Fix tile rendering

src/Data/Tile.hs

@@ -4,12 +4,12 @@ module Data.Tile
 import Geometry.Data
 
 import Control.Lens
+
 data Tile = Tile
     { _tilePoly :: [Point2]
-    , _tileCenter :: Point2
-    , _tileX :: Point2
-    , _tileY :: Point2
-    , _tileZ :: Float
+    , _tileZero :: Point2   -- ^ point in the world where tile texture is 0,0
+    , _tileX    :: Point2   -- ^ vector in the X direction (1,0)
+    , _tileZ    :: Float
     }
   deriving (Eq, Ord, Show)
 makeLenses ''Tile