Merge remote-tracking branch 'upstream/stabilization/2106' into mnaumov/StabilizationJun15

# Conflicts:
#	Code/CryEngine/CrySystem/LevelSystem/LevelSystem.cpp

Code/CryEngine/CrySystem/LevelSystem/LevelSystem.cpp

@@ -321,7 +321,7 @@ void CLevelSystem::ScanFolder(const char* subfolder, bool modFolder)
             {
                 if (AZ::StringFunc::Equal(handle.m_filename.data(), LevelPakName))
                 {
-                    // level folder contain pak files like 'level.pak' 
+                    // level folder contain pak files like 'level.pak'
                     // which we only want to load during level loading.
                     continue;
                 }
@@ -352,7 +352,7 @@ void CLevelSystem::ScanFolder(const char* subfolder, bool modFolder)
     PopulateLevels(search, folder, pPak, modFolder, false);
     // Load levels outside of the bundles to maintain backward compatibility.
     PopulateLevels(search, folder, pPak, modFolder, true);
-      
+
 }
 
 void CLevelSystem::PopulateLevels(
@@ -974,7 +974,7 @@ void CLevelSystem::UnloadLevel()
     m_lastLevelName.clear();
 
     SAFE_RELEASE(m_pCurrentLevel);
-    
+
     // Force Lua garbage collection (may no longer be needed now the legacy renderer has been removed).
     // Normally the GC step is triggered at the end of this method (by the ESYSTEM_EVENT_LEVEL_POST_UNLOAD event).
     EBUS_EVENT(AZ::ScriptSystemRequestBus, GarbageCollect);

Code/Framework/AzAutoGen/CMakeLists.txt

@@ -9,8 +9,6 @@
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 #
 
-cmake_minimum_required(VERSION 3.0)
-
 ly_add_target(
     NAME AzAutoGen HEADERONLY
     NAMESPACE AZ

Code/Framework/AzCore/AzCore/Math/Internal/SimdMathCommon_simd.inl

@@ -292,8 +292,13 @@ namespace AZ
                 const typename VecType::FloatType cmp2 = VecType::AndNot(cmp0, cmp1);
 
                 // -1/x
+                // this step is calculated for all values of x, but only used if x > Sqrt(2) + 1
+                // in order to avoid a division by zero, detect if xabs is zero here and replace it with an arbitrary value
+                // if xabs does equal zero, the value here doesn't matter because the result will be thrown away
+                typename VecType::FloatType xabsSafe =
+                    VecType::Add(xabs, VecType::And(VecType::CmpEq(xabs, VecType::ZeroFloat()), FastLoadConstant<VecType>(Simd::g_vec1111)));
                 const typename VecType::FloatType y0 = VecType::And(cmp0, FastLoadConstant<VecType>(Simd::g_HalfPi));
-                typename VecType::FloatType x0 = VecType::Div(FastLoadConstant<VecType>(Simd::g_vec1111), xabs);
+                typename VecType::FloatType x0 = VecType::Div(FastLoadConstant<VecType>(Simd::g_vec1111), xabsSafe);
                 x0 = VecType::Xor(x0, VecType::CastToFloat(FastLoadConstant<VecType>(Simd::g_negateMask)));
 
                 const typename VecType::FloatType y1 = VecType::And(cmp2, FastLoadConstant<VecType>(Simd::g_QuarterPi));
@@ -368,8 +373,12 @@ namespace AZ
 
                 typename VecType::FloatType offset = VecType::And(x_lt_0, offset1);
 
+                // the result of this part of the computation is thrown away if x equals 0,
+                // but if x does equal 0, it will cause a division by zero
+                // so replace zero by an arbitrary value here in that case
+                typename VecType::FloatType xSafe = VecType::Add(x, VecType::And(x_eq_0, FastLoadConstant<VecType>(Simd::g_vec1111)));
                 const typename VecType::FloatType atan_mask = VecType::Not(VecType::Or(x_eq_0, y_eq_0));
-                const typename VecType::FloatType atan_arg = VecType::Div(y, x);
+                const typename VecType::FloatType atan_arg = VecType::Div(y, xSafe);
                 typename VecType::FloatType atan_result = VecType::Atan(atan_arg);
                 atan_result = VecType::Add(atan_result, offset);
                 atan_result = VecType::AndNot(pio2_mask, atan_result);

Code/Framework/AzCore/AzCore/Math/Internal/SimdMathVec2_sse.inl

@@ -471,6 +471,7 @@ namespace AZ
 
         AZ_MATH_INLINE Vec2::FloatType Vec2::Reciprocal(FloatArgType value)
         {
+            value = Sse::ReplaceFourth(Sse::ReplaceThird(value, 1.0f), 1.0f);
             return Sse::Reciprocal(value);
         }
 
@@ -513,6 +514,7 @@ namespace AZ
 
         AZ_MATH_INLINE Vec2::FloatType Vec2::SqrtInv(FloatArgType value)
         {
+            value = Sse::ReplaceFourth(Sse::ReplaceThird(value, 1.0f), 1.0f);
             return Sse::SqrtInv(value);
         }
 

Code/Framework/AzCore/AzCore/Math/Internal/SimdMathVec3_sse.inl

@@ -507,6 +507,7 @@ namespace AZ
 
         AZ_MATH_INLINE Vec3::FloatType Vec3::Reciprocal(FloatArgType value)
         {
+            value = Sse::ReplaceFourth(value, 1.0f);
             return Sse::Reciprocal(value);
         }
 
@@ -549,6 +550,7 @@ namespace AZ
 
         AZ_MATH_INLINE Vec3::FloatType Vec3::SqrtInv(FloatArgType value)
         {
+            value = Sse::ReplaceFourth(value, 1.0f);
             return Sse::SqrtInv(value);
         }
 

Code/Framework/AzCore/AzCore/Utils/Utils.cpp

@@ -175,4 +175,11 @@ namespace AZ::Utils
         path /= ".o3de";
         return path.Native();
     }
+
+    AZ::IO::FixedMaxPathString GetO3deLogsDirectory()
+    {
+        AZ::IO::FixedMaxPath path = GetO3deManifestDirectory();
+        path /= "Logs";
+        return path.Native();
+    }
 }

Code/Framework/AzCore/AzCore/Utils/Utils.h

@@ -97,6 +97,9 @@ namespace AZ
         //! Retrieves the full path where the manifest file lives, i.e. "<userhome>/.o3de/o3de_manifest.json"
         AZ::IO::FixedMaxPathString GetEngineManifestPath();
 
+        //! Retrieves the full directory to the O3DE logs directory, i.e. "<userhome>/.o3de/Logs"
+        AZ::IO::FixedMaxPathString GetO3deLogsDirectory();
+
         //! Retrieves the App root path to use on the current platform
         //! If the optional is not engaged the AppRootPath should be calculated based
         //! on the location of the bootstrap.cfg file

Code/Framework/AzFramework/AzFramework/Script/ScriptComponent.cpp

@@ -693,11 +693,11 @@ namespace AzFramework
             // set the __index so we can read values in case we change the script
             // after we export the component
             lua_pushliteral(lua, "__index");
-            lua_pushcclosure(lua, &Internal::Properties__Index, 1);
+            lua_pushcclosure(lua, &Internal::Properties__Index, 0);
             lua_rawset(lua, -3);
 
             lua_pushliteral(lua, "__newindex");
-            lua_pushcclosure(lua, &Internal::Properties__NewIndex, 1);
+            lua_pushcclosure(lua, &Internal::Properties__NewIndex, 0);
             lua_rawset(lua, -3);
         }
         lua_pop(lua, 1); // pop the properties table (or the nil value)
@@ -900,11 +900,11 @@ namespace AzFramework
             // Ensure that this instance of Properties table has the proper __index and __newIndex metamethods.
             lua_newtable(lua);  // This new table will become the Properties instance metatable.  Stack: ScriptRootTable PropertiesTable EntityTable "Properties" {} {} 
             lua_pushliteral(lua, "__index");  // Stack: ScriptRootTable PropertiesTable EntityTable "Properties" {} {} __index
-            lua_pushcclosure(lua, &Internal::Properties__Index, 1);  // Stack: ScriptRootTable PropertiesTable EntityTable "Properties" {} {} __index function
+            lua_pushcclosure(lua, &Internal::Properties__Index, 0);  // Stack: ScriptRootTable PropertiesTable EntityTable "Properties" {} {} __index function
             lua_rawset(lua, -3);  // Stack: ScriptRootTable PropertiesTable EntityTable "Properties" {} {__index=Internal::Properties__Index} 
 
             lua_pushliteral(lua, "__newindex");
-            lua_pushcclosure(lua, &Internal::Properties__NewIndex, 1);
+            lua_pushcclosure(lua, &Internal::Properties__NewIndex, 0);
             lua_rawset(lua, -3);  // Stack: ScriptRootTable PropertiesTable EntityTable "Properties" {} {__index=Internal::Properties__Index __newindex=Internal::Properties__NewIndex} 
             lua_setmetatable(lua, -2);  // Stack: ScriptRootTable PropertiesTable EntityTable "Properties" {Meta{__index=Internal::Properties__Index __newindex=Internal::Properties__NewIndex} } 
 

Code/Framework/AzTest/CMakeLists.txt

@@ -8,25 +8,27 @@
 # remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
 # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 #
-   
-ly_get_list_relative_pal_filename(pal_dir ${CMAKE_CURRENT_LIST_DIR}/AzTest/Platform/${PAL_PLATFORM_NAME})
 
-ly_add_target(
-    NAME AzTest STATIC
-    NAMESPACE AZ
-    FILES_CMAKE
-        AzTest/aztest_files.cmake
-        ${pal_dir}/platform_${PAL_PLATFORM_NAME_LOWERCASE}_files.cmake
-    INCLUDE_DIRECTORIES
-        PUBLIC
-            .
-            ${pal_dir}
-    BUILD_DEPENDENCIES
-        PUBLIC
-            3rdParty::googletest::GMock
-            3rdParty::googletest::GTest
-            3rdParty::GoogleBenchmark
-            AZ::AzCore
-    PLATFORM_INCLUDE_FILES
+if(NOT LY_MONOLITHIC_GAME)
+    ly_get_list_relative_pal_filename(pal_dir ${CMAKE_CURRENT_LIST_DIR}/AzTest/Platform/${PAL_PLATFORM_NAME})
+
+    ly_add_target(
+        NAME AzTest STATIC
+        NAMESPACE AZ
+        FILES_CMAKE
+            AzTest/aztest_files.cmake
+            ${pal_dir}/platform_${PAL_PLATFORM_NAME_LOWERCASE}_files.cmake
+        INCLUDE_DIRECTORIES
+            PUBLIC
+                .
+                ${pal_dir}
+        BUILD_DEPENDENCIES
+            PUBLIC
+                3rdParty::googletest::GMock
+                3rdParty::googletest::GTest
+                3rdParty::GoogleBenchmark
+                AZ::AzCore
+        PLATFORM_INCLUDE_FILES
             ${pal_dir}/platform_${PAL_PLATFORM_NAME_LOWERCASE}.cmake
-)
+    )
+endif()

Code/Framework/AzToolsFramework/AzToolsFramework/Entity/PrefabEditorEntityOwnershipService.cpp

@@ -159,12 +159,23 @@ namespace AzToolsFramework
 
     void PrefabEditorEntityOwnershipService::GetNonPrefabEntities(EntityList& entities)
     {
-        m_rootInstance->GetEntities(entities, false);
+        m_rootInstance->GetEntities(
+            [&entities](const AZStd::unique_ptr<AZ::Entity>& entity)
+            {
+                entities.emplace_back(entity.get());
+                return true;
+            });
     }
 
     bool PrefabEditorEntityOwnershipService::GetAllEntities(EntityList& entities)
     {
-        m_rootInstance->GetEntities(entities, true);
+        m_rootInstance->GetAllEntitiesInHierarchy(
+            [&entities](const AZStd::unique_ptr<AZ::Entity>& entity)
+            {
+                entities.emplace_back(entity.get());
+                return true;
+            });
+
         return true;
     }
 
@@ -252,13 +263,20 @@ namespace AzToolsFramework
         }
 
         AZStd::string out;
-        if (m_loaderInterface->SaveTemplateToString(m_rootInstance->GetTemplateId(), out))
+
+        if (!m_loaderInterface->SaveTemplateToString(m_rootInstance->GetTemplateId(), out))
         {
-            const size_t bytesToWrite = out.size();
-            const size_t bytesWritten = stream.Write(bytesToWrite, out.data());
-            return bytesWritten == bytesToWrite;
+            return false;
         }
-        return false;
+
+        const size_t bytesToWrite = out.size();
+        const size_t bytesWritten = stream.Write(bytesToWrite, out.data());
+        if(bytesWritten != bytesToWrite)
+        {
+            return false;
+        }
+        m_prefabSystemComponent->SetTemplateDirtyFlag(templateId, false);
+        return true;
     }
 
     void PrefabEditorEntityOwnershipService::CreateNewLevelPrefab(AZStd::string_view filename, const AZStd::string& templateFilename)
@@ -544,7 +562,7 @@ namespace AzToolsFramework
                     return;
                 }
 
-                m_rootInstance->GetNestedEntities([this](AZStd::unique_ptr<AZ::Entity>& entity)
+                m_rootInstance->GetAllEntitiesInHierarchy([this](AZStd::unique_ptr<AZ::Entity>& entity)
                     {
                         AZ_Assert(entity, "Invalid entity found in root instance while starting play in editor.");
                         if (entity->GetState() == AZ::Entity::State::Active)

