You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
70 lines
1.5 KiB
70 lines
1.5 KiB
module Maths
|
|
( dotP,
|
|
lengthSquared,
|
|
unitVector,
|
|
randV3,
|
|
rand,
|
|
reflect,
|
|
refract,
|
|
reflectance,
|
|
clamp,
|
|
)
|
|
where
|
|
|
|
import Control.Monad.Random
|
|
import Linear.V3
|
|
import Linear.Vector
|
|
import System.Random
|
|
|
|
rand :: (RandomGen g) => Rand g Double
|
|
rand = getRandomR (-1.0, 1.0 :: Double)
|
|
|
|
randV3 :: (RandomGen g) => Rand g (V3 Double)
|
|
randV3 = do
|
|
x <- rand
|
|
y <- rand
|
|
z <- rand
|
|
if vectorLength (V3 x y z) >= 1.0
|
|
then randV3
|
|
else return $ unitVector (V3 x y z)
|
|
|
|
-- _ -> randV3
|
|
|
|
--inf = read "Infinity"
|
|
|
|
degToRadians :: Double -> Double
|
|
degToRadians d = (d * pi) / 180.0
|
|
|
|
dotP :: V3 Double -> V3 Double -> Double
|
|
dotP (V3 a b c) (V3 d e f) = a * d + b * e + c * f
|
|
|
|
lengthSquared :: V3 Double -> Double
|
|
lengthSquared (V3 x y z) = x ^ 2 + y ^ 2 + z ^ 2
|
|
|
|
vectorLength :: V3 Double -> Double
|
|
vectorLength v = sqrt (lengthSquared v)
|
|
|
|
unitVector :: V3 Double -> V3 Double
|
|
unitVector v = v ^/ vectorLength v
|
|
|
|
reflect :: V3 Double -> V3 Double -> V3 Double
|
|
reflect v n = v - (2 * (v `dotP` n)) *^ n
|
|
|
|
refract :: V3 Double -> V3 Double -> Double -> V3 Double
|
|
refract uv n etai_over_etat = perp ^+^ parallel
|
|
where
|
|
ct = min (uv `dotP` n) 1.0
|
|
perp = etai_over_etat *^ ((-1.0 *^ uv) ^+^ (ct *^ n))
|
|
parallel = -1.0 * sqrt (abs (1.0 - lengthSquared perp)) *^ n
|
|
|
|
reflectance :: Double -> Double -> Double
|
|
reflectance c r = r00 + (1 - r00) * (1 - c) ^ 5
|
|
where
|
|
r0 = (1 - r) / (1 + r)
|
|
r00 = r0 * r0
|
|
|
|
clamp :: Double -> Double -> Double -> Double
|
|
clamp x mi ma
|
|
| x < mi = mi
|
|
| x > ma = ma
|
|
| otherwise = x
|
|
|