Beef up minigun

src/Geometry/Vector.hs

@@ -91,7 +91,9 @@ radToDeg r      = r * 180 / pi
 -- | Normalize an angle to be between 0 and 2*pi radians
 normalizeAngle :: Float -> Float
 {-# INLINE normalizeAngle #-}
-normalizeAngle f = f - 2 * pi * floor' (f / (2 * pi))
+normalizeAngle f 
+    | f >= 0 && f < 2*pi = f
+    | otherwise = f - 2 * pi * floor' (f / (2 * pi))
   where  
     floor' :: Float -> Float
     floor' x = fromIntegral (floor x :: Int)
@@ -126,3 +128,18 @@ projV fromv onv
 dist :: Point2 -> Point2 -> Float
 {-# INLINE dist #-}
 dist !p1 !p2 = magV (p2 -.- p1)
+-- | Finds a new angle a given fraction between two other angles
+tweenAngles 
+    :: Float 
+    -> Float 
+    -> Float
+    -> Float
+{-# INLINE tweenAngles #-}
+tweenAngles frac a1 a2
+    | abs (a1 - a2) < pi = frac * (a1 - a2) + a2
+    | otherwise = normalizeAngle $ go frac a1 a2
+  where
+    go frac' a1' a2'
+        | abs (a1' - a2') < pi = frac' * (a1' - a2') + a2'
+        | a1' > a2'   = go frac' (a1' - 2*pi) a2'
+        | otherwise = go frac' a1' (a2' - 2*pi)