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Instance/Instance.cpp

@@ -373,17 +373,25 @@ namespace AzToolsFramework
             }
         }
 
-        void Instance::GetConstNestedEntities(const AZStd::function<bool(const AZ::Entity&)>& callback)
+        bool Instance::GetEntities_Impl(const AZStd::function<bool(AZStd::unique_ptr<AZ::Entity>&)>& callback)
         {
-            GetConstEntities(callback);
-
-            for (const auto& [instanceAlias, instance] : m_nestedInstances)
+            for (auto& [entityAlias, entity] : m_entities)
             {
-                instance->GetConstNestedEntities(callback);
+                if (!entity)
+                {
+                    continue;
+                }
+
+                if (!callback(entity))
+                {
+                    return false;
+                }
             }
+
+            return true;
         }
 
-        void Instance::GetConstEntities(const AZStd::function<bool(const AZ::Entity&)>& callback)
+        bool Instance::GetConstEntities_Impl(const AZStd::function<bool(const AZ::Entity&)>& callback) const
         {
             for (const auto& [entityAlias, entity] : m_entities)
             {
@@ -394,19 +402,83 @@ namespace AzToolsFramework
 
                 if (!callback(*entity))
                 {
-                    break;
+                    return false;
                 }
             }
+
+            return true;
         }
 
-        void Instance::GetNestedEntities(const AZStd::function<bool(AZStd::unique_ptr<AZ::Entity>&)>& callback)
+        bool Instance::GetAllEntitiesInHierarchy_Impl(const AZStd::function<bool(AZStd::unique_ptr<AZ::Entity>&)>& callback)
         {
-            GetEntities(callback);
+            if (HasContainerEntity())
+            {
+                if (!callback(m_containerEntity))
+                {
+                    return false;
+                }
+            }
+
+            if (!GetEntities_Impl(callback))
+            {
+                return false;
+            }
 
             for (auto& [instanceAlias, instance] : m_nestedInstances)
             {
-                instance->GetNestedEntities(callback);
+                if (!instance->GetAllEntitiesInHierarchy_Impl(callback))
+                {
+                    return false;
+                }
             }
+
+            return true;
+        }
+
+        bool Instance::GetAllEntitiesInHierarchyConst_Impl(const AZStd::function<bool(const AZ::Entity&)>& callback) const
+        {
+            if (HasContainerEntity())
+            {
+                if (!callback(*m_containerEntity))
+                {
+                    return false;
+                }
+            }
+
+            if (!GetConstEntities_Impl(callback))
+            {
+                return false;
+            }
+
+            for (const auto& [instanceAlias, instance] : m_nestedInstances)
+            {
+                if (!instance->GetAllEntitiesInHierarchyConst_Impl(callback))
+                {
+                    return false;
+                }
+            }
+
+            return true;
+        }
+
+        void Instance::GetEntities(const AZStd::function<bool(AZStd::unique_ptr<AZ::Entity>&)>& callback)
+        {
+            GetEntities_Impl(callback);
+        }
+
+        void Instance::GetConstEntities(const AZStd::function<bool(const AZ::Entity&)>& callback) const
+        {
+            GetConstEntities_Impl(callback);
+        }
+
+        void Instance::GetAllEntitiesInHierarchy(const AZStd::function<bool(AZStd::unique_ptr<AZ::Entity>&)>& callback)
+        {
+            GetAllEntitiesInHierarchy_Impl(callback);
+        }
+
+        void Instance::GetAllEntitiesInHierarchyConst(const AZStd::function<bool(const AZ::Entity&)>& callback) const
+        {
+            GetAllEntitiesInHierarchyConst_Impl(callback);
         }
 
         void Instance::GetNestedInstances(const AZStd::function<void(AZStd::unique_ptr<Instance>&)>& callback)
@@ -417,44 +489,6 @@ namespace AzToolsFramework
             }
         }
 
-        void Instance::GetEntities(const AZStd::function<bool(AZStd::unique_ptr<AZ::Entity>&)>& callback)
-        {
-            for (auto& [entityAlias, entity] : m_entities)
-            {
-                if (!callback(entity))
-                {
-                    break;
-                }
-            }
-        }
-
-        void Instance::GetEntities(EntityList& entities, bool includeNestedEntities)
-        {
-            // Non-recursive traversal of instances
-            AZStd::vector<Instance*> instancesToTraverse = { this };
-            while (!instancesToTraverse.empty())
-            {
-                Instance* currentInstance = instancesToTraverse.back();
-                instancesToTraverse.pop_back();
-                if (includeNestedEntities)
-                {
-                    instancesToTraverse.reserve(instancesToTraverse.size() + currentInstance->m_nestedInstances.size());
-                    for (const auto& instanceByAlias : currentInstance->m_nestedInstances)
-                    {
-                        instancesToTraverse.push_back(instanceByAlias.second.get());
-                    }
-                }
-
-                // Size increases by 1 for each instance because we have to count the container entity also.
-                entities.reserve(entities.size() + currentInstance->m_entities.size() + 1);
-                entities.push_back(m_containerEntity.get());
-                for (const auto& entityByAlias : currentInstance->m_entities)
-                {
-                    entities.push_back(entityByAlias.second.get());
-                }
-            }
-        }
-
         EntityAliasOptionalReference Instance::GetEntityAlias(const AZ::EntityId& id)
         {
             if (m_instanceToTemplateEntityIdMap.count(id))

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Instance/Instance.h

@@ -121,10 +121,10 @@ namespace AzToolsFramework
             /**
             * Gets the entities in the Instance DOM.  Can recursively trace all nested instances.
             */
-            void GetConstNestedEntities(const AZStd::function<bool(const AZ::Entity&)>& callback);
-            void GetConstEntities(const AZStd::function<bool(const AZ::Entity&)>& callback);
-            void GetNestedEntities(const AZStd::function<bool(AZStd::unique_ptr<AZ::Entity>&)>& callback);
             void GetEntities(const AZStd::function<bool(AZStd::unique_ptr<AZ::Entity>&)>& callback);
+            void GetConstEntities(const AZStd::function<bool(const AZ::Entity&)>& callback) const;
+            void GetAllEntitiesInHierarchy(const AZStd::function<bool(AZStd::unique_ptr<AZ::Entity>&)>& callback);
+            void GetAllEntitiesInHierarchyConst(const AZStd::function<bool(const AZ::Entity&)>& callback) const;
             void GetNestedInstances(const AZStd::function<void(AZStd::unique_ptr<Instance>&)>& callback);
 
             /**
@@ -184,12 +184,6 @@ namespace AzToolsFramework
 
             static InstanceAlias GenerateInstanceAlias();
 
-        protected:
-            /**
-            * Gets the entities owned by this instance
-            */
-            void GetEntities(EntityList& entities, bool includeNestedEntities = false);
-
         private:
             static constexpr const char s_aliasPathSeparator = '/';
 
@@ -197,6 +191,11 @@ namespace AzToolsFramework
 
             void RemoveEntities(const AZStd::function<bool(const AZStd::unique_ptr<AZ::Entity>&)>& filter);
 
+            bool GetEntities_Impl(const AZStd::function<bool(AZStd::unique_ptr<AZ::Entity>&)>& callback);
+            bool GetConstEntities_Impl(const AZStd::function<bool(const AZ::Entity&)>& callback) const;
+            bool GetAllEntitiesInHierarchy_Impl(const AZStd::function<bool(AZStd::unique_ptr<AZ::Entity>&)>& callback);
+            bool GetAllEntitiesInHierarchyConst_Impl(const AZStd::function<bool(const AZ::Entity&)>& callback) const;
+
             bool RegisterEntity(const AZ::EntityId& entityId, const EntityAlias& entityAlias);
             AZStd::unique_ptr<AZ::Entity> DetachEntity(const EntityAlias& entityAlias);
 

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Spawnable/EditorInfoRemover.cpp

@@ -62,25 +62,16 @@ namespace AzToolsFramework::Prefab::PrefabConversionUtils
         }
     }
 
-    AZStd::vector<AZ::Entity*> EditorInfoRemover::GetEntitiesFromInstance(AZStd::unique_ptr<Instance>& instance)
+    void EditorInfoRemover::GetEntitiesFromInstance(
+        AZStd::unique_ptr<AzToolsFramework::Prefab::Instance>& instance, EntityList& hierarchyEntities)
     {
-        AZStd::vector<AZ::Entity*> result;
-
-        instance->GetNestedEntities(
-            [&result](const AZStd::unique_ptr<AZ::Entity>& entity)
+        instance->GetAllEntitiesInHierarchy(
+            [&hierarchyEntities](const AZStd::unique_ptr<AZ::Entity>& entity)
             {
-                result.emplace_back(entity.get());
+                hierarchyEntities.emplace_back(entity.get());
                 return true;
             }
         );
-
-        if (instance->HasContainerEntity())
-        {
-            auto containerEntityReference = instance->GetContainerEntity();
-            result.emplace_back(&containerEntityReference->get());
-        }
-
-        return result;
     }
 
     void EditorInfoRemover::SetEditorOnlyEntityHandlerFromCandidates(const EntityList& entities)
@@ -543,7 +534,9 @@ exportComponent, prefabProcessorContext);
         }
 
         // grab all nested entities from the Instance as source entities.
-        EntityList sourceEntities = GetEntitiesFromInstance(instance);
+        EntityList sourceEntities;
+        GetEntitiesFromInstance(instance, sourceEntities);
+
         EntityList exportEntities;
 
         // prepare for validation of component requirements.
@@ -616,7 +609,7 @@ exportComponent, prefabProcessorContext);
         );
 
         // replace entities of instance with exported ones.
-        instance->GetNestedEntities(
+        instance->GetAllEntitiesInHierarchy(
             [&exportEntitiesMap](AZStd::unique_ptr<AZ::Entity>& entity)
             {
                 auto entityId = entity->GetId();
@@ -625,14 +618,6 @@ exportComponent, prefabProcessorContext);
             }
         );
 
-        if (instance->HasContainerEntity())
-        {
-            if (auto found = exportEntitiesMap.find(instance->GetContainerEntityId()); found != exportEntitiesMap.end())
-            {
-                instance->SetContainerEntity(*found->second);
-            }
-        }
-
         // save the final result in the target Prefab DOM.
         PrefabDom filteredPrefab;
         if (!PrefabDomUtils::StoreInstanceInPrefabDom(*instance, filteredPrefab))

Code/Framework/AzToolsFramework/AzToolsFramework/Prefab/Spawnable/EditorInfoRemover.h

@@ -55,8 +55,8 @@ namespace AzToolsFramework::Prefab::PrefabConversionUtils
 
      protected:
         using EntityList = AZStd::vector<AZ::Entity*>;
-        static EntityList GetEntitiesFromInstance(
-            AZStd::unique_ptr<AzToolsFramework::Prefab::Instance>& instance);
+        static void GetEntitiesFromInstance(
+            AZStd::unique_ptr<AzToolsFramework::Prefab::Instance>& instance, EntityList& hierarchyEntities);
 
         static bool ReadComponentAttribute(
             AZ::Component* component,

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/LevelRootUiHandler.cpp

@@ -58,8 +58,17 @@ namespace AzToolsFramework
 
         if (!path.empty())
         {
-            infoString =
-                QObject::tr("<span style=\"font-style: italic; font-weight: 400;\">(%1)</span>").arg(path.Filename().Native().data());
+            QString saveFlag = "";
+            auto dirtyOutcome = m_prefabPublicInterface->HasUnsavedChanges(path);
+
+            if (dirtyOutcome.IsSuccess() && dirtyOutcome.GetValue() == true)
+            {
+                saveFlag = "*";
+            }
+
+            infoString = QObject::tr("<span style=\"font-style: italic; font-weight: 400;\">(%1%2)</span>")
+                             .arg(path.Filename().Native().data())
+                             .arg(saveFlag);
         }
 
         return infoString;

Code/Framework/AzToolsFramework/AzToolsFramework/UI/Prefab/PrefabIntegrationManager.cpp

@@ -28,6 +28,7 @@
 #include <AzToolsFramework/ToolsComponents/EditorLayerComponentBus.h>
 #include <AzToolsFramework/UI/EditorEntityUi/EditorEntityUiInterface.h>
 #include <AzToolsFramework/UI/Prefab/PrefabIntegrationInterface.h>
+#include <AzToolsFramework/UI/UICore/WidgetHelpers.h>
 
 #include <QApplication>
 #include <QFileDialog>
@@ -588,15 +589,6 @@ namespace AzToolsFramework
 
         bool PrefabIntegrationManager::QueryUserForPrefabFilePath(AZStd::string& outPrefabFilePath)
         {
-            QWidget* mainWindow = nullptr;
-            EditorRequests::Bus::BroadcastResult(mainWindow, &EditorRequests::Bus::Events::GetMainWindow);
-
-            if (mainWindow == nullptr)
-            {
-                AZ_Assert(false, "Prefab - Could not detect Editor main window to generate the asset picker.");
-                return false;
-            }
-
             AssetSelectionModel selection;
 
             // Note, stringfilter will match every source file CONTAINING ".prefab".
@@ -624,7 +616,7 @@ namespace AzToolsFramework
             selection.SetDisplayFilter(compositeFilterPtr);
             selection.SetSelectionFilter(compositeFilterPtr);
 
-            AssetBrowserComponentRequestBus::Broadcast(&AssetBrowserComponentRequests::PickAssets, selection, mainWindow);
+            AssetBrowserComponentRequestBus::Broadcast(&AssetBrowserComponentRequests::PickAssets, selection, AzToolsFramework::GetActiveWindow());
 
             if (!selection.IsValid())
             {
@@ -983,12 +975,7 @@ namespace AzToolsFramework
                         includedEntities.c_str(),
                         referencedEntities.c_str());
 
