version: "1.0.1" name: godot-genre-horror description: "Expert blueprint for horror games including tension pacing (sawtooth wave: buildup/peak/relief), Director system (macro AI controlling pacing), sensory AI (vision/sound detection), sanity/stress systems (camera shake, audio distortion), lighting atmosphere (volumetric fog, dynamic shadows), and \"dual brain\" AI (cheating director + honest senses). Use for psychological horror, survival horror, or atmospheric games. Trigger keywords: horror_game, tension_pacing, director_system, sensory_perception, sanity_system, volumetric_fog, AI_reaction_time."

Genre: Horror

Expert blueprint for horror games balancing tension, atmosphere, and player agency.

NEVER Do (Expert Anti-Patterns)

Atmosphere & Tension

• NEVER maintain 100% tension at all times; strictly use a Sawtooth Pacing model (buildup → peak/scare → dedicated relief period) to prevent player "numbing" and exhaustion.
• NEVER rely on jump-scares as the primary source of horror; focus on atmosphere, spatial audio cues, and the anticipation of a threat to build genuine dread.
• NEVER make environments pitch black to the point of frustrating navigation; darkness should obscure threats (details), not the floor. Use rim lighting or a limited-battery flashlight.
• NEVER grant the player unlimited resources; survival horror relies on Scarcity. Limited battery, rare ammo, and slow animations are mandatory to force stressful decision-making.

AI & Senses

• NEVER allow AI to detect the player instantly; implement a Suspicion Meter or a 1-3s reaction window before the AI enters full aggression to avoid "unfair cheating" feel.
• NEVER use predictable AI paths; an enemy on a perfect loop is a puzzle, not a predator. Use the Director to periodically "hint" a new destination near the player.
• NEVER use Area3D overlap signals for instant, frame-perfect Line-of-Sight (LoS) checks; use nodeless raycasting via PhysicsDirectSpaceState3D.intersect_ray() for fixed-physics sync.
• NEVER calculate complex AI vision or pathfinding for monsters far outside the camera's frustum; use VisibleOnScreenNotifier3D to disable processing logic.
• NEVER leave navigation avoidance layers unconfigured on chasing monsters; explicitly assign avoidance masks to prevent visual "stacking" in tight corridors.

Technical & Scarcity

• NEVER use the visual SceneTree (like GridContainer children) as the source of truth for inventory; strictly maintain a typed memory structure like Dictionary[StringName, Resource].
• NEVER rely on instantiating standard Nodes to store base item stats/definitions; use custom Resource scripts to reduce memory overhead and allow direct Inspector editing.
• NEVER forget to call duplicate(true) on an item's Resource when adding to inventory; if items have mutable states (ammo/durability), you will overwrite the global resource otherwise.
• NEVER parse massive JSON save files synchronously; strictly offload heavy parsing to the WorkerThreadPool to prevent auto-save freezes.
• NEVER use standard strings for hot-path IDs (states, item types); strictly use StringName (&"chasing") for pointer-speed comparisons.
• NEVER evaluate exact floating-point equality (sanity == 0.0); strictly use is_equal_approx() or threshold checks for deterministic triggers.
• NEVER write screen-reading shaders expecting Godot 3 SCREEN_TEXTURE; strictly use sampler2D with hint_screen_texture.
• NEVER instantiate detailed monster meshes or lights without culling; strictly configure visibility_range for automatic HLOD efficiency.
• NEVER rely on AnimationPlayer for random flickering; use Tween for programmatic, clean energy manipulation.
• NEVER load heavy scare scenes or 4K textures synchronously via load(); strictly use ResourceLoader.load_threaded_request() to prevent frame stalls.
• NEVER scale CollisionShape3D non-uniformly; strictly adjust internal shape resource parameters (radius, height) to prevent erratic physics.
• NEVER perform synchronous, heavy file I/O in a Safe Room; strictly use `Thread` and `Mutex` to handle background saving without stalling the main game thread.
• NEVER check for hiding spot types by casting; strictly use `Object` metadata (`set_meta`) for performant, decoupled AI queries.

🛠 Expert Components (scripts/)

Original Expert Patterns

• predator_stalking_ai.gd - Sophisticated "Stalker" AI using dual-brain logic (Director + Senses) and player view-cone avoidance.
• director_pacing.gd - Invisible orchestrator managing the "Sawtooth" tension wave and relief periods.

Modular Components

• monster_los_check.gd - Physics-synced raycasting for high-performance visibility checks.
• flashlight_flicker.gd - Procedural light interference for atmospheric tension.
• inventory_data_storage.gd - Typed data structure for sparse resource management.
• async_scare_loader.gd - Threaded resource loading for hitch-free jump-scares.
• spatial_noise_emitter.gd - Shape-based sound sensing for sensory AI.
• item_state_duplicator.gd - Deep duplication for managing unique weapon/item states.
• fog_claus_intensifier.gd - Volumetric fog manipulation for dread buildup.
• offscreen_logic_suspender.gd - Culling logic for AI processing outside camera view.
• sanity_shader_manager.gd - Instance-uniform driven distortion effects.
• optimized_horror_state_machine.gd - High-speed predator behavior logic.

