diff --git a/src-client/Client/Graphics.hs b/src-client/Client/Graphics.hs
index 69904f9..1ea21c2 100644
--- a/src-client/Client/Graphics.hs
+++ b/src-client/Client/Graphics.hs
@@ -101,10 +101,11 @@ castRay wizard (row, col) (x, y) (width, height) =
       tMaxRow = min dMaxRow (recip 0)
       tMin = max 0 $ max dMinCol dMinRow
       tMax = min (recip 0) $ min dMaxCol dMaxRow
+      vec = (tMin *) <$> direction
   in
     if tMin < tMax
     then
-      let result = sqrt (quadrance ((tMin *) <$> direction)) * abs ((- vFOV) / 2 + y * vFOV / height)
+      let result = sqrt (vec `dot` vec) / cos ((- vFOV) / 2 + y * vFOV / height)
       -- in trace ("ray length: " <> show result) result
       -- in trace ("vector: " <> show (sqrt $ quadrance $ (tMin *) <$> direction)) result
       -- in trace ("wStep: " <> show wStep) result