-                    QWidget* mainWindow = nullptr;
-                    AzToolsFramework::EditorRequests::Bus::BroadcastResult(
-                        mainWindow,
-                        &AzToolsFramework::EditorRequests::Bus::Events::GetMainWindow);
-
-                    QMessageBox msgBox(mainWindow);
+                    QMessageBox msgBox(AzToolsFramework::GetActiveWindow());
                     msgBox.setWindowTitle("External Entity References");
                     msgBox.setText("The prefab contains references to external entities that are not selected.");
                     msgBox.setInformativeText("You can move the referenced entities into this prefab or retain the external references.");

Code/Framework/AzToolsFramework/Tests/Prefab/PrefabUpdateWithPatchesTests.cpp

@@ -93,7 +93,7 @@ namespace UnitTest
 
         // Retrieve the entity pointer from the component application bus.
         AZ::Entity* wheelEntityUnderAxle = nullptr;
-        axleInstance->GetNestedEntities([&wheelEntityUnderAxle, wheelEntityIdUnderAxle](AZStd::unique_ptr<AZ::Entity>& entity)
+        axleInstance->GetAllEntitiesInHierarchy([&wheelEntityUnderAxle, wheelEntityIdUnderAxle](AZStd::unique_ptr<AZ::Entity>& entity)
             {
                 if (entity->GetId() == wheelEntityIdUnderAxle)
                 {

Code/LauncherUnified/launcher_generator.cmake

@@ -196,6 +196,16 @@ function(ly_delayed_generate_static_modules_inl)
             ly_get_gem_load_dependencies(all_game_gem_dependencies ${project_name}.GameLauncher)
 
             foreach(game_gem_dependency ${all_game_gem_dependencies})
+                # Sometimes, a gem's Client variant may be an interface library
+                # which dependes on multiple gem targets. The interface libraries
+                # should be skipped; the real dependencies of the interface will be processed
+                if(TARGET ${game_gem_dependency})
+                    get_target_property(target_type ${game_gem_dependency} TYPE)
+                    if(${target_type} STREQUAL "INTERFACE_LIBRARY")
+                        continue()
+                    endif()
+                endif()
+
                 # To match the convention on how gems targets vs gem modules are named,
                 # we remove the ".Static" from the suffix
                 # Replace "." with "_"
@@ -224,6 +234,14 @@ function(ly_delayed_generate_static_modules_inl)
                     list(APPEND all_server_gem_dependencies ${server_gem_load_dependencies} ${server_gem_dependency})
                 endforeach()
                 foreach(server_gem_dependency ${all_server_gem_dependencies})
+                    # Skip interface libraries
+                    if(TARGET ${server_gem_dependency})
+                        get_target_property(target_type ${server_gem_dependency} TYPE)
+                        if(${target_type} STREQUAL "INTERFACE_LIBRARY")
+                            continue()
+                        endif()
+                    endif()
+
                     # Replace "." with "_"
                     string(REPLACE "." "_" server_gem_dependency ${server_gem_dependency})
 

Code/Sandbox/Editor/Core/LevelEditorMenuHandler.cpp

@@ -715,10 +715,11 @@ QMenu* LevelEditorMenuHandler::CreateViewMenu()
         {
             return view.IsViewportPane();
         });
-#endif
 
     viewportViewsMenuWrapper.AddSeparator();
 
+#endif
+
     if (CViewManager::IsMultiViewportEnabled())
     {
         viewportViewsMenuWrapper.AddAction(ID_VIEW_CONFIGURELAYOUT);

Code/Sandbox/Editor/CryEdit.cpp

@@ -2886,7 +2886,7 @@ void CCryEditApp::OpenProjectManager(const AZStd::string& screen)
 {
     // provide the current project path for in case we want to update the project
     AZ::IO::FixedMaxPathString projectPath = AZ::Utils::GetProjectPath();
-    const AZStd::string commandLineOptions = AZStd::string::format(" --screen %s --project_path %s", screen.c_str(), projectPath.c_str());
+    const AZStd::string commandLineOptions = AZStd::string::format(" --screen %s --project-path %s", screen.c_str(), projectPath.c_str());
     bool launchSuccess = AzFramework::ProjectManager::LaunchProjectManager(commandLineOptions);
     if (!launchSuccess)
     {

Code/Sandbox/Editor/EditorViewportWidget.cpp

@@ -513,18 +513,28 @@ void EditorViewportWidget::Update()
             // Disable rendering to avoid recursion into Update()
             PushDisableRendering();
 
+
+            //get debug display interface for the viewport
+            AzFramework::DebugDisplayRequestBus::BusPtr debugDisplayBus;
+            AzFramework::DebugDisplayRequestBus::Bind(debugDisplayBus, GetViewportId());
+            AZ_Assert(debugDisplayBus, "Invalid DebugDisplayRequestBus.");
+
+            AzFramework::DebugDisplayRequests* debugDisplay =
+                AzFramework::DebugDisplayRequestBus::FindFirstHandler(debugDisplayBus);
+
+
             // draw debug visualizations
-            if (m_debugDisplay)
+            if (debugDisplay)
             {
-                const AZ::u32 prevState = m_debugDisplay->GetState();
-                m_debugDisplay->SetState(
+                const AZ::u32 prevState = debugDisplay->GetState();
+                debugDisplay->SetState(
                     e_Mode3D | e_AlphaBlended | e_FillModeSolid | e_CullModeBack | e_DepthWriteOn | e_DepthTestOn);
 
                 AzFramework::EntityDebugDisplayEventBus::Broadcast(
                     &AzFramework::EntityDebugDisplayEvents::DisplayEntityViewport,
-                    AzFramework::ViewportInfo{ GetViewportId() }, *m_debugDisplay);
+                    AzFramework::ViewportInfo{ GetViewportId() }, *debugDisplay);
 
-                m_debugDisplay->SetState(prevState);
+                debugDisplay->SetState(prevState);
             }
 
             QtViewport::Update();

Code/Tools/AssetProcessor/assetprocessor_static_files.cmake

@@ -19,6 +19,7 @@ set(FILES
     native/AssetManager/AssetRequestHandler.cpp
     native/AssetManager/AssetRequestHandler.h
     native/AssetManager/assetScanFolderInfo.h
+    native/AssetManager/assetScanFolderInfo.cpp
     native/AssetManager/assetScanner.cpp
     native/AssetManager/assetScanner.h
     native/AssetManager/assetScannerWorker.cpp

Code/Tools/AssetProcessor/native/AssetManager/assetScanFolderInfo.cpp

@@ -0,0 +1,42 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include <native/AssetManager/assetScanFolderInfo.h>
+#include <native/utilities/assetUtils.h>
+
+namespace AssetProcessor
+{
+        ScanFolderInfo::ScanFolderInfo(
+            QString path,
+            QString displayName,
+            QString portableKey,
+            bool isRoot,
+            bool recurseSubFolders,
+            AZStd::vector<AssetBuilderSDK::PlatformInfo> platforms,
+            int order,
+            AZ::s64 scanFolderID,
+            bool canSaveNewAssets)
+            : m_scanPath(path)
+            , m_displayName(displayName)
+            , m_portableKey (portableKey)
+            , m_isRoot(isRoot)
+            , m_recurseSubFolders(recurseSubFolders)
+            , m_order(order)
+            , m_scanFolderID(scanFolderID)
+            , m_platforms(platforms)
+            , m_canSaveNewAssets(canSaveNewAssets)
+        {
+            m_scanPath = AssetUtilities::NormalizeFilePath(m_scanPath);
+            // note that m_scanFolderID is 0 unless its filled in from the DB.
+        }
+
+} // end namespace AssetProcessor

Code/Tools/AssetProcessor/native/AssetManager/assetScanFolderInfo.h

@@ -33,19 +33,7 @@ namespace AssetProcessor
             AZStd::vector<AssetBuilderSDK::PlatformInfo> platforms = AZStd::vector<AssetBuilderSDK::PlatformInfo>{},
             int order = 0,
             AZ::s64 scanFolderID = 0,
-            bool canSaveNewAssets = false)
-            : m_scanPath(path)
-            , m_displayName(displayName)
-            , m_portableKey (portableKey)
-            , m_isRoot(isRoot)
-            , m_recurseSubFolders(recurseSubFolders)
-            , m_order(order)
-            , m_scanFolderID(scanFolderID)
-            , m_platforms(platforms)
-            , m_canSaveNewAssets(canSaveNewAssets)
-        {
-            // note that m_scanFolderID is 0 unless its filled in from the DB.
-        }
+            bool canSaveNewAssets = false);
 
         ScanFolderInfo() = default;
         ScanFolderInfo(const ScanFolderInfo& other) = default;

Code/Tools/AzTestRunner/CMakeLists.txt

@@ -13,7 +13,7 @@ ly_get_list_relative_pal_filename(pal_dir ${CMAKE_CURRENT_LIST_DIR}/Platform/${P
 
 include(${pal_dir}/platform_traits_${PAL_PLATFORM_NAME_LOWERCASE}.cmake)
 
-if(PAL_TRAIT_AZTESTRUNNER_SUPPORTED)
+if(PAL_TRAIT_AZTESTRUNNER_SUPPORTED AND NOT LY_MONOLITHIC_GAME)
     
     ly_add_target(
         NAME AzTestRunner ${PAL_TRAIT_AZTESTRUNNER_LAUNCHER_TYPE}

Code/Tools/ProjectManager/CMakeLists.txt

@@ -20,12 +20,11 @@ if (NOT python_package_name)
     message(WARNING "Python was not found in the package assocation list.  Did someone call ly_associate_package(xxxxxxx Python) ?")
 endif()
 
+
 ly_add_target(
-    NAME ProjectManager APPLICATION
-    OUTPUT_NAME o3de
+    NAME ProjectManager.Static STATIC
     NAMESPACE AZ
     AUTOMOC
-    AUTORCC
     FILES_CMAKE
         project_manager_files.cmake
         Platform/${PAL_PLATFORM_NAME}/PAL_${PAL_PLATFORM_NAME_LOWERCASE}_files.cmake
@@ -47,6 +46,60 @@ ly_add_target(
             3rdParty::pybind11
             AZ::AzCore
             AZ::AzFramework
-            AZ::AzToolsFramework
             AZ::AzQtComponents
-)
+)
+
+ly_add_target(
+    NAME ProjectManager APPLICATION
+    OUTPUT_NAME o3de
+    NAMESPACE AZ
+    AUTORCC
+    FILES_CMAKE
+        project_manager_app_files.cmake
+    INCLUDE_DIRECTORIES
+        PRIVATE
+            Source
+    BUILD_DEPENDENCIES
+        PRIVATE
+            3rdParty::Qt::Core
+            3rdParty::Qt::Concurrent
+            3rdParty::Qt::Widgets
+            3rdParty::Python
+            3rdParty::pybind11
+            AZ::AzCore
+            AZ::AzFramework
+            AZ::AzQtComponents
+            AZ::ProjectManager.Static
+)
+
+if(PAL_TRAIT_BUILD_TESTS_SUPPORTED)
+    ly_add_target(
+        NAME ProjectManager.Tests EXECUTABLE
+        NAMESPACE AZ
+        AUTORCC
+        FILES_CMAKE
+            project_manager_tests_files.cmake
+            Platform/${PAL_PLATFORM_NAME}/PAL_${PAL_PLATFORM_NAME_LOWERCASE}_tests_files.cmake
+        INCLUDE_DIRECTORIES
+            PRIVATE
+                Source
+                Platform/${PAL_PLATFORM_NAME}
+        BUILD_DEPENDENCIES
+            PRIVATE
+                3rdParty::Qt::Core
+                3rdParty::Qt::Concurrent
+                3rdParty::Qt::Widgets
+                3rdParty::Python
+                3rdParty::pybind11
+                AZ::AzTest
+                AZ::AzFramework
+                AZ::AzFrameworkTestShared
+                AZ::ProjectManager.Static
+    )
+
+    ly_add_googletest(
+        NAME AZ::ProjectManager.Tests
+        TEST_COMMAND $<TARGET_FILE:AZ::ProjectManager.Tests> --unittest
+    )
+
+endif()

Code/Tools/ProjectManager/Platform/Linux/PAL_linux_tests_files.cmake

@@ -0,0 +1,15 @@
+#
+# All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+# its licensors.
+#
+# For complete copyright and license terms please see the LICENSE at the root of this
+# distribution (the "License"). All use of this software is governed by the License,
+# or, if provided, by the license below or the license accompanying this file. Do not
+# remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#
+
+set(FILES
+    ProjectManager_Test_Traits_Platform.h
+    ProjectManager_Test_Traits_Linux.h
+)

Code/Tools/ProjectManager/Platform/Linux/ProjectManager_Test_Traits_Linux.h

@@ -0,0 +1,15 @@
+/*
+ * All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+ * its licensors.
+ *
+ * For complete copyright and license terms please see the LICENSE at the root of this
+ * distribution (the "License"). All use of this software is governed by the License,
+ * or, if provided, by the license below or the license accompanying this file. Do not
+ * remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ */
+
+#pragma once
+
+#define AZ_TRAIT_DISABLE_FAILED_PROJECT_MANAGER_TESTS true

Code/Tools/ProjectManager/Platform/Linux/ProjectManager_Test_Traits_Platform.h

@@ -0,0 +1,15 @@
+/*
+ * All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+ * its licensors.
+ *
+ * For complete copyright and license terms please see the LICENSE at the root of this
+ * distribution (the "License"). All use of this software is governed by the License,
+ * or, if provided, by the license below or the license accompanying this file. Do not
+ * remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ */
+
+#pragma once
+
+#include <ProjectManager_Test_Traits_Linux.h>

