Add initial custom slide movement implementation

Source/Nakatomi/Nakatomi.h

@@ -3,3 +3,6 @@
 #pragma once
 
 #include "CoreMinimal.h"
+
+class ANakatomiCharacter;
+class UNakatomiCMC;

Source/Nakatomi/NakatomiCMC.cpp

@@ -3,13 +3,22 @@
 
 #include "NakatomiCMC.h"
 
+#include <Components/CapsuleComponent.h>
 #include <GameFramework/Character.h>
+#include "NakatomiCharacter.h"
 
 UNakatomiCMC::UNakatomiCMC(): Safe_bWantsToSprint(false)
 {
 	NavAgentProps.bCanCrouch = true;
 }
 
+void UNakatomiCMC::InitializeComponent()
+{
+	Super::InitializeComponent();
+
+	NakatomiCharacterOwner = Cast<ANakatomiCharacter>(GetOwner());
+}
+
 // Checks if we can combine the NewMove with the current move to save on data.
 // If all the data in a saved move is identical, if true, we cam tell the server to run the existing move instead.
 bool UNakatomiCMC::FSavedMove_Nakatomi::CanCombineWith(const FSavedMovePtr& NewMove, ACharacter* InCharacter,
@@ -51,6 +60,7 @@ void UNakatomiCMC::FSavedMove_Nakatomi::SetMoveFor(ACharacter* C, float InDeltaT
 	UNakatomiCMC* CharacterMovement = Cast<UNakatomiCMC>(C->GetCharacterMovement());
 
 	Saved_bWantsToSprint = CharacterMovement->Safe_bWantsToSprint;
+	Saved_bPrevWantsToCrouch = CharacterMovement->Safe_bPrevWantsToCrouch;
 }
 
 void UNakatomiCMC::FSavedMove_Nakatomi::PrepMoveFor(ACharacter* C)
@@ -60,6 +70,7 @@ void UNakatomiCMC::FSavedMove_Nakatomi::PrepMoveFor(ACharacter* C)
 	UNakatomiCMC* CharacterMovement = Cast<UNakatomiCMC>(C->GetCharacterMovement());
 
 	CharacterMovement->Safe_bWantsToSprint = Saved_bWantsToSprint;
+	CharacterMovement->Safe_bPrevWantsToCrouch = Saved_bPrevWantsToCrouch;
 }
 
 UNakatomiCMC::FNetworkPredictionData_Client_Nakatomi::FNetworkPredictionData_Client_Nakatomi(
@@ -110,6 +121,51 @@ void UNakatomiCMC::OnMovementUpdated(float DeltaSeconds, const FVector& OldLocat
 			MaxWalkSpeed = Walk_MaxWalkSpeed;
 		}
 	}
+
+	Safe_bPrevWantsToCrouch = bWantsToCrouch;
+}
+
+bool UNakatomiCMC::IsMovingOnGround() const
+{
+	return Super::IsMovingOnGround() || IsCustomMovementMode(CMOVE_Slide);
+}
+
+bool UNakatomiCMC::CanCrouchInCurrentState() const
+{
+	return Super::CanCrouchInCurrentState() && IsMovingOnGround();
+}
+
+void UNakatomiCMC::UpdateCharacterStateBeforeMovement(float DeltaSeconds)
+{
+	if (MovementMode == MOVE_Walking && !bWantsToCrouch && Safe_bPrevWantsToCrouch)
+	{
+		FHitResult PotentialSlideSurface;
+		if (Velocity.SizeSquared() > pow(Slide_MinSpeed, 2) && GetSlideSurface(PotentialSlideSurface))
+		{
+			EnterSlide();
+		}
+	}
+
+	if (IsCustomMovementMode(CMOVE_Slide) && !bWantsToCrouch)
+	{
+		ExitSlide();
+	}
+	
+	Super::UpdateCharacterStateBeforeMovement(DeltaSeconds);
+}
+
+void UNakatomiCMC::PhysCustom(float deltaTime, int32 Iterations)
+{
+	Super::PhysCustom(deltaTime, Iterations);
+
+	switch (CustomMovementMode)
+	{
+	case CMOVE_Slide:
+		PhysSlide(deltaTime, Iterations);
+		break;
+	default:
+		UE_LOG(LogTemp, Fatal, TEXT("Invalid Movement Mode"));
+	}
 }
 
