missing cardinal file + some minor fiddling on the raytracer front

hgeometry-examples/raytracer/Main.hs

@@ -125,9 +125,10 @@ rayColor gen = rayColor'
           Nothing      -> pure backgroundColor
           Just (obj,q) -> do
                              let normal = normalUnitVectorAt q (obj^.geom)
-                             v <- uniformUpwardDirectionWrt normal gen
+                             v <- (normal ^+^) <$>
+                                  uniformUpwardDirectionWrt normal gen
                              -- shoot a new ray
-                             (blend 0.5 (opaque black))
+                             (blend 0.1 (opaque black))
                                <$> rayColor' (HalfLine (q^.core) v) (depth-1) scene
 
 -- -- | Compute the color of the object at the intersection point with the ray
@@ -229,7 +230,7 @@ renderWithProgress reportProgress screenDims@(Vector2 w h) camera scene = do
                         viewportDims
                         screenDims
 
-    theViewport = Vector2 topLeft (topLeft .+^ (xVec ^+^ yVec))
+    -- theViewport = Vector2 topLeft (topLeft .+^ (xVec ^+^ yVec))
 
 
 --------------------------------------------------------------------------------

hgeometry-examples/raytracer/Settings.hs

@@ -47,7 +47,7 @@ fromDesiredHeight desiredHeight = let Vector2 w h = fromIntegral <$> outputDimen
 
 -- | The number of samples we take for each pixel
 numSamplesPerPixel :: Int
-numSamplesPerPixel = 10 -- 100
+numSamplesPerPixel = 20 -- 100
 
 -- | Maximum complexity of a single ray; (in number of segments)
 maxRayComplexity :: Int

hgeometry/kernel/src/HGeometry/Direction/Cardinal.hs

@@ -0,0 +1,59 @@
+--------------------------------------------------------------------------------
+-- |
+-- Module      :  HGeometry.Direction.Cardinal
+-- Copyright   :  (C) Frank Staals
+-- License     :  see the LICENSE file
+-- Maintainer  :  Frank Staals
+--
+-- Cardinal and Intercardinal directions.
+--
+--------------------------------------------------------------------------------
+module HGeometry.Direction.Cardinal
+  ( CardinalDirection(..)
+    -- , _North, _East, _South, _West
+  , oppositeDirection
+
+  , InterCardinalDirection(..)
+    -- , _NorthWest, _NorthEast, _SouthEast, _SouthWest
+
+  , interCardinalsOf
+  ) where
+
+import GHC.Generics (Generic)
+import HGeometry.Vector
+
+--------------------------------------------------------------------------------
+
+-- | The four cardinal directions.
+data CardinalDirection = North | East | South | West deriving (Show,Read,Eq,Ord,Enum,Bounded)
+-- makePrisms ''CardinalDirection
+
+--------------------------------------------------------------------------------
+-- * Functions on Cardinal Directions
+
+-- | Computes the direction opposite to the given one.
+oppositeDirection :: CardinalDirection -> CardinalDirection
+oppositeDirection = \case
+  North -> South
+  East  -> West
+  South -> North
+  West  -> East
+
+--------------------------------------------------------------------------------
+
+-- | Intercardinal directions
+data InterCardinalDirection = NorthWest | NorthEast | SouthEast | SouthWest
+  deriving (Show,Read,Eq,Ord,Enum,Generic)
+-- makePrisms ''InterCardinalDirection
+
+--------------------------------------------------------------------------------
+-- * Functions on InterCardinal Directions
+
+-- | Get the two intercardinal directions, in increasing order,
+-- corresponding to the cardinal direction.
+interCardinalsOf :: CardinalDirection -> Vector 2 InterCardinalDirection
+interCardinalsOf = \case
+  North -> Vector2 NorthWest NorthEast
+  East  -> Vector2 NorthEast SouthEast
+  South -> Vector2 SouthEast SouthWest
+  West  -> Vector2 SouthWest NorthWest