UE5-Modular-Game-Framework/docs/game/atmosphere-audio.md

Atmosphere & Audio — Horror Environment Systems

Game: Project Void | Build Phases: 14, 16, 17, 18 Framework Systems: 89-101 (adaptive) + 132-135 (MetaSounds audio), 96_BPC_LightEventController, 97_BPC_MemoryDriftSystem, 98_BPC_PacingDirector, 101_BPC_ScareEventSystem

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Purpose

Defines every atmosphere profile, scare event, light event, room audio zone, and adaptive environment system used to create the horror experience. This is where the game's "feel" comes from.

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Atmosphere Profiles (DA_AtmosphereProfile)

Each area has a Data Asset that defines its default audio, lighting, fog, and post-process settings:

Profile	Area	Tension	Lighting	Audio Bus	Fog
DA_Atmosphere_WardA_Standard	WardA	0.3	Dim overheads, cool blue	WardA reverb	Light volumetric
DA_Atmosphere_WardB_Dark	WardB	0.6	Flickering, warm amber	WardB echo	Medium volumetric
DA_Atmosphere_Basement_Dark	Basement	0.9	NONE (player-provided)	Heavy reverb, drips	Heavy fog
DA_Atmosphere_VoidSpace	Void	1.0	Inverted (dark fog, white shadows)	Reversed whispers	Black fog
DA_Atmosphere_WardensOffice	WardensOffice	0.7	Single desk lamp, moonlight	Quiet, ticking clock	None
DA_Atmosphere_SafeRoom	Safe Rooms	0.0	Warm, steady lamp light	Soft hum, safe	None

Profile Properties

DA_AtmosphereProfile Structure:
  ├─ ProfileTag (GameplayTag)
  ├─ TensionLevel (Float 0.0-1.0)
  ├─ LightingSettings (struct)
  │    ├─ bOverrideLights (Bool)
  │    ├─ LightColorTint (LinearColor)
  │    ├─ LightIntensityMultiplier (Float)
  │    └─ bEnableFlicker (Bool)
  ├─ FogSettings (struct)
  │    ├─ FogDensity (Float)
  │    ├─ FogColor (LinearColor)
  │    └─ bVolumetricFogEnabled (Bool)
  ├─ PostProcessSettings
  │    ├─ ColorGradingIntensity (Float)
  │    ├─ Saturation (Float 0.0-2.0)
  │    ├─ Contrast (Float 0.0-2.0)
  │    └─ VignetteIntensity (Float)
  ├─ AudioSettings
  │    ├─ RoomAcousticPreset (DA_RoomAcousticPreset*)
  │    ├─ AmbientLoop (SoundBase*)
  │    ├─ MusicTrack (SoundBase*)
  │    └─ BusVolumeOverrides (Map<BusTag, Float>)
  └─ ScareEventPool (Array<DA_ScareEvent*>)

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Audio Architecture (MetaSounds)

Mix Bus Hierarchy

                      ┌─────────────┐
                      │ MS_MasterBus │
                      └──────┬──────┘
           ┌─────────┬───────┼───────┬─────────┐
           ▼         ▼       ▼       ▼         ▼
      ┌────────┐ ┌──────┐ ┌──────┐ ┌──────┐ ┌────────┐
      │MS_SFXBus│ │MS_Amb│ │MS_Mus│ │MS_Dia│ │(Future)│
      │         │ │Bus   │ │Bus   │ │Bus   │ │        │
      └────────┘ └──────┘ └──────┘ └──────┘ └────────┘
         SFX      Ambience  Music   Dialogue

Bus Configuration (DA_AudioSettings_Horror)

Bus	Default Volume	Ducking Target	Ducking Amount	Purpose
MS_SFXBus	1.0	MS_DialogueBus	-6dB	Gunshots, footsteps, scares, UI
MS_AmbientBus	0.8	MS_DialogueBus	-3dB	Wind, creaks, drips, whispers
MS_MusicBus	0.7	MS_DialogueBus	-8dB	Tension drones, combat music, theme
MS_DialogueBus	1.0	None	—	VO, subtitles, entity speech

Gameplay Parameters (Pushed via SS_AudioManager)

SS_AudioManager.SetFloatParameter(ParamName, Value):

