V4 — Architecture (Page Index) — Tactical Action

This directory holds the V4 (a UE5 tactical-action universe of multiple game-style "cells" — tactical FPS, stealth, action-RPG, RTS, 2D run-and-gun — on a shared engine) architecture reference, decomposed from the single ../V4_ARCHITECTURE.md hub into focused, in-depth, code-grounded pages. The hub remains the canonical entry point and preserves every section heading; each page below expands one part of the system with richer, code-grounded detail and an honest implemented / spec-only status. The companion feature map lives in ../V4_features.md.

Cross-reference convention. Page-to-page links are relative (./<slug>.md). Platform-foundation links point at the shared platform/ space.

Architecture landscape#

flowchart TB Host[V4 game host] --> Plugins[Cell and mode plugins] Plugins --> Gameplay[GAS animation input and cell specialization] Gameplay --> AI[Perception stealth crowds and AI director] Gameplay --> Authority[Networking determinism online and persistence] AI --> World[World streaming procgen maps and content] Authority --> World World --> Presentation[Audio VFX cinematics UI accessibility and hardware] Plugins --> Data[(Versioned cell mode asset save and progression data)] Authority --> Evidence[(Replays telemetry receipts and audits)] Data --> Build[Build cook performance security compliance and launch] Presentation --> Build Evidence --> Build

The host controls compatible composition; plugins own cell/mode specialization; shared systems own reusable contracts; server or deterministic authority owns effects; and build/operations own deployability. An arrow does not authorize a cell to bypass another layer's version, safety, or persistence boundary.

Trace an affected behavior from plugin activation and canonical data through input/GAS/animation, AI/world, authority/persistence, presentation, telemetry, build, and recovery evidence. Pair that trace with the feature index and name the target cells—one cell's functional or performance result cannot certify the others.

Every focused architecture topic appears exactly once below. The V4 documentation guide provides the status vocabulary and role paths; the diagram atlas supplies cross-system models. Backlog, dependencies, decisions, current code/assets/tests/builds, verification, and platform release evidence remain authoritative.

Orientation#

V4 Product Promise & Architectural Overview — what V4 commits to and the multi-cell-on-one-engine thesis.
Subsystem Glossary & Module Map — every V4 module mapped to code.
High-Level Architecture — the runtime topology and the cell-hosting model.

Combat, Character & Input Systems#

Gameplay Ability System (GAS) Layout — attribute sets, abilities, and effects across the cells.
Animation Pipeline — state machines, blending, and per-cell specialization.
Input Pipeline — Enhanced Input, contexts, and per-cell input schemes.

AI, Stealth & Per-Cell Combat#

AI, Perception & Stealth — the AI architecture, perception, and the stealth systems.
Per-Cell Architecture Deep-Dives — how each game-style cell is built on the shared engine.

Netcode, Modes & World#

Networking & Determinism — the netcode model, replication, and determinism.
Game Modes & Live Service — the mode architecture across cells and live service.
World Streaming & Procedural Generation — world streaming, procgen, and crowds.

Online, Persistence & Platform#

Online Services & Persistence — online services and the persistence/save layer.

Presentation, Production & Launch#

Presentation Pipelines: Audio, VFX, Cinematics & UI — the audio, VFX, cinematic, and UI/HUD pipelines.
Build, Data & Content Pipeline — build/cook/patch, data architecture, and the content pipeline.
Telemetry, Observability & Performance — telemetry, observability, and performance budgets.
Security, Compliance & Launch — security, compliance, testing/cert, and launch readiness.