Buttons - LCK Documentation

ULCKBaseButton

Base class for all UI button components providing touch interaction, visual state management, and event delegation.

Properties

Property	Type	Description
`ButtonType`	`ELCKButtonType`	Button shape type
`CollisionBox`	`UBoxComponent*`	Touch collision detection
`ButtonSmc`	`UStaticMeshComponent*`	Visual mesh
`ButtonLabel`	`UTextRenderComponent*`	Text label
`ButtonName`	`FName`	Identifier
`PressedOffset`	`FVector`	Visual offset when pressed

Events

OnTapStarted

FOnTapStarted

Broadcast when button is tapped.

DECLARE_DYNAMIC_MULTICAST_DELEGATE(FOnTapStarted);

Methods

Method	Description
`ButtonPressed(TapData)`	Handle press input
`ButtonReleased(TapData)`	Handle release input
`UpdateVisualsOnPressed()`	Set pressed visual state
`UpdateVisualsOnReleased()`	Set released visual state
`Show()`	Make visible
`Hide()`	Make hidden
`SetUVOffset(UVOffset)`	Set primary UV offset
`SetSecondUVOffset(UVOffset)`	Set secondary UV offset

Example

ULCKBaseButton* Button = CreateDefaultSubobject<ULCKBaseButton>(TEXT("ActionButton"));
Button->SetupAttachment(RootComponent);
Button->ButtonName = TEXT("MyAction");

Button->OnTapStarted.AddDynamic(this, &AMyActor::HandleButtonTap);

void AMyActor::HandleButtonTap()
{
    UE_LOG(LogTemp, Log, TEXT("Button tapped!"));
}

ULCKToggle

Toggle button with on/off states and state-dependent icons.

Properties

Property	Type	Description
`ToggleOnIcon`	`UTexture2D*`	Icon for on state
`ToggleOffIcon`	`UTexture2D*`	Icon for off state

Methods

Method	Description
`UpdateVisuals(bIsOn)`	Update appearance based on state

Derived Classes

ULCKMicButton

Microphone toggle button with mute/unmute icons.

ULCKFollowButton

Camera follow mode toggle for selfie camera.

ULCKScreenOrientationButton

Landscape/portrait orientation toggle.

ULCKRectToggle

Rectangle-shaped toggle button.

Example

ULCKToggle* MicToggle = CreateDefaultSubobject<ULCKToggle>(TEXT("MicToggle"));
MicToggle->ToggleOnIcon = MicOnTexture;
MicToggle->ToggleOffIcon = MicOffTexture;

MicToggle->OnTapStarted.AddDynamic(this, &AMyActor::OnMicToggled);

void AMyActor::OnMicToggled()
{
    bMicEnabled = !bMicEnabled;
    MicToggle->UpdateVisuals(bMicEnabled);
    Service->SetMicrophoneEnabled(bMicEnabled);
}

ULCKRectButton

Rectangle-shaped button for text labels and actions.

Derived Classes

ULCKFlipButton

Camera flip/mirror toggle button.

ULCKRecordButton

Record button with time display and recording state visualization. Implements ILCKRecordable.

Events

OnRecordButtonPressed

FOnRecordButtonPressed

Broadcast when record button is pressed.

DECLARE_MULTICAST_DELEGATE_OneParam(FOnRecordButtonPressed, ILCKRecordable*);

Methods

Method	Description
`SetTime(NewTime)`	Update displayed recording time
`UpdateVisuals(NewState)`	Update for recording state

Example

ULCKRecordButton* RecordButton = CreateDefaultSubobject<ULCKRecordButton>(TEXT("RecordButton"));

RecordButton->OnRecordButtonPressed.AddLambda([this](ILCKRecordable* Recordable) {
    if (Service->IsRecording())
    {
        Service->StopRecording();
        Recordable->UpdateVisuals(ELCKRecordingState::Saving);
    }
    else
    {
        Service->StartRecording();
        Recordable->UpdateVisuals(ELCKRecordingState::Recording);
    }
});

// Update time display during recording
void AMyActor::Tick(float DeltaTime)
{
    if (Service->IsRecording())
    {
        RecordButton->SetTime(Service->GetCurrentRecordingDuration());
    }
}

ULCKVideoQualityButton

Video quality selection button cycling through SD, HD, 2K, 4K presets.

ULCKOnScreenButton

Button rendered on the display surface for in-viewport interaction.

Derived Classes

ULCKOnScreenFlipButton

Flip button on display surface.

ULCKOnScreenPhotoButton

Photo capture button on display surface.

Touch Interaction

Enabling Interactions

Interaction with the UI is collision-based. The simplest way to enable interactions is to add a SphereCollider with 5-10mm radius to the index fingertip.

Make sure that the collider has the UICollision tag. It’s used to filter collision for UI.

FLCKTapData

Touch event data structure.

USTRUCT()
struct LCKUI_API FLCKTapData
{
    FVector ButtonLocation;      // World position of button
    FVector ButtonRightVector;   // Button's right vector
    FVector ButtonForwardVector; // Button's forward vector
    FVector TapLocation;         // World position of tap
    bool IsPressed;              // Currently pressed state
};

Interaction Direction

Configure which direction validates touch input:

UENUM(BlueprintType)
enum class ELCKButtonInteractionDirection : uint8
{
    Forward,  // Touch must come from front
    Up        // Touch must come from above
};

Button->SetButtonInteractionDirection(ELCKButtonInteractionDirection::Forward);

Cooldown

Buttons have a built-in 0.25s cooldown to prevent accidental double-taps. This is handled automatically by FLCKConstants::CoolDownTime.

Don’t add additional cooldown logic in your code — the SDK handles this automatically.

​ULCKBaseButton

​Properties

​Events

​Methods

​Example

​ULCKToggle

​Properties

​Methods

​Derived Classes

​Example

​ULCKRectButton

​Derived Classes

​ULCKRecordButton

​Events

​Methods

​Example

​ULCKVideoQualityButton

​ULCKOnScreenButton

​Derived Classes

​Touch Interaction

​Enabling Interactions

​FLCKTapData

​Interaction Direction

​Cooldown

ULCKBaseButton

Properties

Events

Methods

Example

ULCKToggle

Properties

Methods

Derived Classes

Example

ULCKRectButton

Derived Classes

ULCKRecordButton

Events

Methods

Example

ULCKVideoQualityButton

ULCKOnScreenButton

Derived Classes

Touch Interaction

Enabling Interactions

FLCKTapData

Interaction Direction

Cooldown