From 91de09cff532b066938d34c832afd3306c1188c2 Mon Sep 17 00:00:00 2001
From: Benjamin Jillich <43751992+amzn-jillich@users.noreply.github.com>
Date: Mon, 12 Jul 2021 23:32:35 -0700
Subject: [PATCH] EMotion FX: Root bone not initialized without opening Scene
 Settings (#2088)

* User provided model was exporting correctly with an .assetinfo while it was not when just placing the .fbx file in the project folder.
* Turned out that the best matching root bone was set by opening the Scene Settings for the first time, so after saving it again it worked correctly.
* We're now chosing the best matching root bone when initializing the actor group, which fixes the issue.

Signed-off-by: Benjamin Jillich <jillich@amazon.com>
---
 .../Behaviors/ActorGroupBehavior.cpp          |  1 +
 .../SceneAPIExt/Groups/ActorGroup.cpp         | 20 +++++++++++++++++++
 .../Pipeline/SceneAPIExt/Groups/ActorGroup.h  |  2 +-
 .../Pipeline/SceneAPIExt/Groups/IActorGroup.h |  6 ++++++
 4 files changed, 28 insertions(+), 1 deletion(-)

diff --git a/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Behaviors/ActorGroupBehavior.cpp b/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Behaviors/ActorGroupBehavior.cpp
index c3202398b4..1e9c14d2e0 100644
--- a/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Behaviors/ActorGroupBehavior.cpp
+++ b/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Behaviors/ActorGroupBehavior.cpp
@@ -143,6 +143,7 @@ namespace EMotionFX
 
                 Group::ActorGroup* group = azrtti_cast<Group::ActorGroup*>(&target);
                 group->SetName(AZ::SceneAPI::DataTypes::Utilities::CreateUniqueName<Group::IActorGroup>(scene.GetName(), scene.GetManifest()));
+                group->SetBestMatchingRootBone(scene.GetGraph());
 
                 // LOD Rule need to be built first in the actor, so we know which mesh and bone belongs to LOD.
                 // After this call, LOD rule will be populated with all the LOD bones
diff --git a/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/ActorGroup.cpp b/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/ActorGroup.cpp
index e4065f58e0..b623086bc1 100644
--- a/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/ActorGroup.cpp
+++ b/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/ActorGroup.cpp
@@ -9,10 +9,14 @@
 #include <AzCore/Memory/SystemAllocator.h>
 #include <AzCore/Serialization/SerializeContext.h>
 #include <AzCore/Serialization/EditContext.h>
+#include <SceneAPI/SceneCore/Containers/SceneGraph.h>
+#include <SceneAPI/SceneCore/Containers/Views/PairIterator.h>
+#include <SceneAPI/SceneCore/Containers/Views/SceneGraphDownwardsIterator.h>
 #include <SceneAPI/SceneCore/DataTypes/Rules/IRule.h>
 #include <SceneAPI/SceneCore/DataTypes/GraphData/IBoneData.h>
 #include <SceneAPI/SceneCore/DataTypes/GraphData/IMeshData.h>
 #include <SceneAPI/SceneCore/DataTypes/Groups/ISceneNodeGroup.h>
+#include <SceneAPI/SceneData/GraphData/RootBoneData.h>
 #include <SceneAPI/SceneCore/Utilities/Reporting.h>
 #include <SceneAPI/SceneData/Rules/CoordinateSystemRule.h>
 #include <SceneAPIExt/Groups/ActorGroup.h>
@@ -76,6 +80,22 @@ namespace EMotionFX
                 m_selectedRootBone = selectedRootBone;
             }
 
+            void ActorGroup::SetBestMatchingRootBone(const AZ::SceneAPI::Containers::SceneGraph& sceneGraph)
+            {
+                auto nameContentView = AZ::SceneAPI::Containers::Views::MakePairView(sceneGraph.GetNameStorage(), sceneGraph.GetContentStorage());
+                auto graphDownwardsView = AZ::SceneAPI::Containers::Views::MakeSceneGraphDownwardsView<AZ::SceneAPI::Containers::Views::BreadthFirst>(
+                    sceneGraph, sceneGraph.GetRoot(), nameContentView.begin(), true);
+
+                for (auto it = graphDownwardsView.begin(); it != graphDownwardsView.end(); ++it)
+                {
+                    if (it->second && it->second->RTTI_IsTypeOf(AZ::SceneData::GraphData::RootBoneData::TYPEINFO_Uuid()))
+                    {
+                        SetSelectedRootBone(it->first.GetPath());
+                        return;
+                    }
+                }
+            }
+
             void ActorGroup::Reflect(AZ::ReflectContext* context)
             {
                 AZ::SerializeContext* serializeContext = azrtti_cast<AZ::SerializeContext*>(context);
diff --git a/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/ActorGroup.h b/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/ActorGroup.h
index fddb0d6afc..0725b3e88b 100644
--- a/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/ActorGroup.h
+++ b/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/ActorGroup.h
@@ -45,8 +45,8 @@ namespace EMotionFX
 
                 // IActorGroup overrides
                 const AZStd::string& GetSelectedRootBone() const override;
-
                 void SetSelectedRootBone(const AZStd::string& selectedRootBone)  override;
+                void SetBestMatchingRootBone(const AZ::SceneAPI::Containers::SceneGraph& sceneGraph) override;
 
                 static void Reflect(AZ::ReflectContext* context);
                 static bool IActorGroupVersionConverter(AZ::SerializeContext& context, AZ::SerializeContext::DataElementNode& classElement);
diff --git a/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/IActorGroup.h b/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/IActorGroup.h
index 398ec2c559..b57a9dfb13 100644
--- a/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/IActorGroup.h
+++ b/Gems/EMotionFX/Code/EMotionFX/Pipeline/SceneAPIExt/Groups/IActorGroup.h
@@ -10,6 +10,11 @@
 #include <AzCore/RTTI/RTTI.h>
 #include <SceneAPI/SceneCore/DataTypes/Groups/IGroup.h>
 
+namespace AZ::SceneAPI::Containers
+{
+    class SceneGraph;
+}
+
 namespace EMotionFX
 {
     namespace Pipeline
@@ -26,6 +31,7 @@ namespace EMotionFX
 
                 virtual const AZStd::string& GetSelectedRootBone() const = 0;
                 virtual void SetSelectedRootBone(const AZStd::string& selectedRootBone) = 0;
+                virtual void SetBestMatchingRootBone(const AZ::SceneAPI::Containers::SceneGraph& sceneGraph) = 0;
             };
         }
     }