fixed x & y

app/Main.hs

@@ -29,7 +29,7 @@ scatter (Ray o d) (Hit t p n (Lambertian c)) = do
   let target = p ^+^ colorWithNormal (unitVector n) ^+^ r
   return $ Ray p (target ^-^ p)
 scatter (Ray o d) (Hit t p n (Metal c)) = do
-  let reflected = reflect (unitVector d) n
+  let reflected = reflect (unitVector d) (unitVector n)
   return $ Ray p reflected
 scatter (Ray o d) (Hit t p n (Glass c)) = do
   let refraction_ratio = if isFrontFace (Ray o d) n then 1.0 / 1.5 else 1.0
@@ -40,17 +40,16 @@ scatter (Ray o d) (Hit t p n (Glass c)) = do
 
   if refraction_ratio * st > 1.0 || reflectance ct refraction_ratio < rVal
     then do
-      let reflected = reflect ud n
+      let reflected = reflect ud (unitVector n)
       return $ Ray p reflected
     else do
-      let refracted = refract ud n refraction_ratio
+      let refracted = refract ud (unitVector n) refraction_ratio
       return $ Ray p refracted
 
 getRayColor :: (Shape s, RandomGen g) => [s] -> Int -> Ray -> Rand g (V3 Double)
 getRayColor ws d r = do
   let h = getBestHit (mapMaybe (testHit r) ws)
-  v <- getRayColor' r h ws d
-  return v
+  getRayColor' r h ws d
 
 -- get color of pixel according to the closest hit found
 getRayColor' :: (Shape s, RandomGen g) => Ray -> Maybe Hit -> [s] -> Int -> Rand g (V3 Double)
@@ -88,7 +87,7 @@ colorWithNormal v = 0.5 *^ (v ^+^ V3 1.0 1.0 1.0)
 rayTrace :: (Shape s) => (Int, Int) -> ImageDimensions -> ViewPortDimensions -> [s] -> Int -> IO (V3 Double)
 rayTrace (x, y) (w, h) (vw, vh) world samples = do
   let maxDepth = 50
-  l <- replicateM samples (evalRandIO (getRayColor world maxDepth $ buildRay (xf * (vw / wf)) (yf * (vh / hf))))
+  l <- replicateM samples (evalRandIO (getRayColor world maxDepth $ (buildRay (xf * (vw / wf)) (yf * (vh / hf)))))
   return $ foldl (^+^) (V3 0.0 0.0 0.0) l
   where
     xf = fromIntegral x
@@ -102,11 +101,11 @@ main = do
   let h = 400
   let samples = 25
   let world =
-        [ Circle (V3 (0.0) 0.0 (-1.0)) 0.25 (Glass (V3 1.0 1.0 1.0)),
-          Circle (V3 (-0.5) 0.0 (-1.0)) 0.25 (Lambertian (V3 0.7 0.1 0.1)),
+        [ Circle (V3 0.0 0.0 (-1.0)) 0.25 (Glass (V3 1.0 1.0 1.0)),
+          Circle (V3 0.5 0.0 (-1.0)) 0.25 (Lambertian (V3 0.7 0.1 0.1)),
           Circle (V3 0.0 (-10.25) (-1.0)) 10 (Lambertian (V3 0.7 0.6 0.5))
         ]
-  let coords = reverse $ range ((-1 * (w `div` 2), -1 * (h `div` 2)), ((w `div` 2) - 1, (h `div` 2) - 1)) -- "canvas"
+  let coords = [(x, y) | x <- reverse $ [-1 * (w `div` 2) .. (w `div` 2) - 1], y <- [-1 * (h `div` 2) .. (h `div` 2) - 1]]
   colors <- mapM (\x -> rayTrace x (w, h) (1.0, 1.0) world samples) coords
   let convertedColors = map v3ToColor colors
   -- print ppm header

src/Maths.hs

@@ -28,10 +28,6 @@ randV3 = do
     then randV3
     else return $ unitVector (V3 x y z)
 
---  _ -> randV3
-
---inf = read "Infinity"
-
 degToRadians :: Double -> Double
 degToRadians d = (d * pi) / 180.0
 

src/Ray.hs

@@ -3,6 +3,7 @@ module Ray
     rayAt,
     calculateRayNormal,
     buildRay,
+    buildRayAA,
   )
 where
 
@@ -21,5 +22,11 @@ rayAt (Ray origin dir) t = origin + (t *^ dir)
 calculateRayNormal :: Ray -> Double -> V3 Double
 calculateRayNormal r t = unitVector (rayAt r t ^-^ V3 0.0 0.0 1.0)
 
+buildRayAA :: (RandomGen g) => Double -> Double -> Rand g Ray
+buildRayAA u v = do
+  ur <- rand
+  vr <- rand
+  return (Ray (V3 0.0 0.0 0.0) (V3 (v + vr) (u + ur) (-1.0)))
+
 buildRay :: Double -> Double -> Ray
 buildRay u v = Ray (V3 0.0 0.0 0.0) (V3 v u (-1.0))