Data commit

Task/Death-Star/Haskell/death-star.hs

@@ -0,0 +1,23 @@
+import Data.List (genericLength)
+
+shades = ".:!*oe%#&@"
+n = genericLength shades
+dot a b = sum $ zipWith (*) a b
+normalize x = (/ sqrt (x `dot` x)) <$> x
+
+deathStar r k amb = unlines $
+  [ [ if x*x + y*y <= r*r
+      then let vec = normalize $ normal x y
+               b = (light `dot` vec) ** k + amb
+               intensity = (1 - b)*(n - 1)
+           in shades !! round ((0 `max` intensity) `min` n)
+      else ' '
+    | y <- map (/2.12) [- 2*r - 0.5 .. 2*r + 0.5]  ]
+  | x <- [ - r - 0.5 .. r + 0.5] ]
+  where
+    light = normalize [-30,-30,-50]
+    normal x y
+      | (x+r)**2 + (y+r)**2 <= r**2 = [x+r, y+r, sph2 x y]
+      | otherwise = [x, y, sph1 x y]
+    sph1 x y = sqrt (r*r - x*x - y*y)
+    sph2 x y = r - sqrt (r*r - (x+r)**2 - (y+r)**2)