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

#pragma once

#include "BoneControllers/AnimNode_SkeletalControlBase.h"
#include "Components/SkeletalMeshComponent.h"
#include "Physics/ImmediatePhysics/ImmediatePhysicsDeclares.h"
#include "PhysicsEngine/PhysicsAsset.h"
#include "PhysicsProxy/PerSolverFieldSystem.h"
#include "Tasks/Task.h"
#include "AnimNode_RigidBody.generated.h"

struct FBodyInstance;
struct FConstraintInstance;
class FEvent;

extern ANIMGRAPHRUNTIME_API bool bEnableRigidBodyNode;
extern ANIMGRAPHRUNTIME_API FAutoConsoleVariableRef CVarEnableRigidBodyNode;
extern ANIMGRAPHRUNTIME_API TAutoConsoleVariable<int32> CVarEnableRigidBodyNodeSimulation;
extern ANIMGRAPHRUNTIME_API TAutoConsoleVariable<int32> CVarRigidBodyLODThreshold;

/** Determines in what space the simulation should run */
UENUM()
enum class ESimulationSpace : uint8
{
	/** Simulate in component space. Moving the entire skeletal mesh will have no affect on velocities */
	ComponentSpace,
	/** Simulate in world space. Moving the skeletal mesh will generate velocity changes */
	WorldSpace,
	/** Simulate in another bone space. Moving the entire skeletal mesh and individually modifying the base bone will have no affect on velocities */
	BaseBoneSpace,
};

/** Determines behaviour regarding deferral of simulation tasks. */
UENUM()
enum class ESimulationTiming : uint8
{
	/** Use the default project setting as defined by p.RigidBodyNode.DeferredSimulationDefault. */
	Default,
	/** Always run the simulation to completion during animation evaluation. */
	Synchronous,
	/** Always run the simulation in the background and retrieve the result on the next animation evaluation. */
	Deferred
};

/**
 * Settings for the system which passes motion of the simulation's space into the simulation. This allows the simulation to pass a 
 * fraction of the world space motion onto the bodies which allows Bone-Space and Component-Space simulations to react to world-space 
 * movement in a controllable way.
 */
template <> struct TIsPODType<FSimSpaceSettings> { enum { Value = true }; };

USTRUCT(BlueprintType)
struct FSimSpaceSettings
{
	GENERATED_USTRUCT_BODY()

	ANIMGRAPHRUNTIME_API FSimSpaceSettings();

	// Disable deprecation errors by providing defaults wrapped with pragma disable
	PRAGMA_DISABLE_DEPRECATION_WARNINGS
	~FSimSpaceSettings() = default;
	FSimSpaceSettings(FSimSpaceSettings const&) = default;
	FSimSpaceSettings& operator=(const FSimSpaceSettings &) = default;
	PRAGMA_ENABLE_DEPRECATION_WARNINGS

	// Global multipler on the effects of simulation space movement. Must be in range [0, 1]. If WorldAlpha = 0.0, the system is disabled and the simulation will
	// be fully local (i.e., world-space actor movement and rotation does not affect the simulation). When WorldAlpha = 1.0 the simulation effectively acts as a 
	// world-space sim, but with the ability to apply limits using the other parameters.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings, meta = (ClampMin = "0.0", ClampMax = "1.0"))
	float WorldAlpha;

#if WITH_EDITORONLY_DATA
	UE_DEPRECATED(5.1, "This property has been deprecated. Please, use WorldAlpha.")
	float MasterAlpha = 0.f;
#endif // WITH_EDITORONLY_DATA

	// Multiplier on the Z-component of velocity and acceleration that is passed to the simulation. Usually from 0.0 to 1.0 to 
	// reduce the effects of jumping and crouching on the simulation, but it can be higher than 1.0 if you need to exaggerate this motion for some reason.
	// Should probably have been called "WorldAlphaScaleZ".
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings, meta = (ClampMin = "0.0"))
	float VelocityScaleZ;

	// A muliplier to control how much of the simulation space movement is used to calculate the drag forces from Linear/Angular Damping in the Physics Asset.
	// When DampingAlpha=1.0, Damping drag forces are equivalent to a world-space simulation. This is similar to air resistance.
	// When DampingAlpha=0.0, Damping drag forces depend only on local-space body velocity and not on the simulation space velocity.
	// It can be useful to set this to zero so that the Linear/Angular Damping settings on the BodyInstances do not contribute to air resistance. 
	// Air resistance can be re-added in a controlled way using the ExternalLinearDrag setting below.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings, meta = (ClampMin = "0.0"))
	float DampingAlpha;