  "PlayerHealthPercent"    → 0.0–1.0 (BPC_HealthSystem)
      └─ MS_SFXBus: heartbeat loudness, breathing intensity
  
  "StressTier"             → 0–4 (BPC_StressSystem)
      └─ MS_AmbientBus: whisper density, drone intensity
      └─ MS_MusicBus: tension layer volume
  
  "HeartRate"              → 60–180 (BPC_StateManager)
      └─ MS_SFXBus: heartbeat speed, pulse intensity
  
  "FearIntensity"          → 0.0–1.0 (GI_HorrorGame)
      └─ MS_MusicBus: orchestral intensity, dissonance level
  
  "TensionLevel"           → 0.0–1.0 (BPC_AtmosphereStateController)
      └─ MS_AmbientBus: ambient layer crossfade
      └─ MS_MusicBus: music layer selection
  
  "PlayerSpeed"            → 0–600 (BPC_MovementStateSystem)
      └─ MS_SFXBus: footstep volume and frequency
  
  "IsHiding"               → 0/1 (BPC_HidingSystem)
      └─ MS_AmbientBus: muffled external sounds
      └─ MS_SFXBus: heartbeat + breath prominence increase
  
  "VoidActive"             → 0/1 (GS_HorrorGameState)
      └─ ALL buses: spectral reverb, reversed samples, pitch shift

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Room Audio Zones (BP_RoomAudioZone)

Each zone is a TriggerVolume that switches acoustic preset on overlap:

Zone	Preset	Location
BP_RoomAudioZone_WardA	DA_RoomAcoustic_WardA	All WardA rooms
BP_RoomAudioZone_WardB	DA_RoomAcoustic_WardB	All WardB rooms
BP_RoomAudioZone_Basement	DA_RoomAcoustic_Basement	Basement corridors
BP_RoomAudioZone_Void	DA_RoomAcoustic_Void	Void space
BP_RoomAudioZone_Courtyard	DA_RoomAcoustic_Outdoor	WardB courtyard
BP_RoomAudioZone_SafeRoom	DA_RoomAcoustic_SmallRoom	All safe rooms

Acoustic Presets

Preset	Reverb Time	Early Reflections	Occlusion	EQ
DA_RoomAcoustic_WardA	1.2s (medium hall)	Moderate	Low	Flat
DA_RoomAcoustic_WardB	2.0s (large echo)	Heavy	Medium	Boost 200Hz
DA_RoomAcoustic_Basement	3.5s (cathedral)	Heavy wet	High	Cut highs above 4kHz
DA_RoomAcoustic_Void	8.0s (infinite)	Spectral	Full	Reverse delay
DA_RoomAcoustic_Outdoor	0.3s (open)	None	None	Wind filter
DA_RoomAcoustic_SmallRoom	0.5s (office)	Light	Low	Warm boost

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Scare Event System (BPC_ScareEventSystem)

Scare Event Data Assets

DA_ScareEvent	Type	Trigger	Anticipation	Payoff
DA_Scare_LockerJumpscare	Proximity	Player within 200u of locker	3s (rattling sound)	Locker door BANG open
DA_Scare_MirrorApparition	Look-at	Player looks at mirror > 2s	5s (reflection distorts)	Face appears behind player
DA_Scare_WindowFace	Proximity	Player walks past window	2s (breath fog on glass)	Hand SLAMS from outside
DA_Scare_VoidWhisper	Random timer	5-15 min intervals	None (sudden)	Loud whisper in player's ear
DA_Scare_CeilingThump	Proximity	Player in basement corridor	4s (distant footsteps above)	Loud THUMP directly above
DA_Scare_BreathingBehind	Stress trigger	Stress > 70	6s (breathing fades in behind)	Nothing there — just audio