Code/Tools/ProjectManager/Platform/Mac/PAL_mac_tests_files.cmake

@@ -0,0 +1,15 @@
+#
+# All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+# its licensors.
+#
+# For complete copyright and license terms please see the LICENSE at the root of this
+# distribution (the "License"). All use of this software is governed by the License,
+# or, if provided, by the license below or the license accompanying this file. Do not
+# remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#
+
+set(FILES
+    ProjectManager_Test_Traits_Platform.h
+    ProjectManager_Test_Traits_Mac.h
+)

Code/Tools/ProjectManager/Platform/Mac/ProjectManager_Test_Traits_Mac.h

@@ -0,0 +1,15 @@
+/*
+ * All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+ * its licensors.
+ *
+ * For complete copyright and license terms please see the LICENSE at the root of this
+ * distribution (the "License"). All use of this software is governed by the License,
+ * or, if provided, by the license below or the license accompanying this file. Do not
+ * remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ */
+
+#pragma once
+
+#define AZ_TRAIT_DISABLE_FAILED_PROJECT_MANAGER_TESTS false

Code/Tools/ProjectManager/Platform/Mac/ProjectManager_Test_Traits_Platform.h

@@ -0,0 +1,15 @@
+/*
+ * All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+ * its licensors.
+ *
+ * For complete copyright and license terms please see the LICENSE at the root of this
+ * distribution (the "License"). All use of this software is governed by the License,
+ * or, if provided, by the license below or the license accompanying this file. Do not
+ * remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ */
+
+#pragma once
+
+#include <ProjectManager_Test_Traits_Mac.h>

Code/Tools/ProjectManager/Platform/Windows/PAL_windows_tests_files.cmake

@@ -0,0 +1,15 @@
+#
+# All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+# its licensors.
+#
+# For complete copyright and license terms please see the LICENSE at the root of this
+# distribution (the "License"). All use of this software is governed by the License,
+# or, if provided, by the license below or the license accompanying this file. Do not
+# remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#
+
+set(FILES
+    ProjectManager_Test_Traits_Platform.h
+    ProjectManager_Test_Traits_Windows.h
+)

Code/Tools/ProjectManager/Platform/Windows/ProjectManager_Test_Traits_Platform.h

@@ -0,0 +1,15 @@
+/*
+ * All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+ * its licensors.
+ *
+ * For complete copyright and license terms please see the LICENSE at the root of this
+ * distribution (the "License"). All use of this software is governed by the License,
+ * or, if provided, by the license below or the license accompanying this file. Do not
+ * remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ */
+
+#pragma once
+
+#include <ProjectManager_Test_Traits_Windows.h>

Code/Tools/ProjectManager/Platform/Windows/ProjectManager_Test_Traits_Windows.h

@@ -0,0 +1,15 @@
+/*
+ * All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+ * its licensors.
+ *
+ * For complete copyright and license terms please see the LICENSE at the root of this
+ * distribution (the "License"). All use of this software is governed by the License,
+ * or, if provided, by the license below or the license accompanying this file. Do not
+ * remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ */
+
+#pragma once
+
+#define AZ_TRAIT_DISABLE_FAILED_PROJECT_MANAGER_TESTS false

Code/Tools/ProjectManager/Resources/ProjectManager.qss

@@ -7,6 +7,11 @@ QMainWindow {
     margin:0;
 }
 
+#ScreensCtrl {
+    min-width:1200px;
+    min-height:800px;
+}
+
 QPushButton:focus {
     outline: none;
     border:1px solid #1e70eb;

Code/Tools/ProjectManager/Source/Application.cpp

@@ -0,0 +1,186 @@
+/*
+ * All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+ * its licensors.
+ *
+ * For complete copyright and license terms please see the LICENSE at the root of this
+ * distribution (the "License"). All use of this software is governed by the License,
+ * or, if provided, by the license below or the license accompanying this file. Do not
+ * remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ */
+
+#include <Application.h>
+#include <ProjectUtils.h>
+
+#include <AzCore/IO/FileIO.h>
+#include <AzCore/Utils/Utils.h>
+#include <AzCore/Settings/SettingsRegistryMergeUtils.h>
+#include <AzFramework/Logging/LoggingComponent.h>
+#include <AzQtComponents/Utilities/HandleDpiAwareness.h>
+#include <AzQtComponents/Components/StyleManager.h>
+#include <AzQtComponents/Components/WindowDecorationWrapper.h>
+
+#include <QApplication>
+#include <QDir>
+#include <QMessageBox>
+
+namespace O3DE::ProjectManager
+{
+    Application::~Application()
+    {
+        TearDown();
+    }
+
+    bool Application::Init(bool interactive)
+    {
+        constexpr const char* applicationName { "O3DE" };
+
+        QApplication::setOrganizationName(applicationName);
+        QApplication::setOrganizationDomain("o3de.org");
+
+        QCoreApplication::setApplicationName(applicationName);
+        QCoreApplication::setApplicationVersion("1.0");
+
+        // Use the LogComponent for non-dev logging log
+        RegisterComponentDescriptor(AzFramework::LogComponent::CreateDescriptor());
+
+        // set the log alias to .o3de/Logs instead of the default user/logs
+        AZ::IO::FixedMaxPath path = AZ::Utils::GetO3deLogsDirectory();
+
+        // DevWriteStorage is where the event log is written during development
+        m_settingsRegistry->Set(AZ::SettingsRegistryMergeUtils::FilePathKey_DevWriteStorage, path.LexicallyNormal().Native());
+
+        // Save event logs to .o3de/Logs/eventlogger/EventLogO3DE.azsl
+        m_settingsRegistry->Set(AZ::SettingsRegistryMergeUtils::BuildTargetNameKey, applicationName);
+
+        Start(AzFramework::Application::Descriptor());
+
+        QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
+        QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
+        QCoreApplication::setAttribute(Qt::AA_DontCreateNativeWidgetSiblings);
+
+        QLocale::setDefault(QLocale(QLocale::English, QLocale::UnitedStates));
+
+        QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
+        AzQtComponents::Utilities::HandleDpiAwareness(AzQtComponents::Utilities::SystemDpiAware);
+
+        // Create the actual Qt Application - this needs to happen before using QMessageBox
+        m_app.reset(new QApplication(*GetArgC(), *GetArgV()));
+
+        if(!InitLog(applicationName))
+        {
+            AZ_Warning("ProjectManager", false, "Failed to init logging");
+        }
+
+        m_pythonBindings = AZStd::make_unique<PythonBindings>(GetEngineRoot());
+        if (!m_pythonBindings || !m_pythonBindings->PythonStarted())
+        {
+            if (interactive)
+            {
+                QMessageBox::critical(nullptr, QObject::tr("Failed to start Python"),
+                    QObject::tr("This tool requires an O3DE engine with a Python runtime, "
+                        "but either Python is missing or mis-configured. Please rename "
+                        "your python/runtime folder to python/runtime_bak, then run "
+                        "python/get_python.bat to restore the Python runtime folder."));
+            }
+            return false;
+        }
+
+        const AZ::CommandLine* commandLine = GetCommandLine();
+        AZ_Assert(commandLine, "Failed to get command line");
+
+        ProjectManagerScreen startScreen = ProjectManagerScreen::Projects;
+        if (size_t screenSwitchCount = commandLine->GetNumSwitchValues("screen"); screenSwitchCount > 0)
+        {
+            QString screenOption = commandLine->GetSwitchValue("screen", screenSwitchCount - 1).c_str();
+            ProjectManagerScreen screen = ProjectUtils::GetProjectManagerScreen(screenOption);
+            if (screen != ProjectManagerScreen::Invalid)
+            {
+                startScreen = screen;
+            }
+        }
+
+        AZ::IO::FixedMaxPath projectPath;
+        if (size_t projectSwitchCount = commandLine->GetNumSwitchValues("project-path"); projectSwitchCount > 0)
+        {
+            projectPath = commandLine->GetSwitchValue("project-path", projectSwitchCount - 1).c_str();
+        }
+
+        m_mainWindow.reset(new ProjectManagerWindow(nullptr, projectPath, startScreen));
+
+        return true;
+    }
+
+    bool Application::InitLog(const char* logName)
+    {
+        if (!m_entity)
+        {
+            // override the log alias to the O3de Logs directory instead of the default project user/Logs folder
+            AZ::IO::FixedMaxPath path = AZ::Utils::GetO3deLogsDirectory();
+            AZ::IO::FileIOBase* fileIO = AZ::IO::FileIOBase::GetInstance();
+            AZ_Assert(fileIO, "Failed to get FileIOBase instance");
+
+            fileIO->SetAlias("@log@", path.LexicallyNormal().Native().c_str());
+
+            // this entity exists because we need a home for LogComponent
+            // and cannot use the system entity because we need to be able to call SetLogFileBaseName 
+            // so the log will be named O3DE.log
+            m_entity = aznew AZ::Entity("Application Entity");
+            if (m_entity)
+            {
+                AzFramework::LogComponent* logger = aznew AzFramework::LogComponent();
+                AZ_Assert(logger, "Failed to create LogComponent");
+                logger->SetLogFileBaseName(logName);
+                m_entity->AddComponent(logger);
+                m_entity->Init();
+                m_entity->Activate();
+            }
+        }
+
+        return m_entity != nullptr;
+    }
+
+    void Application::TearDown()
+    {
+        if (m_entity)
+        {
+            m_entity->Deactivate();
+            delete m_entity;
+            m_entity = nullptr;
+        }
+
+        m_pythonBindings.reset();
+        m_mainWindow.reset();
+        m_app.reset();
+    }
+
+    bool Application::Run()
+    {
+        // Set up the Style Manager
+        AzQtComponents::StyleManager styleManager(qApp);
+        styleManager.initialize(qApp, GetEngineRoot());
+
+        // setup stylesheets and hot reloading 
+        AZ::IO::FixedMaxPath engineRoot(GetEngineRoot());
+        QDir rootDir(engineRoot.c_str());
+        const auto pathOnDisk = rootDir.absoluteFilePath("Code/Tools/ProjectManager/Resources");
+        const auto qrcPath = QStringLiteral(":/ProjectManager/style");
+        AzQtComponents::StyleManager::addSearchPaths("style", pathOnDisk, qrcPath, engineRoot);
+
+        // set stylesheet after creating the main window or their styles won't get updated
+        AzQtComponents::StyleManager::setStyleSheet(m_mainWindow.data(), QStringLiteral("style:ProjectManager.qss"));
+
+        // the decoration wrapper is intended to remember window positioning and sizing 
+        auto wrapper = new AzQtComponents::WindowDecorationWrapper();
+        wrapper->setGuest(m_mainWindow.data());
+        wrapper->show();
+        m_mainWindow->show();
+
+        qApp->setQuitOnLastWindowClosed(true);
+
+        // Run the application
+        return qApp->exec();
+    }
+
+}

Code/Tools/ProjectManager/Source/Application.h

@@ -0,0 +1,48 @@
+/*
+ * All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+ * its licensors.
+ *
+ * For complete copyright and license terms please see the LICENSE at the root of this
+ * distribution (the "License"). All use of this software is governed by the License,
+ * or, if provided, by the license below or the license accompanying this file. Do not
+ * remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *
+ */
+#pragma once
+
+#if !defined(Q_MOC_RUN)
+#include <AzFramework/Application/Application.h>
+#include <QCoreApplication>
+#include <PythonBindings.h>
+#include <ProjectManagerWindow.h>
+#endif
+
+namespace AZ
+{
+    class Entity;
+}
+
+namespace O3DE::ProjectManager
+{
+    class Application
+        : public AzFramework::Application
+    {
+    public:
+        using AzFramework::Application::Application;
+        virtual ~Application();
+
+        bool Init(bool interactive = true);
+        bool Run();
+        void TearDown();
+
+    private:
+        bool InitLog(const char* logName);
+
+        AZStd::unique_ptr<PythonBindings> m_pythonBindings;
+        QSharedPointer<QCoreApplication> m_app;
+        QSharedPointer<ProjectManagerWindow> m_mainWindow;
+
+        AZ::Entity* m_entity = nullptr;
+    };
+}

Code/Tools/ProjectManager/Source/EngineSettingsScreen.cpp

@@ -25,7 +25,7 @@ namespace O3DE::ProjectManager
     EngineSettingsScreen::EngineSettingsScreen(QWidget* parent)
         : ScreenWidget(parent)
     {
-        auto* layout = new QVBoxLayout(this);
+        auto* layout = new QVBoxLayout();
         layout->setAlignment(Qt::AlignTop);
 
         setObjectName("engineSettingsScreen");

Code/Tools/ProjectManager/Source/GemCatalog/GemCatalogScreen.cpp

@@ -82,6 +82,8 @@ namespace O3DE::ProjectManager
 
         m_headerWidget->ReinitForProject();
 
+        connect(m_gemModel, &GemModel::dataChanged, m_filterWidget, &GemFilterWidget::ResetGemStatusFilter);
+
         // Select the first entry after everything got correctly sized
         QTimer::singleShot(200, [=]{
             QModelIndex firstModelIndex = m_gemListView->model()->index(0,0);

