# API Reference

AfterPrime Systems | AP Attribute Suite | Version 1.0.0

# Contents


Enums	`EAP_ModifierType`
Structs	`FAP_AttributeDefinition`, `FAP_AttributeModifier`, `FAP_AttributeModifierHandle`, `FAP_AttributeSnapshot`
UAP_AttributeSet	Data asset defining a collection of attributes
UAP_AttributeSuiteComponent	Primary component — add to any replicated actor
UAP_AttributeWidgetBase	UMG base class for attribute display widgets
IAP_AttributeInterface	Optional interface for typed component resolution
UAP_AttributeStatics	Static helper library — zero-setup attribute access

# Enums

# EAP_ModifierType

Controls how a modifier affects an attribute's EffectiveMax.

Value	Description
`Additive`	Added to the base max. `+50` raises max by 50.
`Multiplicative`	Multiplied after additive modifiers. `1.5` = 50% increase.
`Override`	Replaces EffectiveMax entirely. Only one Override can be active per attribute — adding a second removes the first.

Evaluation order:

Base MaxValue
  → sum all Additive modifiers
  → apply Multiplicative modifiers sequentially
  → Override replaces result entirely (if present)
  → clamp to >= MinValue

# Structs

# FAP_AttributeDefinition

One row in a UAP_AttributeSet DataAsset. Defines a single attribute's starting configuration.

Property	Type	Default	Description
`Tag`	`FGameplayTag`	—	Gameplay Tag identifying this attribute.
`BaseValue`	`float`	`100.0`	Starting and reset value.
`MinValue`	`float`	`0.0`	Minimum value this attribute can reach.
`MaxValue`	`float`	`100.0`	Maximum value before modifiers are applied.
`bRegenEnabled`	`bool`	`false`	Whether this attribute regenerates over time.
`RegenRatePerSecond`	`float`	`5.0`	Units per second regenerated when regen is active.
`RegenDelay`	`float`	`3.0`	Seconds after a negative delta before regeneration begins.

# FAP_AttributeModifier

Blueprint-facing modifier definition. Pass to AddModifier to alter an attribute's EffectiveMax.

Property	Type	Default	Description
`ModifierType`	`EAP_ModifierType`	`Additive`	How this modifier combines with others.
`Value`	`float`	`0.0`	The modifier value, applied according to `ModifierType`.
`Duration`	`float`	`0.0`	Duration in seconds. `0` = permanent. Timed modifiers auto-expire.
`Handle`	`FGuid`	—	Assigned automatically by `AddModifier`. Do not set manually.

# FAP_AttributeModifierHandle

Blueprint-safe wrapper returned by AddModifier. Pass to RemoveModifier to remove a specific modifier.

Property	Type	Description
`Handle`	`FGuid`	Unique identifier for the modifier instance.
`AttributeTag`	`FGameplayTag`	The attribute this modifier is applied to.

# FAP_AttributeSnapshot

Full state dump of one attribute. Returned by GetSnapshot.

Property	Type	Description
`Tag`	`FGameplayTag`	Attribute identifier.
`CurrentValue`	`float`	Current replicated value.
`BaseValue`	`float`	Base unmodified value.
`MinValue`	`float`	Minimum allowed value.
`EffectiveMax`	`float`	Effective maximum after modifiers.
`NormalizedValue`	`float`	`CurrentValue / EffectiveMax` clamped to `[0,1]`.
`bRegenActive`	`bool`	Whether regen is currently active.
`ActiveModifierCount`	`int32`	Number of active modifiers. Accurate on server only — always `0` on clients.

# UAP_AttributeSet

Type: UDataAsset Category: AP Attribute

A data asset defining a collection of attribute definitions. Create in the Content Browser: Right-click → Miscellaneous → Data Asset → AP_AttributeSet.

# Properties

Property	Type	Description
`Definitions`	`TArray<FAP_AttributeDefinition>`	List of attribute definitions. Tags must be unique within a set.

Assign one or more UAP_AttributeSet assets to the component's AttributeSets array. Multiple sets are merged at BeginPlay.

# UAP_AttributeSuiteComponent

Type: UActorComponent Display Name: AP_AttributeSuite Category: AP Attribute

Add this component to any Actor Blueprint via the Components panel. All attribute state is authoritative on the server and replicates to clients via FastArray.

