70 — BPC_ProceduralEncounter

Blueprint Spec — UE 5.5–5.7

Parent Class

ActorComponent

Dependencies

BPC_DifficultyManager — Encounter difficulty scaling
BPC_FearSystem — Fear-based encounter intensity
BPC_AtmosphereController — Atmosphere-aligned encounters
BP_DynamicEvent — Encounter as dynamic event
DA_EncounterTable — Encounter data tables (Phase 12)
I_Damageable — Enemy damage integration
AI_EnemyBase — Enemy AI controller
BP_EnemyBase — Enemy pawn reference

Purpose

Procedurally generates enemy encounters, ambushes, and spawn events based on player state, difficulty, fear level, atmosphere, and narrative progression. Operates as a tactical encounter director that decides when, where, and what enemies to spawn, how they behave, and when to retreat or reinforce. Prevents encounter fatigue by managing cooldowns, variety, and pacing. Supports wave-based encounters, ambushes, patrol reinforcement, and boss encounters.

Enums

EEncounterType

Value	Description
Patrol	Wandering enemy, player can evade
Ambush	Pre-placed enemies triggered by player
WaveBased	Multiple waves of increasing difficulty
Reinforcement	Enemies called in during combat
Boss	Single powerful enemy
Escalation	Increasing intensity until player leaves area
Environmental	Hazard-based encounter (not enemies)
Scripted	Level designer placed encounter

ESpawnMethod

Value	Description
FromLocations	Use pre-placed spawn points
FromNavMesh	Random point on nav mesh
FromVolumes	Spawn in volume bounds
FromPortals	Enemy emerges from gate/door
FromVent	Spawn at vent locations
CeilingDrop	Enemy drops from above
ClosestNav	Closest valid nav point to player

EEncounterIntensity

Value	Description
Low	1–2 weak enemies
Moderate	2–3 standard enemies
High	3–5 mixed enemies
Critical	5+ enemies with elites
Boss	Single boss enemy

Structs

FEncounterSpawnSlot

Field	Type	Description
SpawnLocation	FVector	World position
EnemyClass	TSubclassOf<BP_EnemyBase>	Enemy to spawn
SpawnDelay	Float	Delay before this enemy appears
bDropIn	Bool	Animated drop-in
SpawnEffect	UNiagaraSystem	Visual spawn effect
PatrolRouteIndex	Int32	Patrol path to follow

FEncounterWave

Field	Type	Description
WaveName	FName	Identifier
SpawnSlots	TArray<FEncounterSpawnSlot>	Enemies in this wave
ActivationDelay	Float	Time before wave starts
bWaitForAllDead	Bool	Next wave waits for all dead
DifficultyMultiplier	Float	Wave-specific difficulty
DialogueTrigger	FName	Optional dialogue on wave start

Variables

Name	Type	Description
`ActiveEncounterType`	EEncounterType	Current encounter type
`EncounterState`	FName	Active, Cooldown, Completed
`bPlayerInEncounterZone`	Bool	Player proximity trigger
`EncounterRadius`	Float	Zone size
`MinEnemyDistance`	Float	Min distance from player to spawn
`MaxConcurrentEnemies`	Int32	Hard limit on active enemies
`ActiveEnemies`	TArray<BP_EnemyBase>	Currently alive enemies
`Waves`	TArray<FEncounterWave>	Defined waves
`CurrentWaveIndex`	Int32	Active wave
`bWaveInProgress`	Bool	Currently executing wave
`CooldownRemaining`	Float	Encounter cooldown
`MinCooldown`	Float	Min time between encounters
`MaxCooldown`	Float	Max time between encounters
`EncounterCount`	Int32	Encounters this session
`MaxEncountersPerZone`	Int32	Encounters before exhaustion
`bZoneExhausted`	Bool	No more encounters in this zone
`SpawnLocations`	TArray<FEncounterSpawnSlot>	Configured spawn points
`bUseNavMesh`	Bool	Use nav mesh for spawns
`EncounterVolumeBox`	FBox	Spawn volume bounds

