gloss stuff

blah.hs

import Graphics.Gloss
import Graphics.Gloss.Interface.Pure.Game

main = play w white 60 st0 draw ev advance

w = InWindow "a boring game." (640,480) (30,30)

data State = State {s, x, y, ds, dx, dy :: Float}

st0 = State 10 30 30 0 0 0

draw (State s x y _ _ _) = translate x y (circle s)

ev (EventKey k d _ _) st =
    case k of
      Char '+'            -> st {ds = amt 0.5}
      Char '-'            -> st {ds = amt (-0.5)}
      SpecialKey KeyUp    -> st {dy = amt 1}
      SpecialKey KeyDown  -> st {dy = amt 1}
      SpecialKey KeyRight -> st {dx = amt (-1)}
      SpecialKey KeyLeft  -> st {dx = amt 1}
      _                   -> st
  where
    amt i = case d of Down -> i
                      Up   -> 0
ev _ st = st

advance t st@(State s x y ds dx dy) =
    st {ds = next s ds, dx = next x dx, y = next y dy}
  where next a da = (60*t*da) + a