Introduction and System Architecture

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The Multiplayer Shooter System (MSS) is a modular framework based on components (Component-Based Architecture) designed to implement replicated shooting mechanics in Unreal Engine 5.

The system resides in Content/DMD/Blueprints/Components/Shooter_System/. Its design centralizes all combat logic into a single component, decoupling mechanics from the Pawn to allow implementation in Characters, Vehicles, or Turrets via composition.

"A flow diagram where the BPC_Shooter_System is at the center. It receives inputs from the Player Controller. It controls the BP_Weapon_Master, and the system communicates with the Animation Blueprint via Interfaces."

1. Core: BPC_Shooter_System

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The heart of the system is the Actor Component 🟦 BPC_Shooter_System. This component acts as the main state manager and does not require inheritance in the character class.

Its core responsibilities are:

Input Management: Processes actions from the 🟦 IMC_Shooter context (Fire, Reload, Weapon Swap).
State Machine: Manages complex modes like Throwing (Grenades), Reloading, or WallBlocked.
Network Validation: Executes authoritative logic on the server to validate ammo and hits, replicating visual effects (Cosmetics) to clients.

2. Actor Polymorphism

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The system automatically adapts its behavior based on the variable 🟩 Actor_Type (based on the enumerator 🟨 ENU_Actor_Type). This divides the architecture into two flows:

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A. Characters (Humanoids)

Enables advanced infantry logic:

Light Weapons (LW): Interactable weapons with physics.
Holster System: Uses child actors 🟦 BP_Holster_Socket to visualize weapons on the body.
Wall Detection: Sphere tracing that detects collisions with the environment and procedurally raises the weapon.
Animation: Integration via Linked Anim Layer 🟦 ABP_Overlay_Shooter. </aside>

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B. Vehicles / Pawns (Machinery)

Enables simplified logic for mechanical units:

Heavy Weapons (HW): Fixed weapons integrated into the chassis.
Static Inventory: No pickup logic (Pickup) or human animations. </aside>

3. Weapon Architecture

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The arsenal uses a strict class hierarchy derived from 🟦 BP_Weapon_Master, avoiding Data Tables for logic.

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A. Light Weapons (LW)

Children of 🟦 BP_LW_Master. Designed for characters.

Optimized Physics: Simulates real physics only when in the world (without an Owner). Upon touching the ground, they disable simulation (Sleep) to save performance.
Interaction: Logic to be picked up and equipped to the socket 🟩 Weapon_TPS (Right Hand).
IK Hand Left: Uses a visual billboard named 🟩 IK_Hand_Left within the Blueprint to define the left hand's position without adjusting numeric coordinates. </aside>

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B. Heavy Weapons (HW)

Children of 🟦 BP_HW_Master. Designed for vehicles.

Function as fixed components with no physical inventory or wall collision. </aside>

4. Ballistics and Feedback

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The firing system manages two types of projectiles:

Physical: Actors derived from 🟦 BP_Projectile_Master (Collision channel Projectile). They manage their own damage and impact VFX.
HitScan: Immediate tracing for lasers (Collision channel Laser). </aside>

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User Interface (UI)

Visual feedback is centralized in the widget 🟦 WBP_Shooter_Hud.

Manages the Dynamic Crosshair (🟦 WBP_Crosshair_Master), whose spread is calculated via a dispersion alpha (Current_Dispersion) based on movement and firing. </aside>

5. Modular Integration

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The MSS communicates with external systems exclusively via interfaces to avoid direct dependencies:

Locomotion: Via 🟨 BPI_Locomotion, it receives the movement state (from MLS or GASP) to adapt upper body animation layers.
Targets: Via 🟨 BPI_Target, it queries the actor's identity (Ally/Enemy) to manage Friendly Fire and Crosshair color.