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diff --git a/src/Xanthous/Data/EntityMap/Graphics.hs b/src/Xanthous/Data/EntityMap/Graphics.hs
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+{-# LANGUAGE ViewPatterns #-}
+--------------------------------------------------------------------------------
+module Xanthous.Data.EntityMap.Graphics where
+--------------------------------------------------------------------------------
+import Xanthous.Prelude
+--------------------------------------------------------------------------------
+import Xanthous.Util (takeWhileInclusive)
+import Xanthous.Data
+import Xanthous.Data.EntityMap
+import Xanthous.Entities
+import Xanthous.Util.Graphics (circle, line)
+--------------------------------------------------------------------------------
+
+-- | Given a point and a radius of vision, returns a list of all entities that
+-- are *visible* (eg, not blocked by an entity that obscures vision) from that
+-- point
+visibleEntities :: Position -> Word -> EntityMap SomeEntity -> EntityMap SomeEntity
+visibleEntities (view _Position -> pos) visionRadius em
+  = fromEIDsAndPositioned . fold . fold $ sightAdjustedLines
+  where
+    -- I love laziness!
+    radius = circle pos $ fromIntegral visionRadius
+    linesOfSight = radius <&> line pos
+    entitiesOnLines = linesOfSight <&> map getPositionedAt
+    sightAdjustedLines = entitiesOnLines <&> takeWhileInclusive (none $ blocksVision . snd)
+    getPositionedAt p =
+      let ppos = _Position # p
+      in atPositionWithIDs ppos em