Functions

Name	Inputs	Outputs	Description
`Initialize`	—	—	Register spawn points, validate setup
`TriggerEncounter`	Type: EEncounterType, Intensity: EEncounterIntensity	—	Start encounter
`TriggerWaveBasedEncounter`	Intensity: EEncounterIntensity	—	Multi-wave encounter
`SpawnWave`	WaveIndex: Int32	—	Execute wave spawning
`SpawnSingleEnemy`	Slot: FEncounterSpawnSlot	BP_EnemyBase	Spawn one enemy
`GetRandomSpawnLocation`	—	FVector	Pick valid spawn point
`GetSpawnLocationByMethod`	Method: ESpawnMethod	FVector	Contextual spawn position
`OnEnemyKilled`	Enemy: BP_EnemyBase	—	Track enemy death
`OnAllEnemiesDead`	—	—	Wave completed or encounter ended
`ReinforceEncounter`	Count: Int32	—	Spawn additional enemies
`EndEncounter`	—	—	Cleanup and cooldown
`RetreatEnemies`	—	—	All enemies flee
`CalculateIntensity`	—	EEncounterIntensity	Based on difficulty + fear + atmosphere
`IsSpawnLocationValid`	Location: FVector	Bool	Check line of sight, nav mesh
`IsInEncounterZone`	PlayerLocation: FVector	Bool	Proximity check
`StartCooldown`	—	—	Begin cooldown timer
`ExhaustZone`	—	—	Mark zone as depleted
`ResetEncounter`	—	—	Full reset for reuse

Blueprint Flow

[Initialize]
  └─► Register spawn point locations from child actors or volume
  └─► If bUseNavMesh:
         Get nav mesh bounds from EncounterVolumeBox
  └─► Listen for player proximity via overlap events
  └─► Set initial EncounterState = Ready

[TriggerEncounter]
  └─► If CooldownRemaining > 0 or bZoneExhausted: return
  └─► EncounterState = Active
  └─► ActiveEncounterType = Type
  └─► CalculateIntensity()
  └─► Based on Type:
         Patrol:       Spawn 1-2 patrol enemies, set patrol routes
         Ambush:       All enemies spawn at once, no delay, trigger dialogue
         WaveBased:    TriggerWaveBasedEncounter(Intensity)
         Reinforcement: Spawn 1-3 enemies near existing combat
         Boss:         Spawn single boss enemy, lock area
         Escalation:   Start wave timer, spawn escalating until retreat or all dead
         Environmental: Trigger hazard events instead of enemies
         Scripted:     Execute designer-defined encounter
  └─► Broadcast OnEncounterStarted

[TriggerWaveBasedEncounter]
  └─► CurrentWaveIndex = 0
  └─► For each wave in Waves:
         Wave.DifficultyMultiplier = Get difficulty scale from BPC_DifficultyManager
         Apply difficulty scaling to each enemy class
  └─► SpawnWave(0)

[SpawnWave]
  └─► bWaveInProgress = true
  └─► For each FEncounterSpawnSlot in Waves[WaveIndex].SpawnSlots:
         Delay(SpawnSlot.SpawnDelay)
         SSpawnSingleEnemy(SpawnSlot)
  └─► If Waves[WaveIndex].DialogueTrigger:
         Trigger dialogue via BPC_DialoguePlayback

[SpawnSingleEnemy]
  └─► SpawnLocation = Slot.SpawnLocation
  └─► If Slot.SpawnLocation == ZeroVector:
         SpawnLocation = GetSpawnLocationByMethod(FromLocations or FromNavMesh)
  └─► If not IsSpawnLocationValid(SpawnLocation): return
  └─► Enemy = SpawnActor Deferred(Slot.EnemyClass, SpawnLocation)
  └─► Set difficulty-scaled stats on Enemy:
         Health *= DifficultyManager.HealthMultiplier
         Damage *= DifficultyManager.DamageMultiplier
         Speed *= DifficultyManager.SpeedMultiplier
  └─► If Slot.PatrolRouteIndex >= 0:
         Assign patrol path to enemy
  └─► FinishSpawning(Enemy)
  └─► If Slot.bDropIn:
         Play drop-in animation on Enemy
  └─► If Slot.SpawnEffect:
         UNiagaraFunctionLibrary::SpawnSystemAtLocation
  └─► Bind OnEnemyKilled to Enemy.OnDestroyed
  └─► ActiveEnemies.Add(Enemy)