	// A clamp on the effective world-space velocity that is passed to the simulation. Units are cm/s. The default value effectively means "unlimited". It is not usually required to
	// change this but you would reduce this to limit the effects of drag on the bodies in the simulation (if you have bodies that have LinearDrag set to non-zero in the physics asset). 
	// Expected values in this case would be somewhat less than the usual velocities of your object which is commonly a few hundred for a character.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings, meta = (ClampMin = "0.0"))
	float MaxLinearVelocity;

	// A clamp on the effective world-space angular velocity that is passed to the simulation. Units are radian/s, so a value of about 6.0 is one rotation per second.
	// The default value effectively means "unlimited". You would reduce this (and MaxAngularAcceleration) to limit how much bodies "fly out" when the actor spins on the spot. 
	// This is especially useful if you have characters than can rotate very quickly and you would probably want values around or less than 10 in this case.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings, meta = (ClampMin = "0.0"))
	float MaxAngularVelocity;
	
	// A clamp on the effective world-space acceleration that is passed to the simulation. Units are cm/s/s. The default value effectively means "unlimited". 
	// This property is used to stop the bodies of the simulation flying out when suddenly changing linear speed. It is useful when you have characters than can 
	// changes from stationary to running very quickly such as in an FPS. A common value for a character might be in the few hundreds.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings, meta = (ClampMin = "0.0"))
	float MaxLinearAcceleration;
	
	// A clamp on the effective world-space angular accleration that is passed to the simulation. Units are radian/s/s. The default value effectively means "unlimited". 
	// This has a similar effect to MaxAngularVelocity, except that it is related to the flying out of bodies when the rotation speed suddenly changes. Typical limist for
	// a character might be around 100.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings, meta = (ClampMin = "0.0"))
	float MaxAngularAcceleration;

#if WITH_EDITORONLY_DATA
	UPROPERTY(meta = (DeprecatedProperty, DeprecationMessage = "ExternalLinearDrag is deprecated. Please use ExternalLinearDragV instead."))
	float ExternalLinearDrag_DEPRECATED;
#endif

	// Additional linear drag applied to each body based on total body velocity. This is in addition to per-body linear damping in the physics asset (but see DampingAlpha to control that).
	// (NOTE: The "V" suffix is to differentiate from the deprecated float property of the same name. It means "Vector" and not "Velocity").
	//
	// NOTE: ExternalLinearDragV is in simulation space, so if the RB AnimNode is set to Bone Space the ExternalLinearDragV.Z will be the drag in the
	// Up direction of the selected bone.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings)
	FVector ExternalLinearDragV;

	// Additional velocity that is added to the component velocity so the simulation acts as if the actor is moving at speed, even when stationary. 
	// Vector is in world space. Units are cm/s. Could be used for a wind effects etc. Typical values are similar to the velocity of the object or effect, 
	// and usually around or less than 1000 for characters/wind.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings)
	FVector ExternalLinearVelocity;

	// Additional angular velocity that is added to the component angular velocity. This can be used to make the simulation act as if the actor is rotating
	// even when it is not. E.g., to apply physics to a character on a podium as the camera rotates around it, to emulate the podium itself rotating.
	// Vector is in world space. Units are rad/s.
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Settings)
	FVector ExternalAngularVelocity;

	ANIMGRAPHRUNTIME_API void PostSerialize(const FArchive& Ar);
};

#if WITH_EDITORONLY_DATA
template<>
struct TStructOpsTypeTraits<FSimSpaceSettings> : public TStructOpsTypeTraitsBase2<FSimSpaceSettings>
{
	enum
	{
		WithPostSerialize = true
	};
};
#endif


/**
 *	Controller that simulates physics based on the physics asset of the skeletal mesh component
 */
USTRUCT()
struct FAnimNode_RigidBody : public FAnimNode_SkeletalControlBase
{
	GENERATED_USTRUCT_BODY()