 void UNakatomiCMC::EnableSprint()
@@ -131,3 +187,101 @@ void UNakatomiCMC::DisableCrouch()
 {
 	bWantsToCrouch = false;
 }
+
+bool UNakatomiCMC::IsCustomMovementMode(ECustomMovementMove InCustomMovementMode) const
+{
+	return MovementMode == MOVE_Custom && CustomMovementMode == InCustomMovementMode;
+}
+
+void UNakatomiCMC::EnterSlide()
+{
+	bWantsToCrouch = true;
+	Velocity += Velocity.GetSafeNormal2D() * Slide_EnterImpulse;
+	SetMovementMode(MOVE_Custom, CMOVE_Slide);
+}
+
+void UNakatomiCMC::ExitSlide()
+{
+	bWantsToCrouch = false;
+
+	FQuat NewRotation = FRotationMatrix::MakeFromXZ(UpdatedComponent->GetForwardVector().GetSafeNormal2D(), FVector::UpVector).ToQuat();
+	FHitResult Hit;
+	SafeMoveUpdatedComponent(FVector::ZeroVector, NewRotation, true, Hit);
+	SetMovementMode(MOVE_Walking);
+}
+
+void UNakatomiCMC::PhysSlide(float deltaTime, int32 Iterations)
+{
+	if (deltaTime < MIN_TICK_TIME) return;
+
+	// This is probably not needed for Sliding but including for completeness, will likely remove later.
+	RestorePreAdditiveRootMotionVelocity();
+
+	FHitResult SurfaceHit;
+	if (!GetSlideSurface(SurfaceHit) || Velocity.SizeSquared() < pow(Slide_MinSpeed, 2))
+	{
+		ExitSlide();
+		StartNewPhysics(deltaTime, Iterations);
+	}
+
+	// Surface Gravity
+	Velocity += Slide_GravityForce * FVector::DownVector * deltaTime;
+
+	// Calculate Strafe
+	if (FMath::Abs(FVector::DotProduct(Acceleration.GetSafeNormal(), UpdatedComponent->GetRightVector())) > 0.5f)
+	{
+		Acceleration = Acceleration.ProjectOnTo(UpdatedComponent->GetRightVector());
+	}
+	else
+	{
+		Acceleration = FVector::ZeroVector;
+	}
+
+	// Calculate Velocity
+	if (!HasAnimRootMotion() && !CurrentRootMotion.HasOverrideVelocity())
+	{
+		CalcVelocity(deltaTime, Slide_Friction, true, GetMaxBrakingDeceleration());
+	}
+	ApplyRootMotionToVelocity(deltaTime);
+
+	// Perform Move
+	Iterations++;
+	bJustTeleported = false;
+
+	FVector OldLocation = UpdatedComponent->GetComponentLocation();
+	FQuat OldRotation = UpdatedComponent->GetComponentRotation().Quaternion();
+	
+	FHitResult Hit(1.f);
+	FVector AdjustedVelocity = Velocity * deltaTime;
+	FVector VelocityPlaneDirection = FVector::VectorPlaneProject(Velocity, SurfaceHit.Normal).GetSafeNormal();
+	FQuat NewRotation = FRotationMatrix::MakeFromXZ(VelocityPlaneDirection, SurfaceHit.Normal).ToQuat();
+	SafeMoveUpdatedComponent(AdjustedVelocity, NewRotation, true, Hit);
+
+	// Post Move Checks
+	if (Hit.Time < 1.f)
+	{
+		HandleImpact(Hit, deltaTime, AdjustedVelocity);
+		SlideAlongSurface(AdjustedVelocity, (1.f - Hit.Time), Hit.Normal, Hit, true);
+	}
+
+	FHitResult NewSurfaceHit;
+	if (!GetSlideSurface(NewSurfaceHit) || Velocity.SizeSquared() < pow(Slide_MinSpeed, 2))
+	{
+		ExitSlide();
+	}
+
+	// Update outgoing Velocity and Acceleration
+	if (!bJustTeleported && !HasAnimRootMotion() && !CurrentRootMotion.HasOverrideVelocity())
+	{
+		Velocity = (UpdatedComponent->GetComponentLocation() - OldLocation) / deltaTime;
+	}
+}
+
+bool UNakatomiCMC::GetSlideSurface(FHitResult& Hit) const
+{
+	const FVector Start = UpdatedComponent->GetComponentLocation();
+	const FVector End = Start + CharacterOwner->GetCapsuleComponent()->GetScaledCapsuleHalfHeight() * 2.f * FVector::DownVector;
+	const FName ProfileName = TEXT("BlockAll");
+	
+	return GetWorld()->LineTraceSingleByProfile(Hit, Start, End, ProfileName);
+}

