From c1ebbbc176a2e383d226c61ca4c28732f70518ef Mon Sep 17 00:00:00 2001
From: Benjamin Jillich <43751992+amzn-jillich@users.noreply.github.com>
Date: Fri, 16 Jul 2021 08:53:04 -0700
Subject: [PATCH] EMotion FX: Root bone not initialized without opening Scene
 Settings #2088 (#2231)

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;
             };
         }
     }