	ANIMGRAPHRUNTIME_API FAnimNode_RigidBody();
	ANIMGRAPHRUNTIME_API ~FAnimNode_RigidBody();

	// FAnimNode_Base interface
	ANIMGRAPHRUNTIME_API virtual void GatherDebugData(FNodeDebugData& DebugData) override;
	ANIMGRAPHRUNTIME_API virtual void Initialize_AnyThread(const FAnimationInitializeContext& Context) override;
	// End of FAnimNode_Base interface

	// FAnimNode_SkeletalControlBase interface
	ANIMGRAPHRUNTIME_API virtual void UpdateComponentPose_AnyThread(const FAnimationUpdateContext& Context) override;
	ANIMGRAPHRUNTIME_API virtual void EvaluateComponentPose_AnyThread(FComponentSpacePoseContext& Output) override;
	ANIMGRAPHRUNTIME_API virtual void EvaluateSkeletalControl_AnyThread(FComponentSpacePoseContext& Output, TArray<FBoneTransform>& OutBoneTransforms) override;
	ANIMGRAPHRUNTIME_API virtual void OnInitializeAnimInstance(const FAnimInstanceProxy* InProxy, const UAnimInstance* InAnimInstance) override;
	virtual bool NeedsOnInitializeAnimInstance() const override { return true; }
	ANIMGRAPHRUNTIME_API virtual void PreUpdate(const UAnimInstance* InAnimInstance) override;
	ANIMGRAPHRUNTIME_API virtual void UpdateInternal(const FAnimationUpdateContext& Context) override;
	virtual bool HasPreUpdate() const override { return true; }
	ANIMGRAPHRUNTIME_API virtual bool IsValidToEvaluate(const USkeleton* Skeleton, const FBoneContainer& RequiredBones) override;
	ANIMGRAPHRUNTIME_API virtual bool NeedsDynamicReset() const override;
	ANIMGRAPHRUNTIME_API virtual void ResetDynamics(ETeleportType InTeleportType) override;
	ANIMGRAPHRUNTIME_API virtual int32 GetLODThreshold() const override;
	// End of FAnimNode_SkeletalControlBase interface

	ANIMGRAPHRUNTIME_API virtual void AddImpulseAtLocation(FVector Impulse, FVector Location, FName BoneName = NAME_None);

	// TEMP: Exposed for use in PhAt as a quick way to get drag handles working with Chaos
	virtual ImmediatePhysics::FSimulation* GetSimulation() { return PhysicsSimulation; }

	/**
	 * Set the override physics asset. This will automatically trigger a physics re-init in case the override physics asset changes. 
	 * Users can get access to this in the Animation Blueprint via the Animation Node Functions.
	 */
	void SetOverridePhysicsAsset(UPhysicsAsset* PhysicsAsset);

	UPhysicsAsset* GetPhysicsAsset() const { return UsePhysicsAsset; }

public:
	/** Physics asset to use. If empty use the skeletal mesh's default physics asset in case Default To Skeletal Mesh Physics Asset is set to True. */
	UPROPERTY(EditAnywhere, Category = Settings)
	TObjectPtr<UPhysicsAsset> OverridePhysicsAsset;

	/** Use the skeletal mesh physics asset as default in case set to True. The Override Physics Asset will always have priority over this. */
	UPROPERTY(EditAnywhere, Category = Settings)
	bool bDefaultToSkeletalMeshPhysicsAsset = true;

private:
	/** Get the physics asset candidate to be used while respecting the bDefaultToSkeletalMeshPhysicsAsset and the priority to the override physics asset. */
	UPhysicsAsset* GetPhysicsAssetToBeUsed(const UAnimInstance* InAnimInstance) const;

	FTransform PreviousCompWorldSpaceTM;
	FTransform CurrentTransform;
	FTransform PreviousTransform;

	UPhysicsAsset* UsePhysicsAsset;

public:
	/** Enable if you want to ignore the p.RigidBodyLODThreshold CVAR and force the node to solely use the LOD threshold. */
	UPROPERTY(EditAnywhere, BlueprintReadWrite, Category = Performance, meta = (PinHiddenByDefault))
	bool bUseLocalLODThresholdOnly = false;

	/** Override gravity*/
	UPROPERTY(EditAnywhere, Category = Settings, meta = (PinHiddenByDefault, editcondition = "bOverrideWorldGravity"))
	FVector OverrideWorldGravity;

