Advanced Modular Leveling system

A modular, replicated XP and leveling plugin for Unreal Engine (C++ and Blueprint). Data-driven curves, ascension level caps, milestone rewards, and overflow-XP conversion.

Features

Drop-in componentAdd AMLSLevelComponent to any Actor: players, enemies, weapons, buildings.

3 XP curve typesExplicit array, mathematical formula, or Unreal Float Curve asset.

Ascension gatingHard level caps that must be broken by calling Ascend.

Milestone rewardsGameplay-Tag rewards per level plus custom Blueprint or C++ reward processors.

Overflow XPConvert XP gained at max level into a currency via a tag and multiplier.

Multiplayer readyServer-authoritative with replicated level, XP and ascension phase.

Save system hooksA SaveGame struct for saving and restoring progression.

Blueprint friendlyPure getters, authority-only callables, and assignable events.

Quick Start

Enable the plugin and make sure the GameplayTags module is available in your project.
Create a data asset: Content Browser → Miscellaneous → Data Asset → AMLSLevelUpConfigDataAsset.
Set Max Level, pick an XP Curve Method, and optionally add reward milestones.
Add AMLS Level Component to your Actor (your Character) and assign the data asset to Level Config Data.
On the server, call AddXP whenever the Actor earns experience.
Bind to OnLevelUpDelegate / OnXPChangedDelegate to drive your UI.

// C++ 

if (UAMLSLevelComponent* Level = Actor->FindComponentByClass<UAMLSLevelComponent>())
{
    Level->OnLevelUpDelegate.AddDynamic(this, &AMyClass::HandleLevelUp);
    Level->AddXP(250); // server only
}

If no config asset is assigned, a warning is logged and fallback values are used (level cap 50, XP required = level × 100).

Level Component (`UAMLSLevelComponent`)

Starts at Level 1, 0 XP, Ascension Phase 1. Functions marked Authority only run on the server.

Function	Type	Description
AddXP(Amount)	Authority	Adds XP and processes chained level-ups. At absolute max level, XP is routed to overflow conversion.
SetLevel(NewLevel)	Authority	Adds XP and processes chained level-ups. At absolute max level, XP is routed to overflow conversion.
AddLevels(LevelsToAdd)	Authority	Grants flat levels, respecting ascension caps.
Ascend()	Authority	Moves to the next ascension phase if `CanAscend()` is true.
ResetProgression()	Authority	Resets level, XP and phase to defaults (useful for prestige).
LoadProgressionSaveData(Data)	Authority	Restores progression from a save struct.
GetProgressionSaveData()	Pure	Returns an `FAMLSProgressionSaveData` snapshot.
GetCurrentLevel /GetCurrentXP	Pure	Current values.
GetXPRequiredForNextLevel	Pure	XP needed to complete the current level.
GetRemainingXPToNextLevel	Pure	XP needed to complete the current level.
GetXPProgressPercentage	Pure	0.0 – 1.0 progress bar value.
GetCurrentLevelCap	Pure	0.0 – 1.0 progress bar value.
GetCurrentLevelCap	Pure	Hard cap for the current ascension phase.
IsAtCurrentLevelCap/IsAtAbsoluteMaxLevel	Pure	Cap checks.
CanAscend	Pure	True when at the current cap and not at absolute max.
GetCurrentAscensionPhase	Pure	Current phase (starts at 1).
GetRequiredAscensionPhaseForLevel	Pure	Phase required to reach a given level.
HasReachedLevel(Level)	Pure	True if current level ≥ target.
GetLevelStatus(Level)	Pure	Returns `FAMLSLevelStatusData`: bHasReached, bRequiresAscension, bIsAbsoluteMaxLevel, bIsInvalid. Ideal for level-map UIs.
GetRewardsForLevel(Level)	Pure	Reward items configured for a level.

