dqz00116/skill-lib/ue5-umg

UE5 UMG Studio

Orchestrate C++ logic and Blueprint visuals for production UE5 user interfaces. Work in two layers: C++ for architecture and data binding, Blueprints for layout and polish.

Overview

Build production-ready Unreal Engine 5 user interfaces using a hybrid C++/Blueprint approach. C++ handles widget architecture, data binding, lifecycle, and performance; Blueprints handle layout, styling, animation, and visual state management.

When to Use

• Creating HUDs, menus, inventories, settings panels, or any widget-based interface
• Binding C++ properties to Blueprint widget components via BindWidget
• Handling gamepad or keyboard focus navigation and input modes
• Designing responsive UMG layouts, animations, and visual states
• Optimizing UI performance (widget pooling, ListView, Tick abuse, material overhead)
• Troubleshooting memory leaks from widget pools or dangling delegate references

When NOT to Use

• Editor tools, debug overlays, or custom Slate drawing — see references/slate-fundamentals.md
• Deep Common UI Plugin specifics — refer to official Epic documentation
• General gameplay programming unrelated to UI

Core Pattern: Hybrid C++/Blueprint Workflow

Without separation: Blueprint-only logic becomes spaghetti, C++-only UI is slow to iterate. With separation: C++ owns data, state, and lifecycle; Blueprints own layout, style, and animation.

// C++ Logic Layer: data binding and state
UCLASS(Abstract)
class UMyWidget : public UUserWidget
{
    GENERATED_BODY()
 
protected:
    UPROPERTY(meta = (BindWidget))
    TObjectPtr<UProgressBar> HealthBar;
 
    virtual void NativeConstruct() override;
    virtual void NativeDestruct() override;
};

void UMyWidget::NativeConstruct()
{
    Super::NativeConstruct();
    if (HealthBar)
    {
        HealthBar->SetPercent(1.0f);
    }
}

The Blueprint subclass of UMyWidget places a ProgressBar named HealthBar in the Designer and styles it without any logic nodes.

Quick Reference

Key Rules

C++ Logic:

• Always use UCLASS(Abstract) on base classes meant for Blueprint subclassing
• BindWidget names must match Blueprint component names exactly (case-sensitive)
• Bind delegates in NativeConstruct, unbind in NativeDestruct
• Override ReleaseSlateResources when using FUserWidgetPool

Blueprint Visuals:

• Design at your minimum supported resolution (e.g. 1280x720)
• Use Collapsed visibility for hiding; Hidden only to preserve layout space
• Use WidgetSwitcher for mutually exclusive pages, not Visibility toggling
• Never use Blueprint "Bind" properties — they run every frame

Performance:

• Use UListView / UTileView for scrollable lists with 10+ items
• Avoid NativeTick for polling; use delegates and events
• Call SetVisibility only when state actually changes

Quality Gates

• [ ] UCLASS(Abstract) on base classes; BindWidget names match exactly
• [ ] Delegates bound in NativeConstruct, unbound in NativeDestruct
• [ ] Input mode and focus set when showing or hiding UI
• [ ] ReleaseSlateResources implemented if using widget pools
• [ ] ListView used for scrollable lists with 10+ items
• [ ] No Blueprint "Bind" properties used for dynamic values
• [ ] UI designed at minimum target resolution; anchors used for responsiveness