module Tile
    ( tileTexCoords
    , makeTileFromPoly
    , baseFloorTileSize
    )
     where
import Data.Tile
import Geometry

tileTexCoords :: Tile -> [Point2]
tileTexCoords t = map 
    (calcTexCoord (_tileZero t) tangent (- vNormal tangent))
    (_tilePoly t)
  where
    tangent = _tileTangentPos t - _tileZero t

calcTexCoord
    :: Point2   -- ^ tile (0,0)
    -> Point2   -- ^ tile tangent
    -> Point2   -- ^ tile cotangent
    -> Point2   -- ^ world point
    -> Point2
calcTexCoord zp tangent cotangent p = V2 (f tangent) (f cotangent)
  where
    f t = closestPointOnLineParam zp (zp + t) p
    

makeTileFromPoly :: [Point2] -> Float -> Tile
makeTileFromPoly poly z = Tile
    { _tilePoly = poly
    , _tileZero = c
    , _tileTangentPos = c + (baseFloorTileSize *.* normalizeV (d -.- c))
    , _tileArrayZ = z
    }
  where
    (c:d:_) = poly

baseFloorTileSize :: Float
baseFloorTileSize = 50