// Copyright Epic Games, Inc. All Rights Reserved.

#include "GeometryCollection/GeometryCollectionComponent.h"

#include "Async/ParallelFor.h"
#include "Components/BoxComponent.h"
#include "ComponentRecreateRenderStateContext.h"
#include "GeometryCollection/GeometryCollectionObject.h"
#include "GeometryCollection/GeometryCollectionAlgo.h"
#include "GeometryCollection/GeometryCollectionComponentPluginPrivate.h"
#include "GeometryCollection/GeometryCollectionSceneProxy.h"
#include "GeometryCollection/GeometryCollectionSQAccelerator.h"
#include "GeometryCollection/GeometryCollectionUtility.h"
#include "GeometryCollection/GeometryCollectionClusteringUtility.h"
#include "GeometryCollection/GeometryCollectionProximityUtility.h"
#include "GeometryCollection/GeometryCollectionCache.h"
#include "GeometryCollection/GeometryCollectionActor.h"
#include "GeometryCollection/GeometryCollectionDebugDrawComponent.h"
#include "Physics/Experimental/PhysScene_Chaos.h"
#include "Modules/ModuleManager.h"
#include "ChaosSolversModule.h"
#include "ChaosStats.h"
#include "PhysicsProxy/GeometryCollectionPhysicsProxy.h"
#include "PhysicsSolver.h"
#include "Physics/PhysicsFiltering.h"
#include "Chaos/ChaosPhysicalMaterial.h"
#include "AI/NavigationSystemHelpers.h"
#include "Net/UnrealNetwork.h"
#include "Net/Core/PushModel/PushModel.h"
#include "PhysicalMaterials/PhysicalMaterial.h"
#include "PhysicsField/PhysicsFieldComponent.h"
#include "Engine/InstancedStaticMesh.h"

#include "Algo/RemoveIf.h"

#if WITH_EDITOR
#include "AssetToolsModule.h"
#include "Editor.h"
#endif

#include "PhysicsEngine/BodySetup.h"
#include "PhysicsEngine/BodyInstance.h"
#include "Chaos/ChaosGameplayEventDispatcher.h"

#include "Rendering/NaniteResources.h"
#include "PrimitiveSceneInfo.h"

#if !(UE_BUILD_SHIPPING || UE_BUILD_TEST)
#include "Logging/MessageLog.h"
#include "Misc/UObjectToken.h"
#endif //!(UE_BUILD_SHIPPING || UE_BUILD_TEST)

#if INTEL_ISPC

#if USING_CODE_ANALYSIS
MSVC_PRAGMA(warning(push))
MSVC_PRAGMA(warning(disable : ALL_CODE_ANALYSIS_WARNINGS))
#endif    // USING_CODE_ANALYSIS

#include "GeometryCollectionComponent.ispc.generated.h"

#if USING_CODE_ANALYSIS
MSVC_PRAGMA(warning(pop))
#endif    // USING_CODE_ANALYSIS

static_assert(sizeof(ispc::FMatrix) == sizeof(FMatrix), "sizeof(ispc::FMatrix) != sizeof(FMatrix)");
static_assert(sizeof(ispc::FBox) == sizeof(FBox), "sizeof(ispc::FBox) != sizeof(FBox)");
#endif

#if !defined(CHAOS_BOX_CALC_BOUNDS_ISPC_ENABLED_DEFAULT)
#define CHAOS_BOX_CALC_BOUNDS_ISPC_ENABLED_DEFAULT 1
#endif

// Support run-time toggling on supported platforms in non-shipping configurations
#if !INTEL_ISPC || UE_BUILD_SHIPPING
static constexpr bool bChaos_BoxCalcBounds_ISPC_Enabled = INTEL_ISPC && CHAOS_BOX_CALC_BOUNDS_ISPC_ENABLED_DEFAULT;
#else
static bool bChaos_BoxCalcBounds_ISPC_Enabled = CHAOS_BOX_CALC_BOUNDS_ISPC_ENABLED_DEFAULT;
static FAutoConsoleVariableRef CVarChaosBoxCalcBoundsISPCEnabled(TEXT("p.Chaos.BoxCalcBounds.ISPC"), bChaos_BoxCalcBounds_ISPC_Enabled, TEXT("Whether to use ISPC optimizations in calculating box bounds in geometry collections"));
#endif

bool bChaos_GC_CacheComponentSpaceBounds = true;
FAutoConsoleVariableRef CVarChaosGCCacheComponentSpaceBounds(TEXT("p.Chaos.GC.CacheComponentSpaceBounds"), bChaos_GC_CacheComponentSpaceBounds, TEXT("Cache component space bounds for performance"));

DEFINE_LOG_CATEGORY_STATIC(UGCC_LOG, Error, All);

extern FGeometryCollectionDynamicDataPool GDynamicDataPool;

FString NetModeToString(ENetMode InMode)
{
	switch(InMode)
	{
	case ENetMode::NM_Client:
		return FString("Client");
	case ENetMode::NM_DedicatedServer:
		return FString("DedicatedServer");
	case ENetMode::NM_ListenServer:
		return FString("ListenServer");
	case ENetMode::NM_Standalone:
		return FString("Standalone");
	default:
		break;
	}

	return FString("INVALID NETMODE");
}

FString RoleToString(ENetRole InRole)
{
	switch(InRole)
	{
	case ROLE_None:
		return FString(TEXT("None"));
	case ROLE_SimulatedProxy:
		return FString(TEXT("SimProxy"));
	case ROLE_AutonomousProxy:
		return FString(TEXT("AutoProxy"));
	case ROLE_Authority:
		return FString(TEXT("Auth"));
	default:
		break;
	}

	return FString(TEXT("Invalid Role"));
}

int32 GetClusterLevel(const FTransformCollection* Collection, int32 TransformGroupIndex)
{
	int32 Level = 0;
	while(Collection && Collection->Parent[TransformGroupIndex] != -1)
	{
		TransformGroupIndex = Collection->Parent[TransformGroupIndex];
		Level++;
	}
	return Level;
}

bool FGeometryCollectionRepData::Identical(const FGeometryCollectionRepData* Other, uint32 PortFlags) const
{
	return Other && (Version == Other->Version);
}

bool FGeometryCollectionRepData::NetSerialize(FArchive& Ar, class UPackageMap* Map, bool& bOutSuccess)
{
	bOutSuccess = true;

	Ar << Version;

	Ar << OneOffActivated;

	int32 NumClusters = Clusters.Num();
	Ar << NumClusters;

	if(Ar.IsLoading())
	{
		Clusters.SetNum(NumClusters);
	}

	for(FGeometryCollectionClusterRep& Cluster : Clusters)
	{
		Ar << Cluster.Position;
		Ar << Cluster.LinearVelocity;
		Ar << Cluster.AngularVelocity;
		Ar << Cluster.Rotation;
		Ar << Cluster.ClusterIdx;
		Ar << Cluster.ObjectState;
	}

	return true;
}

int32 GGeometryCollectionNanite = 1;
FAutoConsoleVariableRef CVarGeometryCollectionNanite(
	TEXT("r.GeometryCollection.Nanite"),
	GGeometryCollectionNanite,
	TEXT("Render geometry collections using Nanite."),
	FConsoleVariableDelegate::CreateLambda([](IConsoleVariable* InVariable)
	{
		FGlobalComponentRecreateRenderStateContext Context;
	}),
	ECVF_RenderThreadSafe
);

// Size in CM used as a threshold for whether a geometry in the collection is collected and exported for
// navigation purposes. Measured as the diagonal of the leaf node bounds.
float GGeometryCollectionNavigationSizeThreshold = 20.0f;
FAutoConsoleVariableRef CVarGeometryCollectionNavigationSizeThreshold(TEXT("p.GeometryCollectionNavigationSizeThreshold"), GGeometryCollectionNavigationSizeThreshold, TEXT("Size in CM used as a threshold for whether a geometry in the collection is collected and exported for navigation purposes. Measured as the diagonal of the leaf node bounds."));

// Single-Threaded Bounds
bool bGeometryCollectionSingleThreadedBoundsCalculation = false;
FAutoConsoleVariableRef CVarGeometryCollectionSingleThreadedBoundsCalculation(TEXT("p.GeometryCollectionSingleThreadedBoundsCalculation"), bGeometryCollectionSingleThreadedBoundsCalculation, TEXT("[Debug Only] Single threaded bounds calculation. [def:false]"));



FGeomComponentCacheParameters::FGeomComponentCacheParameters()
	: CacheMode(EGeometryCollectionCacheType::None)
	, TargetCache(nullptr)
	, ReverseCacheBeginTime(0.0f)
	, SaveCollisionData(false)
	, DoGenerateCollisionData(false)
	, CollisionDataSizeMax(512)
	, DoCollisionDataSpatialHash(false)
	, CollisionDataSpatialHashRadius(50.f)
	, MaxCollisionPerCell(1)
	, SaveBreakingData(false)
	, DoGenerateBreakingData(false)
	, BreakingDataSizeMax(512)
	, DoBreakingDataSpatialHash(false)
	, BreakingDataSpatialHashRadius(50.f)
	, MaxBreakingPerCell(1)
	, SaveTrailingData(false)
	, DoGenerateTrailingData(false)
	, TrailingDataSizeMax(512)
	, TrailingMinSpeedThreshold(200.f)
	, TrailingMinVolumeThreshold(10000.f)
{
}

UGeometryCollectionComponent::UGeometryCollectionComponent(const FObjectInitializer& ObjectInitializer)
	: Super(ObjectInitializer)
	, ChaosSolverActor(nullptr)
	, InitializationState(ESimulationInitializationState::Unintialized)
	, ObjectType(EObjectStateTypeEnum::Chaos_Object_Dynamic)
	, bForceMotionBlur()
	, EnableClustering(true)
	, ClusterGroupIndex(0)
	, MaxClusterLevel(100)
	, DamageThreshold({ 500000.f, 50000.f, 5000.f })
	, bUseSizeSpecificDamageThreshold(false)
	, ClusterConnectionType_DEPRECATED(EClusterConnectionTypeEnum::Chaos_MinimalSpanningSubsetDelaunayTriangulation)
	, CollisionGroup(0)
	, CollisionSampleFraction(1.0)
	, InitialVelocityType(EInitialVelocityTypeEnum::Chaos_Initial_Velocity_User_Defined)
	, InitialLinearVelocity(0.f, 0.f, 0.f)
	, InitialAngularVelocity(0.f, 0.f, 0.f)
	, BaseRigidBodyIndex(INDEX_NONE)
	, NumParticlesAdded(0)
	, CachePlayback(false)
	, bNotifyBreaks(false)
	, bNotifyCollisions(false)
	, bNotifyRemovals(false)
	, bStoreVelocities(false)
	, bShowBoneColors(false)
#if WITH_EDITORONLY_DATA 
	, bEnableRunTimeDataCollection(false)
	, RunTimeDataCollectionGuid(FGuid::NewGuid())
#endif
	, bEnableReplication(false)
	, bEnableAbandonAfterLevel(true)
	, ReplicationAbandonClusterLevel(0)
	, bRenderStateDirty(true)
	, bEnableBoneSelection(false)
	, ViewLevel(-1)
	, NavmeshInvalidationTimeSliceIndex(0)
	, IsObjectDynamic(false)
	, IsObjectLoading(true)
	, PhysicsProxy(nullptr)
#if WITH_EDITOR && WITH_EDITORONLY_DATA
	, EditorActor(nullptr)
#endif
#if GEOMETRYCOLLECTION_EDITOR_SELECTION
	, bIsTransformSelectionModeEnabled(false)
#endif  // #if GEOMETRYCOLLECTION_EDITOR_SELECTION
	, bIsMoving(false)
{
	PrimaryComponentTick.bCanEverTick = true;
	bTickInEditor = true;
	bAutoActivate = true;

	static uint32 GlobalNavMeshInvalidationCounter = 0;
	//space these out over several frames (3 is arbitrary)
	GlobalNavMeshInvalidationCounter += 3;
	NavmeshInvalidationTimeSliceIndex = GlobalNavMeshInvalidationCounter;

	WorldBounds = FBoxSphereBounds(FBox(ForceInit));	

	// default current cache time
	CurrentCacheTime = MAX_flt;

	SetGenerateOverlapEvents(false);

	// By default use the destructible object channel unless the user specifies otherwise
	BodyInstance.SetObjectType(ECC_Destructible);

	// By default, we initialize immediately. If this is set false, we defer initialization.
	BodyInstance.bSimulatePhysics = true;

	EventDispatcher = ObjectInitializer.CreateDefaultSubobject<UChaosGameplayEventDispatcher>(this, TEXT("GameplayEventDispatcher"));

	DynamicCollection = nullptr;
	bHasCustomNavigableGeometry = EHasCustomNavigableGeometry::Yes;

	bWantsInitializeComponent = true;

}

Chaos::FPhysicsSolver* GetSolver(const UGeometryCollectionComponent& GeometryCollectionComponent)
{
	if(GeometryCollectionComponent.ChaosSolverActor)
	{
		return GeometryCollectionComponent.ChaosSolverActor->GetSolver();
	}
	else if(UWorld* CurrentWorld = GeometryCollectionComponent.GetWorld())
	{
		if(FPhysScene* Scene = CurrentWorld->GetPhysicsScene())
		{
			return Scene->GetSolver();
		}
	}
	return nullptr;
}

void UGeometryCollectionComponent::BeginPlay()
{
	Super::BeginPlay();

#if WITH_EDITOR
	if (RestCollection != nullptr)
	{
		if (RestCollection->GetGeometryCollection()->HasAttribute("ExplodedVector", FGeometryCollection::TransformGroup))
		{
			RestCollection->GetGeometryCollection()->RemoveAttribute("ExplodedVector", FGeometryCollection::TransformGroup);
		}
	}
#endif

	//////////////////////////////////////////////////////////////////////////
	// Commenting out these callbacks for now due to the threading model. The callbacks here
	// expect the rest collection to be mutable which is not the case when running in multiple
	// threads. Ideally we have some separate animation collection or track that we cache to
	// without affecting the data we've dispatched to the physics thread
	//////////////////////////////////////////////////////////////////////////
	// ---------- SolverCallbacks->SetResetAnimationCacheFunction([&]()
	// ---------- {
	// ---------- 	FGeometryCollectionEdit Edit = EditRestCollection();
	// ---------- 	Edit.GetRestCollection()->RecordedData.SetNum(0);
	// ---------- });
	// ---------- SolverCallbacks->SetUpdateTransformsFunction([&](const TArrayView<FTransform>&)
	// ---------- {
	// ---------- 	// todo : Move the update to the array passed here...
	// ---------- });
	// ---------- 
	// ---------- SolverCallbacks->SetUpdateRestStateFunction([&](const int32 & CurrentFrame, const TManagedArray<int32> & RigidBodyID, const TManagedArray<FGeometryCollectionBoneNode>& Hierarchy, const FSolverCallbacks::FParticlesType& Particles)
	// ---------- {
	// ---------- 	FGeometryCollectionEdit Edit = EditRestCollection();
	// ---------- 	UGeometryCollection * RestCollection = Edit.GetRestCollection();
	// ---------- 	check(RestCollection);
	// ---------- 
	// ---------- 	if (CurrentFrame >= RestCollection->RecordedData.Num())
	// ---------- 	{
	// ---------- 		RestCollection->RecordedData.SetNum(CurrentFrame + 1);
	// ---------- 		RestCollection->RecordedData[CurrentFrame].SetNum(RigidBodyID.Num());
	// ---------- 		ParallelFor(RigidBodyID.Num(), [&](int32 i)
	// ---------- 		{
	// ---------- 			if (!Hierarchy[i].Children.Num())
	// ---------- 			{
	// ---------- 				RestCollection->RecordedData[CurrentFrame][i].SetTranslation(Particles.X(RigidBodyID[i]));
	// ---------- 				RestCollection->RecordedData[CurrentFrame][i].SetRotation(Particles.R(RigidBodyID[i]));
	// ---------- 			}
	// ---------- 			else
	// ---------- 			{
	// ---------- 				RestCollection->RecordedData[CurrentFrame][i].SetTranslation(FVector::ZeroVector);
	// ---------- 				RestCollection->RecordedData[CurrentFrame][i].SetRotation(FQuat::Identity);
	// ---------- 			}
	// ---------- 		});
	// ---------- 	}
	// ---------- });
	//////////////////////////////////////////////////////////////////////////

	// default current cache time
	CurrentCacheTime = MAX_flt;	
}


void UGeometryCollectionComponent::EndPlay(const EEndPlayReason::Type ReasonEnd)
{
#if WITH_EDITOR && WITH_EDITORONLY_DATA
	// Track our editor component if needed for syncing simulations back from PIE on shutdown
	EditorActor = EditorUtilities::GetEditorWorldCounterpartActor(GetTypedOuter<AActor>());
#endif

	Super::EndPlay(ReasonEnd);

	CurrentCacheTime = MAX_flt;
}

void UGeometryCollectionComponent::GetLifetimeReplicatedProps(TArray<FLifetimeProperty>& OutLifetimeProps) const
{
	Super::GetLifetimeReplicatedProps(OutLifetimeProps);
	
	/*
	FDoRepLifetimeParams Params;
	Params.bIsPushBased = true;
	Params.RepNotifyCondition = REPNOTIFY_OnChanged;
	DOREPLIFETIME_WITH_PARAMS_FAST(UGeometryCollectionComponent, RepData, Params);*/
	DOREPLIFETIME(UGeometryCollectionComponent, RepData);
}

FBox UGeometryCollectionComponent::ComputeBounds(const FMatrix& LocalToWorldWithScale) const
{
	FBox BoundingBox(ForceInit);
	if (RestCollection)
	{
		//Hold on to reference so it doesn't get GC'ed
		auto HackGeometryCollectionPtr = RestCollection->GetGeometryCollection();

		const TManagedArray<FBox>& BoundingBoxes = GetBoundingBoxArray();
		const TManagedArray<int32>& TransformIndices = GetTransformIndexArray();
		const TManagedArray<int32>& ParentIndices = GetParentArray();
		const TManagedArray<int32>& TransformToGeometryIndex = GetTransformToGeometryIndexArray();
		const TManagedArray<FTransform>& Transforms = GetTransformArray();

		const int32 NumBoxes = BoundingBoxes.Num();
	
		int32 NumElements = HackGeometryCollectionPtr->NumElements(FGeometryCollection::TransformGroup);
		if (RestCollection->EnableNanite && HackGeometryCollectionPtr->HasAttribute("BoundingBox", FGeometryCollection::TransformGroup) && NumElements)
		{
			TArray<FMatrix> TmpGlobalMatrices;
			GeometryCollectionAlgo::GlobalMatrices(Transforms, ParentIndices, TmpGlobalMatrices);

			TManagedArray<FBox>& TransformBounds = HackGeometryCollectionPtr->ModifyAttribute<FBox>("BoundingBox", "Transform");
			for (int32 TransformIndex = 0; TransformIndex < HackGeometryCollectionPtr->NumElements(FGeometryCollection::TransformGroup); TransformIndex++)
			{
				BoundingBox += TransformBounds[TransformIndex].TransformBy(TmpGlobalMatrices[TransformIndex] * LocalToWorldWithScale);
			}
		}
		else if (NumElements == 0 || GlobalMatrices.Num() != RestCollection->NumElements(FGeometryCollection::TransformGroup))
		{
			// #todo(dmp): we could do the bbox transform in parallel with a bit of reformulating		
			// #todo(dmp):  there are some cases where the calcbounds function is called before the component
			// has set the global matrices cache while in the editor.  This is a somewhat weak guard against this
			// to default to just calculating tmp global matrices.  This should be removed or modified somehow
			// such that we always cache the global matrices and this method always does the correct behavior