Authority Model

All mutation methods require server authority. All query methods are safe to call on any machine — attribute state (CurrentValue, EffectiveMax, MinValue) replicates via FastArray.

# Properties

Property	Type	Description
`AttributeSets`	`TArray<UAP_AttributeSet*>`	One or more DataAssets defining this component's attributes. Loaded at BeginPlay.

# Delegates

All delegates are BlueprintAssignable.

Multiplayer Binding

OnAttributeChanged, OnAttributeDepleted, and OnAttributeRestored fire on both server and client. Bind on both — do not gate behind HasAuthority.

OnModifierAdded and OnModifierRemoved fire on the server only. Gate these bindings inside Switch Has Authority.

# OnAttributeChanged

Fires after any mutation to CurrentValue — on server after state mutation, on clients from FastArray replication callbacks.

Parameter	Type	Description
`AttributeTag`	`FGameplayTag`	The attribute that changed
`OldValue`	`float`	Value before the change
`NewValue`	`float`	Value after the change

Client OldValue

On clients, OldValue is derived from a client-local cached value set during the previous replication callback — it is not transmitted from the server.

# OnAttributeDepleted

Fires when CurrentValue reaches MinValue. Edge-detected — fires only on the transition from above-minimum to at-minimum. Will not fire again until the attribute is restored and depleted again.

Parameter	Type	Description
`AttributeTag`	`FGameplayTag`	The attribute that reached minimum

# OnAttributeRestored

Fires when CurrentValue rises above MinValue after being depleted. Edge-detected — fires only on the transition from at-minimum to above-minimum.

Parameter	Type	Description
`AttributeTag`	`FGameplayTag`	The attribute that recovered

# OnModifierAdded

Server Only

Fires when AddModifier succeeds.

Parameter	Type	Description
`AttributeTag`	`FGameplayTag`	The attribute the modifier was applied to
`Handle`	`FAP_AttributeModifierHandle`	Handle for the new modifier

# OnModifierRemoved

Server Only

Fires when a modifier is removed via RemoveModifier, RemoveAllModifiers, or timer expiry.

Parameter	Type	Description
`AttributeTag`	`FGameplayTag`	The attribute the modifier was on
`Handle`	`FAP_AttributeModifierHandle`	Handle of the removed modifier

# Query Functions

Server + Client BlueprintPure

# `GetCurrentValue`

float GetCurrentValue(FGameplayTag AttributeTag) const

Returns the current replicated value. Returns 0.0 and logs a warning if the tag is not found.

# `GetBaseValue`

float GetBaseValue(FGameplayTag AttributeTag) const

Returns the base unmodified value defined in the DataAsset.

# `GetMaxValue`

float GetMaxValue(FGameplayTag AttributeTag) const

Returns the effective maximum after all active modifiers. Reads the replicated EffectiveMax.

# `GetMinValue`

float GetMinValue(FGameplayTag AttributeTag) const

Returns the minimum value for the attribute.

# `GetNormalizedValue`

float GetNormalizedValue(FGameplayTag AttributeTag) const

Returns CurrentValue / EffectiveMax clamped to [0, 1]. Returns 0.0 if EffectiveMax is zero. Use directly to drive progress bars.

# `HasAttribute`

bool HasAttribute(FGameplayTag AttributeTag) const

Returns true if this component owns an attribute with the given tag.

# `GetAllAttributeTags`

TArray<FGameplayTag> GetAllAttributeTags() const

Returns all registered attribute tags on this component.

# Mutation Functions

Server Only

# `ApplyDelta`

void ApplyDelta(FGameplayTag AttributeTag, float Delta)

Adds Delta to CurrentValue, clamped to [MinValue, EffectiveMax]. Negative deltas restart the regen delay timer. Fires OnAttributeChanged. May fire OnAttributeDepleted or OnAttributeRestored on state transitions.

# `SetCurrentValue`

void SetCurrentValue(FGameplayTag AttributeTag, float Value)

Directly sets CurrentValue, clamped to [MinValue, EffectiveMax]. Fires the same delegates as ApplyDelta.

# `SetBaseValue`

void SetBaseValue(FGameplayTag AttributeTag, float Value)

Changes the base value. Recomputes EffectiveMax and clamps CurrentValue if it exceeds the new max.

