From a84d8f644c6642393866ea205cecd4ed76908026 Mon Sep 17 00:00:00 2001
From: "Matthias P. Braendli" <matthias.braendli@mpb.li>
Date: Mon, 2 Dec 2013 21:14:57 +0100
Subject: all messed up

---
 raytracer.hs | 46 ++++++++++++++++++++++++++--------------------
 1 file changed, 26 insertions(+), 20 deletions(-)

diff --git a/raytracer.hs b/raytracer.hs
index c73bf13..883331f 100644
--- a/raytracer.hs
+++ b/raytracer.hs
@@ -14,7 +14,8 @@ data Sphere = Sphere Coord Double Color deriving (Show, Eq)
 
 degrees = pi / 180
 
-eye = (0, 0, 20)
+eye :: Coord
+eye = (0, -20, 20)
 
 x_of (x, _, _) = x
 y_of (_, y, _) = y
@@ -43,16 +44,16 @@ writenum num = trace ("Rendering " ++ show (filename num))
 main = mapM writenum spherepos
 
 
-alpha1 = 360 * degrees
-alpha2 = 0 * degrees
+alpha1 = 0 * degrees
+alpha2 = 360 * degrees
 
 beta1 = 20 * degrees
-beta2 = -90 * degrees
+beta2 = -100 * degrees
 
 floorscale = 4
 
-w = 800
-h = 300
+w = 500
+h = 200
 
 oversampling = 1 -- each pixel is 2x2 rays
 
@@ -117,18 +118,18 @@ intersect_sphere source (alpha, beta) (Sphere centre radius color)
 
 
 intersect_point_floor :: Coord -> ScreenCoord -> (Coord, Double)
-intersect_point_floor (_, _, z) (alpha, beta) =
-                      (  (-z * ((cos alpha) + (cos beta)) / (sin beta),
-                         -z * (sin alpha) / (sin beta),
+intersect_point_floor (x, y, z) (alpha, beta) =
+                      (  (-z * ((cos alpha) + (cos beta)) / (sin beta) + x,
+                         -z * (sin alpha) / (sin beta) + y,
                          0),
                       -z / (sin beta) )
 
 direction_color :: Double -> Double -> Int -> Color
 direction_color x y attn
-        | x > 0 && y > 0  = (attn, 0, 0)
-        | x <= 0 && y > 0 = (0, attn, 0)
-        | x > 0 && y <= 0 = (attn, attn, 0)
-        | otherwise       = (0, 0, attn)
+        | x > 0 && y > 0  = (attn, 0, 0) -- red
+        | x <= 0 && y > 0 = (0, attn, 0) -- green
+        | x > 0 && y <= 0 = (attn, attn, 0) -- yellow
+        | otherwise       = (0, 0, attn) -- blue
 
 checkerboard_pattern :: Double -> Double -> Int -> Color
 checkerboard_pattern x y attn
@@ -137,11 +138,12 @@ checkerboard_pattern x y attn
 
 intersect_floor :: Coord -> ScreenCoord -> (Coord, Double, Color)
 intersect_floor source (alpha, beta)
-        | beta >= 0              = ((0, 0, 0), 0, black)
-        | x > (-0.5) && x < 0.5  = ((x, y, z), t, (0, attn, attn))
-        | y > (-0.5) && y < 0.5  = ((x, y, z), t, (attn, attn, 0))
+--        | beta >= 0              = ((0, 0, 0), 0, black)
+        | x > (-0.5) && x < 0.5  = ((x, y, z), t, (0, attn, attn)) -- x near 0 : cyan
+        | y > (-0.5) && y < 0.5  = ((x, y, z), t, (attn, attn, 0)) -- y near 0 : yellow
+        | beta >= 0              = ((x, y, z), -t, checkerboard_pattern x y 128)
         | otherwise              = ((x, y, z), t, checkerboard_pattern x y attn)
-        where   attn = max 0 (round (255 - 8*(sqrt t)))
+        where   attn = max 0 (round (255 - 8*(sqrt $ abs t)))
                 ((x, y, z), t) = intersect_point_floor source (alpha, beta)
 
 -- blue is beautiful, but a green tint is nice too
@@ -173,10 +175,14 @@ nearest_obj source scoord spheres
 
 -- First iteration
 pixel_color :: Coord -> [Sphere] -> ScreenCoord -> Color
-pixel_color source spheres scoord
+pixel_color source spheres scoord =  floorcolor
+                    where   ((x,y,z), floordist, floorcolor) = intersect_floor source scoord
+                            (alpha, beta) = scoord
+
+pixel_colorold source spheres scoord
             | nearest_object_dist > 0 = objcolor
-            | beta == 0 = (0, 255, 0)
-            | otherwise = skycolor source scoord
+            | beta == 0               = (0, 255, 0)
+            | otherwise               = skycolor source scoord
             where   (_, beta) = scoord
                     (nearest_object_dist, objcolor) = nearest_obj source scoord spheres
 
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