			TArray<FMatrix> TmpGlobalMatrices;
			
			GeometryCollectionAlgo::GlobalMatrices(Transforms, ParentIndices, TmpGlobalMatrices);
			if (TmpGlobalMatrices.Num() == 0)
			{
				BoundingBox = FBox(ForceInitToZero);
			}
			else
			{
				for (int32 BoxIdx = 0; BoxIdx < NumBoxes; ++BoxIdx)
				{
					const int32 TransformIndex = TransformIndices[BoxIdx];

					if(RestCollection->GetGeometryCollection()->IsGeometry(TransformIndex))
					{
						BoundingBox += BoundingBoxes[BoxIdx].TransformBy(TmpGlobalMatrices[TransformIndex] * LocalToWorldWithScale);
					}
				}

			}
		}
		else if (bGeometryCollectionSingleThreadedBoundsCalculation)
		{
			CHAOS_ENSURE(false); // this is slower and only enabled through a pvar debugging, disable bGeometryCollectionSingleThreadedBoundsCalculation in a production environment. 
			for (int32 BoxIdx = 0; BoxIdx < NumBoxes; ++BoxIdx)
			{
				const int32 TransformIndex = TransformIndices[BoxIdx];

				if (RestCollection->GetGeometryCollection()->IsGeometry(TransformIndex))
				{
					BoundingBox += BoundingBoxes[BoxIdx].TransformBy(GlobalMatrices[TransformIndex] * LocalToWorldWithScale);
				}
			}
		}
		else
		{
			if (bChaos_BoxCalcBounds_ISPC_Enabled)
			{
#if INTEL_ISPC
				ispc::BoxCalcBounds(
					(int32*)&TransformToGeometryIndex[0],
					(int32*)&TransformIndices[0],
					(ispc::FMatrix*)&GlobalMatrices[0],
					(ispc::FBox*)&BoundingBoxes[0],
					(ispc::FMatrix&)LocalToWorldWithScale,
					(ispc::FBox&)BoundingBox,
					NumBoxes);
#endif
			}
			else
			{
				for (int32 BoxIdx = 0; BoxIdx < NumBoxes; ++BoxIdx)
				{
					const int32 TransformIndex = TransformIndices[BoxIdx];

					if (RestCollection->GetGeometryCollection()->IsGeometry(TransformIndex))
					{
						BoundingBox += BoundingBoxes[BoxIdx].TransformBy(GlobalMatrices[TransformIndex] * LocalToWorldWithScale);
					}
				}
			}
		}
	}
	return BoundingBox;
}

FBoxSphereBounds UGeometryCollectionComponent::CalcBounds(const FTransform& LocalToWorldIn) const
{	
	SCOPE_CYCLE_COUNTER(STAT_GCCUpdateBounds);

	// #todo(dmp): hack to make bounds calculation work when we don't have valid physics proxy data.  This will
	// force bounds calculation.

	const FGeometryCollectionResults* Results = PhysicsProxy ? PhysicsProxy->GetConsumerResultsGT() : nullptr;
	const int32 NumTransforms = Results ? Results->GlobalTransforms.Num() : 0;

	if (bChaos_GC_CacheComponentSpaceBounds)
	{
		bool NeedBoundsUpdate = false;
		NeedBoundsUpdate |= (ComponentSpaceBounds.GetSphere().W < 1e-5);
		NeedBoundsUpdate |= CachePlayback;
		NeedBoundsUpdate |= (NumTransforms > 0);
		NeedBoundsUpdate |= (DynamicCollection && DynamicCollection->IsDirty());
		
		if (NeedBoundsUpdate)
		{
			ComponentSpaceBounds = ComputeBounds(FMatrix::Identity);
		}
		else
		{
			NeedBoundsUpdate = false;
		}

		return ComponentSpaceBounds.TransformBy(LocalToWorldIn);
	}

	// non cached bounds path 
	if (!CachePlayback && WorldBounds.GetSphere().W > 1e-5 && NumTransforms > 0)
	{
		return WorldBounds;
	} 

	const FMatrix LocalToWorldWithScale = LocalToWorldIn.ToMatrixWithScale();
	return FBoxSphereBounds(ComputeBounds(LocalToWorldWithScale));
}

void UGeometryCollectionComponent::CreateRenderState_Concurrent(FRegisterComponentContext* Context)
{
	Super::CreateRenderState_Concurrent(Context);
}

FPrimitiveSceneProxy* UGeometryCollectionComponent::CreateSceneProxy()
{
	static const auto NaniteProxyRenderModeVar = IConsoleManager::Get().FindConsoleVariable(TEXT("r.Nanite.ProxyRenderMode"));
	const int32 NaniteProxyRenderMode = (NaniteProxyRenderModeVar != nullptr) ? (NaniteProxyRenderModeVar->GetInt() != 0) : 0;

	FPrimitiveSceneProxy* LocalSceneProxy = nullptr;

	if (RestCollection)
	{
		if (UseNanite(GetScene()->GetShaderPlatform()) &&
			RestCollection->EnableNanite &&
			RestCollection->NaniteData != nullptr &&
			GGeometryCollectionNanite != 0)
		{
			LocalSceneProxy = new FNaniteGeometryCollectionSceneProxy(this);

			// ForceMotionBlur means we maintain bIsMoving, regardless of actual state.
			if (bForceMotionBlur)
			{
				bIsMoving = true;
				if (LocalSceneProxy)
				{
					FNaniteGeometryCollectionSceneProxy* NaniteProxy = static_cast<FNaniteGeometryCollectionSceneProxy*>(LocalSceneProxy);
					ENQUEUE_RENDER_COMMAND(NaniteProxyOnMotionEnd)(
						[NaniteProxy](FRHICommandListImmediate& RHICmdList)
						{
							NaniteProxy->OnMotionBegin();
						}
					);
				}
			}
		}
		// If we didn't get a proxy, but Nanite was enabled on the asset when it was built, evaluate proxy creation
		else if (RestCollection->EnableNanite && NaniteProxyRenderMode != 0)
		{
			// Do not render Nanite proxy
			return nullptr;
		}
		else
		{
			LocalSceneProxy = new FGeometryCollectionSceneProxy(this);
		}

		if (RestCollection->HasVisibleGeometry())
		{
			FGeometryCollectionConstantData* const ConstantData = ::new FGeometryCollectionConstantData;
			InitConstantData(ConstantData);

			FGeometryCollectionDynamicData* const DynamicData = InitDynamicData(true /* initialization */);

			if (LocalSceneProxy->IsNaniteMesh())
			{
				FNaniteGeometryCollectionSceneProxy* const GeometryCollectionSceneProxy = static_cast<FNaniteGeometryCollectionSceneProxy*>(LocalSceneProxy);

				// ...

			#if GEOMETRYCOLLECTION_EDITOR_SELECTION
				if (bIsTransformSelectionModeEnabled)
				{
					// ...
				}
			#endif

				ENQUEUE_RENDER_COMMAND(CreateRenderState)(
					[GeometryCollectionSceneProxy, ConstantData, DynamicData](FRHICommandListImmediate& RHICmdList)
					{
						GeometryCollectionSceneProxy->SetConstantData_RenderThread(ConstantData);

						if (DynamicData)
						{
							GeometryCollectionSceneProxy->SetDynamicData_RenderThread(DynamicData);
						}

						bool bValidUpdate = false;
						if (FPrimitiveSceneInfo* PrimitiveSceneInfo = GeometryCollectionSceneProxy->GetPrimitiveSceneInfo())
						{
							bValidUpdate = PrimitiveSceneInfo->RequestGPUSceneUpdate();
						}

						// Deferred the GPU Scene update if the primitive scene info is not yet initialized with a valid index.
						GeometryCollectionSceneProxy->SetRequiresGPUSceneUpdate_RenderThread(!bValidUpdate);
					}
				);
			}
			else
			{
				FGeometryCollectionSceneProxy* const GeometryCollectionSceneProxy = static_cast<FGeometryCollectionSceneProxy*>(LocalSceneProxy);

			#if GEOMETRYCOLLECTION_EDITOR_SELECTION
				// Re-init subsections
				if (bIsTransformSelectionModeEnabled)
				{
					GeometryCollectionSceneProxy->UseSubSections(true, false);  // Do not force reinit now, it'll be done in SetConstantData_RenderThread
				}
			#endif

				ENQUEUE_RENDER_COMMAND(CreateRenderState)(
					[GeometryCollectionSceneProxy, ConstantData, DynamicData](FRHICommandListImmediate& RHICmdList)
					{
						GeometryCollectionSceneProxy->SetConstantData_RenderThread(ConstantData);
						if (DynamicData)
						{
							GeometryCollectionSceneProxy->SetDynamicData_RenderThread(DynamicData);
						}
					}
				);
			}
		}
	}

	return LocalSceneProxy;
}

bool UGeometryCollectionComponent::ShouldCreatePhysicsState() const
{
	// Geometry collections always create physics state, not relying on the
	// underlying implementation that requires the body instance to decide
	return true;
}

bool UGeometryCollectionComponent::HasValidPhysicsState() const
{
	return PhysicsProxy != nullptr;
}

void UGeometryCollectionComponent::SetNotifyBreaks(bool bNewNotifyBreaks)
{
	if (bNotifyBreaks != bNewNotifyBreaks)
	{
		bNotifyBreaks = bNewNotifyBreaks;
		UpdateBreakEventRegistration();
	}
}

void UGeometryCollectionComponent::SetNotifyRemovals(bool bNewNotifyRemovals)
{
	if (bNotifyRemovals != bNewNotifyRemovals)
	{
		bNotifyRemovals = bNewNotifyRemovals;
		UpdateRemovalEventRegistration();
	}
}

FBodyInstance* UGeometryCollectionComponent::GetBodyInstance(FName BoneName /*= NAME_None*/, bool bGetWelded /*= true*/, int32 Index /*=INDEX_NONE*/) const
{
	return nullptr;// const_cast<FBodyInstance*>(&DummyBodyInstance);
}

void UGeometryCollectionComponent::SetNotifyRigidBodyCollision(bool bNewNotifyRigidBodyCollision)
{
	Super::SetNotifyRigidBodyCollision(bNewNotifyRigidBodyCollision);
	UpdateRBCollisionEventRegistration();
}

bool UGeometryCollectionComponent::CanEditSimulatePhysics()
{
	return true;
}

void UGeometryCollectionComponent::SetSimulatePhysics(bool bEnabled)
{
	Super::SetSimulatePhysics(bEnabled);

	if (bEnabled && !PhysicsProxy)
	{
		RegisterAndInitializePhysicsProxy();
	}
}

void UGeometryCollectionComponent::AddForce(FVector Force, FName BoneName, bool bAccelChange)
{
	ensure(bAccelChange == false); // not supported
	
	const FVector Direction = Force.GetSafeNormal(); 
	const FVector::FReal Magnitude = Force.Size();
	const FFieldSystemCommand Command = FFieldObjectCommands::CreateFieldCommand(EFieldPhysicsType::Field_LinearForce, new FUniformVector(Magnitude, Direction));
	DispatchFieldCommand(Command);
}

void UGeometryCollectionComponent::AddImpulse(FVector Impulse, FName BoneName, bool bVelChange)
{
	const FVector Direction = Impulse.GetSafeNormal(); 
	const FVector::FReal Magnitude = Impulse.Size();
	const EFieldPhysicsType FieldType = bVelChange? EFieldPhysicsType::Field_LinearVelocity: EFieldPhysicsType::Field_LinearImpulse;
	
	const FFieldSystemCommand Command = FFieldObjectCommands::CreateFieldCommand(FieldType, new FUniformVector(Magnitude, Direction));
	DispatchFieldCommand(Command);
}

TUniquePtr<FFieldNodeBase> MakeRadialField(const FVector& Origin, float Radius, float Strength, ERadialImpulseFalloff Falloff)
{
	TUniquePtr<FFieldNodeBase> Field;
	if (Falloff == ERadialImpulseFalloff::RIF_Constant)
	{
		Field.Reset(new FRadialVector(Strength, Origin));
	}
	else
	{
		FRadialFalloff * FalloffField = new FRadialFalloff(Strength,0.f, 1.f, 0.f, Radius, Origin, EFieldFalloffType::Field_Falloff_Linear);
		FRadialVector* VectorField = new FRadialVector(1.f, Origin);
		Field.Reset(new FSumVector(1.0, FalloffField, VectorField, nullptr, Field_Multiply));
	}
	return Field;
}

void UGeometryCollectionComponent::AddRadialForce(FVector Origin, float Radius, float Strength, ERadialImpulseFalloff Falloff, bool bAccelChange)
{
	ensure(bAccelChange == false); // not supported
	if(bIgnoreRadialForce)
	{
		return;
	}

	if (TUniquePtr<FFieldNodeBase> Field = MakeRadialField(Origin, Radius, Strength, Falloff))
	{
		const FFieldSystemCommand Command = FFieldObjectCommands::CreateFieldCommand(EFieldPhysicsType::Field_LinearForce, Field.Release());
		DispatchFieldCommand(Command);
	}
}

void UGeometryCollectionComponent::AddRadialImpulse(FVector Origin, float Radius, float Strength, enum ERadialImpulseFalloff Falloff, bool bVelChange)
{
	if(bIgnoreRadialImpulse)
	{
		return;
	}

	if (TUniquePtr<FFieldNodeBase> Field = MakeRadialField(Origin, Radius, Strength, Falloff))
	{
		const EFieldPhysicsType FieldType = bVelChange? EFieldPhysicsType::Field_LinearVelocity: EFieldPhysicsType::Field_LinearImpulse;
		const FFieldSystemCommand Command = FFieldObjectCommands::CreateFieldCommand(FieldType, Field.Release());
		DispatchFieldCommand(Command);
	}
}

void UGeometryCollectionComponent::AddTorqueInRadians(FVector Torque, FName BoneName, bool bAccelChange)
{
	ensure(bAccelChange == false); // not supported
	
	const FVector Direction = Torque.GetSafeNormal(); 
	const FVector::FReal Magnitude = Torque.Size();
	const FFieldSystemCommand Command = FFieldObjectCommands::CreateFieldCommand(EFieldPhysicsType::Field_AngularTorque, new FUniformVector(Magnitude, Direction));
	DispatchFieldCommand(Command);
}

void UGeometryCollectionComponent::DispatchBreakEvent(const FChaosBreakEvent& Event)
{
	// native
	NotifyBreak(Event);

	// bp
	if (OnChaosBreakEvent.IsBound())
	{
		OnChaosBreakEvent.Broadcast(Event);
	}
}

void UGeometryCollectionComponent::DispatchRemovalEvent(const FChaosRemovalEvent& Event)
{
	// native
	NotifyRemoval(Event);

	// bp
	if (OnChaosRemovalEvent.IsBound())
	{
		OnChaosRemovalEvent.Broadcast(Event);
	}
}

bool UGeometryCollectionComponent::DoCustomNavigableGeometryExport(FNavigableGeometryExport& GeomExport) const
{
	if(!RestCollection)
	{
		// No geometry data so skip export - geometry collections don't have other geometry sources
		// so return false here to skip non-custom export for this component as well.
		return false;
	}

	TArray<FVector> OutVertexBuffer;
	TArray<int32> OutIndexBuffer;

	const FGeometryCollection* const Collection = RestCollection->GetGeometryCollection().Get();
	check(Collection);

	const float SizeThreshold = GGeometryCollectionNavigationSizeThreshold * GGeometryCollectionNavigationSizeThreshold;

	// for all geometry. inspect bounding box build int list of transform indices.
	int32 VertexCount = 0;
	int32 FaceCountEstimate = 0;
	TArray<int32> GeometryIndexBuffer;
	TArray<int32> TransformIndexBuffer;

	int32 NumGeometry = Collection->NumElements(FGeometryCollection::GeometryGroup);

	const TManagedArray<FBox>& BoundingBox = Collection->BoundingBox;
	const TManagedArray<int32>& TransformIndexArray = Collection->TransformIndex;
	const TManagedArray<int32>& VertexCountArray = Collection->VertexCount;
	const TManagedArray<int32>& FaceCountArray = Collection->FaceCount;
	const TManagedArray<int32>& VertexStartArray = Collection->VertexStart;
	const TManagedArray<FVector3f>& Vertex = Collection->Vertex;

	for(int32 GeometryGroupIndex = 0; GeometryGroupIndex < NumGeometry; GeometryGroupIndex++)
	{
		if(BoundingBox[GeometryGroupIndex].GetSize().SizeSquared() > SizeThreshold)
		{
			TransformIndexBuffer.Add(TransformIndexArray[GeometryGroupIndex]);
			GeometryIndexBuffer.Add(GeometryGroupIndex);
			VertexCount += VertexCountArray[GeometryGroupIndex];
			FaceCountEstimate += FaceCountArray[GeometryGroupIndex];
		}
	}

	// Get all the geometry transforms in component space (they are stored natively in parent-bone space)
	TArray<FTransform> GeomToComponent;
	GeometryCollectionAlgo::GlobalMatrices(GetTransformArray(), GetParentArray(), TransformIndexBuffer, GeomToComponent);

	OutVertexBuffer.AddUninitialized(VertexCount);

	int32 DestVertex = 0;
	//for each "subset" we care about 
	for(int32 SubsetIndex = 0; SubsetIndex < GeometryIndexBuffer.Num(); ++SubsetIndex)
	{
		//find indices into the collection data
		int32 GeometryIndex = GeometryIndexBuffer[SubsetIndex];
		int32 TransformIndex = TransformIndexBuffer[SubsetIndex];
		
		int32 SourceGeometryVertexStart = VertexStartArray[GeometryIndex];
		int32 SourceGeometryVertexCount = VertexCountArray[GeometryIndex];

		ParallelFor(SourceGeometryVertexCount, [&](int32 PointIdx)
			{
				//extract vertex from source
				int32 SourceGeometryVertexIndex = SourceGeometryVertexStart + PointIdx;
				FVector const VertexInWorldSpace = GeomToComponent[SubsetIndex].TransformPosition((FVector)Vertex[SourceGeometryVertexIndex]);

				int32 DestVertexIndex = DestVertex + PointIdx;
				OutVertexBuffer[DestVertexIndex].X = VertexInWorldSpace.X;
				OutVertexBuffer[DestVertexIndex].Y = VertexInWorldSpace.Y;
				OutVertexBuffer[DestVertexIndex].Z = VertexInWorldSpace.Z;
			});

		DestVertex += SourceGeometryVertexCount;
	}

	//gather data needed for indices
	const TManagedArray<int32>& FaceStartArray = Collection->FaceStart;
	const TManagedArray<FIntVector>& Indices = Collection->Indices;
	const TManagedArray<bool>& Visible = GetVisibleArray();
	const TManagedArray<int32>& MaterialIndex = Collection->MaterialIndex;

	//pre-allocate enough room (assuming all faces are visible)
	OutIndexBuffer.AddUninitialized(3 * FaceCountEstimate);

	//reset vertex counter so that we base the indices off the new location rather than the global vertex list
	DestVertex = 0;
	int32 DestinationIndex = 0;

	//leaving index traversal in a different loop to help cache coherency of source data
	for(int32 SubsetIndex = 0; SubsetIndex < GeometryIndexBuffer.Num(); ++SubsetIndex)
	{
		int32 GeometryIndex = GeometryIndexBuffer[SubsetIndex];

