Rot Radar Minimap

A toggleable, R.E.P.O.-style minimap for Grain Rot.

Grain Rot only shows you the dungeon layout on the physical map-room table and on the end-of-run "Your Journey" screen. Rot Radar puts a live minimap in the corner of your screen: the dungeon layout, your position and facing, your teammates in their spark colors, and the spawn elevator.

Controls

What you see

• White shapes — rooms and corridors, drawn from the dungeon generator's own room grid, so the layout always matches the run
• Dim boxes — the game's hand-built special rooms (extract, hazard rooms and friends), whose interiors the game never describes per-tile; shown as a clean approximate area instead of a confident wrong shape
• Green square — the spawn elevator
• Orange marker — you (rotates with your facing; follows your Spark if your vessel dies)
• Colored dots — your teammates, live, each in their chosen spark color

The whole map auto-rotates so the direction you face when you first step out of the spawn elevator is up — every dungeon, every run, regardless of how the generator spins the layout. The map has no backing panel and translucent fills, so it stays readable without blocking your view of the game.

Installation

Install with the Thunderstore Mod Manager or r2modmanPlus — the required UE4SS setup (GrainRot UE4SS + unreal shimloader) installs automatically as dependencies. Press M in a dungeon.

Installing through the mod manager is strongly recommended — it handles the UE4SS setup and updates for you.

Multiplayer

• Friends do not need the mod to play with you — nothing in the game files is modified, so modded and unmodded players join each other freely.
• The map works whether you host or join: every machine generates the same dungeon from the shared seed, and Rot Radar reads your local copy.
• Teammate markers work even if the teammates don't have the mod — their positions and spark colors replicate natively; only you need the mod to see them.

How it works (for the curious)

Rot Radar does not screenshot or unpack any game asset. It reads the dungeon generator's replicated room grid (room and corridor tile footprints), rebuilds the layout as a UMG overlay at runtime, and converts world positions into the same tile grid — compensating for the per-run rotation the generator applies to the whole dungeon.

Troubleshooting

• "no dungeon map available here" — you're in the outpost or between runs; the map only exists during an active dungeon run.
• Marker slightly off-center from the corridors — tap Home/End/Delete/Insert to nudge it (quarter-tile per tap); the offset shows in the UE4SS log.
• Static transition hallways (some stair sections) don't appear — those exist in no dungeon data; the map draws everything the generator knows.

Credits

• Runs on the GrainRot UE4SS community overlay and RE-UE4SS.
• Minimap concept inspired by R.E.P.O.

Changelog

1.0.0

• Initial release: live self-rendered minimap with per-tile room footprints, auto-rotation to spawn facing, teammate markers in spark colors, Spark follow-through on vessel death, resize and calibration hotkeys.

1.0.4

• Contrast pass: darker, thicker outlines and stronger fills - readable even at max gamma, no backing panel needed
• Resize now also works on the main-row - / = keys (tenkeyless keyboards)
• Player marker has a white direction nose showing where you are facing

1.1.0

• Rooms are now drawn from the dungeon's real placed floor geometry, so hand-built rooms show their true interior shape instead of a rough box

1.1.1

• Fixed the floor geometry from 1.1.0 being silently thrown away on many dungeons, which made the map fall back to plain boxes. The validity check scored floor tiles against the rooms the game describes, so a dungeon with more hand-built or static areas - exactly the ones this feature exists to draw - scored lower and got rejected
• A rejected scan no longer switches off the follow-up scans, so geometry that streams in a moment after the dungeon generates is still picked up

1.2.0

• The map now also reads the game's navigation data, which fills in the narrow connections between rooms that no other source describes
• Removed the F2 floor-source presets (a debugging leftover that could switch the map to a less complete drawing mid-run). The map always draws the full plan: rooms, real floor geometry, and nav connections

1.3.0

• The map is drawn from the dungeon generator's own room grid alone. After playing all three drawing modes side by side, the plain plan tracked the real layout most consistently - the mesh-derived detail from 1.1.0-1.2.0 added ragged edges and occasional false floor around walls
• The floor-mesh and navigation-data sources remain in the mod for the curious, as flags at the top of main.lua