Add Vec module

1 files changed, 39 insertions, 0 deletions

diff --git a/src/Vec.hs b/src/Vec.hs
new file mode 100644
index 0000000..19a8485
--- /dev/null
+++ b/src/Vec.hs
@@ -0,0 +1,39 @@
+{-|
+Module      : Vec
+Description : Small Vector module
+Copyright   : (c) 2019, Yann Herklotz Grave
+License     : GPL-3
+Maintainer  : ymherklotz [at] gmail [dot] com
+Stability   : experimental
+Portability : POSIX
+
+Small Vector module
+-}
+
+module Vec where
+
+newtype Vec a = Vec { unVec :: (a, a, a) }
+            deriving (Show)
+
+instance Functor Vec where
+  fmap f (Vec (a, b, c)) = Vec (f a, f b, f c)
+
+findZ :: (Floating a) => a -> a -> Vec a
+findZ x y =
+  Vec (x, y, sqrt (1 - x^^2 - y^^2))
+
+dot :: (Num a) => Vec a -> Vec a -> a
+dot (Vec (x1, y1, z1)) (Vec (x2, y2, z2)) =
+  x1 * x2 + y1 * y2 + z1 * z2
+
+normalise :: (Floating a) => Int -> (Int, Int) -> Vec a
+normalise size (y, x) =
+  findZ (scale x) $ scale y
+  where
+    scale a = 2 * fromIntegral a / fromIntegral size - 1
+
+reflect :: (Floating a) => Int -> Vec a -> (Int, Int) -> Vec a
+reflect size v (y, x) =
+  n
+  where
+    n = normalise size (y, x)