37 lines
915 B
Haskell
37 lines
915 B
Haskell
{-# LANGUAGE TypeOperators, TypeSynonymInstances #-}
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module Transformable ( Coord
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, Vector3
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, Transform
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, Transformable(..)
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, translate
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, rotate
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, scale
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) where
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import Data.LinearMap
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type Coord = Double
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type Vector3 = (Coord, Coord, Coord)
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type Transform = Vector3 :-* Vector3
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class Transformable a where
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(><) :: Transform -> a -> a
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instance Transformable Transform where
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t1 >< t2 = t1 *.* t2
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instance Transformable Vector3 where
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t >< v = t `lapply` v
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translate :: Coord -> Coord -> Transform
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translate dx dy = linear $ \(x, y, w) -> (x + w*dx, y + w*dy, w)
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rotate :: Coord -> Transform
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rotate a = linear $ \(x, y, w) -> (c*x - s*y, s*x + c*y, w) where
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c = cos a
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s = sin a
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scale :: Coord -> Transform
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scale s = linear $ \(x, y, w) -> (s*y, s*y, w)
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