	/** Applies a uniform external force in world space. This allows for easily faking inertia of movement while still simulating in component space for example */
	UPROPERTY(EditAnywhere, Category = Settings, meta = (PinShownByDefault))
	FVector ExternalForce;

	/** When using non-world-space sim, this controls how much of the components world-space acceleration is passed on to the local-space simulation. */
	UPROPERTY(EditAnywhere, Category = Settings, meta = (PinHiddenByDefault))
	FVector ComponentLinearAccScale;

	/** When using non-world-space sim, this applies a 'drag' to the bodies in the local space simulation, based on the components world-space velocity. */
	UPROPERTY(EditAnywhere, Category = Settings, meta = (PinHiddenByDefault))
	FVector ComponentLinearVelScale;

	/** When using non-world-space sim, this is an overall clamp on acceleration derived from ComponentLinearAccScale and ComponentLinearVelScale, to ensure it is not too large. */
	UPROPERTY(EditAnywhere, Category = Settings)
	FVector	ComponentAppliedLinearAccClamp;

	/**
	 * Settings for the system which passes motion of the simulation's space
	 * into the simulation. This allows the simulation to pass a
	 * fraction of the world space motion onto the bodies which allows Bone-Space
	 * and Component-Space simulations to react to world-space movement in a
	 * controllable way.
	 * This system is a superset of the functionality provided by ComponentLinearAccScale,
	 * ComponentLinearVelScale, and ComponentAppliedLinearAccClamp. In general
	 * you should not have both systems enabled.
	 */
	UPROPERTY(EditAnywhere, Category = Settings, meta = (PinHiddenByDefault))
	FSimSpaceSettings SimSpaceSettings;


	/**
	 * Scale of cached bounds (vs. actual bounds).
	 * Increasing this may improve performance, but overlaps may not work as well.
	 * (A value of 1.0 effectively disables cached bounds).
	 */
	UPROPERTY(EditAnywhere, Category = Settings, meta = (ClampMin="1.0", ClampMax="2.0"))
	float CachedBoundsScale;

	/** Matters if SimulationSpace is BaseBone */
	UPROPERTY(EditAnywhere, Category = Settings)
	FBoneReference BaseBoneRef;

	/** The channel we use to find static geometry to collide with */
	UPROPERTY(EditAnywhere, Category = Settings, meta = (editcondition = "bEnableWorldGeometry"))
	TEnumAsByte<ECollisionChannel> OverlapChannel;

	/** What space to simulate the bodies in. This affects how velocities are generated */
	UPROPERTY(EditAnywhere, Category = Settings)
	ESimulationSpace SimulationSpace;

	/** Whether to allow collisions between two bodies joined by a constraint  */
	UPROPERTY(EditAnywhere, Category = Settings)
	bool bForceDisableCollisionBetweenConstraintBodies;

	/** If true, kinematic objects will be added to the simulation at runtime to represent any cloth colliders defined for the parent object. */
	UPROPERTY(EditAnywhere, Category = Settings)
	bool bUseExternalClothCollision;

private:
	ETeleportType ResetSimulatedTeleportType;

public:
	UPROPERTY(EditAnywhere, Category = Settings, meta = (InlineEditConditionToggle))
	uint8 bEnableWorldGeometry : 1;

	UPROPERTY(EditAnywhere, Category = Settings, meta = (InlineEditConditionToggle))
	uint8 bOverrideWorldGravity : 1;

	/** 
		When simulation starts, transfer previous bone velocities (from animation)
		to make transition into simulation seamless.
	*/
	UPROPERTY(EditAnywhere, Category = Settings, meta=(PinHiddenByDefault))
	uint8 bTransferBoneVelocities : 1;

	/**
		When simulation starts, freeze incoming pose.
		This is useful for ragdolls, when we want the simulation to take over.
		It prevents non simulated bones from animating.
	*/
	UPROPERTY(EditAnywhere, Category = Settings)
	uint8 bFreezeIncomingPoseOnStart : 1;

	/**
		Correct for linear tearing on bodies with all axes Locked.
		This only works if all axes linear translation are locked
	*/
	UPROPERTY(EditAnywhere, Category = Settings)
	uint8 bClampLinearTranslationLimitToRefPose : 1;

