data Ball = Ball
{ ballPos :: Vec2d
, ballVel :: Vec2d
}
initBall = Ball (0, 0) (0, 0)
dt :: GLfloat
dt = 0.3
minVel = 10
main = do
initialize
openWindow (Size width height) [] Window
windowTitle $= title
Основные библиотеки | 293
clearColor $= Color4 1 1 1 1
ortho (-dw2) (dw2) (-dh2) (dh2) (-1) 1
ball <- newIORef initBall
windowCloseCallback $= exitWith ExitSuccess
windowSizeCallback
$= (\size -> viewport $= (Position 0 0, size))
loop ball
loop :: IORef Ball -> IO ()
loop ball = do
display ball
onMouse ball
sleep frameTime
loop ball
display ball = do
(px, py) <- ballPos <$> get ball
(vx, vy) <- ballVel <$> get ball
ball $= Ball (px + dt*vx, py + dt*vy) (vx, vy)
clear [ColorBuffer]
color black
line (-ow2) (-oh2) (-ow2) oh2
line (-ow2) oh2
ow2
oh2
line ow2
oh2
ow2
(-oh2)
line ow2
(-oh2)
(-ow2) (-oh2)
color red
circle px py 10
swapBuffers
where ow2 = w2 - 50
oh2 = h2 - 50
onMouse ball = do