Code/Tools/ProjectManager/Source/GemCatalog/GemFilterWidget.cpp

@@ -26,6 +26,7 @@ namespace O3DE::ProjectManager
         const QVector<QString>& elementNames,
         const QVector<int>& elementCounts,
         bool showAllLessButton,
+        bool collapsed,
         int defaultShowCount,
         QWidget* parent)
         : QWidget(parent)
@@ -40,6 +41,7 @@ namespace O3DE::ProjectManager
         QHBoxLayout* collapseLayout = new QHBoxLayout();
         m_collapseButton = new QPushButton();
         m_collapseButton->setCheckable(true);
+        m_collapseButton->setChecked(collapsed);
         m_collapseButton->setFlat(true);
         m_collapseButton->setFocusPolicy(Qt::NoFocus);
         m_collapseButton->setFixedWidth(s_collapseButtonSize);
@@ -178,6 +180,11 @@ namespace O3DE::ProjectManager
         return m_buttonGroup;
     }
 
+    bool FilterCategoryWidget::IsCollapsed()
+    {
+        return m_collapseButton->isChecked();
+    }
+
     GemFilterWidget::GemFilterWidget(GemSortFilterProxyModel* filterProxyModel, QWidget* parent)
         : QScrollArea(parent)
         , m_filterProxyModel(filterProxyModel)
@@ -193,20 +200,106 @@ namespace O3DE::ProjectManager
         QWidget* mainWidget = new QWidget();
         setWidget(mainWidget);
 
-        m_mainLayout = new QVBoxLayout();
-        m_mainLayout->setAlignment(Qt::AlignTop);
-        mainWidget->setLayout(m_mainLayout);
+        QVBoxLayout* mainLayout = new QVBoxLayout();
+        mainLayout->setAlignment(Qt::AlignTop);
+        mainWidget->setLayout(mainLayout);
 
         QLabel* filterByLabel = new QLabel("Filter by");
         filterByLabel->setStyleSheet("font-size: 16px;");
-        m_mainLayout->addWidget(filterByLabel);
+        mainLayout->addWidget(filterByLabel);
 
+        QWidget* filterSection = new QWidget(this);
+        mainLayout->addWidget(filterSection);
+
+        m_filterLayout = new QVBoxLayout();
+        m_filterLayout->setAlignment(Qt::AlignTop);
+        m_filterLayout->setContentsMargins(0, 0, 0, 0);
+        filterSection->setLayout(m_filterLayout);
+
+        ResetGemStatusFilter();
         AddGemOriginFilter();
         AddTypeFilter();
         AddPlatformFilter();
         AddFeatureFilter();
     }
 
+    void GemFilterWidget::ResetGemStatusFilter()
+    {
+        QVector<QString> elementNames;
+        QVector<int> elementCounts;
+        const int totalGems = m_gemModel->rowCount();
+        const int selectedGemTotal = m_gemModel->TotalAddedGems();
+
+        elementNames.push_back(GemSortFilterProxyModel::GetGemStatusString(GemSortFilterProxyModel::GemStatus::Unselected));
+        elementCounts.push_back(totalGems - selectedGemTotal);
+
+        elementNames.push_back(GemSortFilterProxyModel::GetGemStatusString(GemSortFilterProxyModel::GemStatus::Selected));
+        elementCounts.push_back(selectedGemTotal);
+
+        bool wasCollapsed = false;
+        if (m_statusFilter)
+        {
+            wasCollapsed = m_statusFilter->IsCollapsed();
+        }
+
+        FilterCategoryWidget* filterWidget =
+            new FilterCategoryWidget("Status", elementNames, elementCounts, /*showAllLessButton=*/false, /*collapsed*/wasCollapsed);
+        if (m_statusFilter)
+        {
+            m_filterLayout->replaceWidget(m_statusFilter, filterWidget);
+        }
+        else
+        {
+            m_filterLayout->addWidget(filterWidget);
+        }
+
+        m_statusFilter->deleteLater();
+        m_statusFilter = filterWidget;
+
+        const GemSortFilterProxyModel::GemStatus currentFilterState = m_filterProxyModel->GetGemStatus();
+        const QList<QAbstractButton*> buttons = m_statusFilter->GetButtonGroup()->buttons();
+        for (int statusFilterIndex = 0; statusFilterIndex < buttons.size(); ++statusFilterIndex)
+        {
+            const GemSortFilterProxyModel::GemStatus gemStatus = static_cast<GemSortFilterProxyModel::GemStatus>(statusFilterIndex);
+            QAbstractButton* button = buttons[statusFilterIndex];
+
+            if (static_cast<GemSortFilterProxyModel::GemStatus>(statusFilterIndex) == currentFilterState)
+            {
+                button->setChecked(true);
+            }
+
+            connect(
+                button, &QAbstractButton::toggled, this,
+                [=](bool checked)
+                {
+                    GemSortFilterProxyModel::GemStatus filterStatus = m_filterProxyModel->GetGemStatus();
+                    if (checked)
+                    {
+                        if (filterStatus == GemSortFilterProxyModel::GemStatus::NoFilter)
+                        {
+                            filterStatus = gemStatus;
+                        }
+                        else
+                        {
+                            filterStatus = GemSortFilterProxyModel::GemStatus::NoFilter;
+                        }
+                    }
+                    else
+                    {
+                        if (filterStatus != gemStatus)
+                        {
+                            filterStatus = static_cast<GemSortFilterProxyModel::GemStatus>(!gemStatus);
+                        }
+                        else
+                        {
+                            filterStatus = GemSortFilterProxyModel::GemStatus::NoFilter;
+                        }
+                    }
+                    m_filterProxyModel->SetGemStatus(filterStatus);
+                });
+        }
+    }
+
     void GemFilterWidget::AddGemOriginFilter()
     {
         QVector<QString> elementNames;
@@ -233,7 +326,7 @@ namespace O3DE::ProjectManager
         }
 
         FilterCategoryWidget* filterWidget = new FilterCategoryWidget("Provider", elementNames, elementCounts, /*showAllLessButton=*/false);
-        m_mainLayout->addWidget(filterWidget);
+        m_filterLayout->addWidget(filterWidget);
 
         const QList<QAbstractButton*> buttons = filterWidget->GetButtonGroup()->buttons();
         for (int i = 0; i < buttons.size(); ++i)
@@ -283,7 +376,7 @@ namespace O3DE::ProjectManager
         }
 
         FilterCategoryWidget* filterWidget = new FilterCategoryWidget("Type", elementNames, elementCounts, /*showAllLessButton=*/false);
-        m_mainLayout->addWidget(filterWidget);
+        m_filterLayout->addWidget(filterWidget);
 
         const QList<QAbstractButton*> buttons = filterWidget->GetButtonGroup()->buttons();
         for (int i = 0; i < buttons.size(); ++i)
@@ -333,7 +426,7 @@ namespace O3DE::ProjectManager
         }
 
         FilterCategoryWidget* filterWidget = new FilterCategoryWidget("Supported Platforms", elementNames, elementCounts, /*showAllLessButton=*/false);
-        m_mainLayout->addWidget(filterWidget);
+        m_filterLayout->addWidget(filterWidget);
 
         const QList<QAbstractButton*> buttons = filterWidget->GetButtonGroup()->buttons();
         for (int i = 0; i < buttons.size(); ++i)
@@ -388,8 +481,8 @@ namespace O3DE::ProjectManager
         }
 
         FilterCategoryWidget* filterWidget = new FilterCategoryWidget("Features", elementNames, elementCounts,
-            /*showAllLessButton=*/true, /*defaultShowCount=*/5);
-        m_mainLayout->addWidget(filterWidget);
+            /*showAllLessButton=*/true, false, /*defaultShowCount=*/5);
+        m_filterLayout->addWidget(filterWidget);
 
         const QList<QAbstractButton*> buttons = filterWidget->GetButtonGroup()->buttons();
         for (int i = 0; i < buttons.size(); ++i)

Code/Tools/ProjectManager/Source/GemCatalog/GemFilterWidget.h

@@ -37,11 +37,14 @@ namespace O3DE::ProjectManager
             const QVector<QString>& elementNames,
             const QVector<int>& elementCounts,
             bool showAllLessButton = true,
+            bool collapsed = false,
             int defaultShowCount = 4,
             QWidget* parent = nullptr);
 
         QButtonGroup* GetButtonGroup();
 
+        bool IsCollapsed();
+
     private:
         void UpdateCollapseState();
         void UpdateSeeMoreLess();
@@ -66,14 +69,18 @@ namespace O3DE::ProjectManager
         explicit GemFilterWidget(GemSortFilterProxyModel* filterProxyModel, QWidget* parent = nullptr);
         ~GemFilterWidget() = default;
 
+    public slots:
+        void ResetGemStatusFilter();
+
     private:
         void AddGemOriginFilter();
         void AddTypeFilter();
         void AddPlatformFilter();
         void AddFeatureFilter();
 
-        QVBoxLayout* m_mainLayout = nullptr;
+        QVBoxLayout* m_filterLayout = nullptr;
         GemModel* m_gemModel = nullptr;
         GemSortFilterProxyModel* m_filterProxyModel = nullptr;
+        FilterCategoryWidget* m_statusFilter = nullptr;
     };
 } // namespace O3DE::ProjectManager

Code/Tools/ProjectManager/Source/GemCatalog/GemItemDelegate.cpp

@@ -204,7 +204,6 @@ namespace O3DE::ProjectManager
         painter->save();
         const QRect buttonRect = CalcButtonRect(contentRect);
         QPoint circleCenter;
-        QString buttonText;
 
         const bool isAdded = GemModel::IsAdded(modelIndex);
         if (isAdded)
@@ -213,34 +212,15 @@ namespace O3DE::ProjectManager
             painter->setPen(m_buttonEnabledColor);
 
             circleCenter = buttonRect.center() + QPoint(buttonRect.width() / 2 - s_buttonBorderRadius + 1, 1);
-            buttonText = "Added";
         }
         else
         {
             circleCenter = buttonRect.center() + QPoint(-buttonRect.width() / 2 + s_buttonBorderRadius, 1);
-            buttonText = "Get";
         }
 
         // Rounded rect
         painter->drawRoundedRect(buttonRect, s_buttonBorderRadius, s_buttonBorderRadius);
 
-        // Text
-        QFont font;
-        QRect textRect = GetTextRect(font, buttonText, s_buttonFontSize);
-        if (isAdded)
-        {
-            textRect = QRect(buttonRect.left(), buttonRect.top(), buttonRect.width() - s_buttonCircleRadius * 2.0, buttonRect.height());
-        }
-        else
-        {
-            textRect = QRect(buttonRect.left() + s_buttonCircleRadius * 2.0, buttonRect.top(), buttonRect.width() - s_buttonCircleRadius * 2.0, buttonRect.height());
-        }
-
-        font.setPixelSize(s_buttonFontSize);
-        painter->setFont(font);
-        painter->setPen(m_textColor);
-        painter->drawText(textRect, Qt::AlignCenter, buttonText);
-
         // Circle
         painter->setBrush(m_textColor);
         painter->drawEllipse(circleCenter, s_buttonCircleRadius, s_buttonCircleRadius);

Code/Tools/ProjectManager/Source/GemCatalog/GemListHeaderWidget.cpp

@@ -15,6 +15,7 @@
 #include <QStandardItemModel>
 #include <QLabel>
 #include <QVBoxLayout>
+#include <QSpacerItem>
 
 namespace O3DE::ProjectManager
 {
@@ -74,6 +75,15 @@ namespace O3DE::ProjectManager
         gemSummaryLabel->setStyleSheet("font-size: 12px;");
         columnHeaderLayout->addWidget(gemSummaryLabel);
 
+        QSpacerItem* horizontalSpacer = new QSpacerItem(0, 0, QSizePolicy::Expanding, QSizePolicy::Minimum);
+        columnHeaderLayout->addSpacerItem(horizontalSpacer);
+
+        QLabel* gemSelectedLabel = new QLabel(tr("Selected"));
+        gemSelectedLabel->setStyleSheet("font-size: 12px;");
+        columnHeaderLayout->addWidget(gemSelectedLabel);
+
+        columnHeaderLayout->addSpacing(60);
+
         vLayout->addLayout(columnHeaderLayout);
     }
 } // namespace O3DE::ProjectManager

Code/Tools/ProjectManager/Source/GemCatalog/GemModel.cpp

@@ -235,4 +235,19 @@ namespace O3DE::ProjectManager
         }
         return result;
     }
+
+    int GemModel::TotalAddedGems() const
+    {
+        int result = 0;
+        for (int row = 0; row < rowCount(); ++row)
+        {
+            const QModelIndex modelIndex = index(row, 0);
+            if (IsAdded(modelIndex))
+            {
+                ++result;
+            }
+        }
+        return result;
+    }
+
 } // namespace O3DE::ProjectManager

Code/Tools/ProjectManager/Source/GemCatalog/GemModel.h

@@ -63,6 +63,8 @@ namespace O3DE::ProjectManager
         QVector<QModelIndex> GatherGemsToBeAdded() const;
         QVector<QModelIndex> GatherGemsToBeRemoved() const;
 
+        int TotalAddedGems() const;
+
     private:
         enum UserRole
         {

Code/Tools/ProjectManager/Source/GemCatalog/GemSortFilterProxyModel.cpp

@@ -37,6 +37,16 @@ namespace O3DE::ProjectManager
             return false;
         }
 
+        // Gem status
+        if (m_gemStatusFilter != GemStatus::NoFilter)
+        {
+            const GemStatus sourceGemStatus = static_cast<GemStatus>(GemModel::IsAdded(sourceIndex));
+            if (m_gemStatusFilter != sourceGemStatus)
+            {
+                return false;
+            }
+        }
+
         // Gem origins
         if (m_gemOriginFilter)
         {
@@ -125,6 +135,19 @@ namespace O3DE::ProjectManager
         return true;
     }
 