		//for each index, subtract the starting vertex for that geometry to make it 0-based.  Then add the new starting vertex index for this geometry
		int32 SourceGeometryVertexStart = VertexStartArray[GeometryIndex];
		int32 SourceGeometryVertexCount = VertexCountArray[GeometryIndex];
		int32 IndexDelta = DestVertex - SourceGeometryVertexStart;

		int32 FaceStart = FaceStartArray[GeometryIndex];
		int32 FaceCount = FaceCountArray[GeometryIndex];

		//Copy the faces
		for(int FaceIdx = FaceStart; FaceIdx < FaceStart + FaceCount; FaceIdx++)
		{
			if(Visible[FaceIdx])
			{
				OutIndexBuffer[DestinationIndex++] = Indices[FaceIdx].X + IndexDelta;
				OutIndexBuffer[DestinationIndex++] = Indices[FaceIdx].Y + IndexDelta;
				OutIndexBuffer[DestinationIndex++] = Indices[FaceIdx].Z + IndexDelta;
			}
		}

		DestVertex += SourceGeometryVertexCount;
	}

	// Invisible faces make the index buffer smaller
	OutIndexBuffer.SetNum(DestinationIndex);

	// Push as a custom mesh to navigation system
	// #CHAOSTODO This is pretty inefficient as it copies the whole buffer transforming each vert by the component to world
	// transform. Investigate a move aware custom mesh for pre-transformed verts to speed this up.
	GeomExport.ExportCustomMesh(OutVertexBuffer.GetData(), OutVertexBuffer.Num(), OutIndexBuffer.GetData(), OutIndexBuffer.Num(), GetComponentToWorld());

	return true;
}

UPhysicalMaterial* UGeometryCollectionComponent::GetPhysicalMaterial() const
{
	// Pull material from first mesh element to grab physical material. Prefer an override if one exists
	UPhysicalMaterial* PhysMatToUse = BodyInstance.GetSimplePhysicalMaterial();

	if(!PhysMatToUse || PhysMatToUse->GetFName() == "DefaultPhysicalMaterial")
	{
		// No override, try render materials
		const int32 NumMaterials = GetNumMaterials();

		if(NumMaterials > 0)
		{
			UMaterialInterface* FirstMatInterface = GetMaterial(0);

			if(FirstMatInterface && FirstMatInterface->GetPhysicalMaterial())
			{
				PhysMatToUse = FirstMatInterface->GetPhysicalMaterial();
			}
		}
	}

	if(!PhysMatToUse)
	{
		// Still no material, fallback on default
		PhysMatToUse = GEngine->DefaultPhysMaterial;
	}

	// Should definitely have a material at this point.
	check(PhysMatToUse);
	return PhysMatToUse;
}

void UGeometryCollectionComponent::RefreshEmbeddedGeometry()
{
	const TManagedArray<int32>& ExemplarIndexArray = GetExemplarIndexArray();
	const int32 TransformCount = GlobalMatrices.Num();
	if (!ensureMsgf(TransformCount == ExemplarIndexArray.Num(), TEXT("GlobalMatrices (Num=%d) cached on GeometryCollectionComponent are not in sync with ExemplarIndexArray (Num=%d) on underlying GeometryCollection; likely missed a dynamic data update"), TransformCount, ExemplarIndexArray.Num()))
	{
		return;
	}
	
	const TManagedArray<bool>* HideArray = nullptr;
	if (RestCollection->GetGeometryCollection()->HasAttribute("Hide", FGeometryCollection::TransformGroup))
	{
		HideArray = &RestCollection->GetGeometryCollection()->GetAttribute<bool>("Hide", FGeometryCollection::TransformGroup);
	}

#if WITH_EDITOR	
	EmbeddedInstanceIndex.Init(INDEX_NONE, RestCollection->GetGeometryCollection()->NumElements(FGeometryCollection::TransformGroup));
#endif

	const int32 ExemplarCount = EmbeddedGeometryComponents.Num();
	for (int32 ExemplarIndex = 0; ExemplarIndex < ExemplarCount; ++ExemplarIndex)
	{		
#if WITH_EDITOR
		EmbeddedBoneMaps[ExemplarIndex].Empty(TransformCount);
		EmbeddedBoneMaps[ExemplarIndex].Reserve(TransformCount); // Allocate for worst case
#endif
		
		TArray<FTransform> InstanceTransforms;
		InstanceTransforms.Reserve(TransformCount); // Allocate for worst case

		// Construct instance transforms for this exemplar
		for (int32 Idx = 0; Idx < TransformCount; ++Idx)
		{
			if (ExemplarIndexArray[Idx] == ExemplarIndex)
			{
				if (!HideArray || !(*HideArray)[Idx])
				{ 
					InstanceTransforms.Add(FTransform(GlobalMatrices[Idx]));
#if WITH_EDITOR
					int32 InstanceIndex = EmbeddedBoneMaps[ExemplarIndex].Add(Idx);
					EmbeddedInstanceIndex[Idx] = InstanceIndex;
#endif
				}
			}
		}

		if (EmbeddedGeometryComponents[ExemplarIndex])
		{
			const int32 InstanceCount = EmbeddedGeometryComponents[ExemplarIndex]->GetInstanceCount();

			// If the number of instances has changed, we rebuild the structure.
			if (InstanceCount != InstanceTransforms.Num())
			{
				EmbeddedGeometryComponents[ExemplarIndex]->ClearInstances();
				EmbeddedGeometryComponents[ExemplarIndex]->PreAllocateInstancesMemory(InstanceTransforms.Num());
				for (const FTransform& InstanceTransform : InstanceTransforms)
				{
					EmbeddedGeometryComponents[ExemplarIndex]->AddInstance(InstanceTransform);
				}
				EmbeddedGeometryComponents[ExemplarIndex]->MarkRenderStateDirty();
			}
			else
			{
				// #todo (bmiller) When ISMC has been changed to be able to update transforms in place, we need to switch this function call over.

				EmbeddedGeometryComponents[ExemplarIndex]->BatchUpdateInstancesTransforms(0, InstanceTransforms, false, true, false);

				// EmbeddedGeometryComponents[ExemplarIndex]->UpdateKinematicTransforms(InstanceTransforms);
			}	
		}
	}
}

#if WITH_EDITOR
void UGeometryCollectionComponent::SetEmbeddedGeometrySelectable(bool bSelectableIn)
{
	for (TObjectPtr<UInstancedStaticMeshComponent> EmbeddedGeometryComponent : EmbeddedGeometryComponents)
	{
		EmbeddedGeometryComponent->bSelectable = bSelectable;
		EmbeddedGeometryComponent->bHasPerInstanceHitProxies = bSelectable;
	}
}

int32 UGeometryCollectionComponent::EmbeddedIndexToTransformIndex(const UInstancedStaticMeshComponent* ISMComponent, int32 InstanceIndex) const
{
	for (int32 ISMIdx = 0; ISMIdx < EmbeddedGeometryComponents.Num(); ++ISMIdx)
	{
		if (EmbeddedGeometryComponents[ISMIdx].Get() == ISMComponent)
		{
			return (EmbeddedBoneMaps[ISMIdx][InstanceIndex]);
		}
	}

	return INDEX_NONE;
}
#endif

void UGeometryCollectionComponent::SetRestState(TArray<FTransform>&& InRestTransforms)
{	
	RestTransforms = InRestTransforms;
	
	if (DynamicCollection)
	{
		SetInitialTransforms(RestTransforms);
	}

	FGeometryCollectionDynamicData* DynamicData = GDynamicDataPool.Allocate();
	DynamicData->SetPrevTransforms(GlobalMatrices);
	CalculateGlobalMatrices();
	DynamicData->SetTransforms(GlobalMatrices);
	DynamicData->IsDynamic = true;

	if (SceneProxy)
	{
#if WITH_EDITOR
			// We need to do this in case we're controlled by Sequencer in editor, which doesn't invoke PostEditChangeProperty
			SendRenderTransform_Concurrent();
#endif
		if (SceneProxy->IsNaniteMesh())
		{
			FNaniteGeometryCollectionSceneProxy* GeometryCollectionSceneProxy = static_cast<FNaniteGeometryCollectionSceneProxy*>(SceneProxy);
			ENQUEUE_RENDER_COMMAND(SendRenderDynamicData)(
				[GeometryCollectionSceneProxy, DynamicData](FRHICommandListImmediate& RHICmdList)
				{
					GeometryCollectionSceneProxy->SetDynamicData_RenderThread(DynamicData);
				}
			);
		}
		else
		{
			FGeometryCollectionSceneProxy* GeometryCollectionSceneProxy = static_cast<FGeometryCollectionSceneProxy*>(SceneProxy);
			ENQUEUE_RENDER_COMMAND(SendRenderDynamicData)(
				[GeometryCollectionSceneProxy, DynamicData](FRHICommandListImmediate& RHICmdList)
				{
					GeometryCollectionSceneProxy->SetDynamicData_RenderThread(DynamicData);
				}
			);
		}
	}

	RefreshEmbeddedGeometry();
}

void UGeometryCollectionComponent::InitializeComponent()
{
	Super::InitializeComponent();

	if (DynamicCollection)
	{
		if (bStoreVelocities || bNotifyTrailing)
		{
			if (!DynamicCollection->FindAttributeTyped<FVector3f>("LinearVelocity", FTransformCollection::TransformGroup))
			{
				DynamicCollection->AddAttribute<FVector3f>("LinearVelocity", FTransformCollection::TransformGroup);
			}

			if (!DynamicCollection->FindAttributeTyped<FVector3f>("AngularVelocity", FTransformCollection::TransformGroup))
			{
				DynamicCollection->AddAttribute<FVector3f>("AngularVelocity", FTransformCollection::TransformGroup);
			}
		}
		DynamicCollection->AddAttribute<uint8>("InternalClusterParentTypeArray", FTransformCollection::TransformGroup);
	}

	AActor* Owner = GetOwner();

	if(!Owner)
	{
		return;
	}

	const ENetRole LocalRole = Owner->GetLocalRole();
	const ENetMode NetMode = Owner->GetNetMode();

	// If we're replicating we need some extra setup - check netmode as we don't need this for
	// standalone runtimes where we aren't going to network the component
	if(GetIsReplicated())
	{
		if(LocalRole != ENetRole::ROLE_Authority)
		{

			// We're a replicated component and we're not in control.
			Chaos::FPhysicsSolver* CurrSolver = GetSolver(*this);

			if(CurrSolver)
			{
				CurrSolver->RegisterSimOneShotCallback([Prox = PhysicsProxy, ReplicationLevel = ReplicationAbandonClusterLevel, AbandonAfterLevel = bEnableAbandonAfterLevel, this]()
				{
					// As we're not in control we make it so our simulated proxy cannot break clusters
					// We have to set the strain to a high value but be below the max for the data type
					// so releasing on authority demand works
					const Chaos::FReal MaxStrain = TNumericLimits<Chaos::FReal>::Max() - TNumericLimits<Chaos::FReal>::Min();

					TArray<Chaos::TPBDRigidClusteredParticleHandle<Chaos::FReal, 3>*> Particles = Prox->GetParticles();

					for(Chaos::TPBDRigidClusteredParticleHandle<Chaos::FReal, 3> * P : Particles)
					{
						if(!P)
						{
							continue;
						}

						int32 Level = AbandonAfterLevel ? 0 : -1;
						if(AbandonAfterLevel)
						{
							Chaos::TPBDRigidClusteredParticleHandle<Chaos::FReal, 3>* Current = P;
							while ( Current->Parent())
							{
								Current = Current->Parent();
								++Level;
							}
						}

						if (Level <= ReplicationLevel + 1)	//we only replicate up until level X, but it means we should replicate the breaking event of level X+1 (but not X+1's positions)
						{
							P->SetStrain(MaxStrain);
						}
					}

					Prox->SetInitializedForReplication();
				});
			}
		}
	}
}

#if WITH_EDITOR
void UGeometryCollectionComponent::PostEditChangeChainProperty(FPropertyChangedChainEvent& PropertyChangedEvent)
{
	Super::PostEditChangeChainProperty(PropertyChangedEvent);

	if (PropertyChangedEvent.Property && PropertyChangedEvent.Property->GetFName() == GET_MEMBER_NAME_CHECKED(UGeometryCollectionComponent, bShowBoneColors))
	{
		FScopedColorEdit EditBoneColor(this, true /*bForceUpdate*/); // the property has already changed; this will trigger the color update + render state updates
	}					
}
#endif

static void DispatchGeometryCollectionBreakEvent(const FChaosBreakEvent& Event)
{
	if (UGeometryCollectionComponent* const GC = Cast<UGeometryCollectionComponent>(Event.Component))
	{
		GC->DispatchBreakEvent(Event);
	}
}

static void DispatchGeometryCollectionRemovalEvent(const FChaosRemovalEvent& Event)
{
	if (UGeometryCollectionComponent* const GC = Cast<UGeometryCollectionComponent>(Event.Component))
	{
		GC->DispatchRemovalEvent(Event);
	}
}

void UGeometryCollectionComponent::DispatchChaosPhysicsCollisionBlueprintEvents(const FChaosPhysicsCollisionInfo& CollisionInfo)
{
	ReceivePhysicsCollision(CollisionInfo);
	OnChaosPhysicsCollision.Broadcast(CollisionInfo);
}

// call when first registering
void UGeometryCollectionComponent::RegisterForEvents()
{
	if (BodyInstance.bNotifyRigidBodyCollision || bNotifyBreaks || bNotifyCollisions || bNotifyRemovals)
	{
		Chaos::FPhysicsSolver* Solver = GetWorld()->GetPhysicsScene()->GetSolver();
		if (Solver)
		{
			if (bNotifyCollisions || BodyInstance.bNotifyRigidBodyCollision)
			{
				EventDispatcher->RegisterForCollisionEvents(this, this);

				Solver->EnqueueCommandImmediate([Solver]()
					{
						Solver->SetGenerateCollisionData(true);
					});
			}

			if (bNotifyBreaks)
			{
				EventDispatcher->RegisterForBreakEvents(this, &DispatchGeometryCollectionBreakEvent);

				Solver->EnqueueCommandImmediate([Solver]()
					{
						Solver->SetGenerateBreakingData(true);
					});

			}

			if (bNotifyRemovals)
			{
				EventDispatcher->RegisterForRemovalEvents(this, &DispatchGeometryCollectionRemovalEvent);

				Solver->EnqueueCommandImmediate([Solver]()
					{
						Solver->SetGenerateRemovalData(true);
					});

			}
		}
	}
}

void UGeometryCollectionComponent::UpdateRBCollisionEventRegistration()
{
	if (bNotifyCollisions || BodyInstance.bNotifyRigidBodyCollision)
	{
		EventDispatcher->RegisterForCollisionEvents(this, this);
	}
	else
	{
		EventDispatcher->UnRegisterForCollisionEvents(this, this);
	}
}

void UGeometryCollectionComponent::UpdateBreakEventRegistration()
{
	if (bNotifyBreaks)
	{
		EventDispatcher->RegisterForBreakEvents(this, &DispatchGeometryCollectionBreakEvent);
	}
	else
	{
		EventDispatcher->UnRegisterForBreakEvents(this);
	}
}

void UGeometryCollectionComponent::UpdateRemovalEventRegistration()
{
	if (bNotifyRemovals)
	{
		EventDispatcher->RegisterForRemovalEvents(this, &DispatchGeometryCollectionRemovalEvent);
	}
	else
	{
		EventDispatcher->UnRegisterForRemovalEvents(this);
	}
}

void ActivateClusters(Chaos::FRigidClustering& Clustering, Chaos::TPBDRigidClusteredParticleHandle<Chaos::FReal, 3>* Cluster)
{
	if(!Cluster)
	{
		return;
	}

	if(Cluster->ClusterIds().Id)
	{
		ActivateClusters(Clustering, Cluster->Parent());
	}

	Clustering.DeactivateClusterParticle(Cluster);
}

void UGeometryCollectionComponent::UpdateRepData()
{
	using namespace Chaos;
	if(!bEnableReplication)
	{
		return;
	}

	AActor* Owner = GetOwner();
	
	// If we have no owner or our netmode means we never require replication then early out
	if(!Owner || Owner->GetNetMode() == ENetMode::NM_Standalone)
	{
		return;
	}
	
	if (Owner && GetIsReplicated() && Owner->GetLocalRole() == ROLE_Authority)
	{
		bool bFirstUpdate = false;
		if(ClustersToRep == nullptr)
		{
			//we only allocate set if needed because it's pretty big to have per components that don't replicate
			ClustersToRep = MakeUnique<TSet<Chaos::FPBDRigidClusteredParticleHandle*>>();
			bFirstUpdate = true;
		}

		//We need to build a snapshot of the GC
		//We rely on the fact that clusters always fracture with one off pieces being removed.
		//This means we only need to record the one offs that broke and we get the connected components for free
		//The cluster properties are replicated with the first child of each connected component. These are always children that are known at author time and have a unique id per component
		//If the first child is disabled it means the properties apply to the parent (i.e. the cluster)
		//If the first child is enabled it means it's a one off and the cluster IS the first child
		
		//TODO: for now we have to iterate over all particles to find the clusters, would be better if we had the clusters and children already available
		//Large refactor happening to this stuff so for now we just iterate
		//We are relying on the fact that we fracture one level per step. This means we will see all one offs here

		bool bClustersChanged = false;

		const FPBDRigidsSolver* Solver = PhysicsProxy->GetSolver<Chaos::FPBDRigidsSolver>();
		const FRigidClustering& RigidClustering = Solver->GetEvolution()->GetRigidClustering();

		//see if we have any new clusters that are enabled
		TSet<FPBDRigidClusteredParticleHandle*> Processed;
		for (FPBDRigidClusteredParticleHandle* Particle : PhysicsProxy->GetParticles())
		{
			bool bProcess = true;
			Processed.Add(Particle);
			FPBDRigidClusteredParticleHandle* Root = Particle;
			while (Root->Parent())
			{
				Root = Root->Parent();

				//TODO: set avoids n^2, would be nice if clustered particle cached its root
				if(Processed.Contains(Root))
				{
					bProcess = false;
					break;
				}
				else
				{
					Processed.Add(Root);
				}
			}

			if (bProcess && Root->Disabled() == false && ClustersToRep->Find(Root) == nullptr)
			{
				//first time in here so needs a new count
				//TODO: check root needs to replicate if abandon by level is enabled
				ClustersToRep->Add(Root);
				if(Root->InternalCluster() == false && bFirstUpdate == false)	//if bFirstUpdate it must be that these are the initial roots of the GC. These did not break off so no need to replicate
				{
					//a one off so record it
					const int32 TransformGroupIdx = PhysicsProxy->GetTransformGroupIndexFromHandle(Root);
					ensureMsgf(TransformGroupIdx >= 0, TEXT("Non-internal cluster should always have a group index"));
					ensureMsgf(TransformGroupIdx < TNumericLimits<uint16>::Max(), TEXT("Trying to replicate GC with more than 65k pieces. We assumed uint16 would suffice"));
					RepData.OneOffActivated.Add(FGeometryCollectionActivatedCluster(TransformGroupIdx, Root->V(), Root->W()));
					bClustersChanged = true;
				}
			}
		}

		//build up clusters to replicate and compare with previous frame
		TArray<FGeometryCollectionClusterRep> Clusters;

