elmkade.elm

import Window
import Mouse

relativem : (Int,Int) -> (Int,Int) -> (Float,Float)
relativem (w,h) (x,y) = (toFloat (x-(w//2)), toFloat ((h//2)-y))

type Bullet = {posX: Float, posY: Float, vel: Float}
defaultBullet = {posX=0, posY=-180.0, vel=5}

type GameState = {bullets: [Bullet]}
gameState = {bullets=[]}

spaceship : (Float,Float) -> Form
spaceship (x,y) = let clampedx = clamp -180 180 x
                  in move (clampedx, -180) 
                      <| scale 20 
                      <| filled white 
                      <| polygon [  (-1,0.5), (-0.25,0.5)
                                  , (-0.25,1), (0.25,1)
                                  , (0.25,0.5), (1,0.5)
                                  , (1,0), (-1,0)]

renderBullet : Bullet -> Form
renderBullet blt = rect 5 5 
                     |> filled red 
                     |> move (blt.posX, blt.posY)

render : (Int,Int) -> (Int,Int) -> GameState -> Element
render (w,h) pos state = let spship = spaceship <| relativem (w,h) pos
                             bullets = map renderBullet state.bullets
                         in container w h middle 
                             <| color black 
                             <| collage 400 400 ([spship] ++ bullets)
                       

data Event = Draw (Int,Int) (Int,Int) Time | Click () (Int,Int) (Int,Int)
event = merges [(lift3 Draw Window.dimensions Mouse.position (fps 60)),
                (lift3 Click Mouse.clicks Window.dimensions Mouse.position)]

nextBulletPos : Bullet -> Bullet
nextBulletPos blt = {blt | posY <- blt.posY + blt.vel}



nextStep : Event -> GameState -> GameState
nextStep event currentState = 
  case event of
    Click () dim pos -> let (x,y) = relativem dim pos 
                            clampedx = clamp -180 180 x
                            newBullets = {defaultBullet | posX <- clampedx} :: currentState.bullets
                        in {currentState | bullets <- newBullets}
    Draw dim pos secs -> let newBullets = map nextBulletPos currentState.bullets
                             filtered = filter (\b -> b.posX < 200) newBullets
                         in {currentState | bullets <- filtered}
    

main = lift3 render Window.dimensions Mouse.position <| foldp nextStep gameState event

logo.png