+    QString GemSortFilterProxyModel::GetGemStatusString(GemStatus status)
+    {
+        switch (status)
+        {
+        case Unselected:
+            return "Unselected";
+        case Selected:
+            return "Selected";
+        default:
+            return "<Unknown Gem Status>";
+        }
+    }
+
     void GemSortFilterProxyModel::InvalidateFilter()
     {
         invalidate();

Code/Tools/ProjectManager/Source/GemCatalog/GemSortFilterProxyModel.h

@@ -29,8 +29,17 @@ namespace O3DE::ProjectManager
         Q_OBJECT // AUTOMOC
 
     public:
+        enum GemStatus
+        {
+            NoFilter = -1,
+            Unselected,
+            Selected
+        };
+
         GemSortFilterProxyModel(GemModel* sourceModel, QObject* parent = nullptr);
 
+        static QString GetGemStatusString(GemStatus status);
+
         bool filterAcceptsRow(int sourceRow, const QModelIndex& sourceParent) const override;
 
         GemModel* GetSourceModel() const { return m_sourceModel; } 
@@ -38,6 +47,9 @@ namespace O3DE::ProjectManager
 
         void SetSearchString(const QString& searchString) { m_searchString = searchString; InvalidateFilter(); }
 
+        GemStatus GetGemStatus() const { return m_gemStatusFilter; }
+        void SetGemStatus(GemStatus gemStatus) { m_gemStatusFilter = gemStatus; InvalidateFilter(); }
+
         GemInfo::GemOrigins GetGemOrigins() const { return m_gemOriginFilter; }
         void SetGemOrigins(const GemInfo::GemOrigins& gemOrigins) { m_gemOriginFilter = gemOrigins; InvalidateFilter(); }
 
@@ -61,6 +73,7 @@ namespace O3DE::ProjectManager
         AzQtComponents::SelectionProxyModel* m_selectionProxyModel = nullptr;
 
         QString m_searchString;
+        GemStatus m_gemStatusFilter = GemStatus::NoFilter;
         GemInfo::GemOrigins m_gemOriginFilter = {};
         GemInfo::Platforms m_platformFilter = {};
         GemInfo::Types m_typeFilter = {};

Code/Tools/ProjectManager/Source/ProjectButtonWidget.cpp

@@ -33,7 +33,7 @@ namespace O3DE::ProjectManager
     {
         setObjectName("labelButton");
 
-        QVBoxLayout* vLayout = new QVBoxLayout(this);
+        QVBoxLayout* vLayout = new QVBoxLayout();
         vLayout->setContentsMargins(0, 0, 0, 0);
         vLayout->setSpacing(5);
 

Code/Tools/ProjectManager/Source/ProjectManagerWindow.cpp

@@ -13,21 +13,11 @@
 #include <ProjectManagerWindow.h>
 #include <ScreensCtrl.h>
 
-#include <AzQtComponents/Components/StyleManager.h>
-#include <AzCore/IO/FileIO.h>
-#include <AzCore/IO/Path/Path.h>
-#include <AzFramework/CommandLine/CommandLine.h>
-#include <AzFramework/Application/Application.h>
-
-#include <QDir>
-
 namespace O3DE::ProjectManager
 {
-    ProjectManagerWindow::ProjectManagerWindow(QWidget* parent, const AZ::IO::PathView& engineRootPath, const AZ::IO::PathView& projectPath, ProjectManagerScreen startScreen)
+    ProjectManagerWindow::ProjectManagerWindow(QWidget* parent, const AZ::IO::PathView& projectPath, ProjectManagerScreen startScreen)
         : QMainWindow(parent)
     {
-        m_pythonBindings = AZStd::make_unique<PythonBindings>(engineRootPath);
-
         setWindowTitle(tr("O3DE Project Manager"));
 
         ScreensCtrl* screensCtrl = new ScreensCtrl();
@@ -44,15 +34,6 @@ namespace O3DE::ProjectManager
 
         setCentralWidget(screensCtrl);
 
-        // setup stylesheets and hot reloading 
-        QDir rootDir = QString::fromUtf8(engineRootPath.Native().data(), aznumeric_cast<int>(engineRootPath.Native().size()));
-        const auto pathOnDisk = rootDir.absoluteFilePath("Code/Tools/ProjectManager/Resources");
-        const auto qrcPath = QStringLiteral(":/ProjectManager/style");
-        AzQtComponents::StyleManager::addSearchPaths("style", pathOnDisk, qrcPath, engineRootPath);
-
-        // set stylesheet after creating the screens or their styles won't get updated
-        AzQtComponents::StyleManager::setStyleSheet(this, QStringLiteral("style:ProjectManager.qss"));
-
         // always push the projects screen first so we have something to come back to
         if (startScreen != ProjectManagerScreen::Projects)
         {
@@ -66,10 +47,4 @@ namespace O3DE::ProjectManager
             emit screensCtrl->NotifyCurrentProject(path);
         }
     }
-
-    ProjectManagerWindow::~ProjectManagerWindow()
-    {
-        m_pythonBindings.reset();
-    }
-
 } // namespace O3DE::ProjectManager

Code/Tools/ProjectManager/Source/ProjectManagerWindow.h

@@ -13,7 +13,7 @@
 
 #if !defined(Q_MOC_RUN)
 #include <QMainWindow>
-#include <PythonBindings.h>
+#include <AzCore/IO/Path/Path.h>
 #include <ScreenDefs.h>
 #endif
 
@@ -25,12 +25,8 @@ namespace O3DE::ProjectManager
         Q_OBJECT
 
     public:
-        explicit ProjectManagerWindow(QWidget* parent, const AZ::IO::PathView& engineRootPath, const AZ::IO::PathView& projectPath,
+        explicit ProjectManagerWindow(QWidget* parent, const AZ::IO::PathView& projectPath,
             ProjectManagerScreen startScreen = ProjectManagerScreen::Projects);
-        ~ProjectManagerWindow();
-
-    private:
-        AZStd::unique_ptr<PythonBindings> m_pythonBindings;
     };
 
 } // namespace O3DE::ProjectManager

Code/Tools/ProjectManager/Source/ProjectSettingsScreen.cpp

@@ -37,7 +37,7 @@ namespace O3DE::ProjectManager
         // if we don't set this in a frame (just use a sub-layout) all the content will align incorrectly horizontally
         QFrame* projectSettingsFrame = new QFrame(this);
         projectSettingsFrame->setObjectName("projectSettings");
-        m_verticalLayout = new QVBoxLayout(this);
+        m_verticalLayout = new QVBoxLayout();
 
         // you cannot remove content margins in qss
         m_verticalLayout->setContentsMargins(0, 0, 0, 0);

Code/Tools/ProjectManager/Source/ProjectsScreen.cpp

@@ -85,7 +85,7 @@ namespace O3DE::ProjectManager
         QFrame* frame = new QFrame(this);
         frame->setObjectName("firstTimeContent");
         {
-            QVBoxLayout* layout = new QVBoxLayout(this);
+            QVBoxLayout* layout = new QVBoxLayout();
             layout->setContentsMargins(0, 0, 0, 0);
             layout->setAlignment(Qt::AlignTop);
             frame->setLayout(layout);
@@ -100,7 +100,7 @@ namespace O3DE::ProjectManager
                                    "available by downloading our sample project."));
             layout->addWidget(introLabel);
 
-            QHBoxLayout* buttonLayout = new QHBoxLayout(this);
+            QHBoxLayout* buttonLayout = new QHBoxLayout();
             buttonLayout->setAlignment(Qt::AlignLeft);
             buttonLayout->setSpacing(s_spacerSize);
 

Code/Tools/ProjectManager/Source/PythonBindings.cpp

@@ -226,7 +226,7 @@ namespace O3DE::ProjectManager
     PythonBindings::PythonBindings(const AZ::IO::PathView& enginePath)
         : m_enginePath(enginePath)
     {
-        StartPython();
+        m_pythonStarted = StartPython();
     }
 
     PythonBindings::~PythonBindings()
@@ -234,6 +234,11 @@ namespace O3DE::ProjectManager
         StopPython();
     }
 
+    bool PythonBindings::PythonStarted()
+    {
+        return m_pythonStarted && Py_IsInitialized();
+    }
+
     bool PythonBindings::StartPython()
     {
         if (Py_IsInitialized())
@@ -246,7 +251,7 @@ namespace O3DE::ProjectManager
         AZStd::string pyBasePath = Platform::GetPythonHomePath(PY_PACKAGE, m_enginePath.c_str());
         if (!AZ::IO::SystemFile::Exists(pyBasePath.c_str()))
         {
-            AZ_Assert(false, "Python home path must exist. path:%s", pyBasePath.c_str());
+            AZ_Error("python", false, "Python home path does not exist: %s", pyBasePath.c_str());
             return false;
         }
 
@@ -351,6 +356,11 @@ namespace O3DE::ProjectManager
 
     AZ::Outcome<void, AZStd::string> PythonBindings::ExecuteWithLockErrorHandling(AZStd::function<void()> executionCallback)
     {
+        if (!Py_IsInitialized())
+        {
+            return AZ::Failure<AZStd::string>("Python is not initialized");
+        }
+
         AZStd::lock_guard<decltype(m_lock)> lock(m_lock);
         pybind11::gil_scoped_release release;
         pybind11::gil_scoped_acquire acquire;

Code/Tools/ProjectManager/Source/PythonBindings.h

@@ -34,6 +34,8 @@ namespace O3DE::ProjectManager
         ~PythonBindings() override;
 
         // PythonBindings overrides
+        bool PythonStarted() override;
+
         // Engine
         AZ::Outcome<EngineInfo> GetEngineInfo() override;
         bool SetEngineInfo(const EngineInfo& engineInfo) override;
@@ -70,6 +72,8 @@ namespace O3DE::ProjectManager
         bool StopPython();
 
 
+        bool m_pythonStarted = false;
+
         AZ::IO::FixedMaxPath m_enginePath;
         pybind11::handle m_engineTemplate;
         AZStd::recursive_mutex m_lock;

Code/Tools/ProjectManager/Source/PythonBindingsInterface.h

@@ -34,6 +34,12 @@ namespace O3DE::ProjectManager
         IPythonBindings() = default;
         virtual ~IPythonBindings() = default;
 
+        /**
+         * Get whether Python was started or not.  All Python functionality will fail if Python
+         * failed to start. 
+         * @return true if Python was started successfully, false on failure 
+         */
+        virtual bool PythonStarted() = 0;
 
         // Engine
 

Code/Tools/ProjectManager/Source/UpdateProjectCtrl.cpp

@@ -189,11 +189,13 @@ namespace O3DE::ProjectManager
     {
         if (m_stack->currentIndex() == ScreenOrder::Gems)
         {
-            m_header->setSubTitle(QString(tr("Configure Gems for \"%1\"")).arg(m_projectInfo.m_projectName));
-            m_nextButton->setText(tr("Confirm"));
+            m_header->setTitle(QString(tr("Edit Project Settings: \"%1\"")).arg(m_projectInfo.m_projectName));
+            m_header->setSubTitle(QString(tr("Configure Gems")));
+            m_nextButton->setText(tr("Finalize"));
         }
         else
         {
+            m_header->setTitle("");
             m_header->setSubTitle(QString(tr("Edit Project Settings: \"%1\"")).arg(m_projectInfo.m_projectName));
             m_nextButton->setText(tr("Save"));
         }

Code/Tools/ProjectManager/Source/main.cpp

@@ -10,85 +10,26 @@
 *
 */
 
-#include <AzQtComponents/Utilities/HandleDpiAwareness.h>
-#include <AzQtComponents/Components/StyleManager.h>
-#include <AzCore/Component/ComponentApplication.h>
-#include <AzCore/Settings/SettingsRegistryMergeUtils.h>
-#include <AzCore/IO/Path/Path.h>
-#include <AzFramework/CommandLine/CommandLine.h>
-
-#include <ProjectManagerWindow.h>
-#include <ProjectUtils.h>
-
-#include <QApplication>
-#include <QCoreApplication>
-#include <QGuiApplication>
-
-using namespace O3DE::ProjectManager;
+#include <AzQtComponents/Utilities/QtPluginPaths.h>
+#include <Application.h>
 