Scare Event Flow

BPC_ScareEventSystem.TriggerScare(DA_ScareEvent)
   │
   ├─ [Cooldown Check]
   │    └─ Was a scare triggered in last 15 seconds? → Return (no spam)
   │
   ├─ [Eligibility Check]
   │    ├─ Player state allows scare? (Not dead, not cutscene)
   │    ├─ Accessibility: "reduce_jumpscares" setting? → use soft variant
   │    └─ Difficulty: scale intensity by difficulty scalar
   │
   ├─ [Anticipation Phase] (duration from DA_ScareEvent.AnticipationTime)
   │    ├─ Audio: fade in tension sound (creaking, breathing, footsteps)
   │    ├─ BPC_StressSystem.AddStress(+5) during anticipation
   │    ├─ WBP_ScreenEffectController: subtle vignette darkening
   │    └─ (Player is tense — they know something is coming)
   │
   ├─ [Payoff Phase] (instant)
   │    ├─ Audio: scare sting (loud sound per scare type)
   │    ├─ Visual: screen shake, flash, or particle burst
   │    ├─ BPC_StressSystem.AddStress(+15) — spike
   │    ├─ SS_AudioManager.PlaySFX(ScareSting)
   │    └─ BPC_PlayerMetricsTracker.RecordScare(ScareType)
   │
   ├─ [Recovery Phase] (3-5 seconds)
   │    ├─ Audio: fade scare sting, return to ambient
   │    ├─ Visual: vignette fades back
   │    ├─ BPC_StressSystem.StartDecay() (5 seconds of rapid decay)
   │    └─ WBP_HUDController: subtle "heartbeat" indicator pulse
   │
   └─ Record scare in PS_HorrorPlayerState.FearHistory

---

Light Events (BPC_LightEventController)

Light Event	Trigger	Effect	Duration
Flicker	Random (5-15 min intervals)	All lights flicker 3-5 times	1-2s
BulbExplosion	Scripted (basement morgue)	Light bulb bursts → sparks → darkness	Permanent
EmergencyRed	Void shift active	All lights tint red, strobe effect	30s
ShadowPass	Random (3-8 min intervals)	Shadow passes across lights (like something walked past)	0.5s
TotalBlackout	Scripted (basement entry)	All lights off. Flashlight-only.	Until generator puzzle solved
GhostLight	Rare event	Blue-white orb floats down hallway → vanishes	5s

Light Event Flow

BPC_LightEventController.TriggerLightEvent(LightEventTag)
   │
   ├─ [Flicker]
   │    ├─ For each PointLight in tagged group:
   │    │    └─ Random Delay(0.1-0.4s) → ToggleVisibility × 4 iterations
   │    └─ SS_AudioManager.PlaySFX("light_flicker")
   │
   ├─ [BulbExplosion]
   │    ├─ Target Light → SetIntensity(0) + Play spark particle
   │    ├─ SS_AudioManager.PlaySFX("glass_shatter")
   │    └─ Room now darker → update atmosphere profile
   │
   ├─ [TotalBlackout]
   │    ├─ All lights → SetIntensity(0) over 1s (smooth dim)
   │    ├─ SS_AudioManager.CrossfadeAmbient("basement_dark")
   │    └─ BPC_StressSystem.StartContinuousStress(+2/sec, "Darkness")
   │
   └─ [ShadowPass]
        ├─ Spawn invisible actor moving across lights
        └─ Light shafts briefly occluded

---

Memory Drift System (BPC_MemoryDriftSystem)

Hallucinations triggered by high stress. Intensity scaled by stress tier:

BPC_MemoryDriftSystem.SetIntensity(Tier: 0-4)
   │
   ├─ Tier 0 (Calm):         No effects
   │
   ├─ Tier 1 (Uneasy):       Very rare whisper audio cues
   │
   ├─ Tier 2 (Disturbed):    Peripheral vision flickers
   │                          Occasional false sound cues
   │                          Text in journal shifts subtly
   │
   ├─ Tier 3 (Breaking):     Tunnel vision + desaturation
   │                          False enemy movement (corner of eye)
   │                          Dialogue lines sometimes echo/repeat
   │                          Environment "breathes" (wall textures warp)
   │
   └─ Tier 4 (Catatonic):    Near-black peripheral vision
                              False enemies appear (visual only)
                              Player name whispered in audio
                              Doors appear where none exist (can't walk through)
                              Text unreadable (shifts rapidly)

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Pacing Director (BPC_PacingDirector)

Manages the rhythm of horror: exploration → tension → encounter → recovery.

