easing.elm

import Color exposing (..)
import Graphics.Collage exposing (..)
import Graphics.Element exposing (..)
import Mouse
import Window
import Time
import Signal


main : Signal Element
main =
  Signal.map2 scene dmouse Window.dimensions

ease : (Float,Float) -> (Float,Float) -> (Float,Float)
ease (nx,ny) (px,py) = ((px + (nx - px) * 0.1),(py + (ny - py) * 0.1))

fmouse : Signal (Float,Float)
fmouse = Signal.map (\(x,y) -> (toFloat x, toFloat y)) Mouse.position

dmouse : Signal (Float,Float)
dmouse = Signal.foldp ease (0,0) fmouse

scene : (Float,Float) -> (Int,Int) -> Element
scene (x,y) (w,h) =
  let
    (dx,dy) =
      (x - toFloat w / 2, toFloat h / 2 - y)
  in
    collage w h
      [ ngon 3 100
          |> filled blue
          |> rotate (atan2 dy dx)
      , ngon 6 30
          |> filled orange
          |> move (dx, dy)
      ]