		//remove disabled clusters and update rep data if needed
		for (auto Itr = ClustersToRep->CreateIterator(); Itr; ++Itr)
		{
			FPBDRigidClusteredParticleHandle* Cluster = *Itr;
			if (Cluster->Disabled())
			{
				Itr.RemoveCurrent();
			}
			else
			{
				Clusters.AddDefaulted();
				FGeometryCollectionClusterRep& ClusterRep = Clusters.Last();

				ClusterRep.Position = Cluster->X();
				ClusterRep.Rotation = Cluster->R();
				ClusterRep.LinearVelocity = Cluster->V();
				ClusterRep.AngularVelocity = Cluster->W();
				ClusterRep.ObjectState = static_cast<int8>(Cluster->ObjectState());
				int32 TransformGroupIdx;
				if(Cluster->InternalCluster())
				{
					const TArray<FPBDRigidParticleHandle*>& Children = RigidClustering.GetChildrenMap()[Cluster];
					ensureMsgf(Children.Num(), TEXT("Internal cluster yet we have no children?"));
					TransformGroupIdx = PhysicsProxy->GetTransformGroupIndexFromHandle(Children[0]);
				}
				else
				{
					//not internal so we can just use the cluster's ID. On client we'll know based on the parent whether to use this index or the parent
					TransformGroupIdx = PhysicsProxy->GetTransformGroupIndexFromHandle(Cluster);
				}

				ensureMsgf(TransformGroupIdx < TNumericLimits<uint16>::Max(), TEXT("Trying to replicate GC with more than 65k pieces. We assumed uint16 would suffice"));
				ClusterRep.ClusterIdx = TransformGroupIdx;

				if(!bClustersChanged)
				{
					//compare to previous frame data
					if(RepData.Clusters.Num() >= Clusters.Num())
					{
						const FGeometryCollectionClusterRep& PrevCluster = RepData.Clusters[Clusters.Num() - 1];
						if(ClusterRep.ClusterChanged(PrevCluster))
						{
							bClustersChanged = true;
						}
					}
					else
					{
						//must be some new clusters so definitely changed
						bClustersChanged = true;
					}
				}
			}
		}

		if (bClustersChanged)
		{
			RepData.Clusters = MoveTemp(Clusters);

			MARK_PROPERTY_DIRTY_FROM_NAME(UGeometryCollectionComponent, RepData, this);
			++RepData.Version;

			if(Owner->NetDormancy != DORM_Awake)
			{
				//If net dormancy is Initial it must be for perf reasons, but since a cluster changed we need to replicate down
				//TODO: set back to dormant when sim goes to sleep
				Owner->SetNetDormancy(DORM_Awake);
			}
		}
	}
}

int32 GeometryCollectionHardMissingUpdatesSnapThreshold = 20;
FAutoConsoleVariableRef CVarGeometryCollectionHardMissingUpdatesSnapThreshold(TEXT("p.GeometryCollectionHardMissingUpdatesSnapThreshold"), GeometryCollectionHardMissingUpdatesSnapThreshold,
	TEXT("Determines how many missing updates before we trigger a hard snap"));

void UGeometryCollectionComponent::ProcessRepData()
{
	using namespace Chaos;
	if(VersionProcessed == RepData.Version || PhysicsProxy->GetInitializedForReplication() == false)
	{
		return;
	}

	bool bHardSnap = false;
	if(VersionProcessed < RepData.Version)
	{
		//TODO: this will not really work if a fracture happens and then immediately goes to sleep without updating client enough times
		//A time method would work better here, but is limited to async mode. Maybe we can support both
		bHardSnap = (RepData.Version - VersionProcessed) > GeometryCollectionHardMissingUpdatesSnapThreshold;
	}
	else
	{
		//rollover so just treat as hard snap - this case is extremely rare and a one off
		bHardSnap = true;
	}

	FPBDRigidsSolver* Solver = PhysicsProxy->GetSolver<Chaos::FPBDRigidsSolver>();
	FRigidClustering& RigidClustering = Solver->GetEvolution()->GetRigidClustering();

	//First make sure all one off activations have been applied. This ensures our connectivity graph is the same and we have the same clusters as the server
	for (; OneOffActivatedProcessed < RepData.OneOffActivated.Num(); ++OneOffActivatedProcessed)
	{
		const FGeometryCollectionActivatedCluster& ActivatedCluster = RepData.OneOffActivated[OneOffActivatedProcessed];
		FPBDRigidParticleHandle* OneOff = PhysicsProxy->GetParticles()[ActivatedCluster.ActivatedIndex];

		// Set initial velocities if not hard snapping
		if(!bHardSnap)
		{
			// TODO: should we invalidate?
			OneOff->SetV(ActivatedCluster.InitialLinearVelocity);
			OneOff->SetW(ActivatedCluster.InitialAngularVelocity);
		}

		RigidClustering.ReleaseClusterParticles(TArray<FPBDRigidParticleHandle*>{ OneOff });
	}

	if(bHardSnap)
	{
		for (const FGeometryCollectionClusterRep& RepCluster : RepData.Clusters)
		{
			FPBDRigidParticleHandle* Cluster = PhysicsProxy->GetParticles()[RepCluster.ClusterIdx];
			if(Cluster->Disabled() == false)
			{
				Cluster->SetX(RepCluster.Position);
				Cluster->SetR(RepCluster.Rotation);
				Cluster->SetV(RepCluster.LinearVelocity);
				Cluster->SetW(RepCluster.AngularVelocity);
				//TODO: snap object state too once we fix interpolation
				//Solver->GetEvolution()->SetParticleObjectState(Cluster, static_cast<Chaos::EObjectStateType>(RepCluster.ObjectState));
			}
		}
	}

	VersionProcessed = RepData.Version;
}

void UGeometryCollectionComponent::SetDynamicState(const Chaos::EObjectStateType& NewDynamicState)
{
	if (DynamicCollection)
	{
		TManagedArray<int32>& DynamicState = DynamicCollection->DynamicState;
		for (int i = 0; i < DynamicState.Num(); i++)
		{
			DynamicState[i] = static_cast<int32>(NewDynamicState);
		}
	}
}

void UGeometryCollectionComponent::SetInitialTransforms(const TArray<FTransform>& InitialTransforms)
{
	if (DynamicCollection)
	{
		TManagedArray<FTransform>& Transform = DynamicCollection->Transform;
		int32 MaxIdx = FMath::Min(Transform.Num(), InitialTransforms.Num());
		for (int32 Idx = 0; Idx < MaxIdx; ++Idx)
		{
			Transform[Idx] = InitialTransforms[Idx];
		}
	}
}

void UGeometryCollectionComponent::SetInitialClusterBreaks(const TArray<int32>& ReleaseIndices)
{
	if (DynamicCollection)
	{
		TManagedArray<int32>& Parent = DynamicCollection->Parent;
		TManagedArray <TSet<int32>>& Children = DynamicCollection->Children;
		const int32 NumTransforms = Parent.Num();

		for (int32 ReleaseIndex : ReleaseIndices)
		{
			if (ReleaseIndex < NumTransforms)
			{
				if (Parent[ReleaseIndex] > INDEX_NONE)
				{
					Children[Parent[ReleaseIndex]].Remove(ReleaseIndex);
					Parent[ReleaseIndex] = INDEX_NONE;
				}
			}
		}
	}
}

void SetHierarchyStrain(Chaos::TPBDRigidClusteredParticleHandle<Chaos::FReal, 3>* P, TMap<Chaos::TPBDRigidClusteredParticleHandle<Chaos::FReal, 3>*, TArray<Chaos::TPBDRigidParticleHandle<Chaos::FReal, 3>*>>& Map, float Strain)
{
	TArray<Chaos::TPBDRigidParticleHandle<Chaos::FReal, 3>*>* Children = Map.Find(P);

	if(Children)	
	{
		for(Chaos::TPBDRigidParticleHandle<Chaos::FReal, 3> * ChildP : (*Children))
		{
			SetHierarchyStrain(ChildP->CastToClustered(), Map, Strain);
		}
	}

	if(P)
	{
		P->SetStrain(Strain);
	}
}

void UGeometryCollectionComponent::InitConstantData(FGeometryCollectionConstantData* ConstantData) const
{
	// Constant data should all be moved to the DDC as time permits.

	check(ConstantData);
	check(RestCollection);
	const FGeometryCollection* Collection = RestCollection->GetGeometryCollection().Get();
	check(Collection);

	if (!RestCollection->EnableNanite)
	{
		const int32 NumPoints = Collection->NumElements(FGeometryCollection::VerticesGroup);
		const TManagedArray<FVector3f>& Vertex = Collection->Vertex;
		const TManagedArray<int32>& BoneMap = Collection->BoneMap;
		const TManagedArray<FVector3f>& TangentU = Collection->TangentU;
		const TManagedArray<FVector3f>& TangentV = Collection->TangentV;
		const TManagedArray<FVector3f>& Normal = Collection->Normal;
		const TManagedArray<TArray<FVector2f>>& UVs = Collection->UVs;
		const TManagedArray<FLinearColor>& Color = Collection->Color;
		const TManagedArray<FLinearColor>& BoneColors = Collection->BoneColor;
		
		const int32 NumGeom = Collection->NumElements(FGeometryCollection::GeometryGroup);
		const TManagedArray<int32>& TransformIndex = Collection->TransformIndex;
		const TManagedArray<int32>& FaceStart = Collection->FaceStart;
		const TManagedArray<int32>& FaceCount = Collection->FaceCount;

		ConstantData->Vertices = TArray<FVector3f>(Vertex.GetData(), Vertex.Num());
		ConstantData->BoneMap = TArray<int32>(BoneMap.GetData(), BoneMap.Num());
		ConstantData->TangentU = TArray<FVector3f>(TangentU.GetData(), TangentU.Num());
		ConstantData->TangentV = TArray<FVector3f>(TangentV.GetData(), TangentV.Num());
		ConstantData->Normals = TArray<FVector3f>(Normal.GetData(), Normal.Num());
		ConstantData->UVs = TArray<TArray<FVector2f>>(UVs.GetData(), UVs.Num());
		ConstantData->Colors = TArray<FLinearColor>(Color.GetData(), Color.Num());

		ConstantData->BoneColors.AddUninitialized(NumPoints);

		ParallelFor(NumPoints, [&](const int32 InPointIndex)
			{
				const int32 BoneIndex = ConstantData->BoneMap[InPointIndex];
				ConstantData->BoneColors[InPointIndex] = BoneColors[BoneIndex];
			});

		int32 NumIndices = 0;
		const TManagedArray<FIntVector>& Indices = Collection->Indices;
		const TManagedArray<int32>& MaterialID = Collection->MaterialID;

		const TManagedArray<bool>& Visible = GetVisibleArray();  // Use copy on write attribute. The rest collection visible array can be overriden for the convenience of debug drawing the collision volumes
		
#if WITH_EDITOR
		// We will override visibility with the Hide array (if available).
		TArray<bool> VisibleOverride;
		VisibleOverride.SetNumUninitialized(Visible.Num());
		for (int32 FaceIdx = 0; FaceIdx < Visible.Num(); FaceIdx++)
		{
			VisibleOverride[FaceIdx] = Visible[FaceIdx];
		}
		bool bUsingHideArray = false;

		if (Collection->HasAttribute("Hide", FGeometryCollection::TransformGroup))
		{
			bUsingHideArray = true;

			bool bAllHidden = true;

			const TManagedArray<bool>& Hide = Collection->GetAttribute<bool>("Hide", FGeometryCollection::TransformGroup);
			for (int32 GeomIdx = 0; GeomIdx < NumGeom; ++GeomIdx)
			{
				int32 TransformIdx = TransformIndex[GeomIdx];
				if (Hide[TransformIdx])
				{
					// (Temporarily) hide faces of this hidden geometry
					for (int32 FaceIdxOffset = 0; FaceIdxOffset < FaceCount[GeomIdx]; ++FaceIdxOffset)
					{
						VisibleOverride[FaceStart[GeomIdx]+FaceIdxOffset] = false;
					}
				}
				else if (bAllHidden && Collection->IsVisible(TransformIdx))
				{
					bAllHidden = false;
				}
			}
			if (!ensure(!bAllHidden)) // if they're all hidden, rendering would crash -- reset to default visibility instead
			{
				for (int32 FaceIdx = 0; FaceIdx < VisibleOverride.Num(); ++FaceIdx)
				{
					VisibleOverride[FaceIdx] = Visible[FaceIdx];
				}
			}
		}
#endif
		
		const TManagedArray<int32>& MaterialIndex = Collection->MaterialIndex;

		const int32 NumFaceGroupEntries = Collection->NumElements(FGeometryCollection::FacesGroup);

		for (int FaceIndex = 0; FaceIndex < NumFaceGroupEntries; ++FaceIndex)
		{
#if WITH_EDITOR
			NumIndices += bUsingHideArray ? static_cast<int>(VisibleOverride[FaceIndex]) : static_cast<int>(Visible[FaceIndex]);
#else
			NumIndices += static_cast<int>(Visible[FaceIndex]);
#endif
		}

		ConstantData->Indices.AddUninitialized(NumIndices);
		for (int IndexIdx = 0, cdx = 0; IndexIdx < NumFaceGroupEntries; ++IndexIdx)
		{
#if WITH_EDITOR
			const bool bUseVisible = bUsingHideArray ? VisibleOverride[MaterialIndex[IndexIdx]] : Visible[MaterialIndex[IndexIdx]];
			if (bUseVisible)
#else
			if (Visible[MaterialIndex[IndexIdx]])
#endif
			{
				ConstantData->Indices[cdx++] = Indices[MaterialIndex[IndexIdx]];
			}
		}

		// We need to correct the section index start point & number of triangles since only the visible ones have been copied across in the code above
		const int32 NumMaterialSections = Collection->NumElements(FGeometryCollection::MaterialGroup);
		ConstantData->Sections.AddUninitialized(NumMaterialSections);
		const TManagedArray<FGeometryCollectionSection>& Sections = Collection->Sections;
		for (int SectionIndex = 0; SectionIndex < NumMaterialSections; ++SectionIndex)
		{
			FGeometryCollectionSection Section = Sections[SectionIndex]; // deliberate copy

			for (int32 TriangleIndex = 0; TriangleIndex < Sections[SectionIndex].FirstIndex / 3; TriangleIndex++)
			{
#if WITH_EDITOR
				const bool bUseVisible = bUsingHideArray ? VisibleOverride[MaterialIndex[TriangleIndex]] : Visible[MaterialIndex[TriangleIndex]];
				if (!bUseVisible)
#else
				if (!Visible[MaterialIndex[TriangleIndex]])
#endif
				{
					Section.FirstIndex -= 3;
				}
			}

			for (int32 TriangleIndex = 0; TriangleIndex < Sections[SectionIndex].NumTriangles; TriangleIndex++)
			{
				int32 FaceIdx = MaterialIndex[Sections[SectionIndex].FirstIndex / 3 + TriangleIndex];
#if WITH_EDITOR
				const bool bUseVisible = bUsingHideArray ? VisibleOverride[FaceIdx] : Visible[FaceIdx];
				if (!bUseVisible)
#else
				if (!Visible[FaceIdx])
#endif
				{
					Section.NumTriangles--;
				}
			}

			ConstantData->Sections[SectionIndex] = MoveTemp(Section);
		}
		
		
		ConstantData->NumTransforms = Collection->NumElements(FGeometryCollection::TransformGroup);
		ConstantData->LocalBounds = LocalBounds;

		// store the index buffer and render sections for the base unfractured mesh
		const TManagedArray<int32>& TransformToGeometryIndex = Collection->TransformToGeometryIndex;
		
		const int32 NumFaces = Collection->NumElements(FGeometryCollection::FacesGroup);
		TArray<FIntVector> BaseMeshIndices;
		TArray<int32> BaseMeshOriginalFaceIndices;

		BaseMeshIndices.Reserve(NumFaces);
		BaseMeshOriginalFaceIndices.Reserve(NumFaces);

		// add all visible external faces to the original geometry index array
		// #note:  This is a stopgap because the original geometry array is broken
		for (int FaceIndex = 0; FaceIndex < NumFaces; ++FaceIndex)
		{
			// only add visible external faces.  MaterialID that is even is an external material
#if WITH_EDITOR
			const bool bUseVisible = bUsingHideArray ? VisibleOverride[FaceIndex] : Visible[FaceIndex];
			if (bUseVisible && (MaterialID[FaceIndex] % 2 == 0 || bUsingHideArray))
#else
			if (Visible[FaceIndex] && MaterialID[FaceIndex] % 2 == 0)
#endif
			{
				BaseMeshIndices.Add(Indices[FaceIndex]);
				BaseMeshOriginalFaceIndices.Add(FaceIndex);
			}
		}

		// We should always have external faces of a geometry collection
		ensure(BaseMeshIndices.Num() > 0);

		ConstantData->OriginalMeshSections = Collection->BuildMeshSections(BaseMeshIndices, BaseMeshOriginalFaceIndices, ConstantData->OriginalMeshIndices);
	}
	
	TArray<FMatrix> RestMatrices;
	GeometryCollectionAlgo::GlobalMatrices(RestCollection->GetGeometryCollection()->Transform, RestCollection->GetGeometryCollection()->Parent, RestMatrices);

	ConstantData->SetRestTransforms(RestMatrices);
}

FGeometryCollectionDynamicData* UGeometryCollectionComponent::InitDynamicData(bool bInitialization)
{
	SCOPE_CYCLE_COUNTER(STAT_GCInitDynamicData);

	FGeometryCollectionDynamicData* DynamicData = nullptr;

	const bool bEditorMode = bShowBoneColors || bEnableBoneSelection;
	const bool bIsDynamic  = GetIsObjectDynamic() || bEditorMode || bInitialization;

	if (bIsDynamic)
	{
		DynamicData = GDynamicDataPool.Allocate();
		DynamicData->IsDynamic = true;
		DynamicData->IsLoading = GetIsObjectLoading();

		// If we have no transforms stored in the dynamic data, then assign both prev and current to the same global matrices
		if (GlobalMatrices.Num() == 0)
		{
			// Copy global matrices over to DynamicData
			CalculateGlobalMatrices();

			DynamicData->SetAllTransforms(GlobalMatrices);
		}
		else
		{
			// Copy existing global matrices into prev transforms
			DynamicData->SetPrevTransforms(GlobalMatrices);

			// Copy global matrices over to DynamicData
			CalculateGlobalMatrices();

			bool bComputeChanges = true;

			// if the number of matrices has changed between frames, then sync previous to current
			if (GlobalMatrices.Num() != DynamicData->PrevTransforms.Num())
			{
				DynamicData->SetPrevTransforms(GlobalMatrices);
				DynamicData->ChangedCount = GlobalMatrices.Num();
				bComputeChanges = false; // Optimization to just force all transforms as changed and skip comparison
			}

			DynamicData->SetTransforms(GlobalMatrices);

			// The number of transforms for current and previous should match now
			check(DynamicData->PrevTransforms.Num() == DynamicData->Transforms.Num());

			if (bComputeChanges)
			{
				DynamicData->DetermineChanges();
			}
		}
	}

	if (!bEditorMode && !bInitialization)
	{
		if (DynamicData && DynamicData->ChangedCount == 0)
		{
			GDynamicDataPool.Release(DynamicData);
			DynamicData = nullptr;