	/**
		For world-space simulations, if the magnitude of the component's 3D scale is less than WorldSpaceMinimumScale, do not update the node.
	*/
	UPROPERTY(EditAnywhere, Category = Settings)
	float WorldSpaceMinimumScale;

	/**
		If the node is not evaluated for this amount of time (seconds), either because a lower LOD was in use for a while or the component was
		not visible, reset the simulation to the default pose on the next evaluation. Set to 0 to disable time-based reset.
	*/
	UPROPERTY(EditAnywhere, Category = Settings)
	float EvaluationResetTime;

private:
	uint8 bEnabled : 1;
	uint8 bSimulationStarted : 1;
	uint8 bCheckForBodyTransformInit : 1;

public:
	ANIMGRAPHRUNTIME_API void PostSerialize(const FArchive& Ar);

private:

#if WITH_EDITORONLY_DATA
	UPROPERTY()
	bool bComponentSpaceSimulation_DEPRECATED;	//use SimulationSpace
#endif

	// FAnimNode_SkeletalControlBase interface
	ANIMGRAPHRUNTIME_API virtual void InitializeBoneReferences(const FBoneContainer& RequiredBones) override;
	// End of FAnimNode_SkeletalControlBase interface

	ANIMGRAPHRUNTIME_API void InitPhysics(const UAnimInstance* InAnimInstance);
	ANIMGRAPHRUNTIME_API void UpdateWorldGeometry(const UWorld& World, const USkeletalMeshComponent& SKC);
	ANIMGRAPHRUNTIME_API void UpdateWorldForces(const FTransform& ComponentToWorld, const FTransform& RootBoneTM, const float DeltaSeconds);

	ANIMGRAPHRUNTIME_API void InitializeNewBodyTransformsDuringSimulation(FComponentSpacePoseContext& Output, const FTransform& ComponentTransform, const FTransform& BaseBoneTM);

	ANIMGRAPHRUNTIME_API void InitSimulationSpace(
		const FTransform& ComponentToWorld,
		const FTransform& BoneToComponent);

	// Calculate simulation space transform, velocity etc to pass into the solver
	ANIMGRAPHRUNTIME_API void CalculateSimulationSpaceMotion(
		ESimulationSpace Space,
		const FTransform& SpaceTransform,
		const FTransform& ComponentToWorld,
		const float Dt,
		const FSimSpaceSettings& Settings,
		FVector& SpaceLinearVel,
		FVector& SpaceAngularVel,
		FVector& SpaceLinearAcc,
		FVector& SpaceAngularAcc);

	// Gather cloth collision sources from the supplied Skeltal Mesh and add a kinematic actor representing each one of them to the sim.
	ANIMGRAPHRUNTIME_API void CollectClothColliderObjects(const USkeletalMeshComponent* SkeletalMeshComp);
	
	// Remove all cloth collider objects from the sim.
	ANIMGRAPHRUNTIME_API void RemoveClothColliderObjects();

	// Update the sim-space transforms of all cloth collider objects.
	ANIMGRAPHRUNTIME_API void UpdateClothColliderObjects(const FTransform& SpaceTransform);

	// Gather nearby world objects and add them to the sim
	ANIMGRAPHRUNTIME_API void CollectWorldObjects();

	// Flag invalid world objects to be removed from the sim
	ANIMGRAPHRUNTIME_API void ExpireWorldObjects();

	// Remove simulation objects that are flagged as expired
	ANIMGRAPHRUNTIME_API void PurgeExpiredWorldObjects();

	// Update sim-space transforms of world objects
	ANIMGRAPHRUNTIME_API void UpdateWorldObjects(const FTransform& SpaceTransform);

	// Advances the simulation by a given timestep
	ANIMGRAPHRUNTIME_API void RunPhysicsSimulation(float DeltaSeconds, const FVector& SimSpaceGravity);

	// Waits for the deferred simulation task to complete if it's not already finished
	ANIMGRAPHRUNTIME_API void FlushDeferredSimulationTask();

	// Destroy the simulation and free related structures
	ANIMGRAPHRUNTIME_API void DestroyPhysicsSimulation();

public:

