ProjectileMovementComponent.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#if UE_ENABLE_INCLUDE_ORDER_DEPRECATED_IN_5_4
#include "CoreMinimal.h"
#include "Engine/HitResult.h"
#endif // UE_ENABLE_INCLUDE_ORDER_DEPRECATED_IN_5_4
#include "GameFramework/MovementComponent.h"
#include "UObject/ObjectMacros.h"
#include "ProjectileMovementComponent.generated.h"
 
struct FHitResult;
 
UCLASS(ClassGroup=Movement, meta=(BlueprintSpawnableComponent), ShowCategories=(Velocity), MinimalAPI)
class UProjectileMovementComponent : public UMovementComponent
{
    GENERATED_UCLASS_BODY()
 
    DECLARE_DYNAMIC_MULTICAST_DELEGATE_TwoParams( FOnProjectileBounceDelegate, const FHitResult&, ImpactResult, const FVector&, ImpactVelocity );
    DECLARE_DYNAMIC_MULTICAST_DELEGATE_OneParam( FOnProjectileStopDelegate, const FHitResult&, ImpactResult );
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=Projectile)
    float InitialSpeed;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=Projectile)
    float MaxSpeed;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=Projectile)
    uint8 bRotationFollowsVelocity:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=Projectile, meta = (EditCondition = "bRotationFollowsVelocity"))
    uint8 bRotationRemainsVertical:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileBounces)
    uint8 bShouldBounce:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=Projectile)
    uint8 bInitialVelocityInLocalSpace:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileSimulation)
    uint8 bForceSubStepping:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileSimulation)
    uint8 bSimulationEnabled:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileSimulation)
    uint8 bSweepCollision:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=Homing)
    uint8 bIsHomingProjectile:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileBounces)
    uint8 bBounceAngleAffectsFriction:1;
 
    UPROPERTY(VisibleInstanceOnly, BlueprintReadOnly, Category=ProjectileBounces)
    uint8 bIsSliding:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileInterpolation)
    uint8 bInterpMovement:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileInterpolation)
    uint8 bInterpRotation:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileInterpolation)
    uint8 bThrottleInterpolation:1;
 
protected:
    uint8 bInterpolationComplete:1;
 
    int32 ThrottleInterpolationFramesSinceInterp;
 
public:
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, AdvancedDisplay, Category=ProjectileInterpolation)
    uint8 bSimulationUseScopedMovement:1;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, AdvancedDisplay, Category=ProjectileInterpolation)
    uint8 bInterpolationUseScopedMovement:1;
 
    UPROPERTY(VisibleInstanceOnly, BlueprintReadOnly, Category=ProjectileBounces)
    float PreviousHitTime;
 
    UPROPERTY(VisibleInstanceOnly, BlueprintReadOnly, Category=ProjectileBounces)
    FVector PreviousHitNormal;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=Projectile)
    float ProjectileGravityScale;
 
    UPROPERTY()
    float Buoyancy;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileBounces, meta=(ClampMin="0", UIMin="0"))
    float Bounciness;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileBounces, meta=(ClampMin="0", UIMin="0"))
    float Friction;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileBounces)
    float BounceVelocityStopSimulatingThreshold;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileBounces, AdvancedDisplay, meta=(ClampMin="0", UIMin="0", ClampMax="1", UIMax="1"))
    float MinFrictionFraction;
 
    UFUNCTION(BlueprintCallable, Category="Game|Components|ProjectileMovement")
    bool IsVelocityUnderSimulationThreshold() const { return Velocity.SizeSquared() < FMath::Square(BounceVelocityStopSimulatingThreshold); }
 
    UPROPERTY(BlueprintAssignable)
    FOnProjectileBounceDelegate OnProjectileBounce;
 
    UPROPERTY(BlueprintAssignable)
    FOnProjectileStopDelegate OnProjectileStop;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=Homing)
    float HomingAccelerationMagnitude;
 
    UPROPERTY(VisibleInstanceOnly, BlueprintReadWrite, Category=Homing)
    TWeakObjectPtr<USceneComponent> HomingTargetComponent;
 
    UFUNCTION(BlueprintCallable, Category="Game|Components|ProjectileMovement")
    ENGINE_API virtual void SetVelocityInLocalSpace(FVector NewVelocity);
 
    //Begin UActorComponent Interface
    ENGINE_API virtual void TickComponent(float DeltaTime, enum ELevelTick TickType, FActorComponentTickFunction *ThisTickFunction) override;
    ENGINE_API virtual void PostLoad() override;
    //End UActorComponent Interface
 
    //Begin UMovementComponent Interface
    virtual float GetMaxSpeed() const override { return MaxSpeed; }
    ENGINE_API virtual void InitializeComponent() override;
    ENGINE_API virtual void UpdateTickRegistration() override;
    //End UMovementComponent Interface
 
    ENGINE_API virtual bool CheckStillInWorld();
 
    float GetBuoyancy() const { return Buoyancy; }; 
 
    bool ShouldApplyGravity() const { return ProjectileGravityScale != 0.f; }
 
    ENGINE_API virtual FVector ComputeVelocity(FVector InitialVelocity, float DeltaTime) const;
 
    UFUNCTION(BlueprintCallable, Category="Game|Components|ProjectileMovement")
    ENGINE_API virtual void StopSimulating(const FHitResult& HitResult);
 
    bool HasStoppedSimulation() { return (UpdatedComponent == nullptr) || (IsActive() == false); }
 
    ENGINE_API float GetSimulationTimeStep(float RemainingTime, int32 Iterations) const;
 