			// Change of state?
			if (bIsMoving && !bForceMotionBlur)
			{
				bIsMoving = false;
				if (SceneProxy && SceneProxy->IsNaniteMesh())
				{
					FNaniteGeometryCollectionSceneProxy* NaniteProxy = static_cast<FNaniteGeometryCollectionSceneProxy*>(SceneProxy);
					ENQUEUE_RENDER_COMMAND(NaniteProxyOnMotionEnd)(
						[NaniteProxy](FRHICommandListImmediate& RHICmdList)
						{
							NaniteProxy->OnMotionEnd();
						}
					);
				}
			}
		}
		else
		{
			// Change of state?
			if (!bIsMoving && !bForceMotionBlur)
			{
				bIsMoving = true;
				if (SceneProxy && SceneProxy->IsNaniteMesh())
				{
					FNaniteGeometryCollectionSceneProxy* NaniteProxy = static_cast<FNaniteGeometryCollectionSceneProxy*>(SceneProxy);
					ENQUEUE_RENDER_COMMAND(NaniteProxyOnMotionBegin)(
						[NaniteProxy](FRHICommandListImmediate& RHICmdList)
						{
							NaniteProxy->OnMotionBegin();
						}
					);
				}
			}
		}
	}

	return DynamicData;
}

void UGeometryCollectionComponent::OnUpdateTransform(EUpdateTransformFlags UpdateTransformFlags, ETeleportType Teleport)
{
	Super::OnUpdateTransform(UpdateTransformFlags, Teleport);

	if (PhysicsProxy)
	{
		PhysicsProxy->SetWorldTransform(GetComponentTransform());
	}
}

void UGeometryCollectionComponent::TickComponent(float DeltaTime, enum ELevelTick TickType, FActorComponentTickFunction *ThisTickFunction)
{
	//UE_LOG(UGCC_LOG, Log, TEXT("GeometryCollectionComponent[%p]::TickComponent()"), this);
	Super::TickComponent(DeltaTime, TickType, ThisTickFunction);

#if WITH_EDITOR
	if (IsRegistered() && SceneProxy && RestCollection)
	{
		const bool bWantNanite = RestCollection->EnableNanite && GGeometryCollectionNanite != 0;
		const bool bHaveNanite = SceneProxy->IsNaniteMesh();
		bool bRecreateProxy = bWantNanite != bHaveNanite;
		if (bRecreateProxy)
		{
			// Wait until resources are released
			FlushRenderingCommands();

			FComponentReregisterContext ReregisterContext(this);
			UpdateAllPrimitiveSceneInfosForSingleComponent(this);
		}
	}
#endif

	//if (bRenderStateDirty && DynamicCollection)	//todo: always send for now
	if (RestCollection)
	{
		// In editor mode we have no DynamicCollection so this test is necessary
		if(DynamicCollection) //, TEXT("No dynamic collection available for component %s during tick."), *GetName()))
		{
			if (RestCollection->bRemoveOnMaxSleep)
			{ 
				IncrementSleepTimer(DeltaTime);
			}
			IncrementBreakTimer(DeltaTime);

			if (RestCollection->HasVisibleGeometry() || DynamicCollection->IsDirty())
			{
				// #todo review: When we've made changes to ISMC, we need to move this function call to SetRenderDynamicData_Concurrent
				RefreshEmbeddedGeometry();

				if (SceneProxy && SceneProxy->IsNaniteMesh())
				{
					FNaniteGeometryCollectionSceneProxy* NaniteProxy = static_cast<FNaniteGeometryCollectionSceneProxy*>(SceneProxy);
					NaniteProxy->FlushGPUSceneUpdate_GameThread();
				}
				
				MarkRenderTransformDirty();
				MarkRenderDynamicDataDirty();
				bRenderStateDirty = false;
				
				const UWorld* MyWorld = GetWorld();
				if (MyWorld && MyWorld->IsGameWorld())
				{
					//cycle every 0xff frames
					//@todo - Need way of seeing if the collection is actually changing
					if (bNavigationRelevant && bRegistered && (((GFrameCounter + NavmeshInvalidationTimeSliceIndex) & 0xff) == 0))
					{
						UpdateNavigationData();
					}
				}
			}
		}
	}
}

void UGeometryCollectionComponent::AsyncPhysicsTickComponent(float DeltaTime, float SimTime)
{
	Super::AsyncPhysicsTickComponent(DeltaTime, SimTime);

	const ENetRole LocalRole = GetOwnerRole();
	if (LocalRole == ROLE_Authority)
	{
		UpdateRepData();
	}
	else
	{
		ProcessRepData();
	}
}

void UGeometryCollectionComponent::OnRegister()
{
	//UE_LOG(UGCC_LOG, Log, TEXT("GeometryCollectionComponent[%p]::OnRegister()[%p]"), this,RestCollection );
	ResetDynamicCollection();

	bool bIsReplicated = false;
	const bool bHasClusterGroup = (ClusterGroupIndex != 0);
	if (bEnableReplication)
	{
		if (ensureMsgf(!bHasClusterGroup, TEXT("Replication with cluster groups is not supported - disabling replication")))
		{
			bIsReplicated = true; 
		}
	}
	SetIsReplicated(bIsReplicated);

	InitializeEmbeddedGeometry();

	Super::OnRegister();
}

void UGeometryCollectionComponent::ResetDynamicCollection()
{
	bool bCreateDynamicCollection = true;
#if WITH_EDITOR
	bCreateDynamicCollection = false;
	if (UWorld* World = GetWorld())
	{
		if(World->IsGameWorld())
		{
			bCreateDynamicCollection = true;
		}
	}
#endif
	//UE_LOG(UGCC_LOG, Log, TEXT("GeometryCollectionComponent[%p]::ResetDynamicCollection()"), static_cast<const void*>(this));
	if (bCreateDynamicCollection && RestCollection)
	{
		DynamicCollection = MakeUnique<FGeometryDynamicCollection>();
		for (const auto DynamicArray : CopyOnWriteAttributeList)
		{
			*DynamicArray = nullptr;
		}

		GetTransformArrayCopyOnWrite();
		GetParentArrayCopyOnWrite();
		GetChildrenArrayCopyOnWrite();
		GetSimulationTypeArrayCopyOnWrite();
		GetStatusFlagsArrayCopyOnWrite();

		if (RestCollection->bRemoveOnMaxSleep)
		{
			if (!DynamicCollection->HasAttribute("SleepTimer", FGeometryCollection::TransformGroup))
			{
				TManagedArray<float>& SleepTimer = DynamicCollection->AddAttribute<float>("SleepTimer", FGeometryCollection::TransformGroup);
				SleepTimer.Fill(0.f);
			}

			if (!DynamicCollection->HasAttribute("Decay", FGeometryCollection::TransformGroup))
			{
				TManagedArray<float>& Decay = DynamicCollection->AddAttribute<float>("Decay", FGeometryCollection::TransformGroup);
				Decay.Fill(0);
			}

			if (!DynamicCollection->HasAttribute("LastPosition", FGeometryCollection::TransformGroup))
			{
				TManagedArray<FVector>& LastPosition = DynamicCollection->AddAttribute<FVector>("LastPosition", FGeometryCollection::TransformGroup);
				LastPosition.Fill(FVector::Zero());
			}
			
			if (!DynamicCollection->HasAttribute("UniformScale", FGeometryCollection::TransformGroup))
			{
				TManagedArray<FTransform>& UniformScale = DynamicCollection->AddAttribute<FTransform>("UniformScale", FGeometryCollection::TransformGroup);
				UniformScale.Fill(FTransform::Identity);
			}

			if (!DynamicCollection->HasAttribute("MaxSleepTime", FGeometryCollection::TransformGroup))
			{
				float MinTime = FMath::Max(0.0f, RestCollection->MaximumSleepTime.X);
				float MaxTime = FMath::Max(MinTime, RestCollection->MaximumSleepTime.Y);
				TManagedArray<float>& MaxSleepTime = DynamicCollection->AddAttribute<float>("MaxSleepTime", FGeometryCollection::TransformGroup);
				for (int32 Idx = 0; Idx < MaxSleepTime.Num(); ++Idx)
				{
					MaxSleepTime[Idx] = FMath::RandRange(MinTime, MaxTime);
				}
			}

			if (!DynamicCollection->HasAttribute("SleepRemovalDuration", FGeometryCollection::TransformGroup))
			{
				float MinTime = FMath::Max(0.0f, RestCollection->RemovalDuration.X);
				float MaxTime = FMath::Max(MinTime, RestCollection->RemovalDuration.Y);
				TManagedArray<float>& SleepRemovalDuration = DynamicCollection->AddAttribute<float>("SleepRemovalDuration", FGeometryCollection::TransformGroup);
				for (int32 Idx = 0; Idx < SleepRemovalDuration.Num(); ++Idx)
				{
					SleepRemovalDuration[Idx] = FMath::RandRange(MinTime, MaxTime);
				}
			}
		}
		
		// Remove on break feature related dynamic attribute arrays
		if (const TManagedArray<FVector4f>* RemoveOnBreak = RestCollection->GetGeometryCollection()->FindAttribute<FVector4f>("RemoveOnBreak", FGeometryCollection::TransformGroup))
		{
			// Needs to be checked here too because remove on sleep and remove on break features are orthogonal
			if (!DynamicCollection->HasAttribute("Decay", FGeometryCollection::TransformGroup))
			{
				TManagedArray<float>& Decay = DynamicCollection->AddAttribute<float>("Decay", FGeometryCollection::TransformGroup);
				Decay.Fill(0);
			}

			if (!DynamicCollection->HasAttribute("UniformScale", FGeometryCollection::TransformGroup))
			{
				TManagedArray<FTransform>& UniformScale = DynamicCollection->AddAttribute<FTransform>("UniformScale", FGeometryCollection::TransformGroup);
				UniformScale.Fill(FTransform::Identity);
			}
		
			if (!DynamicCollection->HasAttribute("BreakTimer", FGeometryCollection::TransformGroup))
			{
				TManagedArray<float>& BreakTimer = DynamicCollection->AddAttribute<float>("BreakTimer", FGeometryCollection::TransformGroup);
				BreakTimer.Fill(-1); // disabled timer , waiting for the break event
			}
			
			if (!DynamicCollection->HasAttribute("PostBreakDuration", FGeometryCollection::TransformGroup))
			{
				TManagedArray<float>& PostBreakDuration = DynamicCollection->AddAttribute<float>("PostBreakDuration", FGeometryCollection::TransformGroup);
				for (int32 Idx = 0; Idx < PostBreakDuration.Num(); ++Idx)
				{
					const FRemoveOnBreakData RemoveOnBreakData{ (*RemoveOnBreak)[Idx] };
					const FVector2f PostBreakTimer = RemoveOnBreakData.GetBreakTimer();
					const float MinTime = FMath::Max(0.0f, PostBreakTimer.X);
					const float MaxTime = FMath::Max(MinTime, PostBreakTimer.Y);
					PostBreakDuration[Idx] = RemoveOnBreakData.IsEnabled()? FMath::RandRange(MinTime, MaxTime): -1;
				}
			}

			if (!DynamicCollection->HasAttribute("BreakRemovalDuration", FGeometryCollection::TransformGroup))
			{
				const TManagedArray<TSet<int32>>& Children = DynamicCollection->Children;
				TManagedArray<float>& BreakRemovalDuration = DynamicCollection->AddAttribute<float>("BreakRemovalDuration", FGeometryCollection::TransformGroup);
				for (int32 Idx = 0; Idx < BreakRemovalDuration.Num(); ++Idx)
				{
					const FRemoveOnBreakData RemoveOnBreakData{ (*RemoveOnBreak)[Idx] };
					const FVector2f RemovalTimer = RemoveOnBreakData.GetRemovalTimer();
					const float MinTime = FMath::Max(0.0f, RemovalTimer.X);
					const float MaxTime = FMath::Max(MinTime, RemovalTimer.Y);
					const bool bIsCluster = (Children[Idx].Num() > 0);
					const bool bUseClusterCrumbling = (bIsCluster && RemoveOnBreakData.GetClusterCrumbling());
					BreakRemovalDuration[Idx] = bUseClusterCrumbling? -1: FMath::RandRange(MinTime, MaxTime);
				}
			}
		}

		SetRenderStateDirty();
	}

	if (RestTransforms.Num() > 0)
	{
		SetInitialTransforms(RestTransforms);
	}

	if (RestCollection)
	{
		CalculateGlobalMatrices();
		CalculateLocalBounds();
	}
}

void UGeometryCollectionComponent::OnCreatePhysicsState()
{
	// Skip the chain - don't care about body instance setup
	UActorComponent::OnCreatePhysicsState();
	if (!BodyInstance.bSimulatePhysics) IsObjectLoading = false; // just mark as loaded if we are simulating.

	// Static mesh uses an init framework that goes through FBodyInstance.  We
	// do the same thing, but through the geometry collection proxy and lambdas
	// defined below.  FBodyInstance doesn't work for geometry collections 
	// because FBodyInstance manages a single particle, where we have many.
	if (!PhysicsProxy)
	{
#if WITH_EDITOR && WITH_EDITORONLY_DATA
		EditorActor = nullptr;

		if (RestCollection)
		{
			//hack: find a better place for this
			UGeometryCollection* RestCollectionMutable = const_cast<UGeometryCollection*>(ToRawPtr(RestCollection));
			RestCollectionMutable->CreateSimulationData();
		}
#endif
		const bool bValidWorld = GetWorld() && GetWorld()->IsGameWorld();
		const bool bValidCollection = DynamicCollection && DynamicCollection->Transform.Num() > 0;
		if (bValidWorld && bValidCollection)
		{
			FPhysxUserData::Set<UPrimitiveComponent>(&PhysicsUserData, this);

			// If the Component is set to Dynamic, we look to the RestCollection for initial dynamic state override per transform.
			TManagedArray<int32> & DynamicState = DynamicCollection->DynamicState;

			// if this code is changed you may need to account for bStartAwake
			EObjectStateTypeEnum LocalObjectType = (ObjectType != EObjectStateTypeEnum::Chaos_Object_Sleeping) ? ObjectType : EObjectStateTypeEnum::Chaos_Object_Dynamic;
			if (LocalObjectType != EObjectStateTypeEnum::Chaos_Object_UserDefined)
			{
				if (RestCollection && (LocalObjectType == EObjectStateTypeEnum::Chaos_Object_Dynamic))
				{
					TManagedArray<int32>& InitialDynamicState = RestCollection->GetGeometryCollection()->InitialDynamicState;
					for (int i = 0; i < DynamicState.Num(); i++)
					{
						DynamicState[i] = (InitialDynamicState[i] == static_cast<int32>(Chaos::EObjectStateType::Uninitialized)) ? static_cast<int32>(LocalObjectType) : InitialDynamicState[i];
					}
				}
				else
				{
					for (int i = 0; i < DynamicState.Num(); i++)
					{
						DynamicState[i] = static_cast<int32>(LocalObjectType);
					}
				}
			}

			TManagedArray<bool>& Active = DynamicCollection->Active;
			if (RestCollection->GetGeometryCollection()->HasAttribute(FGeometryCollection::SimulatableParticlesAttribute, FTransformCollection::TransformGroup))
			{
				TManagedArray<bool>* SimulatableParticles = RestCollection->GetGeometryCollection()->FindAttribute<bool>(FGeometryCollection::SimulatableParticlesAttribute, FTransformCollection::TransformGroup);
				for (int i = 0; i < Active.Num(); i++)
				{
					Active[i] = (*SimulatableParticles)[i];
				}
			}
			else
			{
				// If no simulation data is available then default to the simulation of just the rigid geometry.
				for (int i = 0; i < Active.Num(); i++)
				{
					Active[i] = RestCollection->GetGeometryCollection()->IsRigid(i);
				}
			}
			
			TManagedArray<int32> & CollisionGroupArray = DynamicCollection->CollisionGroup;
			{
				for (int i = 0; i < CollisionGroupArray.Num(); i++)
				{
					CollisionGroupArray[i] = CollisionGroup;
				}
			}
	
			// Set up initial filter data for our particles
			// #BGTODO We need a dummy body setup for now to allow the body instance to generate filter information. Change body instance to operate independently.
			DummyBodySetup = NewObject<UBodySetup>(this, UBodySetup::StaticClass());
			BodyInstance.BodySetup = DummyBodySetup;
			BodyInstance.OwnerComponent = this; // Required to make filter data include component/actor ID for ignored actors/components

			BuildInitialFilterData();

			if (BodyInstance.bSimulatePhysics)
			{
				RegisterAndInitializePhysicsProxy();
			}
			
		}
	}
}

void UGeometryCollectionComponent::RegisterAndInitializePhysicsProxy()
{
	FSimulationParameters SimulationParameters;
	{
#if !(UE_BUILD_SHIPPING || UE_BUILD_TEST)
		SimulationParameters.Name = GetPathName();
#endif
		EClusterConnectionTypeEnum ClusterCollectionType = ClusterConnectionType_DEPRECATED;
		float ConnectionGraphBoundsFilteringMargin = 0;
		if (RestCollection)
		{
			RestCollection->GetSharedSimulationParams(SimulationParameters.Shared);
			SimulationParameters.RestCollection = RestCollection->GetGeometryCollection().Get();
			ClusterCollectionType = RestCollection->ClusterConnectionType;
			ConnectionGraphBoundsFilteringMargin = RestCollection->ConnectionGraphBoundsFilteringMargin;
		}
		SimulationParameters.Simulating = BodyInstance.bSimulatePhysics;
		SimulationParameters.EnableClustering = EnableClustering;
		SimulationParameters.ClusterGroupIndex = EnableClustering ? ClusterGroupIndex : 0;
		SimulationParameters.MaxClusterLevel = MaxClusterLevel;
		SimulationParameters.bUseSizeSpecificDamageThresholds = bUseSizeSpecificDamageThreshold;
		SimulationParameters.DamageThreshold = DamageThreshold;
		SimulationParameters.bUsePerClusterOnlyDamageThreshold = RestCollection? RestCollection->PerClusterOnlyDamageThreshold: false; 
		SimulationParameters.ClusterConnectionMethod = (Chaos::FClusterCreationParameters::EConnectionMethod)ClusterCollectionType;
		SimulationParameters.ConnectionGraphBoundsFilteringMargin = ConnectionGraphBoundsFilteringMargin; 
		SimulationParameters.CollisionGroup = CollisionGroup;
		SimulationParameters.CollisionSampleFraction = CollisionSampleFraction;
		SimulationParameters.InitialVelocityType = InitialVelocityType;
		SimulationParameters.InitialLinearVelocity = InitialLinearVelocity;
		SimulationParameters.InitialAngularVelocity = InitialAngularVelocity;
		SimulationParameters.bClearCache = true;
		SimulationParameters.ObjectType = ObjectType;
		SimulationParameters.StartAwake = BodyInstance.bStartAwake;
		SimulationParameters.CacheType = CacheParameters.CacheMode;
		SimulationParameters.ReverseCacheBeginTime = CacheParameters.ReverseCacheBeginTime;
		SimulationParameters.bGenerateBreakingData = bNotifyBreaks;
		SimulationParameters.bGenerateCollisionData = bNotifyCollisions;
		SimulationParameters.bGenerateTrailingData = bNotifyTrailing;
		SimulationParameters.bGenerateRemovalsData = bNotifyRemovals;
		SimulationParameters.RemoveOnFractureEnabled = SimulationParameters.Shared.RemoveOnFractureIndices.Num() > 0;
		SimulationParameters.EnableGravity = BodyInstance.bEnableGravity;
		SimulationParameters.UseInertiaConditioning = BodyInstance.IsInertiaConditioningEnabled();
		SimulationParameters.WorldTransform = GetComponentToWorld();
		SimulationParameters.UserData = static_cast<void*>(&PhysicsUserData);

