The Map Baker

The fog material needs to know where the ground is, so light never spills off the playable area into the void. The Map Baker produces that information as a black-and-white floor map texture:

• White is ground that can be lit.
• Black is permanently dark (off the map, out of bounds).

The fog material samples this texture, so a lit radius shows up only where the floor map is white.

Prepare the level

Lay meshes over your walkable ground. Stretched cube meshes are a simple, reliable choice. These surfaces are the only ones allowed to receive light; treat everything else as out of bounds.

Add and configure the baker

Drag BP_MapBaker from Plugins/FogOfWar/Content/MapBaker into the scene and position it over the play area, then adjust its settings:

Setting	What it does
Map Size	The width and length of the fog-covered area. The map does not need to be square; use the longer of the two dimensions.
Bake Smooth (optional)	Smooths the edges of the baked texture for a more gradual fog falloff between lit and unlit areas.
Is Map Centered	Whether the world origin (0,0,0) is at the center of the map or at a corner, so the baker aligns to the layout.

The Map Size and centering you choose here must also be set on the Fog Manager so the fog and the floor map line up.

Measuring the map

Switch to Top view and hold the middle mouse button to drag-measure from one side of the map to the other.

The Bake Smooth option softens the boundary between lit and dark ground:

Tag the floor meshes

Select your floor actors and add the FLOOR tag. The baker only captures tagged actors, so props and decoration are ignored. White in the baked texture is where these floors are; everything else stays dark.

Bake the floor texture

With every floor actor tagged, click Bake on the Map Baker to generate the floor texture.

Static vs. dynamic use

Once baked, you have two ways to use the result:

Mode	How	When to use
Static	Save the baked texture and assign it to the Fog Manager’s Floor Map Texture, then remove the baker actor from the level.	Recommended. The floor never changes at runtime, so a saved texture is the cheapest option.
Dynamic	Leave BP_MapBaker in the level so it provides its render target to the fog at runtime.	Only if the playable floor can change shape during play.

If you bake a static texture, the Map Baker actor is no longer needed and can be safely removed from the level:

Prefer static

By default the fog material reads the baker’s live render target. Baking a texture and assigning it to the Fog Manager’s Floor Map Texture lets you delete the baker and saves the per-frame render-target cost. Do this once your level layout is final.

Keep sizes consistent

If lit circles appear offset from the floor, or light leaks past the level edge, the Map Baker’s size/centering and the Fog Manager’s Map Size / Is Map Centered are out of sync. Set them to the same values.