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Introduction

Thanks for picking up Multiplayer Fog of War.

Multiplayer Fog of War adds top-down fog of war to your Unreal Engine game. A post-process material lays a dynamic darkness overlay across the map and carves out lit areas around the local player and any vision beacons, while enemy actors hidden inside the fog are concealed by server-authoritative line-of-sight checks. It is built for multiplayer, but works just as well in a single-player top-down game.

Fog of war covering a top-down level, with a lit area around the player

Whole map        →  covered by a dark fog post-process
Around the player →  a lit circle that follows them
Beacons / allies  →  extra lit circles that reveal more of the map
Enemies in fog    →  hidden until a viewer has line of sight to them

How it works

Section titled “How it works”

There is no GPU compute and no per-pixel visibility buffer. Each frame the Fog Manager pushes a small set of values into the post-process material: the local player’s position on the map, their view direction, and the position and radius of every active beacon. The material does the rest, fading the darkness away inside each lit radius and sampling a baked floor map so fog only sits on walkable ground.

Enemy concealment is separate from the visual fog. The Tracker on the viewing character runs overlap tests and line traces on the server to decide whether each tracked enemy is currently visible, then hides or shows that actor on the owning client only. Because it is reference-counted, several viewers (the player plus their beacons) can reveal the same enemy without flicker.

The pieces

Section titled “The pieces”

Map Baker

Bakes a black-and-white floor map: white is ground that can be lit, black is permanently dark. The fog material samples it so light never spills off the playable area.

Fog Manager

One actor per level. Owns the fog post-process and feeds the material the local player’s position, view direction, and all beacon positions every frame.

Tracker

A component on the viewing character. Reveals the area around the player and runs the server-side line-of-sight checks that hide or show tracked enemies.

Beacon

Add it to any actor (allies, watchtowers, wards) to grant the player extra vision from that actor’s location.

Vision Occluder

Add it to a wall or prop to make it cast a vision-blocking shadow, so fog stays behind cover.

What’s covered

Section titled “What’s covered”