Config Data Asset (`UAMLSLevelUpConfigDataAsset`)

Property	Default	Description
Max Level	50	Absolute highest level (min 2).
XP Curve Method	Formulaic	Explicit Array, Formulaic, or Float Curve Asset.
System ID	Player	Identifier used to match reward processors to this asset.
Use Ascension System	false	Enables level caps that require `Ascend()`.
Ascension Level Caps	empty	Cap per phase, e.g. `[20, 40]`.
Explicit XP Thresholds	empty	Index 0 = XP to leave level 1. Missing entries fall back to `Level × FormulaBaseXP`.
Formula Base XP / Multiplier / Exponent	100 / 1.2 / 1.5	See formula below.
Visual Curve Asset	none	Float curve: X = level, Y = XP required.
Reward Milestones	empty	Per-level lists of `(RewardTag, RewardCount)`.
Custom Processor Milestones	empty	Per-level reward processor class.
Convert Overflow XP To Currency	false	Enables overflow conversion at max level.
Overflow Currency Tag	none	Tag sent with the conversion event.
Overflow Conversion Multiplier	10.0	Currency = max(1, round(XP × multiplier)).

Formulaic curve

XP required = round( FormulaBaseXP × Level ^ FormulaExponent × FormulaMultiplier )   (minimum 1)

With defaults, level 1 needs 120 XP and level 10 needs about 3,795 XP. No XP is required at or beyond Max Level.

Ascension System

Ascension lets you gate progression behind a player action (materials, quest, boss). Enable Use Ascension System and define caps:

AscensionLevelCaps = [20, 40, 50]   // Phase 1 cap 20, Phase 2 cap 40, Phase 3 cap 50

The player levels normally until they hit the cap; surplus XP stays banked.
Your game verifies the cost, then calls Ascend() on the server.
The phase increases, OnAscendedDelegate fires, and any banked XP continues leveling.

Use CanAscend() to enable your Ascend button, and GetLevelStatus() to show ascension locks on a level map.

Rewards & Processors

Reward milestones

Add entries to Reward Milestones with a target level and a list of reward items (Gameplay Tag + count). When the level is reached, OnRewardsProcessedDelegate broadcasts the items so your game can grant them.

Custom reward processors

For custom logic, subclass UAMLSLevelUpRewardProcessor (in C++ or Blueprint) and register it under Custom Processor Milestones for the desired level.

Override the Blueprint event On Process Reward Tags, or the C++ virtual NativeProcessTag.
Target System ID on the processor must match the data asset's System ID (set to None to accept all).
The target Actor must implement IAMLSLevelableInterface, otherwise the call is skipped with a warning.
Processor instances are cached per class by the component.

// C++
class UMyRewardProcessor : public UAMLSLevelUpRewardProcessor
{
protected:
    virtual void NativeProcessTag(AActor* Target, const TArray<FAMLSLevelRewardItem>& Items, int32 Level) override;
};

Levelable Interface (`IAMLSLevelableInterface`)

Implement on Actors that should receive callbacks. Blueprint-implementable.

Function	Description
GetLevelComponent()	Return the Actor's `UAMLSLevelComponent`.
OnLevelUp(NewLevel)	Called on level-up: apply stats, heal, unlock content.

Events (Delegates)

Event	Parameters	Fires when
OnLevelUpDelegate	NewLevel, Owner	A level is gained (also on clients when level replicates).
OnXPChangedDelegate	CurrentXP, XPToNextLevel, Percent	XP or level changes; also on BeginPlay.
OnRewardsProcessedDelegate	LevelAchieved, Rewards, Owner	A level with rewards or a processor is reached.
OnOverflowXPConvertedDelegate	WastedXP, CurrencyEarned, CurrencyTag, Owner	XP is earned at max level with conversion enabled.
OnAscendedDelegate	NewAscensionPhase, Owner	The ascension phase changes.

Save & Load

FAMLSProgressionSaveData contains SavedLevel, SavedXP, SavedAscensionPhase and is tagged SaveGame. Store it in your SaveGame object.

// Save
SaveObj->Progression = LevelComp->GetProgressionSaveData();
// Load (server)
LevelComp->LoadProgressionSaveData(SaveObj->Progression);

On load, values are validated against the current caps and pending XP is processed.

Multiplayer & Replication

All state-changing functions run on the server only.
CurrentLevel, CurrentXP and CurrentAscensionPhase replicate to clients with RepNotify, which re-fires the matching delegates for UI.
Reward processing and overflow conversion happen on the server; replicate resulting items through your own systems.

Notes

The component sets bCanEverTick = false, so there is no per-frame cost.
Reward tags such as Reward.Stat must exist in your project's Gameplay Tags.
Reward and processor milestones are matched by exact level number.