# `ResetToBase`

void ResetToBase(FGameplayTag AttributeTag)

Restores CurrentValue to BaseValue. Clears the regen delay timer. Fires OnAttributeChanged and may fire OnAttributeRestored if the attribute was depleted.

# Modifier Functions

Server Only

Modifier Scope

Modifiers affect EffectiveMax — not CurrentValue directly. CurrentValue is clamped after EffectiveMax changes.

# `AddModifier`

FAP_AttributeModifierHandle AddModifier(FGameplayTag AttributeTag, FAP_AttributeModifier Modifier)

Adds a modifier to the attribute's EffectiveMax. Returns a handle for later removal.

If Modifier.Duration > 0, the modifier auto-expires after that many seconds
If ModifierType is Override and an existing Override is active, the old one is removed first before the new one is added
Fires OnModifierAdded

# `RemoveModifier`

void RemoveModifier(FAP_AttributeModifierHandle ModifierHandle)

Removes a modifier by its handle. Clears any associated expiry timer. Recomputes EffectiveMax. Fires OnModifierRemoved.

# `RemoveAllModifiers`

void RemoveAllModifiers(FGameplayTag AttributeTag)

Removes all modifiers on the specified attribute. Fires OnModifierRemoved for each. Recomputes EffectiveMax once after all removals.

# Regen Functions

Server Only

# `SetRegenEnabled`

void SetRegenEnabled(FGameplayTag AttributeTag, bool bEnabled)

Enables or disables regeneration for a specific attribute at runtime. Overrides the DataAsset's bRegenEnabled setting.

Regen activates when:

Regen is enabled for the attribute
CurrentValue is below EffectiveMax
Enough time has passed since the last negative delta (RegenDelay)

# Debug Functions

Server + Client

# `GetSnapshot`

TArray<FAP_AttributeSnapshot> GetSnapshot() const

Returns a full state snapshot of all attributes. ActiveModifierCount is accurate on server only — always 0 on clients.

# `DebugPrint`

void DebugPrint() const

Logs all attribute values, effective maxes, and modifier counts to the Output Log via UE_LOG.

# UAP_AttributeWidgetBase

Type: UUserWidget Category: AP Attribute | Widget

C++ base class for UMG attribute display widgets. Supports two usage patterns:

Single-attribute bar — call BindToAttribute(Actor, Tag) to track one attribute
Multi-attribute panel — call InitForActor(Actor) to receive the component and all tags, then create child bar widgets

# Properties

Property	Type	Description
`CurrentValue`	`float`	Current value of the bound attribute. Updated automatically.
`MaxValue`	`float`	Effective maximum of the bound attribute. Updated automatically.
`NormalizedValue`	`float`	`CurrentValue / MaxValue` clamped to `[0,1]`. Use for progress bars.

# `BindToAttribute`

void BindToAttribute(AActor* TargetActor, FGameplayTag AttributeTag)

Binds this widget to a specific attribute on the target actor. Finds the component, subscribes to OnAttributeChanged, and populates CurrentValue, MaxValue, and NormalizedValue. Calls OnDisplayUpdated once the widget is constructed.

Panel Context

When calling from a panel's OnActorInitialized, use AttributeComponent → GetOwner for TargetActor — do not use GetBoundActor() as the actor reference may not be available on clients yet.

# `OnDisplayUpdated` (BlueprintImplementableEvent)

Called after CurrentValue, MaxValue, and NormalizedValue are updated. Override in your Widget Blueprint to set progress bar percent and text values.

Fires:

Once after BindToAttribute completes (deferred to NativeConstruct if widget isn't ready)
On every subsequent OnAttributeChanged callback for the bound tag

# `InitForActor`

void InitForActor(AActor* TargetActor)

Resolves the attribute component and all tags on the target actor, then calls OnActorInitialized. Use for panel widgets that dynamically create child bar widgets.

# `OnActorInitialized` (BlueprintImplementableEvent)

Called after InitForActor resolves the component. Override in Blueprint to create child bar widgets, add them to a panel, and call BindToAttribute on each.

Parameter	Type	Description
`AttributeComponent`	`UAP_AttributeSuiteComponent*`	The resolved component
`AttributeTags`	`TArray<FGameplayTag>`	All attribute tags on the component

# `GetBoundActor`

AActor* GetBoundActor() const

Returns the actor passed to InitForActor or BindToAttribute.