	/* Whether the physics simulation runs synchronously with the node's evaluation or is run in the background until the next frame. */
	UPROPERTY(EditAnywhere, Category=Settings, AdvancedDisplay)
	ESimulationTiming SimulationTiming;

private:

	double WorldTimeSeconds;
	double LastEvalTimeSeconds;

	float AccumulatedDeltaTime;
	float AnimPhysicsMinDeltaTime;
	bool bSimulateAnimPhysicsAfterReset;
	/** This should only be used for removing the delegate during termination. Do NOT use this for any per frame work */
	TWeakObjectPtr<USkeletalMeshComponent> SkelMeshCompWeakPtr;

	ImmediatePhysics::FSimulation* PhysicsSimulation;
	FPhysicsAssetSolverSettings SolverSettings;
	FSolverIterations SolverIterations;	// to be deprecated

	friend class FRigidBodyNodeSimulationTask;
	UE::Tasks::FTask SimulationTask;

	struct FOutputBoneData
	{
		FOutputBoneData()
			: CompactPoseBoneIndex(INDEX_NONE)
		{}

		TArray<FCompactPoseBoneIndex> BoneIndicesToParentBody;
		FCompactPoseBoneIndex CompactPoseBoneIndex;
		int32 BodyIndex;
		int32 ParentBodyIndex;
	};

	struct FBodyAnimData
	{
		FBodyAnimData()
			: TransferedBoneAngularVelocity(ForceInit)
			, TransferedBoneLinearVelocity(ForceInitToZero)
			, LinearXMotion(ELinearConstraintMotion::LCM_Locked)
			, LinearYMotion(ELinearConstraintMotion::LCM_Locked)
			, LinearZMotion(ELinearConstraintMotion::LCM_Locked)
			, LinearLimit(0.0f)
			, RefPoseLength (0.f)
			, bIsSimulated(false)
			, bBodyTransformInitialized(false)
		{}

		FQuat TransferedBoneAngularVelocity;
		FVector TransferedBoneLinearVelocity;

		ELinearConstraintMotion LinearXMotion;
		ELinearConstraintMotion LinearYMotion;
		ELinearConstraintMotion LinearZMotion;
		float LinearLimit;
		// we don't use linear limit but use default length to limit the bodies
		// linear limits are defined per constraint - it can be any two joints that can limit
		// this is just default length of the local space from parent, and we use that info to limit
		// the translation
		float RefPoseLength;

		bool bIsSimulated : 1;
		bool bBodyTransformInitialized : 1;
	};

	struct FWorldObject
	{
		FWorldObject() : ActorHandle(nullptr), LastSeenTick(0), bExpired(false) {}
		FWorldObject(ImmediatePhysics::FActorHandle* InActorHandle, int32 InLastSeenTick) : ActorHandle(InActorHandle), LastSeenTick(InLastSeenTick), bExpired(false) {}

		ImmediatePhysics::FActorHandle* ActorHandle;
		int32 LastSeenTick;
		bool bExpired;
	};

	TArray<FOutputBoneData> OutputBoneData;
	TArray<ImmediatePhysics::FActorHandle*> Bodies;
	TArray<int32> SkeletonBoneIndexToBodyIndex;
	TArray<FBodyAnimData> BodyAnimData;

	TArray<FPhysicsConstraintHandle*> Constraints;
	TArray<USkeletalMeshComponent::FPendingRadialForces> PendingRadialForces;

	FPerSolverFieldSystem PerSolverField;

	// Information required to identify and update a kinematic object representing a cloth collision source in the sim.
	struct FClothCollider
	{
		FClothCollider(ImmediatePhysics::FActorHandle* const InActorHandle, const USkeletalMeshComponent* const InSkeletalMeshComponent, const uint32 InBoneIndex)
			: ActorHandle(InActorHandle)
			, SkeletalMeshComponent(InSkeletalMeshComponent)
			, BoneIndex(InBoneIndex)
		{}

		ImmediatePhysics::FActorHandle* ActorHandle; // Identifies the physics actor in the sim.
		const USkeletalMeshComponent* SkeletalMeshComponent; // Parent skeleton.
		uint32 BoneIndex; // Bone within parent skeleton that drives physics actors transform.
	};

	// List of actors in the sim that represent objects collected from other parts of this character.
	TArray<FClothCollider> ClothColliders; 
	
	TMap<const UPrimitiveComponent*, FWorldObject> ComponentsInSim;
	int32 ComponentsInSimTick;

