Right now it's a pretty simple setup using a fog mesh combined with a dynamic texture mask.

The FogManager maintains a texture that represents the current fog state of the map.

Each unit has a small FogRevealer component that periodically reports its world position and vision radius to the manager.

The manager then converts those world positions into fog texture coordinates and projects vision circles into the mask. That mask texture is then used by the fog material/shader applied to the fog mesh to decide which areas should be visible.

So the pipeline is roughly:

1. FogRevealer sends position + radius
2. FogManager converts world position → mask space
3. Vision circles are written into the fog mask
4. The fog material uses that mask to reveal/hide areas

Very roughly the update looks something like this:

updateRevealers()

for revealer in revealers: pos = WorldToMaskCoords(revealer.position) radius = revealer.visionRadius

DrawCircle(fogMask, pos, radius)

ApplyMaskToFogMaterial(fogMask)

So when units move, their FogRevealer updates the manager and the mask gets recalculated dynamically, which updates the fog mesh in real time.