# IAP_AttributeInterface

Type: UInterface

Optional interface for typed checking and custom component resolution. Implement on any Actor that owns a UAP_AttributeSuiteComponent.

Not required — UAP_AttributeStatics falls back to FindComponentByClass automatically if the actor doesn't implement this interface.

# `GetAttributeComponent` (BlueprintNativeEvent)

UAP_AttributeSuiteComponent* GetAttributeComponent() const

Returns the attribute component owned by this actor. The default implementation uses FindComponentByClass. Override to return a specific component if the actor has multiple, or to route to a sub-actor's component.

# UAP_AttributeStatics

Type: UBlueprintFunctionLibrary Category: AP Attribute

Static helper functions for zero-setup attribute access. No interface implementation required — works on any actor with a UAP_AttributeSuiteComponent.

Any Machine BlueprintPure

# `GetAttributeComponent`

static UAP_AttributeSuiteComponent* GetAttributeComponent(AActor* Actor)

Returns the attribute component on the actor. Checks IAP_AttributeInterface first, falls back to FindComponentByClass.

# `HasAttributeComponent`

static bool HasAttributeComponent(AActor* Actor)

Returns true if the actor has an attribute component.

# `GetAttributeValue`

static float GetAttributeValue(AActor* Actor, FGameplayTag AttributeTag)

Shorthand for GetAttributeComponent(Actor) → GetCurrentValue(Tag). Returns 0.0 if the component or attribute is not found.

# `GetNormalizedAttributeValue`

static float GetNormalizedAttributeValue(AActor* Actor, FGameplayTag AttributeTag)

Shorthand for GetAttributeComponent(Actor) → GetNormalizedValue(Tag). Returns 0.0 if not found. Use directly for progress bars.

AfterPrime Systems — Building the Gameplay Foundation

# API Reference

# Contents

# Enums

# EAP_ModifierType

# Structs

# FAP_AttributeDefinition

# FAP_AttributeModifier

# FAP_AttributeModifierHandle

# FAP_AttributeSnapshot

# UAP_AttributeSet

# Properties

# UAP_AttributeSuiteComponent

Authority Model

# Properties

# Delegates

Multiplayer Binding

# OnAttributeChanged

Client OldValue

# OnAttributeDepleted

# OnAttributeRestored

# OnModifierAdded

# OnModifierRemoved

# Query Functions

# GetCurrentValue

# GetBaseValue

# GetMaxValue

# GetMinValue

# GetNormalizedValue

# HasAttribute

# GetAllAttributeTags

# Mutation Functions

# ApplyDelta

# SetCurrentValue

# SetBaseValue

# ResetToBase

# Modifier Functions

Modifier Scope

# AddModifier

# RemoveModifier

# RemoveAllModifiers

# Regen Functions

# SetRegenEnabled

# Debug Functions

# GetSnapshot

# DebugPrint

# UAP_AttributeWidgetBase

# Properties

# BindToAttribute

Panel Context

# OnDisplayUpdated (BlueprintImplementableEvent)

# InitForActor

# OnActorInitialized (BlueprintImplementableEvent)

# GetBoundActor

# IAP_AttributeInterface

# GetAttributeComponent (BlueprintNativeEvent)

# UAP_AttributeStatics

# GetAttributeComponent

# HasAttributeComponent

# GetAttributeValue

# GetNormalizedAttributeValue

# `GetCurrentValue`

# `GetBaseValue`

# `GetMaxValue`

# `GetMinValue`

# `GetNormalizedValue`

# `HasAttribute`

# `GetAllAttributeTags`

# `ApplyDelta`

# `SetCurrentValue`

# `SetBaseValue`

# `ResetToBase`

# `AddModifier`

# `RemoveModifier`

# `RemoveAllModifiers`

# `SetRegenEnabled`

# `GetSnapshot`

# `DebugPrint`

# `BindToAttribute`

# `OnDisplayUpdated` (BlueprintImplementableEvent)

# `InitForActor`

# `OnActorInitialized` (BlueprintImplementableEvent)

# `GetBoundActor`

# `GetAttributeComponent` (BlueprintNativeEvent)

# `GetAttributeComponent`

# `HasAttributeComponent`

# `GetAttributeValue`

# `GetNormalizedAttributeValue`