tengri/Source/TengriPlatformer/Camera/TengriCameraComponent.cpp

// Request Games © All rights reserved

// Source/TengriPlatformer/Camera/TengriCameraComponent.cpp

#include "TengriCameraComponent.h"
#include "GameFramework/SpringArmComponent.h"
#include "DrawDebugHelpers.h"
#include "TengriPlatformer/Movement/TengriMovementComponent.h"

UTengriCameraComponent::UTengriCameraComponent()
{
	PrimaryComponentTick.bCanEverTick = true;
	// Update after physics to prevent jitter with interpolated character movement
	PrimaryComponentTick.TickGroup = TG_PostPhysics; 
}

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

	// Initialize focus to owner location to prevent initial snap
	if (const AActor* Owner = GetOwner())
	{
		CurrentFocusLocation = Owner->GetActorLocation();
	}

	// Apply default config if assigned
	if (DefaultConfig)
	{
		SetCameraConfig(DefaultConfig.Get());
	}
}

void UTengriCameraComponent::InitializeCamera(USpringArmComponent* InSpringArm, UCameraComponent* InCamera)
{
	SpringArm = InSpringArm;
	Camera = InCamera;

	if (SpringArm)
	{
		// Take full control of SpringArm transform (no automatic parenting)
		SpringArm->SetUsingAbsoluteLocation(true);
		SpringArm->SetUsingAbsoluteRotation(true);
		
		// Disable built-in lag systems (we implement custom lag)
		SpringArm->bUsePawnControlRotation = false;
		SpringArm->bEnableCameraLag = false;
		SpringArm->bEnableCameraRotationLag = false;
	}
}

void UTengriCameraComponent::SetCameraConfig(UTengriCameraConfig* NewConfig)
{
	CurrentConfig = NewConfig ? NewConfig : DefaultConfig.Get();
}

void UTengriCameraComponent::TickComponent(float DeltaTime, ELevelTick TickType, FActorComponentTickFunction* ThisTickFunction)
{
	Super::TickComponent(DeltaTime, TickType, ThisTickFunction);

	if (!SpringArm || !CurrentConfig || !GetOwner()) return;

	// ════════════════════════════════════════════════════════════════════
	//                  Phase 1: Determine Target Position
	// ════════════════════════════════════════════════════════════════════

	FVector TargetPos;

	// Use interpolated render position to avoid jitter
	if (auto* MoveComp = GetOwner()->FindComponentByClass<UTengriMovementComponent>())
	{
		TargetPos = MoveComp->GetRenderLocation();
	}
	else
	{
		TargetPos = GetOwner()->GetActorLocation(); // Fallback (will jitter)
	}

	// Apply dead zone logic in SideScroller mode
	if (CurrentConfig->BehaviorType == ETengriCameraBehavior::SideScroller)
	{
		TargetPos = CalculateDeadZoneTarget(TargetPos);
	}

	// ════════════════════════════════════════════════════════════════════
	//                  Phase 2: Smooth Camera Movement (Lag)
	// ════════════════════════════════════════════════════════════════════

	if (CurrentConfig->bEnableLag)
	{
		CurrentFocusLocation = FMath::VInterpTo(
			CurrentFocusLocation, 
			TargetPos, 
			DeltaTime, 
			CurrentConfig->LagSpeed
		);
	}
	else
	{
		CurrentFocusLocation = TargetPos;
	}

	// ════════════════════════════════════════════════════════════════════
	//                  Phase 3: Apply Position to SpringArm
	// ════════════════════════════════════════════════════════════════════

	SpringArm->SetWorldLocation(CurrentFocusLocation);

	// ════════════════════════════════════════════════════════════════════
	//                  Phase 4: Interpolate SpringArm Parameters
	// ════════════════════════════════════════════════════════════════════

	const float TransSpeed = CurrentConfig->TransitionSpeed;

	SpringArm->TargetArmLength = FMath::FInterpTo(
		SpringArm->TargetArmLength, 
		CurrentConfig->TargetArmLength, 
		DeltaTime, 
		TransSpeed
	);

	SpringArm->SocketOffset = FMath::VInterpTo(
		SpringArm->SocketOffset, 
		CurrentConfig->SocketOffset, 
		DeltaTime, 
		TransSpeed
	);

	// ════════════════════════════════════════════════════════════════════
	//                  Phase 5: Handle Rotation
	// ════════════════════════════════════════════════════════════════════

	if (CurrentConfig->BehaviorType == ETengriCameraBehavior::FreeLook)
	{
		// Free look: use controller rotation (mouse/gamepad)
		if (const APawn* PawnOwner = Cast<APawn>(GetOwner()))
		{
			SpringArm->SetWorldRotation(PawnOwner->GetControlRotation());
		}
	}
	else 
	{
		// Side scroller: interpolate to fixed rotation
		const FRotator CurrentRot = SpringArm->GetComponentRotation();
		const FRotator NewRot = FMath::RInterpTo(
			CurrentRot, 
			CurrentConfig->FixedRotation, 
			DeltaTime, 
			TransSpeed
		);
		SpringArm->SetWorldRotation(NewRot);

		// Update control rotation to match camera (for correct input interpretation)
		if (APawn* PawnOwner = Cast<APawn>(GetOwner()))
		{
			if (AController* C = PawnOwner->GetController())
			{
				C->SetControlRotation(NewRot);
			}
		}
	}

	// ════════════════════════════════════════════════════════════════════
	//                  Phase 6: Debug Visualization
	// ════════════════════════════════════════════════════════════════════

#if WITH_EDITOR
	if (CurrentConfig->bDrawDebugBox)
	{
		DrawDebugDeadZone(CurrentFocusLocation, CurrentConfig->DeadZoneExtent);
	}
#endif
}

FVector UTengriCameraComponent::CalculateDeadZoneTarget(const FVector& PlayerLocation) const
{
	// Camera doesn't move while player stays inside dead zone box.
	// When player exits bounds, camera shifts just enough to keep player at box edge.

	FVector DesiredFocus = CurrentFocusLocation;
	
	const FVector Diff = PlayerLocation - DesiredFocus;
	const FVector Extent = CurrentConfig->DeadZoneExtent;

	// X-axis (Forward/Backward or Left/Right)
	if (FMath::Abs(Diff.X) > Extent.X)
	{
		DesiredFocus.X = PlayerLocation.X - (FMath::Sign(Diff.X) * Extent.X);
	}

	// Z-axis (Up/Down)
	if (FMath::Abs(Diff.Z) > Extent.Z)
	{
		DesiredFocus.Z = PlayerLocation.Z - (FMath::Sign(Diff.Z) * Extent.Z);
	}

	// Y-axis (Depth) - usually locked to player in 2.5D to prevent going off-screen
	DesiredFocus.Y = PlayerLocation.Y;

	return DesiredFocus;
}

void UTengriCameraComponent::DrawDebugDeadZone(const FVector& Center, const FVector& Extent) const
{
	DrawDebugBox(
		GetWorld(), 
		Center, 
		Extent, 
		FColor::Green, 
		false,  // bPersistentLines
		-1.0f,  // LifeTime
		0,      // DepthPriority
		2.0f    // Thickness
	);
}