 int main(int argc, char* argv[])
 {
-    QApplication::setOrganizationName("O3DE");
-    QApplication::setOrganizationDomain("o3de.org");
-    QCoreApplication::setApplicationName("ProjectManager");
-    QCoreApplication::setApplicationVersion("1.0");
-
-    QCoreApplication::setAttribute(Qt::AA_EnableHighDpiScaling);
-    QCoreApplication::setAttribute(Qt::AA_UseHighDpiPixmaps);
-    QCoreApplication::setAttribute(Qt::AA_DontCreateNativeWidgetSiblings);
-    QGuiApplication::setHighDpiScaleFactorRoundingPolicy(Qt::HighDpiScaleFactorRoundingPolicy::PassThrough);
-    AzQtComponents::Utilities::HandleDpiAwareness(AzQtComponents::Utilities::SystemDpiAware);
-
-    AZ::AllocatorInstance<AZ::SystemAllocator>::Create();
     int runSuccess = 0;
+
+    // Call before using any Qt, or the app may not be able to locate Qt libs
+    AzQtComponents::PrepareQtPaths();
+
+    O3DE::ProjectManager::Application application(&argc, &argv);
+    if (!application.Init())
     {
-        QApplication app(argc, argv);
-
-        // Need to use settings registry to get EngineRootFolder
-        AZ::IO::FixedMaxPath engineRootPath;
-        {
-            AZ::ComponentApplication componentApplication;
-            auto settingsRegistry = AZ::SettingsRegistry::Get();
-            settingsRegistry->Get(engineRootPath.Native(), AZ::SettingsRegistryMergeUtils::FilePathKey_EngineRootFolder);
-        }
-
-        AzQtComponents::StyleManager styleManager(&app);
-        styleManager.initialize(&app, engineRootPath);
-
-        // Get the initial start screen if one is provided via command line
-        constexpr char optionPrefix[] = "--";
-        AZ::CommandLine commandLine(optionPrefix);
-        commandLine.Parse(argc, argv);
-
-        ProjectManagerScreen startScreen = ProjectManagerScreen::Projects;
-        if(commandLine.HasSwitch("screen"))
-        {
-            QString screenOption = commandLine.GetSwitchValue("screen", 0).c_str();
-            ProjectManagerScreen screen = ProjectUtils::GetProjectManagerScreen(screenOption);
-            if (screen != ProjectManagerScreen::Invalid)
-            {
-                startScreen = screen;
-            }
-        }
-
-        AZ::IO::FixedMaxPath projectPath;
-        if (commandLine.HasSwitch("project-path"))
-        {
-            projectPath = commandLine.GetSwitchValue("project-path", 0).c_str();
-        }
-
-        ProjectManagerWindow window(nullptr, engineRootPath, projectPath, startScreen);
-        window.show();
-
-        // somethings is preventing us from moving the window to the center of the
-        // primary screen - likely an Az style or component helper
-        constexpr int width = 1200;
-        constexpr int height = 800;
-        window.resize(width, height);
-
-        runSuccess = app.exec();
+        AZ_Error("ProjectManager", false, "Failed to initialize");
+        runSuccess = 1;
+    }
+    else
+    {
+        runSuccess = application.Run() ? 0 : 1;
     }
-    AZ::AllocatorInstance<AZ::SystemAllocator>::Destroy();
 
     return runSuccess;
 }

Code/Tools/ProjectManager/project_manager_app_files.cmake

@@ -0,0 +1,17 @@
+#
+# All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+# its licensors.
+#
+# For complete copyright and license terms please see the LICENSE at the root of this
+# distribution (the "License"). All use of this software is governed by the License,
+# or, if provided, by the license below or the license accompanying this file. Do not
+# remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#
+
+set(FILES
+    Resources/ProjectManager.rc
+    Resources/ProjectManager.qrc
+    Resources/ProjectManager.qss
+    Source/main.cpp
+)

Code/Tools/ProjectManager/project_manager_files.cmake

@@ -1,4 +1,5 @@
 #
+#
 # All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
 # its licensors.
 #
@@ -10,10 +11,8 @@
 #
 
 set(FILES
-    Resources/ProjectManager.rc
-    Resources/ProjectManager.qrc
-    Resources/ProjectManager.qss
-    Source/main.cpp
+    Source/Application.h
+    Source/Application.cpp
     Source/ScreenDefs.h
     Source/ScreenFactory.h
     Source/ScreenFactory.cpp

Code/Tools/ProjectManager/project_manager_tests_files.cmake

@@ -0,0 +1,17 @@
+#
+# All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+# its licensors.
+#
+# For complete copyright and license terms please see the LICENSE at the root of this
+# distribution (the "License"). All use of this software is governed by the License,
+# or, if provided, by the license below or the license accompanying this file. Do not
+# remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+#
+
+set(FILES
+    Resources/ProjectManager.qrc
+    Resources/ProjectManager.qss
+    tests/ApplicationTests.cpp
+    tests/main.cpp
+)

Code/Tools/ProjectManager/tests/ApplicationTests.cpp

@@ -0,0 +1,47 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include <AzCore/UnitTest/TestTypes.h>
+#include <AzCore/std/smart_ptr/make_shared.h>
+#include <Application.h>
+#include <ProjectManager_Test_Traits_Platform.h>
+
+namespace O3DE::ProjectManager
+{
+    class ProjectManagerApplicationTests 
+        : public ::UnitTest::ScopedAllocatorSetupFixture
+    {
+    public:
+
+        ProjectManagerApplicationTests()
+        {
+            m_application = AZStd::make_unique<ProjectManager::Application>();
+        }
+
+        ~ProjectManagerApplicationTests()
+        {
+            m_application.reset();
+        }
+
+        AZStd::unique_ptr<ProjectManager::Application> m_application;
+    };
+
+#if AZ_TRAIT_DISABLE_FAILED_PROJECT_MANAGER_TESTS
+    TEST_F(ProjectManagerApplicationTests, DISABLED_Application_Init_Succeeds)
+#else
+    TEST_F(ProjectManagerApplicationTests, Application_Init_Succeeds)
+#endif // !AZ_TRAIT_DISABLE_FAILED_PROJECT_MANAGER_TESTS
+    {
+        // we don't want to interact with actual GUI or display it
+        EXPECT_TRUE(m_application->Init(/*interactive=*/false));
+    }
+}

Code/Tools/ProjectManager/tests/main.cpp

@@ -0,0 +1,35 @@
+/*
+* All or portions of this file Copyright (c) Amazon.com, Inc. or its affiliates or
+* its licensors.
+*
+* For complete copyright and license terms please see the LICENSE at the root of this
+* distribution (the "License"). All use of this software is governed by the License,
+* or, if provided, by the license below or the license accompanying this file. Do not
+* remove or modify any license notices. This file is distributed on an "AS IS" BASIS,
+* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+*
+*/
+
+#include <AzTest/AzTest.h>
+
+DECLARE_AZ_UNIT_TEST_MAIN();
+
+int runDefaultRunner(int argc, char* argv[])
+{
+    INVOKE_AZ_UNIT_TEST_MAIN(nullptr)
+    return 0;
+}
+
+int main(int argc, char* argv[])
+{
+    if (argc == 1)
+    {
+        // if no parameters are provided, add the --unittests parameter
+        constexpr int defaultArgc = 2;
+        char unittest_arg[] = "--unittests"; // Conversion from string literal to char* is not allowed per ISO C++11
+        char* defaultArgv[defaultArgc] = { argv[0], unittest_arg };
+        return runDefaultRunner(defaultArgc, defaultArgv);
+    }
+    INVOKE_AZ_UNIT_TEST_MAIN(nullptr); 
+    return 0;
+}

Code/Tools/SceneAPI/FbxSceneBuilder/Importers/AssImpTransformImporter.cpp

@@ -46,22 +46,69 @@ namespace AZ
                     serializeContext->Class<AssImpTransformImporter, SceneCore::LoadingComponent>()->Version(1);
                 }
             }
-            
+
+            void GetAllBones(const aiScene* scene, AZStd::unordered_map<AZStd::string, const aiBone*>& boneLookup)
+            {
+                for (unsigned meshIndex = 0; meshIndex < scene->mNumMeshes; ++meshIndex)
+                {
+                    const aiMesh* mesh = scene->mMeshes[meshIndex];
+
+                    for (unsigned boneIndex = 0; boneIndex < mesh->mNumBones; ++boneIndex)
+                    {
+                        const aiBone* bone = mesh->mBones[boneIndex];
+
+                        boneLookup[bone->mName.C_Str()] = bone;
+                    }
+                }
+            }
+
             Events::ProcessingResult AssImpTransformImporter::ImportTransform(AssImpSceneNodeAppendedContext& context)
             {
                 AZ_TraceContext("Importer", "transform");
                 const aiNode* currentNode = context.m_sourceNode.GetAssImpNode();
                 const aiScene* scene = context.m_sourceScene.GetAssImpScene();
-                
+
                 if (currentNode == scene->mRootNode || IsPivotNode(currentNode->mName))
                 {
                     return Events::ProcessingResult::Ignored;
                 }
 
-                aiMatrix4x4 combinedTransform = GetConcatenatedLocalTransform(currentNode);
+                AZStd::unordered_map<AZStd::string, const aiBone*> boneLookup;
+                GetAllBones(scene, boneLookup);
+
+                auto boneIterator = boneLookup.find(currentNode->mName.C_Str());
+                const bool isBone = boneIterator != boneLookup.end();
+
+                aiMatrix4x4 combinedTransform;
+
+                if (isBone)
+                {
+                    auto parentNode = currentNode->mParent;
+
+                    aiMatrix4x4 offsetMatrix = boneIterator->second->mOffsetMatrix;
+                    aiMatrix4x4 parentOffset {};
+
+                    auto parentBoneIterator = boneLookup.find(parentNode->mName.C_Str());
+
+                    if (parentNode && parentBoneIterator != boneLookup.end())
+                    {
+                        const auto& parentBone = parentBoneIterator->second;
+
+                        parentOffset = parentBone->mOffsetMatrix;
+                    }
+
+                    auto inverseOffset = offsetMatrix;
+                    inverseOffset.Inverse();
+
+                    combinedTransform = parentOffset * inverseOffset;
+                }
+                else
+                {
+                    combinedTransform = GetConcatenatedLocalTransform(currentNode);
+                }
 
                 DataTypes::MatrixType localTransform = AssImpSDKWrapper::AssImpTypeConverter::ToTransform(combinedTransform);
-                
+
                 context.m_sourceSceneSystem.SwapTransformForUpAxis(localTransform);
                 context.m_sourceSceneSystem.ConvertUnit(localTransform);
 
@@ -105,9 +152,7 @@ namespace AZ
                 }
                 else
                 {
-                    bool addedData = context.m_scene.GetGraph().SetContent(
-                        context.m_currentGraphPosition,
-                        transformData);
+                    bool addedData = context.m_scene.GetGraph().SetContent(context.m_currentGraphPosition, transformData);
 
                     AZ_Error(SceneAPI::Utilities::ErrorWindow, addedData, "Failed to add node data");
                     return addedData ? Events::ProcessingResult::Success : Events::ProcessingResult::Failure;

Code/Tools/SceneAPI/SDKWrapper/AssImpSceneWrapper.cpp

@@ -69,13 +69,14 @@ namespace AZ
             // aiProcess_JoinIdenticalVertices is not enabled because O3DE has a mesh optimizer that also does this,
             // this flag is disabled to keep AssImp output similar to FBX SDK to reduce downstream bugs for the initial AssImp release.
             // There's currently a minimum of properties and flags set to maximize compatibility with the existing node graph.
+
+            // aiProcess_LimitBoneWeights is not enabled because it will remove bones which are not associated with a mesh.
+            // This results in the loss of the offset matrix data for nodes without a mesh which is required for the Transform Importer.
             m_importer.SetPropertyBool(AI_CONFIG_IMPORT_FBX_PRESERVE_PIVOTS, false);
             m_importer.SetPropertyBool(AI_CONFIG_IMPORT_FBX_OPTIMIZE_EMPTY_ANIMATION_CURVES, false);
             m_sceneFileName = fileName;
             m_assImpScene = m_importer.ReadFile(fileName,
                 aiProcess_Triangulate //Triangulates all faces of all meshes
-                | aiProcess_LimitBoneWeights //Limits the number of bones that can affect a vertex to a maximum value
-                                             //dropping the least important and re-normalizing
                 | aiProcess_GenNormals); //Generate normals for meshes
 
 #if AZ_TRAIT_COMPILER_SUPPORT_CSIGNAL

Code/Tools/SerializeContextTools/SliceConverter.cpp

@@ -177,9 +177,10 @@ namespace AZ
 
                 AZ::Entity* rootEntity = reinterpret_cast<AZ::Entity*>(classPtr);
                 bool convertResult = ConvertSliceToPrefab(context, outputPath, isDryRun, rootEntity);
-                // Clear out the references to any nested slices so that the nested assets get unloaded correctly at the end of
-                // the conversion.  
-                ClearSliceAssetReferences(rootEntity);
+
+                // Delete the root entity pointer.  Otherwise, it will leak itself along with all of the slice asset references held
+                // within it.
+                delete rootEntity;
                 return convertResult;
             };
 
@@ -229,8 +230,12 @@ namespace AZ
                 return false;
             }
 
-            // Get all of the entities from the slice.
+            // Get all of the entities from the slice.  We're taking ownership of them, so we also remove them from the slice component
+            // without deleting them.
+            constexpr bool deleteEntities = false;
+            constexpr bool removeEmptyInstances = true;
             SliceComponent::EntityList sliceEntities = sliceComponent->GetNewEntities();
+            sliceComponent->RemoveAllEntities(deleteEntities, removeEmptyInstances);
             AZ_Printf("Convert-Slice", "  Slice contains %zu entities.\n", sliceEntities.size());
 
             // Create the Prefab with the entities from the slice.
@@ -273,6 +278,12 @@ namespace AZ
                 }
             }
 
+            // Save off a mapping of the slice's metadata entity ID as well, even though we never converted the entity itself.
+            // This will help us better detect entity ID mapping errors for nested slice instances.
+            AZ::Entity* metadataEntity = sliceComponent->GetMetadataEntity();
+            constexpr bool isMetadataEntity = true;
+            m_aliasIdMapper.emplace(metadataEntity->GetId(), SliceEntityMappingInfo(templateId, "MetadataEntity", isMetadataEntity));
+
             // Update the prefab template with the fixed-up data in our prefab instance.
             AzToolsFramework::Prefab::PrefabDom prefabDom;
             bool storeResult = AzToolsFramework::Prefab::PrefabDomUtils::StoreInstanceInPrefabDom(*sourceInstance, prefabDom);
@@ -402,6 +413,21 @@ namespace AZ
                     "Convert-Slice", "  Attaching %zu instances of nested slice '%s'.\n", instances.size(),
                     nestedPrefabPath.Native().c_str());
 
