trying hard to make it better

examples/example01.hs

@@ -116,16 +116,17 @@ load _ = do
 draw :: Affection UserData ()
 draw = do
   traceM "drawing"
-  AffectionData{..} <- get
-  let UserData{..} = userState
-  liftIO $ SDL.lockSurface drawSurface
-  pixels <- liftIO $ SDL.surfacePixels drawSurface
-  let SDL.Surface rawSurfacePtr _ = drawSurface
-  rawSurface <- liftIO $ peek rawSurfacePtr
-  pixelFormat <- liftIO $ peek $ Raw.surfaceFormat rawSurface
-  format <- liftIO $ (B.babl_format $ B.PixelFormat B.RGBA B.CFu8)
-  SDL.V2 (CInt rw) (CInt rh) <- SDL.surfaceDimensions drawSurface
-  let (w, h) = (fromIntegral rw, fromIntegral rh)
+  UserData{..} <- getAffection
+  -- AffectionData{..} <- get
+  -- let UserData{..} = userState
+  -- -- liftIO $ SDL.lockSurface drawSurface
+  -- pixels <- liftIO $ SDL.surfacePixels drawSurface
+  -- let SDL.Surface rawSurfacePtr _ = drawSurface
+  -- rawSurface <- liftIO $ peek rawSurfacePtr
+  -- pixelFormat <- liftIO $ peek $ Raw.surfaceFormat rawSurface
+  -- format <- liftIO $ (B.babl_format $ B.PixelFormat B.RGBA B.CFu8)
+  -- SDL.V2 (CInt rw) (CInt rh) <- SDL.surfaceDimensions drawSurface
+  -- let (w, h) = (fromIntegral rw, fromIntegral rh)
   drawRect foreground (nodeGraph M.! "over") (G.RGB 1 0 0) (Line 2) (G.GeglRectangle 10 10 500 500)
   -- liftIO $ G.gegl_node_blit
   --   (nodeGraph M.! "over" :: G.GeglNode)
@@ -135,8 +136,8 @@ draw = do
   --   pixels
   --   (fromIntegral (Raw.pixelFormatBytesPerPixel pixelFormat) * w)
   --   [G.GeglBlitDefault]
-  liftIO $ SDL.unlockSurface drawSurface
-  liftIO $ SDL.updateWindowSurface drawWindow
+  -- liftIO $ SDL.unlockSurface drawSurface
+  -- liftIO $ SDL.updateWindowSurface drawWindow
 
 update :: Double -> AffectionState (AffectionData UserData) IO ()
 update sec = do

examples/example03.hs

@@ -117,9 +117,9 @@ update sec = do
                 { psParts = (Particle
                     { particleLife = life
                     , particlePosition = (fromIntegral x, fromIntegral y)
-                    , particleRotation = 0
+                    , particleRotation = Rad 0
                     , particleVelocity = (vx, vy)
-                    , particlePitchRate = 0
+                    , particlePitchRate = Rad 0
                     }) : (psParts $ partsys ud)
                 }
             }

src/Affection/Types.hs

@@ -13,6 +13,8 @@ module Affection.Types
   , RGBA(..)
   , DrawType(..)
   , DrawRequest(..)
+  , Angle(..)
+  , ConvertAngle(..)
     -- | Particle system
   , Particle(..)
   , ParticleSystem(..)
@@ -126,13 +128,42 @@ data DrawType
     { lineWidth :: Int -- ^ Width of line in pixels
     }
 
+-- | Type for defining angles
+data Angle
+  = Rad Double -- ^ Angle in radians
+  | Deg Double -- ^ Angle in degrees
+  deriving (Show)
+
+-- | Typeclass for converting Angles from 'Deg' to 'Rad' and vice versa.
+class ConvertAngle a where
+  toRad :: a -> a -- Convert to 'Rad'
+  toDeg :: a -> a -- Convert to 'Deg'
+
+instance ConvertAngle Angle where
+  toRad (Deg x) = Rad $ x * pi / 180
+  toRad x = x
+
+  toDeg (Rad x) = Deg $ x * 180 / pi
+  toDeg x = x
+
+instance Eq Angle where
+  (==) (Deg x) (Deg y) = x == y
+  (==) (Rad x) (Rad y) = x == y
+  (==) dx@(Deg _) ry@(Rad _) = dx == toDeg ry
+  (==) rx@(Rad _) dy@(Deg _) = toDeg rx == dy
+
 -- | A single particle
 data Particle = Particle
-  { particleLife      :: Double           -- ^ Time to live in seconds
-  , particlePosition  :: (Double, Double) -- ^ Position of particle on canvas
-  , particleRotation  :: Double           -- ^ Particle rotation
-  , particleVelocity  :: (Int, Int)       -- ^ particle velocity as vector of pixels per second
-  , particlePitchRate :: Double           -- ^ Rotational velocity of particle
+  { particleLife      :: Double
+      -- ^ Time to live in seconds
+  , particlePosition  :: (Double, Double)
+      -- ^ Position of particle on canvas
+  , particleRotation  :: Angle
+      -- ^ Particle rotation
+  , particleVelocity  :: (Int, Int)
+      -- ^ particle velocity as vector of pixels per second
+  , particlePitchRate :: Angle
+      -- ^ Rotational velocity of particle in angle per second
   } deriving (Show, Eq)
 
 data ParticleSystem = ParticleSystem