TwoAxisPropertyEditBehavior.h

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// Copyright Epic Games, Inc. All Rights Reserved.
 
#pragma once
 
#include "InputBehavior.h"
#include "BehaviorTargetInterfaces.h"
 
#include "TwoAxisPropertyEditBehavior.generated.h"
 
class FCanvas;
 
class IToolsContextRenderAPI;
 
UCLASS(MinimalAPI)
class UTwoAxisPropertyEditInputBehavior : public UInputBehavior
{
    GENERATED_BODY()
 
public:
    
    INTERACTIVETOOLSFRAMEWORK_API void Initialize(ITwoAxisPropertyEditBehaviorTarget* InTarget);
 
    // Used to define the initial adjustment frame or to update the current reference point alternating between editing the 2 properties.
    INTERACTIVETOOLSFRAMEWORK_API void ResetOrigin(FVector2D InScreenPosition, bool bHorizontalAdjust = true, bool bResetStartOrigin = false);
    INTERACTIVETOOLSFRAMEWORK_API void DrawHUD(FCanvas* Canvas, IToolsContextRenderAPI* RenderAPI) const;
    bool IsEditing() const { return bInDrag; }
 
private:
 
    void OnDragStart(FVector2D InScreenPosition);
    void OnDragUpdate(FVector2D InScreenPosition);
    void OnDragEnd();
    void ResetDragState();
 
    // UInputBehavior implementation
    // Routes input to the device specific handler functions.
    virtual EInputDevices GetSupportedDevices() override { return EInputDevices::Mouse | EInputDevices::Keyboard; }
    virtual FInputCaptureRequest WantsCapture(const FInputDeviceState& InputState) override;
    virtual FInputCaptureUpdate BeginCapture(const FInputDeviceState& InputState, EInputCaptureSide eSide) override;
    virtual FInputCaptureUpdate UpdateCapture(const FInputDeviceState& InputState, const FInputCaptureData& CaptureData) override;
    virtual void ForceEndCapture(const FInputCaptureData& CaptureData) override;
 
    // Mouse input handling - In these functions we assume input is from mouse device.
    // This code is responsible for invoking OnDrag* functions at the proper times.
    FInputCaptureRequest WantsMouseCapture(const FInputDeviceState& InputState);
    FInputCaptureUpdate BeginMouseCapture(const FInputDeviceState& InputState, EInputCaptureSide eSide);
    FInputCaptureUpdate UpdateMouseCapture(const FInputDeviceState& InputState, const FInputCaptureData& CaptureData);
    bool IsMousePressed(const FInputDeviceState& InputState) const;
    
    // Keyboard input handling - In these functions we assume input is from keyboard device.
    // This code is responsible for keeping bKeyPressed in the proper state.
    FInputCaptureRequest WantsKeyboardCapture(const FInputDeviceState& InputState);
    FInputCaptureUpdate BeginKeyboardCapture(const FInputDeviceState& InputState, EInputCaptureSide eSide);
    FInputCaptureUpdate UpdateKeyboardCapture(const FInputDeviceState& InputState, const FInputCaptureData& CaptureData);
    bool IsKeyboardPressed(const FInputDeviceState& InputState) const;
    
private:
 
    // These 2 bools reflect which input we are currently capturing.
    bool bInDrag = false;
    bool bKeyPressed = false;
    
    // Data that is only valid while in a drag (while bInDrag is true13).
    struct FDragState
    {
        float StartValue = 0.f;             // Cached initial values of the property being actively edited.
        FVector2D StartOrigin;              // The screen space coordinate of the brush when the drag started.
        FVector2D CurrentOrigin;            // The screen space coordinate of the origin of the current adjustment. Reset when changing between horizontal and vertical adjustment.
        bool bAdjustingHorizontally = true;
    } State;                                // Only valid if bInDrag is true
    
    ITwoAxisPropertyEditBehaviorTarget* Target = nullptr;
};
 
 
 
UCLASS(MinimalAPI)
class ULocalTwoAxisPropertyEditInputBehavior : public UTwoAxisPropertyEditInputBehavior, public ITwoAxisPropertyEditBehaviorTarget
{
    GENERATED_BODY()
 
public:
    
    /* Lambda implementation of IPropertyInterface */
    struct FPropertyInterface : public IPropertyInterface
    {
        typedef TUniqueFunction<float(void)> FGetValueSignature;
        typedef TUniqueFunction<void(float)> FSetValueSignature;
        typedef TUniqueFunction<float(float)> FMutateDeltaSignature;
 
        FGetValueSignature GetValueFunc;
        FSetValueSignature SetValueFunc;
        FMutateDeltaSignature MutateDeltaFunc = [](float Delta){ return Delta; };
 
        FText Name;
        float EditRate = 0.002f;
        bool bEnabled = false;
 
        bool IsValid() const
        {
            /* Enabled properties must have all mandatory fields set, disabled properties are always valid. */
            if (bEnabled) { return !Name.IsEmpty() && GetValueFunc && SetValueFunc; }
            return true;
        }
        
    private:
        
        virtual FText GetName() override { return Name; }
        virtual float GetValue() override { return GetValueFunc(); }
        virtual void SetValue(float NewValue) override { SetValueFunc(NewValue); }
        virtual float GetEditRate() override { return EditRate; }
        virtual float MutateDelta(float Delta) override { return MutateDeltaFunc(Delta); }
        virtual bool IsEnabled() override { return bEnabled; }
    };
    
public:
    
    using UTwoAxisPropertyEditInputBehavior::Initialize;
    void Initialize()
    {
        UTwoAxisPropertyEditInputBehavior::Initialize(this);
    }
 
    FPropertyInterface HorizontalProperty;
    FPropertyInterface VerticalProperty;
    TUniqueFunction<FKey()> GetCaptureKeyFunc = [](){ return EKeys::B; };
    FSimpleMulticastDelegate OnDragUpdated;
 
private:
 
    // ITwoAxisPropertyEditBehaviorTarget implementation
 
    virtual IPropertyInterface* GetHorizontalProperty() override { return &HorizontalProperty; }
    virtual IPropertyInterface* GetVerticalProperty() override { return &VerticalProperty; }
    virtual FKey GetCaptureKey() override { return GetCaptureKeyFunc(); }
    virtual void PostDragUpdated() override { OnDragUpdated.Broadcast(); }
};