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-- |Math Functions used in HDemo library
module Graphics.HDemo.MathUtils( clamp, toRadians, catmullRomVal ) where
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-- |Return a value x clamped between a within a given range [xmin, xmax].
clamp :: (Ord a) => a -> a -> a -> a
clamp xmin xmax x 
    | x < xmin = xmin 
    | x > xmax = xmax 
    | otherwise = x
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\begin{code}
toRadians :: (Floating a) => a -> a
toRadians a = (pi * a) / 180
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\begin{code}
catmullRomVal :: (Fractional a) => a -> a -> a -> a -> a -> a
catmullRomVal p0 p1 p2 p3 t = 
    0.5 * ((2 * p1)
           + ((-p0) + p2) * t 
           + (2*p0 - 5*p1 + 4*p2 - p3) * t * t 
           + ((-p0) + 3*p1- 3*p2 + p3) * t * t * t)
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