	FVector WorldSpaceGravity;

	double TotalMass;

	// Bounds used to gather world objects copied into the simulation
	FSphere CachedBounds;

	FCollisionQueryParams QueryParams;

	FPhysScene* PhysScene;

	// Used by CollectWorldObjects and UpdateWorldGeometry in Task Thread
	// Typically, World should never be accessed off the Game Thread.
	// However, since we're just doing overlaps this should be OK.
	const UWorld* UnsafeWorld;

	// Used by CollectWorldObjects and UpdateWorldGeometry in Task Thread
	// Only used for a pointer comparison.
	const AActor* UnsafeOwner;

	FBoneContainer CapturedBoneVelocityBoneContainer;
	FCSPose<FCompactHeapPose> CapturedBoneVelocityPose;
	FCSPose<FCompactHeapPose> CapturedFrozenPose;
	FBlendedHeapCurve CapturedFrozenCurves;

	FVector PreviousComponentLinearVelocity;

	// Used by the world-space to simulation-space motion transfer system in Component- or Bone-Space sims
	FTransform PreviousSimulationSpaceTransform;
	FTransform PreviousPreviousSimulationSpaceTransform;
	float PreviousDt;

#if ENABLE_LOW_LEVEL_MEM_TRACKER
	FName OwningAssetPackageName;
	FName OwningAssetName;
#endif
};

#if WITH_EDITORONLY_DATA
template<>
struct TStructOpsTypeTraits<FAnimNode_RigidBody> : public TStructOpsTypeTraitsBase2<FAnimNode_RigidBody>
{
	enum
	{
		WithPostSerialize = true,
	};
};
#endif

FORCEINLINE_DEBUGGABLE FTransform SpaceToWorldTransform(
	ESimulationSpace Space, const FTransform& ComponentToWorld, const FTransform& BaseBoneTM)
{
	switch (Space)
	{
	case ESimulationSpace::ComponentSpace: return ComponentToWorld;
	case ESimulationSpace::WorldSpace: return FTransform::Identity;
	case ESimulationSpace::BaseBoneSpace: return BaseBoneTM * ComponentToWorld;
	default: return FTransform::Identity;
	}
}

FORCEINLINE_DEBUGGABLE FVector WorldVectorToSpaceNoScale(
	ESimulationSpace Space, const FVector& WorldDir, const FTransform& ComponentToWorld, const FTransform& BaseBoneTM)
{
	switch (Space)
	{
	case ESimulationSpace::ComponentSpace: return ComponentToWorld.InverseTransformVectorNoScale(WorldDir);
	case ESimulationSpace::WorldSpace: return WorldDir;
	case ESimulationSpace::BaseBoneSpace:
		return BaseBoneTM.InverseTransformVectorNoScale(ComponentToWorld.InverseTransformVectorNoScale(WorldDir));
	default: return FVector::ZeroVector;
	}
}

FORCEINLINE_DEBUGGABLE FVector WorldPositionToSpace(
	ESimulationSpace Space, const FVector& WorldPoint, const FTransform& ComponentToWorld, const FTransform& BaseBoneTM)
{
	switch (Space)
	{
	case ESimulationSpace::ComponentSpace: return ComponentToWorld.InverseTransformPosition(WorldPoint);
	case ESimulationSpace::WorldSpace: return WorldPoint;
	case ESimulationSpace::BaseBoneSpace:
		return BaseBoneTM.InverseTransformPosition(ComponentToWorld.InverseTransformPosition(WorldPoint));
	default: return FVector::ZeroVector;
	}
}

FORCEINLINE_DEBUGGABLE FTransform ConvertCSTransformToSimSpace(
	ESimulationSpace Space, const FTransform& InCSTransform, const FTransform& ComponentToWorld, const FTransform& BaseBoneTM)
{
	switch (Space)
	{
	case ESimulationSpace::ComponentSpace: return InCSTransform;
	case ESimulationSpace::WorldSpace:  return InCSTransform * ComponentToWorld;
	case ESimulationSpace::BaseBoneSpace: return InCSTransform.GetRelativeTransform(BaseBoneTM); break;
	default: ensureMsgf(false, TEXT("Unsupported Simulation Space")); return InCSTransform;
	}
}