[OnEnemyKilled]
  └─► ActiveEnemies.Remove(Enemy)
  └─► Add to MetricsTracker for scoring
  └─► If ActiveEnemies.Num() == 0:
         OnAllEnemiesDead()
  └─► If EncounterState == Active and ActiveEncounterType == Escalation:
         CalculateIntensity()
         If should escalate:
              SpawnWave more enemies
         If should de-escalate:
              RetreatEnemies()

[OnAllEnemiesDead]
  └─► If ActiveEncounterType == WaveBased:
         CurrentWaveIndex++
         If CurrentWaveIndex < Waves.Num():
              SpawnWave(CurrentWaveIndex)
         Else:
              EndEncounter()
  └─► Else:
         EndEncounter()

[EndEncounter]
  └─► EncounterState = Completed
  └─► EncounterCount++
  └─► If EncounterCount >= MaxEncountersPerZone:
         ExhaustZone()
  └─► Else:
         StartCooldown(MinCooldown, MaxCooldown)
  └─► Broadcast OnEncounterEnded
  └─► Reward player via BPC_PlayerMetricsTracker

[CalculateIntensity]
  └─► Base intensity from BPC_DifficultyManager.CurrentDifficulty
  └─► Multiply by BPC_FearSystem.CurrentFearLevel factor (0.5 at Calm, 2.0 at Panic)
  └─► Adjust by BPC_AtmosphereController.CurrentState:
         Exploration: *0.5 (fewer enemies)
         Suspense:    *1.0 (standard)
         Combat:      *2.0 (more enemies)
         Panic:       *1.5 (intense but fewer than combat)
  └─► Clamp to EEncounterIntensity range
  └─► Return

[GetSpawnLocationByMethod]
  └─► FromLocations: Pick random from SpawnLocations array
  └─► FromNavMesh: Query UNavigationSystemV1::GetRandomPointInNavigableRadius
         Ensure distance from player >= MinEnemyDistance
  └─► FromVolumes: Random point within EncounterVolumeBox
         Project to nav mesh
  └─► FromPortals: Pre-placed portal actor locations
  └─► FromVent: Vent location list
  └─► CeilingDrop: Above player location + random offset
         Ensure valid nav mesh below

[IsSpawnLocationValid]
  └─► Check distance from player >= MinEnemyDistance
  └─► Line trace from player to spawn location:
         If blocked and distance < 500: location is behind obstacle, valid (ambush)
         If clear and distance < 500: location is visible, valid for patrol
         If distance > 2000: always valid
  └─► Check nav mesh projection is valid
  └─► Check not overlapping existing enemies

Event Dispatchers

Name	Payload	Description
`OnEncounterStarted`	EncounterType: EEncounterType, Intensity: EEncounterIntensity	Encounter began
`OnEncounterEnded`	bPlayerSurvived: Bool, EnemiesKilled: Int32	Encounter finished
`OnWaveStarted`	WaveIndex: Int32, WaveName: FName	New wave beginning
`OnWaveCompleted`	WaveIndex: Int32	Wave cleared
`OnEnemySpawned`	Enemy: BP_EnemyBase	Individual enemy spawned

Communications With

Target	Method	Why
`BPC_DifficultyManager`	Direct call	Difficulty scaling for encounter
`BPC_FearSystem`	Get owner	Fear influence on intensity
`BPC_AtmosphereController`	Get owner	Atmosphere alignment
`BP_DynamicEvent`	Cast	Encounter as dynamic event
`AI_EnemyBase`	On spawned	Set encounter-aware behaviors
`BP_EnemyBase`	On spawned	Set difficulty-scaled stats
`BPC_PlayerMetricsTracker`	Event	Encounter scoring
`BPC_NarrativeState`	Event	Narrative-gated encounters
`BPC_DialoguePlayback`	Event	Wave-start dialogue

Reuse Notes

Place BPC_ProceduralEncounter on a volume actor or game mode
Configure spawn points as child actors or arrays in details panel
Encounter exhaustion prevents infinite grinding in one area
Difficulty + Fear + Atmosphere combine to produce dynamic intensity
Nav mesh spawning ensures enemies always have valid pathfinding
Encounter state machine: Ready -> Active -> Cooldown -> Exhausted
All encounters work with or without pre-placed spawn locations
Each enemy spawned gets difficulty-scaled stats at spawn time

12 KiB Raw Blame History Unescape Escape