegisteredForScriptingEvents)
     {
+        _isRegisteredForScriptingEvents = true;
 #if USE_EDITOR
         Scripting::ScriptsReloading.Bind<AnimGraph, &AnimGraph::OnScriptsReloading>(this);
         Scripting::ScriptsReloaded.Bind<AnimGraph, &AnimGraph::OnScriptsReloaded>(this);
@@ -131,6 +132,19 @@ bool AnimGraph::Load(ReadStream* stream, bool loadMeta)
     return false;
 }
 
+AnimGraph::~AnimGraph()
+{
+    // Unregister for scripts reloading events (only if using any custom nodes)
+    if (_isRegisteredForScriptingEvents)
+    {
+#if USE_EDITOR
+        Scripting::ScriptsReloading.Unbind<AnimGraph, &AnimGraph::OnScriptsReloading>(this);
+        Scripting::ScriptsReloaded.Unbind<AnimGraph, &AnimGraph::OnScriptsReloaded>(this);
+#endif
+        Scripting::ScriptsLoaded.Unbind<AnimGraph, &AnimGraph::OnScriptsLoaded>(this);
+    }
+}
+
 bool AnimGraph::onParamCreated(Parameter* p)
 {
     if (p->Identifier == ANIM_GRAPH_PARAM_BASE_MODEL_ID)
diff --git a/Source/Engine/Animations/Graph/AnimGraph.h b/Source/Engine/Animations/Graph/AnimGraph.h
index 34050793a..714f6e9b8 100644
--- a/Source/Engine/Animations/Graph/AnimGraph.h
+++ b/Source/Engine/Animations/Graph/AnimGraph.h
@@ -733,7 +733,7 @@ private:
 
     typedef void (*InitBucketHandler)(AnimGraphInstanceData::Bucket&);
 
-    bool _isFunction;
+    bool _isFunction, _isRegisteredForScriptingEvents;
     int32 _bucketsCounter;
     Array<InitBucketHandler> _bucketInitializerList;
     Array<Node*> _customNodes;
@@ -751,9 +751,12 @@ public:
         , _isFunction(isFunction)
         , _bucketInitializerList(64)
         , _owner(owner)
+        , _isRegisteredForScriptingEvents(false)
     {
     }
 
+    ~AnimGraph();
+
 public:
 
     /// <summary>