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implementation module support
import StdEnv, StdIO
toPoint2 :: Size Pos -> Point2
toPoint2 {w,h} {rx,ry} = {x=toInt ((toReal w)*rx),y=toInt ((toReal h)*ry)}
fromPoint2 :: Size Point2 -> Pos
fromPoint2 {w,h} {x,y} = {rx=(toReal x)/(toReal w),ry=(toReal y)/(toReal h)}
circle :: Int -> Oval
circle r = {oval_rx=r,oval_ry=r}
instance zero Pos where
zero = {rx=zero,ry=zero}
instance zero Vel where
zero = {v0=zero,v1=zero}
instance + Pos where
(+) p1 p2 = {rx=p1.rx+p2.rx,ry=p1.ry+p2.ry}
instance - Pos where
(-) p1 p2 = {rx=p1.rx-p2.rx,ry=p1.ry-p2.ry}
instance + Vel where
(+) a b = {v0=a.v0+b.v0,v1=a.v1+b.v1}
instance - Vel where
(-) a b = {v0=a.v0-b.v0,v1=a.v1-b.v1}
class scale a :: !Real !a -> a
instance scale Pos where
scale r p = {rx=r*p.rx,ry=r*p.ry}
instance scale Vel where
scale r v = {v0=r*v.v0,v1=r*v.v1}
class toVel a :: !a -> Vel
instance toVel Pos where
toVel p = {v0=p.rx,v1=p.ry}
class dist a :: !a !a -> Real
instance dist Pos where
dist p1 p2 = sqrt ((p1.rx - p2.rx)^2.0 + (p1.ry - p2.ry)^2.0)
instance dist Real where
dist r1 r2 = abs (r1 - r2)
movePos :: Vel Pos -> Pos
movePos v p = {p & rx=p.rx+v.v0,ry=p.ry+v.v1}
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