Source/Nakatomi/NakatomiCMC.h

@@ -3,9 +3,18 @@
 #pragma once
 
 #include "CoreMinimal.h"
+#include "Nakatomi.h"
 #include "GameFramework/CharacterMovementComponent.h"
 #include "NakatomiCMC.generated.h"
 
+UENUM(BlueprintType)
+enum ECustomMovementMove
+{
+	CMOVE_None	UMETA(Hidden),
+	CMOVE_Slide UMETA(DisplayName = "Slide"),
+	CMOVE_MAX	UMETA(Hidden),
+};
+
 /**
  * 
  */
@@ -18,8 +27,11 @@ class NAKATOMI_API UNakatomiCMC : public UCharacterMovementComponent
 	{
 		typedef FSavedMove_Character Super;
 
+		// Flag
 		uint8 Saved_bWantsToSprint:1;
 
+		uint8 Saved_bPrevWantsToCrouch:1;
+		
 		virtual bool CanCombineWith(const FSavedMovePtr& NewMove, ACharacter* InCharacter, float MaxDelta) const override;
 		virtual void Clear() override;
 		virtual uint8 GetCompressedFlags() const override;
@@ -37,19 +49,49 @@ class NAKATOMI_API UNakatomiCMC : public UCharacterMovementComponent
 		virtual FSavedMovePtr AllocateNewMove() override;
 	};
 
-	UPROPERTY(EditDefaultsOnly) float Sprint_MaxWalkSpeed;
-	UPROPERTY(EditDefaultsOnly) float Walk_MaxWalkSpeed;
+	UPROPERTY(EditDefaultsOnly)
+	float Sprint_MaxWalkSpeed;
+
+	UPROPERTY(EditDefaultsOnly)
+	float Walk_MaxWalkSpeed;
+
+	UPROPERTY(EditDefaultsOnly)
+	float Slide_MinSpeed = 10.f;
+
+	UPROPERTY(EditDefaultsOnly)
+	float Slide_EnterImpulse = 2000.f;
+
+	UPROPERTY(EditDefaultsOnly)
+	float Slide_GravityForce = 5000.f;
+
+	UPROPERTY(EditDefaultsOnly)
+	float Slide_Friction = 1.3f;
 	
 	bool Safe_bWantsToSprint;
+	bool Safe_bPrevWantsToCrouch;
+
+	UPROPERTY(Transient)
+	ANakatomiCharacter* NakatomiCharacterOwner;
 	
 public:
 	UNakatomiCMC();
 
+protected:
+	void InitializeComponent() override;
+
 	FNetworkPredictionData_Client* GetPredictionData_Client() const override;
 protected:
 	virtual void UpdateFromCompressedFlags(uint8 Flags) override;
 
 	virtual void OnMovementUpdated(float DeltaSeconds, const FVector& OldLocation, const FVector& OldVelocity) override;
+
+	virtual bool IsMovingOnGround() const override;
+
+	virtual bool CanCrouchInCurrentState() const override;
+
+	virtual void UpdateCharacterStateBeforeMovement(float DeltaSeconds) override;
+
+	virtual void PhysCustom(float deltaTime, int32 Iterations) override;
 	
 public:
 	UFUNCTION(BlueprintCallable)
@@ -63,4 +105,17 @@ public:
 
 	UFUNCTION(BlueprintCallable)
 	void DisableCrouch();
+
+	UFUNCTION()
+	bool IsCustomMovementMode(ECustomMovementMove InCustomMovementMode) const;
+
+private:
+
+	void EnterSlide();
+
+	void ExitSlide();
+
+	void PhysSlide(float deltaTime, int32 Iterations); // Every movement mode requires a physics function to work
+
+	bool GetSlideSurface(FHitResult& Hit) const;
 };

Source/Nakatomi/NakatomiCharacter.h

@@ -5,7 +5,7 @@
 #include "CoreMinimal.h"
 #include "GameFramework/Character.h"
 #include "HealthComponent.h"
-#include "NakatomiCMC.h"
+#include "Nakatomi.h"
 #include "Throwable.h"
 #include "Weapon.h"
 #include "NakatomiCharacter.generated.h"