		UPhysicalMaterial* EnginePhysicalMaterial = GetPhysicalMaterial();
		if (ensure(EnginePhysicalMaterial))
		{
			SimulationParameters.PhysicalMaterialHandle = EnginePhysicalMaterial->GetPhysicsMaterial();
		}
		GetInitializationCommands(SimulationParameters.InitializationCommands);
	}

	FGuid CollectorGuid = FGuid::NewGuid();
#if WITH_EDITORONLY_DATA
	CollectorGuid = RunTimeDataCollectionGuid;
	if (bEnableRunTimeDataCollection && RestCollection)
	{
		FRuntimeDataCollector::GetInstance().AddCollector(CollectorGuid, RestCollection->NumElements(FGeometryCollection::TransformGroup));
	}
	else
	{
		FRuntimeDataCollector::GetInstance().RemoveCollector(CollectorGuid);
	}
#endif
	PhysicsProxy = new FGeometryCollectionPhysicsProxy(this, *DynamicCollection, SimulationParameters, InitialSimFilter, InitialQueryFilter, CollectorGuid);
	FPhysScene_Chaos* Scene = GetInnerChaosScene();
	Scene->AddObject(this, PhysicsProxy);

	RegisterForEvents();
	SetAsyncPhysicsTickEnabled(GetIsReplicated());
}

#if WITH_EDITORONLY_DATA
const FDamageCollector* UGeometryCollectionComponent::GetRunTimeDataCollector() const
{
	return FRuntimeDataCollector::GetInstance().Find(RunTimeDataCollectionGuid);
}
#endif

void UGeometryCollectionComponent::OnDestroyPhysicsState()
{
	UActorComponent::OnDestroyPhysicsState();

	if(DummyBodyInstance.IsValidBodyInstance())
	{
		DummyBodyInstance.TermBody();
	}

	if(PhysicsProxy)
	{
		FPhysScene_Chaos* Scene = GetInnerChaosScene();
		Scene->RemoveObject(PhysicsProxy);
		InitializationState = ESimulationInitializationState::Unintialized;

		// Discard the pointer (cleanup happens through the scene or dedicated thread)
		PhysicsProxy = nullptr;
	}
}

void UGeometryCollectionComponent::SendRenderDynamicData_Concurrent()
{
	//UE_LOG(UGCC_LOG, Log, TEXT("GeometryCollectionComponent[%p]::SendRenderDynamicData_Concurrent()"), this);
	Super::SendRenderDynamicData_Concurrent();

	// Only update the dynamic data if the dynamic collection is dirty
	if (SceneProxy && ((DynamicCollection && DynamicCollection->IsDirty()) || CachePlayback)) 
	{
		FGeometryCollectionDynamicData* DynamicData = InitDynamicData(false /* initialization */);

		if (DynamicData || SceneProxy->IsNaniteMesh())
		{
			INC_DWORD_STAT_BY(STAT_GCTotalTransforms, DynamicData ? DynamicData->Transforms.Num() : 0);
			INC_DWORD_STAT_BY(STAT_GCChangedTransforms, DynamicData ? DynamicData->ChangedCount : 0);

			// #todo (bmiller) Once ISMC changes have been complete, this is the best place to call this method
			// but we can't currently because it's an inappropriate place to call MarkRenderStateDirty on the ISMC.
			// RefreshEmbeddedGeometry();

			// Enqueue command to send to render thread
			if (SceneProxy->IsNaniteMesh())
			{
				FNaniteGeometryCollectionSceneProxy* GeometryCollectionSceneProxy = static_cast<FNaniteGeometryCollectionSceneProxy*>(SceneProxy);
				ENQUEUE_RENDER_COMMAND(SendRenderDynamicData)(
					[GeometryCollectionSceneProxy, DynamicData](FRHICommandListImmediate& RHICmdList)
					{
						if (DynamicData)
						{
							GeometryCollectionSceneProxy->SetDynamicData_RenderThread(DynamicData);
						}
						else
						{
							// No longer dynamic, make sure previous transforms are reset
							GeometryCollectionSceneProxy->ResetPreviousTransforms_RenderThread();
						}
					}
				);
			}
			else
			{
				FGeometryCollectionSceneProxy* GeometryCollectionSceneProxy = static_cast<FGeometryCollectionSceneProxy*>(SceneProxy);
				ENQUEUE_RENDER_COMMAND(SendRenderDynamicData)(
					[GeometryCollectionSceneProxy, DynamicData](FRHICommandListImmediate& RHICmdList)
					{
						if (GeometryCollectionSceneProxy)
						{
							GeometryCollectionSceneProxy->SetDynamicData_RenderThread(DynamicData);
						}
					}
				);
			}
		}

		// mark collection clean now that we have rendered
		if (DynamicCollection)
		{
			DynamicCollection->MakeClean();
		}			
	}
}

void UGeometryCollectionComponent::OnActorEnableCollisionChanged()
{
	// Update filters on BI
	BodyInstance.UpdatePhysicsFilterData();

	// Update InitialSimFilter and InitialQueryFilter
	BuildInitialFilterData();

	// Update filters stored on proxy
	if (PhysicsProxy)
	{
		PhysicsProxy->UpdateFilterData_External(InitialSimFilter, InitialQueryFilter);
	}

}

void UGeometryCollectionComponent::BuildInitialFilterData()
{
	FBodyCollisionFilterData FilterData;
	FMaskFilter FilterMask = BodyInstance.GetMaskFilter();
	BodyInstance.BuildBodyFilterData(FilterData);

	InitialSimFilter = FilterData.SimFilter;
	InitialQueryFilter = FilterData.QuerySimpleFilter;

	// Enable for complex and simple (no dual representation currently like other meshes)
	InitialQueryFilter.Word3 |= (EPDF_SimpleCollision | EPDF_ComplexCollision);
	InitialSimFilter.Word3 |= (EPDF_SimpleCollision | EPDF_ComplexCollision);

	if (bNotifyCollisions)
	{
		InitialQueryFilter.Word3 |= EPDF_ContactNotify;
		InitialSimFilter.Word3 |= EPDF_ContactNotify;
	}
}

void UGeometryCollectionComponent::SetRestCollection(const UGeometryCollection* RestCollectionIn)
{
	//UE_LOG(UGCC_LOG, Log, TEXT("GeometryCollectionComponent[%p]::SetRestCollection()"), this);
	if (RestCollectionIn)
	{
		RestCollection = RestCollectionIn;

		const int32 NumTransforms = RestCollection->GetGeometryCollection()->NumElements(FGeometryCollection::TransformGroup);
		RestTransforms.SetNum(NumTransforms);
		for (int32 Idx = 0; Idx < NumTransforms; ++Idx)
		{
			RestTransforms[Idx] = RestCollection->GetGeometryCollection()->Transform[Idx];
		}

		CalculateGlobalMatrices();
		CalculateLocalBounds();

		if (!IsEmbeddedGeometryValid())
		{
			InitializeEmbeddedGeometry();
		}

		// initialize the component per level damage threshold from the asset defaults 
		DamageThreshold = RestCollection->DamageThreshold;
		
		//ResetDynamicCollection();
	}
}

FGeometryCollectionEdit::FGeometryCollectionEdit(UGeometryCollectionComponent* InComponent, GeometryCollection::EEditUpdate InEditUpdate, bool bShapeIsUnchanged)
	: Component(InComponent)
	, EditUpdate(InEditUpdate)
	, bShapeIsUnchanged(bShapeIsUnchanged)
{
	bHadPhysicsState = Component->HasValidPhysicsState();
	if (EnumHasAnyFlags(EditUpdate, GeometryCollection::EEditUpdate::Physics) && bHadPhysicsState)
	{
		Component->DestroyPhysicsState();
	}

	if (EnumHasAnyFlags(EditUpdate, GeometryCollection::EEditUpdate::Rest) && GetRestCollection())
	{
		Component->Modify();
		GetRestCollection()->Modify();
	}
}

FGeometryCollectionEdit::~FGeometryCollectionEdit()
{
#if WITH_EDITOR
	if (!!EditUpdate)
	{
		if (EnumHasAnyFlags(EditUpdate, GeometryCollection::EEditUpdate::Dynamic))
		{
			Component->ResetDynamicCollection();
		}

		if (EnumHasAnyFlags(EditUpdate, GeometryCollection::EEditUpdate::Rest) && GetRestCollection())
		{
			if (!bShapeIsUnchanged)
			{
				GetRestCollection()->UpdateConvexGeometry();
			}
			GetRestCollection()->InvalidateCollection();
		}

		if (EnumHasAnyFlags(EditUpdate, GeometryCollection::EEditUpdate::Physics) && bHadPhysicsState)
		{
			Component->RecreatePhysicsState();
		}
	}
#endif
}

UGeometryCollection* FGeometryCollectionEdit::GetRestCollection()
{
	if (Component)
	{
		return const_cast<UGeometryCollection*>(ToRawPtr(Component->RestCollection));	//const cast is ok here since we are explicitly in edit mode. Should all this editor code be in an editor module?
	}
	return nullptr;
}

#if WITH_EDITOR
TArray<FLinearColor> FScopedColorEdit::RandomColors;

FScopedColorEdit::FScopedColorEdit(UGeometryCollectionComponent* InComponent, bool bForceUpdate) : bUpdated(bForceUpdate), Component(InComponent)
{
	if (RandomColors.Num() == 0)
	{
		FMath::RandInit(2019);
		for (int i = 0; i < 100; i++)
		{
			const FColor Color(FMath::Rand() % 100 + 5, FMath::Rand() % 100 + 5, FMath::Rand() % 100 + 5, 255);
			RandomColors.Push(FLinearColor(Color));
		}
	}
}

FScopedColorEdit::~FScopedColorEdit()
{
	if (bUpdated)
	{
		UpdateBoneColors();
	}
}
void FScopedColorEdit::SetShowBoneColors(bool ShowBoneColorsIn)
{
	if (Component->bShowBoneColors != ShowBoneColorsIn)
	{
		bUpdated = true;
		Component->bShowBoneColors = ShowBoneColorsIn;
	}
}

bool FScopedColorEdit::GetShowBoneColors() const
{
	return Component->bShowBoneColors;
}

void FScopedColorEdit::SetEnableBoneSelection(bool ShowSelectedBonesIn)
{
	if (Component->bEnableBoneSelection != ShowSelectedBonesIn)
	{
		bUpdated = true;
		Component->bEnableBoneSelection = ShowSelectedBonesIn;
	}
}

bool FScopedColorEdit::GetEnableBoneSelection() const
{
	return Component->bEnableBoneSelection;
}

bool FScopedColorEdit::IsBoneSelected(int BoneIndex) const
{
	return Component->SelectedBones.Contains(BoneIndex);
}

void FScopedColorEdit::SetSelectedBones(const TArray<int32>& SelectedBonesIn)
{
	bUpdated = true;
	Component->SelectedBones = SelectedBonesIn;
	Component->SelectEmbeddedGeometry();
}

void FScopedColorEdit::AppendSelectedBones(const TArray<int32>& SelectedBonesIn)
{
	bUpdated = true;
	Component->SelectedBones.Append(SelectedBonesIn);
}

void FScopedColorEdit::ToggleSelectedBones(const TArray<int32>& SelectedBonesIn, bool bAdd, bool bSnapToLevel)
{
	bUpdated = true;
	
	const UGeometryCollection* GeometryCollection = Component->GetRestCollection();
	if (GeometryCollection)
	{ 
		TSharedPtr<FGeometryCollection, ESPMode::ThreadSafe> GeometryCollectionPtr = GeometryCollection->GetGeometryCollection();
		for (int32 BoneIndex : SelectedBonesIn)
		{
		
			int32 ContextBoneIndex = (bSnapToLevel && GetViewLevel() > -1) ? 
				FGeometryCollectionClusteringUtility::GetParentOfBoneAtSpecifiedLevel(GeometryCollectionPtr.Get(), BoneIndex, GetViewLevel(), true /*bSkipFiltered*/) 
				: BoneIndex;
			if (ContextBoneIndex == FGeometryCollection::Invalid)
			{
				continue;
			}
		
			if (bAdd) // shift select
			{
				Component->SelectedBones.Add(BoneIndex);
			}
			else // ctrl select (toggle)
			{ 
				if (Component->SelectedBones.Contains(ContextBoneIndex))
				{
					Component->SelectedBones.Remove(ContextBoneIndex);
				}
				else
				{
					Component->SelectedBones.Add(ContextBoneIndex);
				}
			}
		}
	}
}

void FScopedColorEdit::AddSelectedBone(int32 BoneIndex)
{
	if (!Component->SelectedBones.Contains(BoneIndex))
	{
		bUpdated = true;
		Component->SelectedBones.Push(BoneIndex);
	}
}

void FScopedColorEdit::ClearSelectedBone(int32 BoneIndex)
{
	if (Component->SelectedBones.Contains(BoneIndex))
	{
		bUpdated = true;
		Component->SelectedBones.Remove(BoneIndex);
	}
}

const TArray<int32>& FScopedColorEdit::GetSelectedBones() const
{
	return Component->GetSelectedBones();
}

int32 FScopedColorEdit::GetMaxSelectedLevel(bool bOnlyRigid) const
{
	int32 MaxSelectedLevel = -1;
	const UGeometryCollection* GeometryCollection = Component->GetRestCollection();
	if (GeometryCollection)
	{
		TSharedPtr<FGeometryCollection, ESPMode::ThreadSafe> GeometryCollectionPtr = GeometryCollection->GetGeometryCollection();
		const TManagedArray<int32>& Levels = GeometryCollectionPtr->GetAttribute<int32>("Level", FGeometryCollection::TransformGroup);
		const TManagedArray<int32>& SimTypes = GeometryCollectionPtr->SimulationType;
		for (int32 BoneIndex : Component->SelectedBones)
		{
			if (!bOnlyRigid || SimTypes[BoneIndex] == FGeometryCollection::ESimulationTypes::FST_Rigid)
			{
				MaxSelectedLevel = FMath::Max(MaxSelectedLevel, Levels[BoneIndex]);
			}
		}
	}
	return MaxSelectedLevel;
}

bool FScopedColorEdit::IsSelectionValidAtLevel(int32 TargetLevel) const
{
	if (TargetLevel == -1)
	{
		return true;
	}
	const UGeometryCollection* GeometryCollection = Component->GetRestCollection();
	if (GeometryCollection)
	{
		TSharedPtr<FGeometryCollection, ESPMode::ThreadSafe> GeometryCollectionPtr = GeometryCollection->GetGeometryCollection();
		const TManagedArray<int32>& Levels = GeometryCollectionPtr->GetAttribute<int32>("Level", FGeometryCollection::TransformGroup);
		const TManagedArray<int32>& SimTypes = GeometryCollectionPtr->SimulationType;
		for (int32 BoneIndex : Component->SelectedBones)
		{
			if (SimTypes[BoneIndex] != FGeometryCollection::ESimulationTypes::FST_Clustered && // clusters are always shown in outliner
				Levels[BoneIndex] != TargetLevel && // nodes at the target level are shown in outliner
				// non-cluster parents are shown if they have children that are exact matches (i.e., a rigid parent w/ embedded at the target level)
				(GeometryCollectionPtr->Children[BoneIndex].Num() == 0 || Levels[BoneIndex] + 1 != TargetLevel))
			{
				return false;
			}
		}
	}
	return true;
}

void FScopedColorEdit::ResetBoneSelection()
{
	if (Component->SelectedBones.Num() > 0)
	{
		bUpdated = true;
	}

	Component->SelectedBones.Empty();
}

void FScopedColorEdit::FilterSelectionToLevel(bool bPreferLowestOnly)
{
	const UGeometryCollection* GeometryCollection = Component->GetRestCollection();
	int32 ViewLevel = GetViewLevel();
	bool bNeedsFiltering = ViewLevel >= 0 || bPreferLowestOnly;
	if (GeometryCollection && Component->SelectedBones.Num() > 0 && bNeedsFiltering)
	{
		TSharedPtr<FGeometryCollection, ESPMode::ThreadSafe> GeometryCollectionPtr = GeometryCollection->GetGeometryCollection();

		const TManagedArray<int32>& Levels = GeometryCollectionPtr->GetAttribute<int32>("Level", FGeometryCollection::TransformGroup);
		const TManagedArray<int32>& SimTypes = GeometryCollectionPtr->SimulationType;

		TArray<int32> NewSelection;
		NewSelection.Reserve(Component->SelectedBones.Num());
		if (ViewLevel >= 0)
		{
			for (int32 BoneIdx : Component->SelectedBones)
			{
				bool bIsCluster = SimTypes[BoneIdx] == FGeometryCollection::ESimulationTypes::FST_Clustered;
				if (bPreferLowestOnly && bIsCluster && Levels[BoneIdx] < ViewLevel)
				{
					continue;
				}
				if (Levels[BoneIdx] == ViewLevel || (bIsCluster && Levels[BoneIdx] <= ViewLevel))
				{
					NewSelection.Add(BoneIdx);
				}
			}
		}
		else // bPreferLowestOnly && ViewLevel == -1
		{
			// If view level is "all" and we prefer lowest selection, just select any non-cluster nodes
			for (int32 BoneIdx : Component->SelectedBones)
			{
				bool bIsCluster = SimTypes[BoneIdx] == FGeometryCollection::ESimulationTypes::FST_Clustered;
				if (!bIsCluster)
				{
					NewSelection.Add(BoneIdx);
				}
			}
		}

		if (NewSelection.Num() != Component->SelectedBones.Num())
		{
			SetSelectedBones(NewSelection);
			SetHighlightedBones(NewSelection, true);
		}
	}
}

void FScopedColorEdit::SelectBones(GeometryCollection::ESelectionMode SelectionMode)
{
	check(Component);

	const UGeometryCollection* GeometryCollection = Component->GetRestCollection();
	if (GeometryCollection)
	{
		TSharedPtr<FGeometryCollection, ESPMode::ThreadSafe> GeometryCollectionPtr = GeometryCollection->GetGeometryCollection();

		switch (SelectionMode)
		{
		case GeometryCollection::ESelectionMode::None:
			ResetBoneSelection();
			break;

		case GeometryCollection::ESelectionMode::AllGeometry:
		{
			ResetBoneSelection();
			TArray<int32> BonesToSelect;
			FGeometryCollectionClusteringUtility::GetBonesToLevel(GeometryCollectionPtr.Get(), GetViewLevel(), BonesToSelect, true, true);
			AppendSelectedBones(BonesToSelect);
		}
		break;

		case GeometryCollection::ESelectionMode::Leaves:
		{
			ResetBoneSelection();
			int32 ViewLevel = GetViewLevel();
			TArray<int32> BonesToSelect;
			FGeometryCollectionClusteringUtility::GetBonesToLevel(GeometryCollectionPtr.Get(), GetViewLevel(), BonesToSelect, true, true);
			const TManagedArray<int32>& SimType = GeometryCollectionPtr->SimulationType;
			const TManagedArray<int32>& Levels = GeometryCollectionPtr->GetAttribute<int32>("Level", FGeometryCollection::TransformGroup);
			BonesToSelect.SetNum(Algo::RemoveIf(BonesToSelect, [&](int32 BoneIdx)
				{
					return SimType[BoneIdx] != FGeometryCollection::ESimulationTypes::FST_Rigid
						|| (ViewLevel != -1 && Levels[BoneIdx] != ViewLevel);
				}));
			AppendSelectedBones(BonesToSelect);
		}
		break;

		case GeometryCollection::ESelectionMode::Clusters:
		{
			ResetBoneSelection();
			int32 ViewLevel = GetViewLevel();
			TArray<int32> BonesToSelect;
			FGeometryCollectionClusteringUtility::GetBonesToLevel(GeometryCollectionPtr.Get(), ViewLevel, BonesToSelect, true, true);
			const TManagedArray<int32>& SimType = GeometryCollectionPtr->SimulationType;
			const TManagedArray<int32>& Levels = GeometryCollectionPtr->GetAttribute<int32>("Level", FGeometryCollection::TransformGroup);
			BonesToSelect.SetNum(Algo::RemoveIf(BonesToSelect, [&](int32 BoneIdx)
			{
				return SimType[BoneIdx] != FGeometryCollection::ESimulationTypes::FST_Clustered
					|| (ViewLevel != -1 && Levels[BoneIdx] != ViewLevel);
			}));
			AppendSelectedBones(BonesToSelect);
		}
		break;

		case GeometryCollection::ESelectionMode::InverseGeometry:
		{
			TArray<int32> Roots;
			FGeometryCollectionClusteringUtility::GetRootBones(GeometryCollectionPtr.Get(), Roots);
			TArray<int32> NewSelection;

			for (int32 RootElement : Roots)
			{
				if (GetViewLevel() == -1)
				{
					TArray<int32> LeafBones;
					FGeometryCollectionClusteringUtility::GetLeafBones(GeometryCollectionPtr.Get(), RootElement, true, LeafBones);

					for (int32 Element : LeafBones)
					{
						if (!IsBoneSelected(Element))
						{
							NewSelection.Push(Element);
						}
					}
				}
				else
				{
					TArray<int32> ViewLevelBones;
					FGeometryCollectionClusteringUtility::GetChildBonesAtLevel(GeometryCollectionPtr.Get(), RootElement, GetViewLevel(), ViewLevelBones);
					for (int32 ViewLevelBone : ViewLevelBones)
					{
						if (!IsBoneSelected(ViewLevelBone))
						{
							NewSelection.Push(ViewLevelBone);
						}
					}
				}
			}
			