+                // Before processing any further, save off all the known entity IDs from all the instances and how they map back to
+                // the base nested prefab that they've come from (i.e. this one).  As we proceed up the chain of nesting, this will
+                // build out a hierarchical list of owning instances for each entity that we can trace upwards to know where to add
+                // the entity into our nested prefab instance.
+                // This step needs to occur *before* converting the instances themselves, because while converting instances, they
+                // might have entity ID references that point to other instances.  By having the full instance entity ID map in place
+                // before conversion, we'll be able to fix them up appropriately.
+
+                for (auto& instance : instances)
+                {
+                    AZStd::string instanceAlias = GetInstanceAlias(instance);
+                    UpdateSliceEntityInstanceMappings(instance.GetEntityIdToBaseMap(), instanceAlias);
+                }
+
+                // Now that we have all the entity ID mappings, convert all the instances.
                 for (auto& instance : instances)
                 {
                     bool instanceConvertResult = ConvertSliceInstance(instance, sliceAsset, nestedTemplate, sourceInstance);
@@ -415,6 +441,28 @@ namespace AZ
             return true;
         }
 
+        AZStd::string SliceConverter::GetInstanceAlias(const AZ::SliceComponent::SliceInstance& instance)
+        {
+            // When creating the new instance, we would like to have deterministic instance aliases.  Prefabs that depend on this one
+            // will have patches that reference the alias, so if we reconvert this slice a second time, we would like it to produce
+            // the same results.  To get a deterministic and unique alias, we rely on the slice instance.  The slice instance contains
+            // a map of slice entity IDs to unique instance entity IDs.  We'll just consistently use the first entry in the map as the
+            // unique instance ID.
+            AZStd::string instanceAlias;
+            auto entityIdMap = instance.GetEntityIdMap();
+            if (!entityIdMap.empty())
+            {
+                instanceAlias = AZStd::string::format("Instance_%s", entityIdMap.begin()->second.ToString().c_str());
+            }
+            else
+            {
+                AZ_Error("Convert-Slice", false, "  Couldn't create deterministic instance alias.");
+                instanceAlias = AZStd::string::format("Instance_%s", AZ::Entity::MakeId().ToString().c_str());
+            }
+            return instanceAlias;
+        }
+
+
         bool SliceConverter::ConvertSliceInstance(
             AZ::SliceComponent::SliceInstance& instance,
             AZ::Data::Asset<AZ::SliceAsset>& sliceAsset,
@@ -438,27 +486,7 @@ namespace AZ
             auto instanceToTemplateInterface = AZ::Interface<AzToolsFramework::Prefab::InstanceToTemplateInterface>::Get();
             auto prefabSystemComponentInterface = AZ::Interface<AzToolsFramework::Prefab::PrefabSystemComponentInterface>::Get();
 
-            // When creating the new instance, we would like to have deterministic instance aliases.  Prefabs that depend on this one
-            // will have patches that reference the alias, so if we reconvert this slice a second time, we would like it to produce
-            // the same results.  To get a deterministic and unique alias, we rely on the slice instance.  The slice instance contains
-            // a map of slice entity IDs to unique instance entity IDs.  We'll just consistently use the first entry in the map as the
-            // unique instance ID.
-            AZStd::string instanceAlias;
-            auto entityIdMap = instance.GetEntityIdMap();
-            if (!entityIdMap.empty())
-            {
-                instanceAlias = AZStd::string::format("Instance_%s", entityIdMap.begin()->second.ToString().c_str());
-            }
-            else
-            {
-                instanceAlias = AZStd::string::format("Instance_%s", AZ::Entity::MakeId().ToString().c_str());
-            }
-
-            // Before processing any further, save off all the known entity IDs from this instance and how they map back to the base
-            // nested prefab that they've come from (i.e. this one).  As we proceed up the chain of nesting, this will build out a
-            // hierarchical list of owning instances for each entity that we can trace upwards to know where to add the entity into
-            // our nested prefab instance.
-            UpdateSliceEntityInstanceMappings(instance.GetEntityIdToBaseMap(), instanceAlias);
+            AZStd::string instanceAlias = GetInstanceAlias(instance);
 
             // Create a new unmodified prefab Instance for the nested slice instance.
             auto nestedInstance = AZStd::make_unique<AzToolsFramework::Prefab::Instance>();
@@ -619,6 +647,10 @@ namespace AZ
                 SetParentEntity(containerEntity->get(), topLevelInstance->GetContainerEntityId(), onlySetIfInvalid);
             }
 
+            // After doing all of the above, run through entity references in any of the patched entities, and fix up the entity IDs to
+            // match the new ones in our prefabs.
+            RemapIdReferences(m_aliasIdMapper, topLevelInstance, nestedInstance.get(), instantiated, dependentSlice->GetSerializeContext());
+
             // Add the nested instance itself to the top-level prefab.  To do this, we need to add it to our top-level instance,
             // create a patch out of it, and patch the top-level prefab template.
 
@@ -750,17 +782,6 @@ namespace AZ
             AZ_Error("Convert-Slice", disconnected, "Asset Processor failed to disconnect successfully.");
         }
 
-        void SliceConverter::ClearSliceAssetReferences(AZ::Entity* rootEntity)
-        {
-            SliceComponent* sliceComponent = AZ::EntityUtils::FindFirstDerivedComponent<SliceComponent>(rootEntity);
-            // Make a copy of the slice list and remove all of them from the loaded component.
-            AZ::SliceComponent::SliceList slices = sliceComponent->GetSlices();
-            for (auto& slice : slices)
-            {
-                sliceComponent->RemoveSlice(&slice);
-            }
-        }
-
         void SliceConverter::UpdateSliceEntityInstanceMappings(
             const AZ::SliceComponent::EntityIdToEntityIdMap& sliceEntityIdMap, const AZStd::string& currentInstanceAlias)
         {
@@ -789,9 +810,108 @@ namespace AZ
                         AZ_Assert(oldId == newId, "The same entity instance ID has unexpectedly appeared twice in the same nested prefab.");
                     }
                 }
+                else
+                {
+                    AZ_Warning("Convert-Slice", false, "  Couldn't find an entity ID conversion for %s.", oldId.ToString().c_str());
+                }
             }
         }
 
+        void SliceConverter::RemapIdReferences(
+            const AZStd::unordered_map<AZ::EntityId, SliceEntityMappingInfo>& idMapper,
+            AzToolsFramework::Prefab::Instance* topLevelInstance,
+            AzToolsFramework::Prefab::Instance* nestedInstance,
+            SliceComponent::InstantiatedContainer* instantiatedEntities,
+            SerializeContext* context)
+        {
+            // Given a set of instantiated entities, run through all of them, look for entity references, and replace the entity IDs with
+            // new ones that match up with our prefabs.
+
+            IdUtils::Remapper<EntityId>::ReplaceIdsAndIdRefs(
+                instantiatedEntities,
+                [idMapper, &topLevelInstance, &nestedInstance](
+                    const EntityId& sourceId, bool isEntityId, [[maybe_unused]] const AZStd::function<EntityId()>& idGenerator) -> EntityId
+                {
+                    EntityId newId = sourceId;
+
+                    // Only convert valid entity references.  Actual entity IDs have already been taken care of elsewhere, so ignore them.
+                    if (!isEntityId && sourceId.IsValid())
+                    {
+                        auto entityEntry = idMapper.find(sourceId);
+
+                        // Since we've already remapped transform hierarchies to include container entities, it's possible that our entity
+                        // reference is pointing to a container, which means it won't be in our slice mapping table.  In that case, just
+                        // return it as-is.
+                        if (entityEntry == idMapper.end())
+                        {
+                            return sourceId;
+                        }
+
+                        // We've got a slice->prefab mapping entry, so now we need to use it.
+                        auto& mappingStruct = entityEntry->second;
+
+                        if (mappingStruct.m_nestedInstanceAliases.empty())
+                        {
+                            // If we don't have a chain of nested instance aliases, then this entity reference is either within the
+                            // current nested instance or it's pointing to an entity in the top-level instance.  We'll try them both
+                            // to look for a match.
+
+                            EntityId prefabId = nestedInstance->GetEntityId(mappingStruct.m_entityAlias);
+                            if (!prefabId.IsValid())
+                            {
+                                prefabId = topLevelInstance->GetEntityId(mappingStruct.m_entityAlias);
+                            }
+
+                            if (prefabId.IsValid())
+                            {
+                                newId = prefabId;
+                            }
+                            else
+                            {
+                                AZ_Error("Convert-Slice", false, "  Couldn't find source ID %s", sourceId.ToString().c_str());
+                            }
+                        }
+                        else
+                        {
+                            // We *do* have a chain of nested instance aliases.  This chain could either be relative to the nested instance
+                            // or the top-level instance.  We can tell which one it is by which one can find the first nested instance
+                            // alias.
+
+                            AzToolsFramework::Prefab::Instance* entityInstance = nestedInstance;
+                            auto it = mappingStruct.m_nestedInstanceAliases.rbegin();
+                            if (!entityInstance->FindNestedInstance(*it).has_value())
+                            {
+                                entityInstance = topLevelInstance;
+                            }
+
+                            // Now that we've got a starting point, iterate through the chain of nested instance aliases to find the
+                            // correct instance to get the entity ID for.  We have to go from slice IDs -> entity aliases -> entity IDs
+                            // because prefab instance creation can change some of our entity IDs along the way.
+                            for (; it != mappingStruct.m_nestedInstanceAliases.rend(); it++)
+                            {
+                                auto foundInstance = entityInstance->FindNestedInstance(*it);
+                                if (foundInstance.has_value())
+                                {
+                                    entityInstance = &(foundInstance->get());
+                                }
+                                else
+                                {
+                                    AZ_Assert(false, "Couldn't find nested instance %s", it->c_str());
+                                }
+                            }
+
+                            EntityId prefabId = entityInstance->GetEntityId(mappingStruct.m_entityAlias);
+                            if (prefabId.IsValid())
+                            {
+                                newId = prefabId;
+                            }
+                        }
+                    }
+
+                    return newId;
+                },
+                context);
+        }
 
     } // namespace SerializeContextTools
 } // namespace AZ

Code/Tools/SerializeContextTools/SliceConverter.h

@@ -42,6 +42,28 @@ namespace AZ
             bool ConvertSliceFiles(Application& application);
 
         private:
+            // When converting slice entities, especially for nested slices, we need to keep track of the original
+            // entity ID, the entity alias it uses in the prefab, and which template and nested instance path it maps to.
+            // As we encounter each instanced entity ID, we can look it up in this structure and use this to determine how to properly
+            // add it to the correct place in the hierarchy.
+            struct SliceEntityMappingInfo
+            {
+                SliceEntityMappingInfo(
+                    AzToolsFramework::Prefab::TemplateId templateId,
+                    AzToolsFramework::Prefab::EntityAlias entityAlias,
+                    bool isMetadataEntity = false)
+                    : m_templateId(templateId)
+                    , m_entityAlias(entityAlias)
+                    , m_isMetadataEntity(isMetadataEntity)
+                {
+                }
+
+                AzToolsFramework::Prefab::TemplateId m_templateId;
+                AzToolsFramework::Prefab::EntityAlias m_entityAlias;
+                AZStd::vector<AzToolsFramework::Prefab::InstanceAlias> m_nestedInstanceAliases;
+                bool m_isMetadataEntity{ false };
+            };
+
             bool ConnectToAssetProcessor();
             void DisconnectFromAssetProcessor();
 
@@ -58,27 +80,17 @@ namespace AZ
             void SetParentEntity(const AZ::Entity& entity, const AZ::EntityId& parentId, bool onlySetIfInvalid);
             void PrintPrefab(AzToolsFramework::Prefab::TemplateId templateId);
             bool SavePrefab(AZ::IO::PathView outputPath, AzToolsFramework::Prefab::TemplateId templateId);
-            void ClearSliceAssetReferences(AZ::Entity* rootEntity);
             void UpdateSliceEntityInstanceMappings(
                 const AZ::SliceComponent::EntityIdToEntityIdMap& sliceEntityIdMap,
                 const AZStd::string& currentInstanceAlias);
+            AZStd::string GetInstanceAlias(const AZ::SliceComponent::SliceInstance& instance);
 
-            // When converting slice entities, especially for nested slices, we need to keep track of the original
-            // entity ID, the entity alias it uses in the prefab, and which template and nested instance path it maps to.
-            // As we encounter each instanced entity ID, we can look it up in this structure and use this to determine how to properly
-            // add it to the correct place in the hierarchy.
-            struct SliceEntityMappingInfo
-            {
-                SliceEntityMappingInfo(AzToolsFramework::Prefab::TemplateId templateId, AzToolsFramework::Prefab::EntityAlias entityAlias)
-                    : m_templateId(templateId)
-                    , m_entityAlias(entityAlias)
-                {
-                }
-
-                AzToolsFramework::Prefab::TemplateId m_templateId;
-                AzToolsFramework::Prefab::EntityAlias m_entityAlias;
-                AZStd::vector<AzToolsFramework::Prefab::InstanceAlias> m_nestedInstanceAliases;
-            };
+            void RemapIdReferences(
+                const AZStd::unordered_map<AZ::EntityId, SliceEntityMappingInfo>& idMapper,
+                AzToolsFramework::Prefab::Instance* topLevelInstance,
+                AzToolsFramework::Prefab::Instance* nestedInstance,
+                SliceComponent::InstantiatedContainer* instantiatedEntities,
+                SerializeContext* context);
 
             // Track all of the entity IDs created and associate them with enough conversion information to know how to place the
             // entities in the correct place in the prefab hierarchy and fix up parent entity ID mappings to work with the nested