Core Loop

1. Explore: Player navigates a threatening environment.
2. Sense: Player hears/sees signs of danger.
3. React: Player hides, runs, or fights (disempowered combat).
4. Survive: Player reaches safety or solves a puzzle.
5. Relief: Brief moment of calm before tension builds again.

Skill Chain

Architecture Overview

1. The Director System (Macro AI)

Controls the pacing of the game to prevent constant exhaustion.

# director.gd
extends Node
 
enum TensionState { BUILDUP, PEAK, RELIEF, QUIET }
var current_tension: float = 0.0
var player_stress_level: float = 0.0
 
func _process(delta: float) -> void:
    match current_tension_state:
        TensionState.BUILDUP:
            current_tension += 0.5 * delta
            if current_tension > 75.0:
                 trigger_event()
        TensionState.RELIEF:
            current_tension -= 2.0 * delta
 
func trigger_event() -> void:
    # Hints the Monster AI to check a room NEAR the player, not ON the player
    monster_ai.investigate_area(player.global_position + Vector3(randf(), 0, randf()) * 10)

2. Sensory Perception (Micro AI)

The monster's actual senses.

# sensory_component.gd
extends Area3D
 
signal sound_heard(position: Vector3, volume: float)
signal player_spotted(position: Vector3)
 
func check_vision(target: Node3D) -> bool:
    var space_state = get_world_3d().direct_space_state
    var query = PhysicsRayQueryParameters3D.create(global_position, target.global_position)
    var result = space_state.intersect_ray(query)
    
    if result and result.collider == target:
        return true
    return false

3. Sanity / Stress System

Distorting the world based on fear.

# sanity_manager.gd
func update_sanity(amount: float) -> void:
    current_sanity = clamp(current_sanity + amount, 0.0, 100.0)
    # Effect: Camera Shake
    camera_shake_intensity = (100.0 - current_sanity) * 0.01
    # Effect: Audio Distortion
    audio_bus.get_effect(0).drive = (100.0 - current_sanity) * 0.05

Key Mechanics Implementation

Pacing (The Sawtooth Wave)

Horror needs peaks and valleys.

1. Safety: Save room.
2. Unease: Strange noise, lights flicker.
3. Dread: Monster is known to be close.
4. Terror: Chase sequence / Combat.
5. Relief: Escape to Safety.

The "Dual Brain" AI

• Director (All-knowing): Cheats to keep the alien relevant (teleports it closer if far away, guides it to player's general area).
• Alien (Senses only): Honest AI. Must actually see/hear the player to attack.

3. Hiding-Spot Metadata System

Use decoupled Object metadata so AI can query state without knowing the class.

# hiding_spot.gd
func _ready():
    add_to_group("hiding_spots")
    set_meta("is_occupied", false)
 
# predator_ai.gd
func search_hiding_spots():
    for spot in get_tree().get_nodes_in_group("hiding_spots"):
        if spot.get_meta("is_occupied"):
            investigate(spot.global_position)

4. Adaptive Audio (Stress Muffling)

Dynamic low-pass filtering via AudioServer.

# audio_stress_manager.gd
func update_stress(fear_level: float):
    # Enable LPF effect on Master bus (index 0) if fear is high
    AudioServer.set_bus_effect_enabled(0, 0, fear_level > 0.5)
    # Attenuate volume linearly
    AudioServer.set_bus_volume_linear(0, 1.0 - (fear_level * 0.4))

5. Safe-Room Multithreaded Save

Use Thread and Mutex to prevent frame drops during checkpoint saves.

# safe_room.gd
var _save_thread: Thread = Thread.new()
var _mutex: Mutex = Mutex.new()
 
func trigger_save(data: Dictionary):
    _mutex.lock()
    if not _save_thread.is_alive():
        _save_thread.start(_do_save.bind(data.duplicate(true)))
    _mutex.unlock()
 
func _do_save(data):
    var file = FileAccess.open("user://save.dat", FileAccess.WRITE)
    file.store_var(data)
    file.close()

Godot-Specific Tips

• Volumetric Fog: Use WorldEnvironment -> VolumetricFog for instant atmosphere. Animate density for dynamic dread.
• Light Occluder 2D: For 2D horror, shadow casting is essential.
• AudioBus: Use Reverb and LowPassFilter on the Master bus, controlled by scripts, to simulate "muffled" hearing when scared or hiding.
• AnimationTree: Use blend spaces to smooth transitions between "Sneak", "Walk", and "Run" animations.

Common Pitfalls

1. Constant Tension: Player gets numb. Fix: Enforce "Relief" periods where nothing happens.
2. Frustrating AI: AI sees player instantly. Fix: Give AI a "reaction time" or "suspicion meter" before full aggro.
3. Too Dark: Player can't see anything. Fix: Darkness should obscure details, not navigation. Use rim lighting or a weak flashlight.

Reference

• Master Skill: godot-master