			ResetBoneSelection();
			AppendSelectedBones(NewSelection);
		}
		break;


		case GeometryCollection::ESelectionMode::Neighbors:
		{
			FGeometryCollectionProximityUtility ProximityUtility(GeometryCollectionPtr.Get());
			ProximityUtility.UpdateProximity();

			const TManagedArray<int32>& TransformIndex = GeometryCollectionPtr->TransformIndex;
			const TManagedArray<int32>& TransformToGeometryIndex = GeometryCollectionPtr->TransformToGeometryIndex;
			const TManagedArray<TSet<int32>>& Proximity = GeometryCollectionPtr->GetAttribute<TSet<int32>>("Proximity", FGeometryCollection::GeometryGroup);

			const TArray<int32> SelectedBones = GetSelectedBones();

			TSet<int32> NewSelection;
			for (int32 Bone : SelectedBones)
			{
				NewSelection.Add(Bone);
				int32 GeometryIdx = TransformToGeometryIndex[Bone];
				if (GeometryIdx != INDEX_NONE)
				{
					const TSet<int32>& Neighbors = Proximity[GeometryIdx];
					for (int32 NeighborGeometryIndex : Neighbors)
					{
						NewSelection.Add(TransformIndex[NeighborGeometryIndex]);
					}
				}
			}

			ResetBoneSelection();
			AppendSelectedBones(NewSelection.Array());
		}
		break;

		case GeometryCollection::ESelectionMode::Parent:
		{
			const TManagedArray<int32>& Parents = GeometryCollectionPtr->Parent;
			
			const TArray<int32> SelectedBones = GetSelectedBones();

			TSet<int32> NewSelection;
			for (int32 Bone : SelectedBones)
			{
				int32 ParentBone = Parents[Bone];
				if (ParentBone != FGeometryCollection::Invalid)
				{
					NewSelection.Add(ParentBone);
				}
			}

			ResetBoneSelection();
			AppendSelectedBones(NewSelection.Array());
		}
		break;

		case GeometryCollection::ESelectionMode::Children:
		{
			const TManagedArray<TSet<int32>>& Children = GeometryCollectionPtr->Children;

			const TArray<int32> SelectedBones = GetSelectedBones();

			TSet<int32> NewSelection;
			for (int32 Bone : SelectedBones)
			{
				if (Children[Bone].IsEmpty())
				{
					NewSelection.Add(Bone);
					continue;
				}
				for (int32 Child : Children[Bone])
				{
					NewSelection.Add(Child);
				}
			}

			ResetBoneSelection();
			AppendSelectedBones(NewSelection.Array());
		}
		break;

		case GeometryCollection::ESelectionMode::Siblings:
		{
			const TManagedArray<int32>& Parents = GeometryCollectionPtr->Parent;
			const TManagedArray<TSet<int32>>& Children = GeometryCollectionPtr->Children;

			const TArray<int32> SelectedBones = GetSelectedBones();

			TSet<int32> NewSelection;
			for (int32 Bone : SelectedBones)
			{
				int32 ParentBone = Parents[Bone];
				if (ParentBone != FGeometryCollection::Invalid)
				{
					for (int32 Child : Children[ParentBone])
					{
						NewSelection.Add(Child);
					}
				}

			}

			ResetBoneSelection();
			AppendSelectedBones(NewSelection.Array());
		}
		break;

		case GeometryCollection::ESelectionMode::Level:
		{
			if (GeometryCollectionPtr->HasAttribute("Level", FTransformCollection::TransformGroup))
			{
				const TManagedArray<int32>& Levels = GeometryCollectionPtr->GetAttribute<int32>("Level", FTransformCollection::TransformGroup);

				const TArray<int32> SelectedBones = GetSelectedBones();

				TSet<int32> NewSelection;
				for (int32 Bone : SelectedBones)
				{
					int32 Level = Levels[Bone];
					for (int32 TransformIdx = 0; TransformIdx < GeometryCollectionPtr->NumElements(FTransformCollection::TransformGroup); ++TransformIdx)
					{
						if (Levels[TransformIdx] == Level)
						{
							NewSelection.Add(TransformIdx);
						}
					}
				}

				ResetBoneSelection();
				AppendSelectedBones(NewSelection.Array());
			}	
		}
		break;

		default: 
			check(false); // unexpected selection mode
		break;
		}

		const TArray<int32>& SelectedBones = GetSelectedBones();
		TArray<int32> HighlightBones;
		for (int32 SelectedBone: SelectedBones)
		{ 
			FGeometryCollectionClusteringUtility::RecursiveAddAllChildren(GeometryCollectionPtr->Children, SelectedBone, HighlightBones);
		}
		SetHighlightedBones(HighlightBones);
	}
}

bool FScopedColorEdit::IsBoneHighlighted(int BoneIndex) const
{
	return Component->HighlightedBones.Contains(BoneIndex);
}

void FScopedColorEdit::SetHighlightedBones(const TArray<int32>& HighlightedBonesIn, bool bHighlightChildren)
{
	if (Component->HighlightedBones != HighlightedBonesIn)
	{
		const UGeometryCollection* GeometryCollection = Component->GetRestCollection();
		if (bHighlightChildren && GeometryCollection)
		{
			Component->HighlightedBones.Reset();
			TSharedPtr<FGeometryCollection, ESPMode::ThreadSafe> GeometryCollectionPtr = GeometryCollection->GetGeometryCollection();
			for (int32 SelectedBone : HighlightedBonesIn)
			{
				FGeometryCollectionClusteringUtility::RecursiveAddAllChildren(GeometryCollectionPtr->Children, SelectedBone, Component->HighlightedBones);
			}
		}
		else
		{
			Component->HighlightedBones = HighlightedBonesIn;
		}
		bUpdated = true;
	}
}

void FScopedColorEdit::AddHighlightedBone(int32 BoneIndex)
{
	Component->HighlightedBones.Push(BoneIndex);
}

const TArray<int32>& FScopedColorEdit::GetHighlightedBones() const
{
	return Component->GetHighlightedBones();
}

void FScopedColorEdit::ResetHighlightedBones()
{
	if (Component->HighlightedBones.Num() > 0)
	{
		bUpdated = true;
		Component->HighlightedBones.Empty();

	}
}

void FScopedColorEdit::SetLevelViewMode(int ViewLevelIn)
{
	if (Component->ViewLevel != ViewLevelIn)
	{
		bUpdated = true;
		Component->ViewLevel = ViewLevelIn;
	}
}

int FScopedColorEdit::GetViewLevel()
{
	return Component->ViewLevel;
}

void FScopedColorEdit::UpdateBoneColors()
{
	// @todo FractureTools - For large fractures updating colors this way is extremely slow because the render state (and thus all buffers) must be recreated.
	// It would be better to push the update to the proxy via a render command and update the existing buffer directly
	FGeometryCollectionEdit GeometryCollectionEdit = Component->EditRestCollection(GeometryCollection::EEditUpdate::None);
	UGeometryCollection* GeometryCollection = GeometryCollectionEdit.GetRestCollection();
	if(GeometryCollection)
	{
		FGeometryCollection* Collection = GeometryCollection->GetGeometryCollection().Get();

		FLinearColor BlankColor(FColor(80, 80, 80, 50));

		const TManagedArray<int>& Parents = Collection->Parent;
		bool HasLevelAttribute = Collection->HasAttribute("Level", FTransformCollection::TransformGroup);
		const TManagedArray<int>* Levels = nullptr;
		if (HasLevelAttribute)
		{
			Levels = &Collection->GetAttribute<int32>("Level", FTransformCollection::TransformGroup);
		}
		TManagedArray<FLinearColor>& BoneColors = Collection->BoneColor;

		for (int32 BoneIndex = 0, NumBones = Parents.Num() ; BoneIndex < NumBones; ++BoneIndex)
		{
			FLinearColor BoneColor = FLinearColor(FColor::Black);

			if (Component->ViewLevel == -1)
			{
				BoneColor = RandomColors[BoneIndex % RandomColors.Num()];
			}
			else
			{
				if (HasLevelAttribute && (*Levels)[BoneIndex] >= Component->ViewLevel)
				{
					// go up until we find parent at the required ViewLevel
					int32 Bone = BoneIndex;
					while (Bone != -1 && (*Levels)[Bone] > Component->ViewLevel)
					{
						Bone = Parents[Bone];
					}

					int32 ColorIndex = Bone + 1; // parent can be -1 for root, range [-1..n]
					BoneColor = RandomColors[ColorIndex % RandomColors.Num()];

					BoneColor.LinearRGBToHSV();
					BoneColor.B *= .5;
					BoneColor.HSVToLinearRGB();
				}
				else
				{
					BoneColor = BlankColor;
				}
			}

			// store the bone selected toggle in alpha so we can use it in the shader
			BoneColor.A = IsBoneHighlighted(BoneIndex) ? 1 : 0;

			BoneColors[BoneIndex] = BoneColor;
		}

		Component->MarkRenderStateDirty();
		Component->MarkRenderDynamicDataDirty();
	}
}
#endif

void UGeometryCollectionComponent::ApplyKinematicField(float Radius, FVector Position)
{
	FFieldSystemCommand Command = FFieldObjectCommands::CreateFieldCommand(EFieldPhysicsType::Field_DynamicState, new FRadialIntMask(Radius, Position, (int32)Chaos::EObjectStateType::Dynamic,
		(int32)Chaos::EObjectStateType::Kinematic, ESetMaskConditionType::Field_Set_IFF_NOT_Interior));
	DispatchFieldCommand(Command);
}

void UGeometryCollectionComponent::ApplyPhysicsField(bool Enabled, EGeometryCollectionPhysicsTypeEnum Target, UFieldSystemMetaData* MetaData, UFieldNodeBase* Field)
{
	if (Enabled && Field)
	{
		FFieldSystemCommand Command = FFieldObjectCommands::CreateFieldCommand(GetGeometryCollectionPhysicsType(Target), Field, MetaData);
		DispatchFieldCommand(Command);
	}
}

bool UGeometryCollectionComponent::GetIsObjectDynamic() const
{ 
	return PhysicsProxy ? PhysicsProxy->GetIsObjectDynamic() : IsObjectDynamic;
}

void UGeometryCollectionComponent::DispatchFieldCommand(const FFieldSystemCommand& InCommand)
{
	if (PhysicsProxy && InCommand.RootNode)
	{
		FChaosSolversModule* ChaosModule = FChaosSolversModule::GetModule();
		checkSlow(ChaosModule);

		auto Solver = PhysicsProxy->GetSolver<Chaos::FPBDRigidsSolver>();
		const FName Name = GetOwner() ? *GetOwner()->GetName() : TEXT("");

		FFieldSystemCommand LocalCommand = InCommand;
		LocalCommand.InitFieldNodes(Solver->GetSolverTime(), Name);

		Solver->EnqueueCommandImmediate([Solver, PhysicsProxy = this->PhysicsProxy, NewCommand = LocalCommand]()
		{
			// Pass through nullptr here as geom component commands can never affect other solvers
			PhysicsProxy->BufferCommand(Solver, NewCommand);
		});
	}
}

void UGeometryCollectionComponent::GetInitializationCommands(TArray<FFieldSystemCommand>& CombinedCommmands)
{
	CombinedCommmands.Reset();
	for (const AFieldSystemActor* FieldSystemActor : InitializationFields)
	{
		if (FieldSystemActor != nullptr)
		{
			if (FieldSystemActor->GetFieldSystemComponent())
			{
				const int32 NumCommands = FieldSystemActor->GetFieldSystemComponent()->ConstructionCommands.GetNumCommands();
				if (NumCommands > 0)
				{
					for (int32 CommandIndex = 0; CommandIndex < NumCommands; ++CommandIndex)
					{
						const FFieldSystemCommand NewCommand = FieldSystemActor->GetFieldSystemComponent()->ConstructionCommands.BuildFieldCommand(CommandIndex);
						if (NewCommand.RootNode)
						{
							CombinedCommmands.Emplace(NewCommand);
						}
					}
				}
				// Legacy path : only there for old levels. New ones will have the commands directly stored onto the component
				else if (FieldSystemActor->GetFieldSystemComponent()->GetFieldSystem())
				{
					const FName Name = GetOwner() ? *GetOwner()->GetName() : TEXT("");
					for (const FFieldSystemCommand& Command : FieldSystemActor->GetFieldSystemComponent()->GetFieldSystem()->Commands)
					{
						if (Command.RootNode)
						{
							FFieldSystemCommand NewCommand = { Command.TargetAttribute, Command.RootNode->NewCopy() };
							NewCommand.InitFieldNodes(0.0, Name);

							for (const TPair<FFieldSystemMetaData::EMetaType, TUniquePtr<FFieldSystemMetaData>>& Elem : Command.MetaData)
							{
								NewCommand.MetaData.Add(Elem.Key, TUniquePtr<FFieldSystemMetaData>(Elem.Value->NewCopy()));
							}
							CombinedCommmands.Emplace(NewCommand);
						}
					}
				}
			}
		}
	}
}

FPhysScene_Chaos* UGeometryCollectionComponent::GetInnerChaosScene() const
{
	if (ChaosSolverActor)
	{
		return ChaosSolverActor->GetPhysicsScene().Get();
	}
	else
	{
		if (ensure(GetOwner()) && ensure(GetOwner()->GetWorld()))
		{
			return GetOwner()->GetWorld()->GetPhysicsScene();
		}

		check(GWorld);
		return GWorld->GetPhysicsScene();
	}
}

AChaosSolverActor* UGeometryCollectionComponent::GetPhysicsSolverActor() const
{
	if (ChaosSolverActor)
	{
		return ChaosSolverActor;
	}
	else
	{
		FPhysScene_Chaos const* const Scene = GetInnerChaosScene();
		return Scene ? Cast<AChaosSolverActor>(Scene->GetSolverActor()) : nullptr;
	}

	return nullptr;
}

void UGeometryCollectionComponent::CalculateLocalBounds()
{
	LocalBounds.Init();
	const TManagedArray<FBox>& BoundingBoxes = GetBoundingBoxArray();
	const TManagedArray<int32>& TransformIndices = GetTransformIndexArray();

	const int32 NumBoxes = BoundingBoxes.Num();

	for (int32 BoxIdx = 0; BoxIdx < NumBoxes; ++BoxIdx)
	{
		const int32 TransformIndex = TransformIndices[BoxIdx];

		if (GetRestCollection()->GetGeometryCollection()->IsGeometry(TransformIndex))
		{
			LocalBounds += BoundingBoxes[BoxIdx];
		}
	}
}

void UGeometryCollectionComponent::CalculateGlobalMatrices()
{
	SCOPE_CYCLE_COUNTER(STAT_GCCUGlobalMatrices);

	const FGeometryCollectionResults* Results = PhysicsProxy ? PhysicsProxy->GetConsumerResultsGT() : nullptr;

	const int32 NumTransforms = Results ? Results->GlobalTransforms.Num() : 0;
	if(NumTransforms > 0)
	{
		// Just calc from results
		GlobalMatrices.Reset();
		GlobalMatrices.Append(Results->GlobalTransforms);	
	}
	else
	{
		// If hierarchy topology has changed, the RestTransforms is invalidated.
		if (RestTransforms.Num() != GetTransformArray().Num())
		{
			RestTransforms.Empty();
		}

		if (!DynamicCollection && RestTransforms.Num() > 0)
		{
			GeometryCollectionAlgo::GlobalMatrices(RestTransforms, GetParentArray(), GlobalMatrices);
		}
		else
		{
			// Have to fully rebuild
			if (DynamicCollection 
				&& DynamicCollection->HasAttribute("UniformScale", FGeometryCollection::TransformGroup)
				&& DynamicCollection->HasAttribute("Decay", FGeometryCollection::TransformGroup))
			{
				const TManagedArray<float>& Decay = DynamicCollection->GetAttribute<float>("Decay", FGeometryCollection::TransformGroup);
				TManagedArray<FTransform>& UniformScale = DynamicCollection->ModifyAttribute<FTransform>("UniformScale", FGeometryCollection::TransformGroup);

				const FTransform InverseComponentTransform = GetComponentTransform().Inverse();
				const FTransform ZeroScaleTransform(FQuat::Identity, FVector::Zero(), FVector(0, 0, 0));
				for (int32 Idx = 0; Idx < GetTransformArray().Num(); ++Idx)
				{
					// only update values if the decay has changed 
					if (Decay[Idx] > 0.f && Decay[Idx] <= 1.f)
					{
						const float Scale = 1.0 - Decay[Idx];
						if (Scale < UE_SMALL_NUMBER)
						{
							UniformScale[Idx] = ZeroScaleTransform;
						}
						else
						{
							float ShrinkRadius = 0.0f;
							FSphere AccumulatedSphere;
							// todo(chaos) : find a faster way to do that ( precompute the data ? )
							if (CalculateInnerSphere(Idx, AccumulatedSphere))
							{
								ShrinkRadius = -AccumulatedSphere.W;
							}
						
							const FQuat LocalRotation = (InverseComponentTransform * FTransform(GlobalMatrices[Idx]).Inverse()).GetRotation();
							const FVector LocalDown = LocalRotation.RotateVector(FVector(0.f, 0.f, ShrinkRadius));
							const FVector CenterOfMass = DynamicCollection->MassToLocal[Idx].GetTranslation();
							const FVector ScaleCenter = LocalDown + CenterOfMass;
							UniformScale[Idx] = FTransform(FQuat::Identity, ScaleCenter * (FVector::FReal)(1.f - Scale), FVector(Scale));
						}
					}
				}
				