    ENGINE_API virtual bool ShouldUseSubStepping() const;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, meta=(ClampMin="0.0166", ClampMax="0.50", UIMin="0.0166", UIMax="0.50"), Category=ProjectileSimulation)
    float MaxSimulationTimeStep;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, meta=(ClampMin="1", ClampMax="25", UIMin="1", UIMax="25"), Category=ProjectileSimulation)
    int32 MaxSimulationIterations;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, meta=(ClampMin="0", ClampMax="4", UIMin="0", UIMax="4"), Category=ProjectileSimulation)
    int32 BounceAdditionalIterations;
 
    UFUNCTION(BlueprintCallable, Category="Game|Components|ProjectileMovement|Interpolation")
    ENGINE_API virtual void SetInterpolatedComponent(USceneComponent* Component);
    
    ENGINE_API USceneComponent* GetInterpolatedComponent() const;
 
    UFUNCTION(BlueprintCallable, Category="Game|Components|ProjectileMovement|Interpolation")
    ENGINE_API virtual void MoveInterpolationTarget(const FVector& NewLocation, const FRotator& NewRotation);
 
    UFUNCTION(BlueprintCallable, Category="Game|Components|ProjectileMovement|Interpolation")
    ENGINE_API virtual void ResetInterpolation();
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileInterpolation, meta=(ClampMin="0"))
    float InterpLocationTime;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileInterpolation, meta=(ClampMin="0"))
    float InterpRotationTime;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileInterpolation, meta=(ClampMin="0"))
    float InterpLocationMaxLagDistance;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileInterpolation, meta=(ClampMin="0"))
    float InterpLocationSnapToTargetDistance;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileInterpolation, AdvancedDisplay)
    float ThrottleInterpolationThresholdNotRenderedShortTime;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileInterpolation, AdvancedDisplay)
    float ThrottleInterpolationThresholdNotRenderedLongTime;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileInterpolation, AdvancedDisplay, meta=(ClampMin="0", UIMin="0"))
    int32 ThrottleInterpolationSkipFramesRecent;
 
    UPROPERTY(EditAnywhere, BlueprintReadWrite, Category=ProjectileInterpolation, AdvancedDisplay, meta=(ClampMin="0", UIMin="0"))
    int32 ThrottleInterpolationSkipFramesNotRecent;
 
    UFUNCTION(BlueprintCallable, Category="Game|Components|ProjectileMovement|Interpolation")
    bool IsInterpolationComplete() const { return bInterpolationComplete || !bInterpMovement; }
 
protected:
 
    ENGINE_API bool UpdateThrottleInterpolation(float DeltaTime, USceneComponent* InterpComponent);
 
    ENGINE_API virtual int32 ComputeThrottleInterpolationMaxFrames(float DeltaTime, USceneComponent* InterpComponent);
    
    ENGINE_API virtual void ResetThrottleInterpolation(float DeltaTime);
 
    // Enum indicating how simulation should proceed after HandleBlockingHit() is called.
    enum class EHandleBlockingHitResult
    {
        Deflect,                
        AdvanceNextSubstep,     
        Abort,                  
    };
 
     ENGINE_API virtual EHandleBlockingHitResult HandleBlockingHit(const FHitResult& Hit, float TimeTick, const FVector& MoveDelta, float& SubTickTimeRemaining);
 
    ENGINE_API virtual void HandleImpact(const FHitResult& Hit, float TimeSlice=0.f, const FVector& MoveDelta = FVector::ZeroVector) override;
 
     ENGINE_API virtual bool HandleDeflection(FHitResult& Hit, const FVector& OldVelocity, const uint32 NumBounces, float& SubTickTimeRemaining);
 
    ENGINE_API virtual bool HandleSliding(FHitResult& Hit, float& SubTickTimeRemaining);
 
    ENGINE_API virtual FVector ComputeBounceResult(const FHitResult& Hit, float TimeSlice, const FVector& MoveDelta);
 
public:
 
    UFUNCTION(BlueprintCallable, Category="Game|Components|ProjectileMovement")
    ENGINE_API FVector LimitVelocity(FVector NewVelocity) const;
 
    ENGINE_API virtual FVector ComputeMoveDelta(const FVector& InVelocity, float DeltaTime) const;
 
    ENGINE_API virtual FVector ComputeAcceleration(const FVector& InVelocity, float DeltaTime) const;
 
    ENGINE_API virtual FVector ComputeHomingAcceleration(const FVector& InVelocity, float DeltaTime) const;
 
    ENGINE_API void AddForce(FVector Force);
 
    FVector GetPendingForce() const { return PendingForce; }
 
    ENGINE_API void ClearPendingForce(bool bClearImmediateForce = false);
    
protected:
 
    // Double-buffer of pending force so that updates can use the accumulated value and reset the data so other AddForce() calls work correctly.
    // Also prevents accumulation over frames where the update aborts for whatever reason, and works with substepping movement.
    FVector PendingForceThisUpdate;
 
    ENGINE_API virtual void TickInterpolation(float DeltaTime);
    
    FVector InterpLocationOffset;
    FVector InterpInitialLocationOffset;
    TWeakObjectPtr<USceneComponent> InterpolatedComponentPtr;
    FQuat InterpRotationOffset;
    FQuat InterpInitialRotationOffset;
 
private:
 
    // Pending force for next tick.
    FVector PendingForce;
 
public:
    ENGINE_API virtual float GetGravityZ() const override;
 
protected:
    static ENGINE_API const float MIN_TICK_TIME;
};