Intensity Bands:
  ├─ Band 0: RECOVERY (Safe rooms, after encounter ends)
  │    └─ Atmosphere: Calm, music: soft, enemies: none
  │
  ├─ Band 1: EXPLORATION (Default, new areas)
  │    └─ Atmosphere: Light tension, music: low drone, enemies: patrol only
  │
  ├─ Band 2: TENSION (Near objectives, dark areas)
  │    └─ Atmosphere: Moderate tension, music: building, enemies: searching
  │
  ├─ Band 3: ENCOUNTER (Enemy sighted, combat)
  │    └─ Atmosphere: High tension, music: combat layer, enemies: hostile
  │
  └─ Band 4: CLIMAX (Void shift, Shade pursuit, ending)
       └─ Atmosphere: Maximum, music: full orchestral, enemies: relentless

Transition Triggers:
  ├─ Recovery → Exploration: Player leaves safe room
  ├─ Exploration → Tension:   Player enters dark area OR finds key item
  ├─ Tension → Encounter:     Enemy spots player
  ├─ Encounter → Recovery:    Enemy killed/evaded + 10 seconds passed
  └─ Recovery → Climax:       Entering void space or ending sequence

---

Adaptive Environment Director (BPC_AdaptiveEnvironmentDirector)

Handles room mutations and dynamic level changes:

TriggerRoomMutation(MutationTag)
   │
   ├─ "VoidShift" → WardB Morgue
   │    ├─ Walls: temporary overlay material (bleeding concrete)
   │    ├─ Corridors: loop — walking forward returns to same room
   │    ├─ Doors: random open/close cycle
   │    ├─ Audio: crossfade to void ambience
   │    └─ Duration: 30 seconds, then revert
   │
   ├─ "BasementMaze" → Basement
   │    ├─ Doors randomize their locked/unlocked state every 60s
   │    └─ Player must navigate changing maze
   │
   └─ "VoidSpaces" → Void level
        ├─ Rooms rearrange via data layers (swap layout presets)
        ├─ Triggered on player entering new room
        └─ Creates non-Euclidean navigation

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Blueprint Wiring Checklist

Atmosphere

• Create all 6 DA_AtmosphereProfile Data Assets
• Wire BPC_AtmosphereStateController.LoadProfile() to apply on level load
• Add BP_AtmosphereController_WardA actor to WardA level

Audio

• Create DA_AudioSettings_Horror — bus volumes, ducking rules
• Create all 6 DA_RoomAcousticPreset Data Assets
• Create BP_RoomAudioZone_* TriggerVolumes for each area
• Wire gameplay parameters: BPC_HealthSystem → "PlayerHealthPercent", etc.
• Set up SS_AudioManager with 4 MetaSound buses

Scares

• Create 6 DA_ScareEvent Data Assets
• Wire BPC_ScareEventSystem.TriggerScare() with cooldown + eligibility checks
• Create BP_ScareEvent_LockerBang and BP_ScareEvent_Mirror actors

Lights

• Wire BPC_LightEventController with 6 light event types
• Create BP_LightEvent_Flicker actor for placed flicker points

Memory Drift

• Wire BPC_MemoryDriftSystem.SetIntensity() to stress tier changes
• Add visual effects for each tier (vignette, texture warp, false actors)

Pacing

• Wire BPC_PacingDirector with 5 intensity bands
• Add transitions: area entry/exit, enemy detection, safe room entry

Adaptive Environment

• Wire BPC_AdaptiveEnvironmentDirector for void shift + basement maze
• Create data layers for swappable room layouts in void space

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Notes for Expansion

• Add dynamic music system: adaptive music that layers stems based on tension/pacing band
• Add environmental storytelling through audio: ghostly voices re-enacting past events
• Add weather system: external rain sounds through windows (only in courtyard-facing rooms)
• Add binaural audio (3D sound) support for headphones — whispers sound like they're behind you
• Add haptic profile (DA_HapticProfile) for DualSense: heartbeat pulse, gunshot kick, floor rumble
• Add room mutation presets as DA_RoomMutation Data Assets for designers to configure
• Consider performance scaling of audio: fewer simultaneous voices on lower-end hardware

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Atmosphere & Audio for Project Void. See GAMEINDEX.md for full game structure. See metasounds-audio-system.md for audio architecture. See sound-catalog.md for full sound trigger list.