				GeometryCollectionAlgo::GlobalMatrices(GetTransformArray(), GetParentArray(), UniformScale, GlobalMatrices);
			}
			else
			{ 
				GeometryCollectionAlgo::GlobalMatrices(GetTransformArray(), GetParentArray(), GlobalMatrices);		
			}
		}
	}
	
#if WITH_EDITOR
	if (GlobalMatrices.Num() > 0)
	{
		if (RestCollection->GetGeometryCollection()->HasAttribute("ExplodedVector", FGeometryCollection::TransformGroup))
		{
			const TManagedArray<FVector3f>& ExplodedVectors = RestCollection->GetGeometryCollection()->GetAttribute<FVector3f>("ExplodedVector", FGeometryCollection::TransformGroup);

			check(GlobalMatrices.Num() == ExplodedVectors.Num());

			for (int32 tt = 0, nt = GlobalMatrices.Num(); tt < nt; ++tt)
			{
				GlobalMatrices[tt] = GlobalMatrices[tt].ConcatTranslation((FVector)ExplodedVectors[tt]);
			}
		}
	}
#endif
}

// #todo(dmp): for backwards compatibility with existing maps, we need to have a default of 3 materials.  Otherwise
// some existing test scenes will crash
int32 UGeometryCollectionComponent::GetNumMaterials() const
{
	return !RestCollection || RestCollection->Materials.Num() == 0 ? 3 : RestCollection->Materials.Num();
}

UMaterialInterface* UGeometryCollectionComponent::GetMaterial(int32 MaterialIndex) const
{
	// If we have a base materials array, use that
	if (OverrideMaterials.IsValidIndex(MaterialIndex) && OverrideMaterials[MaterialIndex])
	{
		return OverrideMaterials[MaterialIndex];
	}
	// Otherwise get from geom collection
	else
	{
		return RestCollection && RestCollection->Materials.IsValidIndex(MaterialIndex) ? RestCollection->Materials[MaterialIndex] : nullptr;
	}
}

#if WITH_EDITOR
void UGeometryCollectionComponent::SelectEmbeddedGeometry()
{
	// First reset the selections
	for (TObjectPtr<UInstancedStaticMeshComponent> EmbeddedGeometryComponent : EmbeddedGeometryComponents)
	{
		EmbeddedGeometryComponent->ClearInstanceSelection();
	}
	
	const TManagedArray<int32>& ExemplarIndex = GetExemplarIndexArray();
	for (int32 SelectedBone : SelectedBones)
	{
		if (EmbeddedGeometryComponents.IsValidIndex(ExemplarIndex[SelectedBone]))
		{
			EmbeddedGeometryComponents[ExemplarIndex[SelectedBone]]->SelectInstance(true, EmbeddedInstanceIndex[SelectedBone], 1);
		}
	}
}
#endif

// #temp HACK for demo, When fracture happens (physics state changes to dynamic) then switch the visible render meshes in a blueprint/actor from static meshes to geometry collections
void UGeometryCollectionComponent::SwitchRenderModels(const AActor* Actor)
{
	// Don't touch visibility if the component is not visible
	if (!IsVisible())
	{
		return;
	}

	TInlineComponentArray<UPrimitiveComponent*> PrimitiveComponents;
	Actor->GetComponents(PrimitiveComponents);
	for (UPrimitiveComponent* PrimitiveComponent : PrimitiveComponents)
	{
		bool ValidComponent = false;

		if (UStaticMeshComponent* StaticMeshComp = Cast<UStaticMeshComponent>(PrimitiveComponent))
		{
			// unhacked.
			//StaticMeshComp->SetVisibility(false);
		}
		else if (UGeometryCollectionComponent* GeometryCollectionComponent = Cast<UGeometryCollectionComponent>(PrimitiveComponent))
		{
			if (!GeometryCollectionComponent->IsVisible())
			{
				continue;
			}

			GeometryCollectionComponent->SetVisibility(true);
		}
	}

	TInlineComponentArray<UChildActorComponent*> ChildActorComponents;
	Actor->GetComponents(ChildActorComponents);
	for (UChildActorComponent* ChildComponent : ChildActorComponents)
	{
		AActor* ChildActor = ChildComponent->GetChildActor();
		if (ChildActor)
		{
			SwitchRenderModels(ChildActor);
		}
	}

}

#if GEOMETRYCOLLECTION_EDITOR_SELECTION
void UGeometryCollectionComponent::EnableTransformSelectionMode(bool bEnable)
{
	// TODO: Support for Nanite?
	if (SceneProxy && !SceneProxy->IsNaniteMesh() && RestCollection && RestCollection->HasVisibleGeometry())
	{
		static_cast<FGeometryCollectionSceneProxy*>(SceneProxy)->UseSubSections(bEnable, true);
	}
	bIsTransformSelectionModeEnabled = bEnable;
}
#endif  // #if GEOMETRYCOLLECTION_EDITOR_SELECTION

bool UGeometryCollectionComponent::IsEmbeddedGeometryValid() const
{
	// Check that the array of ISMCs that implement embedded geometry matches RestCollection Exemplar array.
	if (!RestCollection)
	{
		return false;
	}

	if (RestCollection->EmbeddedGeometryExemplar.Num() != EmbeddedGeometryComponents.Num())
	{
		return false;
	}

	for (int32 Idx = 0; Idx < EmbeddedGeometryComponents.Num(); ++Idx)
	{
		UStaticMesh* ExemplarStaticMesh = Cast<UStaticMesh>(RestCollection->EmbeddedGeometryExemplar[Idx].StaticMeshExemplar.TryLoad());
		if (!ExemplarStaticMesh)
		{
			return false;
		}

		if (ExemplarStaticMesh != EmbeddedGeometryComponents[Idx]->GetStaticMesh())
		{
			return false;
		}
	}

	return true;
}

void UGeometryCollectionComponent::ClearEmbeddedGeometry()
{
	AActor* OwningActor = GetOwner();
	TArray<UActorComponent*> TargetComponents;
	OwningActor->GetComponents(TargetComponents, false);

	for (UActorComponent* TargetComponent : TargetComponents)
	{
		if ((TargetComponent->GetOuter() == this) || !IsValidChecked(TargetComponent->GetOuter()))
		{
			if (UInstancedStaticMeshComponent* ISMComponent = Cast<UInstancedStaticMeshComponent>(TargetComponent))
			{
				ISMComponent->ClearInstances();
				ISMComponent->DestroyComponent();
			}
		}
	}

	EmbeddedGeometryComponents.Empty();
}

void UGeometryCollectionComponent::InitializeEmbeddedGeometry()
{
	if (RestCollection)
	{
		ClearEmbeddedGeometry();
		
		AActor* ActorOwner = GetOwner();
		check(ActorOwner);

		// Construct an InstancedStaticMeshComponent for each exemplar
		for (const FGeometryCollectionEmbeddedExemplar& Exemplar : RestCollection->EmbeddedGeometryExemplar)
		{
			if (UStaticMesh* ExemplarStaticMesh = Cast<UStaticMesh>(Exemplar.StaticMeshExemplar.TryLoad()))
			{
				if (UInstancedStaticMeshComponent* ISMC = NewObject<UInstancedStaticMeshComponent>(this))
				{
					ISMC->SetStaticMesh(ExemplarStaticMesh);
					ISMC->SetCullDistances(Exemplar.StartCullDistance, Exemplar.EndCullDistance);
					ISMC->SetCanEverAffectNavigation(false);
					ISMC->SetCollisionProfileName(UCollisionProfile::NoCollision_ProfileName);
					ISMC->SetCastShadow(false);
					ISMC->SetMobility(EComponentMobility::Stationary);
					ISMC->SetupAttachment(this);
					ActorOwner->AddInstanceComponent(ISMC);
					ISMC->RegisterComponent();

					EmbeddedGeometryComponents.Add(ISMC);
				}
			}
		}

#if WITH_EDITOR
		EmbeddedBoneMaps.SetNum(RestCollection->EmbeddedGeometryExemplar.Num());
		EmbeddedInstanceIndex.Init(INDEX_NONE,RestCollection->GetGeometryCollection()->NumElements(FGeometryCollection::TransformGroup));
#endif

		CalculateGlobalMatrices();
		RefreshEmbeddedGeometry();
		
	}
}

void UGeometryCollectionComponent::IncrementSleepTimer(float DeltaTime)
{
	if (DeltaTime <= 0)
	{
		return;
	}
	
	// If a particle is sleeping, increment its sleep timer, otherwise reset it.
	if (DynamicCollection && PhysicsProxy 
		&& DynamicCollection->HasAttribute("SleepTimer", FGeometryCollection::TransformGroup) 
		&& DynamicCollection->HasAttribute("MaxSleepTime", FGeometryCollection::TransformGroup)
		&& DynamicCollection->HasAttribute("SleepRemovalDuration", FGeometryCollection::TransformGroup)
		&& DynamicCollection->HasAttribute("Decay", FGeometryCollection::TransformGroup)
		&& DynamicCollection->HasAttribute("LastPosition", FGeometryCollection::TransformGroup))
	{
		TManagedArray<float>& SleepTimer = DynamicCollection->ModifyAttribute<float>("SleepTimer", FGeometryCollection::TransformGroup);
		const TManagedArray<float>& SleepRemovalDuration = DynamicCollection->GetAttribute<float>("SleepRemovalDuration", FGeometryCollection::TransformGroup);
		const TManagedArray<float>& MaxSleepTime = DynamicCollection->GetAttribute<float>("MaxSleepTime", FGeometryCollection::TransformGroup);
		TManagedArray<float>& Decay = DynamicCollection->ModifyAttribute<float>("Decay", FGeometryCollection::TransformGroup);
		TManagedArray<FVector>& LastPosition = DynamicCollection->ModifyAttribute<FVector>("LastPosition", FGeometryCollection::TransformGroup);
		const TManagedArray<uint8>& InternalClusterParentType = DynamicCollection->GetAttribute<uint8>("InternalClusterParentTypeArray", FGeometryCollection::TransformGroup);
		const TManagedArray<int32>& Parents = DynamicCollection->Parent;
		
		TArray<int32> ToDisable;
		TArray<int32> ToBreakParent;
		for (int32 TransformIdx = 0; TransformIdx < SleepTimer.Num(); ++TransformIdx)
		{
			// update the sleeping timer accordingly
			const int32 State = DynamicCollection->DynamicState[TransformIdx];
			const bool bIsDynamicOrSleeping = (State == (int)EObjectStateTypeEnum::Chaos_Object_Sleeping) || (State == (int)EObjectStateTypeEnum::Chaos_Object_Dynamic);
			const bool bNoParent = Parents[TransformIdx] == INDEX_NONE;
			const bool bHasKinematicOrStaticInternalClusterParent = (InternalClusterParentType[TransformIdx] == (uint8)Chaos::EInternalClusterType::KinematicOrStatic);
			const bool IsRemovalActive = (MaxSleepTime[TransformIdx] >= 0) && bIsDynamicOrSleeping && bNoParent && !bHasKinematicOrStaticInternalClusterParent;
			if (IsRemovalActive)
			{
				bool bIsNotMoving = false;
				if (RestCollection->bSlowMovingAsSleeping)
				{
					const FVector CurrentPosition = DynamicCollection->Transform[TransformIdx].GetTranslation();
					LastPosition[TransformIdx] = CurrentPosition;
					
					const FVector::FReal InstantVelocity = (CurrentPosition-LastPosition[TransformIdx]).Size() / (FVector::FReal)DeltaTime; 
					bIsNotMoving = (InstantVelocity < RestCollection->SlowMovingVelocityThreshold);
				}
				
				const bool IsSleeping = (DynamicCollection->DynamicState[TransformIdx] == (int)EObjectStateTypeEnum::Chaos_Object_Sleeping);
				const bool HasStartedDecaying = (Decay[TransformIdx] > 0); 
				if (IsSleeping || bIsNotMoving || HasStartedDecaying)
				{
					SleepTimer[TransformIdx] += DeltaTime;
				}
			
				// update the decay and disable the particle when decay has completed 
				const bool bZeroRemovalDuration = (SleepRemovalDuration[TransformIdx] < UE_SMALL_NUMBER);
				const float UpdatedDecay = bZeroRemovalDuration? 1.f: FMath::Clamp<float>((SleepTimer[TransformIdx] - MaxSleepTime[TransformIdx]) / SleepRemovalDuration[TransformIdx], 0.f, 1.f);
				if (UpdatedDecay > Decay[TransformIdx])
				{
					// if parent is internal and dynamic we need to break it before decaying 
					if (InternalClusterParentType[TransformIdx] == (uint8)Chaos::EInternalClusterType::Dynamic)
					{
						ToBreakParent.AddUnique(TransformIdx);
					}

					DynamicCollection->MakeDirty();
					Decay[TransformIdx] = UpdatedDecay;

					if (Decay[TransformIdx] >= 1.0f)
					{
						// Disable the particle if it has been asleep for the requisite time
						Decay[TransformIdx] = 1.0f;
						ToDisable.Add(TransformIdx);
					}
				}
			}
		}

		if (ToBreakParent.Num())
		{
			PhysicsProxy->BreakInternalClusterParents(MoveTemp(ToBreakParent));
		}
		if (ToDisable.Num())
		{
			PhysicsProxy->DisableParticles(MoveTemp(ToDisable));
		}
	}
}

void UGeometryCollectionComponent::IncrementBreakTimer(float DeltaTime)
{
	if (DeltaTime <= 0)
	{
		return;
	}
	
	if (DynamicCollection && PhysicsProxy 
		&& DynamicCollection->HasAttribute("BreakTimer", FGeometryCollection::TransformGroup) 
		&& DynamicCollection->HasAttribute("PostBreakDuration", FGeometryCollection::TransformGroup)
		&& DynamicCollection->HasAttribute("BreakRemovalDuration", FGeometryCollection::TransformGroup)
		&& DynamicCollection->HasAttribute("Decay", FGeometryCollection::TransformGroup)
		)
	{
		TManagedArray<float>& BreakTimer = DynamicCollection->ModifyAttribute<float>("BreakTimer", FGeometryCollection::TransformGroup);
		const TManagedArray<float>& PostBreakDuration = DynamicCollection->GetAttribute<float>("PostBreakDuration", FGeometryCollection::TransformGroup);
		const TManagedArray<float>& BreakRemovalDuration = DynamicCollection->GetAttribute<float>("BreakRemovalDuration", FGeometryCollection::TransformGroup);
		TManagedArray<float>& Decay = DynamicCollection->ModifyAttribute<float>("Decay", FGeometryCollection::TransformGroup);
		
		TArray<int32> ToDisable;
		TArray<int32> ToCrumble;
		for (int32 TransformIdx = 0; TransformIdx < BreakTimer.Num(); ++TransformIdx)
		{
			const bool bIsBroken = DynamicCollection->Active[TransformIdx];
			const bool bIsRemovedFromBreakEnabled = (PostBreakDuration[TransformIdx] >= 0);
			
			const int32 State = DynamicCollection->DynamicState[TransformIdx];
			const bool bIsDynamicOrSleeping = (State == (int)EObjectStateTypeEnum::Chaos_Object_Sleeping) || (State == (int)EObjectStateTypeEnum::Chaos_Object_Dynamic);
			
			if (bIsBroken && bIsRemovedFromBreakEnabled && bIsDynamicOrSleeping)
			{
				BreakTimer[TransformIdx] += DeltaTime;
				const bool bPostBreakTimeExpired = (BreakTimer[TransformIdx] >= PostBreakDuration[TransformIdx]);
				const bool bZeroRemovalDuration = (BreakRemovalDuration[TransformIdx] < UE_SMALL_NUMBER);
				float UpdatedBreakDecay = 0;
				if (bPostBreakTimeExpired)
				{
					UpdatedBreakDecay = bZeroRemovalDuration? 1.f: FMath::Clamp<float>((BreakTimer[TransformIdx] - PostBreakDuration[TransformIdx]) / BreakRemovalDuration[TransformIdx], 0.f, 1.f);
				}
				if (UpdatedBreakDecay > Decay[TransformIdx])
				{
					DynamicCollection->MakeDirty();
					Decay[TransformIdx] = UpdatedBreakDecay;

					const bool bUseClusterCrumbling = (BreakRemovalDuration[TransformIdx] < 0);
					if (bUseClusterCrumbling)
					{
						ToCrumble.AddUnique(TransformIdx);
						Decay[TransformIdx] = 0;
					}
					else
					{
						if (Decay[TransformIdx] >= 1.0f)
						{
							// Disable the particle if it has decayed  the requisite time
							Decay[TransformIdx] = 1.0f;
							ToDisable.Add(TransformIdx);
						}
					}
				}
			}
		}

		if (ToCrumble.Num())
		{
			PhysicsProxy->BreakClusters(MoveTemp(ToCrumble));
		}
		if (ToDisable.Num())
		{
			PhysicsProxy->DisableParticles(MoveTemp(ToDisable));
		}
	}
}


bool UGeometryCollectionComponent::CalculateInnerSphere(int32 TransformIndex, FSphere& SphereOut) const
{
	// Approximates the inscribed sphere. Returns false if no such sphere exists, if for instance the index is to an embedded geometry. 

	const TManagedArray<int32>& TransformToGeometryIndex = RestCollection->GetGeometryCollection()->TransformToGeometryIndex;
	const TManagedArray<Chaos::FRealSingle>& InnerRadius = RestCollection->GetGeometryCollection()->InnerRadius;
	const TManagedArray<TSet<int32>>& Children = RestCollection->GetGeometryCollection()->Children;
	const TManagedArray<FTransform>& MassToLocal = RestCollection->GetGeometryCollection()->GetAttribute<FTransform>("MassToLocal", FGeometryCollection::TransformGroup);

	if (RestCollection->GetGeometryCollection()->IsRigid(TransformIndex))
	{
		// Sphere in component space, centered on body's COM.
		FVector COM = MassToLocal[TransformIndex].GetLocation();
		SphereOut = FSphere(COM, InnerRadius[TransformToGeometryIndex[TransformIndex]]);
		return true;
	}
	else if (RestCollection->GetGeometryCollection()->IsClustered(TransformIndex))
	{
		// Recursively accumulate the cluster's child spheres. 
		bool bSphereFound = false;
		for (int32 ChildIndex: Children[TransformIndex])
		{
			FSphere LocalSphere;
			if (CalculateInnerSphere(ChildIndex, LocalSphere))
			{
				if (!bSphereFound)
				{
					bSphereFound = true;
					SphereOut = LocalSphere;
				}
				else
				{
					SphereOut += LocalSphere;
				}
			}
		}
		return bSphereFound;
	}
	else
	{
		// Likely an embedded geometry, which doesn't count towards volume.
		return false;
	}
}

void UGeometryCollectionComponent::PostLoad()
{
	Super::PostLoad();

	//
	// The UGeometryCollectionComponent::PhysicalMaterial_DEPRECATED needs
	// to be transferred to the BodyInstance simple material. Going forward
	// the deprecated value will not be saved.
	//
	if (PhysicalMaterialOverride_DEPRECATED)
	{
		BodyInstance.SetPhysMaterialOverride(PhysicalMaterialOverride_DEPRECATED.Get());
		PhysicalMaterialOverride_DEPRECATED = nullptr;
	}
}