From dc2de954b63d9ff4eac201e7be7e7be2520d1304 Mon Sep 17 00:00:00 2001
From: Matthias Braendli <matthias.braendli@u-blox.com>
Date: Tue, 3 Dec 2013 09:01:40 +0100
Subject: correct skycolor

---
 raytracer.hs | 11 ++++++-----
 1 file changed, 6 insertions(+), 5 deletions(-)

diff --git a/raytracer.hs b/raytracer.hs
index fe873e0..3b6a8fa 100644
--- a/raytracer.hs
+++ b/raytracer.hs
@@ -32,7 +32,7 @@ filename num = "foo/foo" ++ show num ++ ".ppm"
 
 --spherepos = take 1 [0,20..]
 --spherepos = take 10 [0,36..]
-spherepos = [36]
+spherepos = [72]
 
 spheres num = [ trace ("Sphere at " ++
                     show (round (80 * sin(num * degrees))) ++ "," ++
@@ -58,7 +58,7 @@ floorscale = 4
 w = 600 * 2
 h = 330 * 2
 
-oversampling = 2 -- each pixel is oversampling^2 rays
+oversampling = 4 -- each pixel is oversampling^2 rays
 
 black :: Color
 black = (0,0,0)
@@ -153,9 +153,10 @@ intersect_floor source (alpha, beta)
 
 -- blue is beautiful, but a green tint is nice too
 skycolor :: Coord -> ScreenCoord -> Color
-skycolor source (alpha, beta) = (60,
-            round ((sqrt (alpha/6)) / (sqrt (90 * degrees)) * 128),
-            round ((sqrt (-beta+90*degrees)) / (sqrt (90 * degrees)) * 255) )
+skycolor source (alpha, beta) = (r,g,b)
+            where   r = 60
+                    g = max 0 $ round $ (sqrt (alpha/6)) / (sqrt (90 * degrees)) * 128
+                    b = max 0 $ round $ (sqrt (-beta+90*degrees)) / (sqrt (90 * degrees)) * 255
 
 data SphereIntersect = SphereIntersect Double Color deriving (Eq, Show) -- distance color
 instance Ord SphereIntersect where
-- 
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