Tweak shell spin

src/Geometry.hs

@@ -6,8 +6,8 @@ Description : Geometry helpers
 
 This module provides geometry functions that manipulate pairs of floats.
 Conventions:
-Seg refers to a segment, typically defined by two points, and will typically not extend beyond either of these points.
-Line refers to a line defined by two points, and extends beyond the two points.
+Seg refers to a segment between two points and does not extend beyond either of these points.
+Line is also defined by two points but does extend beyond the two points.
 -}
 module Geometry (
     module Geometry,
@@ -33,9 +33,6 @@ import Geometry.Vector
 import Geometry.Vector3D
 import ListHelp
 
---import Data.Maybe
---import Data.List
-
 {- | Return a point a distance away from a first point towards a second point.
  Does not go past the second point.
  No check is made for a negative distance, so can go past the first point.
@@ -93,9 +90,9 @@ midPoint !a !b = 0.5 *.* (a +.+ b)
 -}
 circOnSegNoEndpoints :: Point2 -> Point2 -> Point2 -> Float -> Bool
 {-# INLINE circOnSegNoEndpoints #-}
-circOnSegNoEndpoints !p1 !p2 !c !rad = intersectSegSegTest p1 p2 (c -.- thenormal) (c +.+ thenormal)
+circOnSegNoEndpoints !p1 !p2 !c !rad = intersectSegSegTest p1 p2 (c -.- norm) (c +.+ norm)
   where
-    thenormal = rad *.* vNormal (normalizeV $ p1 -.- p2)
+    norm = rad *.* vNormal (normalizeV $ p1 -.- p2)
 
 {- | Test whether a circle is on a segment by intersecting a normal and testing
  the distance to the endpoints of the segment.
@@ -106,9 +103,9 @@ circOnSeg :: Point2 -> Float -> Point2 -> Point2 -> Bool
 circOnSeg !c !rad !p1 !p2 =
     magV (p1 -.- c) <= rad
         || magV (p2 -.- c) <= rad
-        || intersectSegSegTest p1 p2 (c -.- thenormal) (c +.+ thenormal)
+        || intersectSegSegTest p1 p2 (c -.- norm) (c +.+ norm)
   where
-    thenormal = rad *.* vNormal (normalizeV $ p1 -.- p2)
+    norm = rad *.* vNormal (normalizeV $ p1 -.- p2)
 
 {- | Test whether a segment intersects a circle by intersecting a normal and testing
  the distance to the endpoints of the segment.
@@ -118,13 +115,13 @@ segOnCirc :: Point2 -> Point2 -> Point2 -> Float -> Bool
 segOnCirc !p1 !p2 !c !rad =
     magV (p1 -.- c) <= rad
         || magV (p2 -.- c) <= rad
-        || intersectSegSegTest p1 p2 (c -.- thenormal) (c +.+ thenormal)
+        || intersectSegSegTest p1 p2 (c -.- norm) (c +.+ norm)
   where
-    thenormal = rad *.* vNormal (normalizeV $ p1 -.- p2)
+    norm = rad *.* vNormal (normalizeV $ p1 -.- p2)
 
 cylinderOnSeg :: Point3 -> Point3 -> Point3 -> Float -> Bool
 {-# INLINE cylinderOnSeg #-}
-cylinderOnSeg = undefined
+cylinderOnSeg = undefined -- TODO
 
 -- | Find the difference between two Nums.
 difference :: (Ord a, Num a) => a -> a -> a
@@ -144,14 +141,15 @@ reflectIn line vec = rotateV (2 * angleBetween line vec) vec
 reflectAngle :: Float -> Point2 -> Point2 -> Float
 reflectAngle a x y = 2 * argV (x - y) - a
 
-{- | Find the representation (by applying +-pi) of an angle 
- - that is nearest to another given angle -}
+{- | Find the representation (by applying +-pi) of an angle
+ - that is nearest to another given angle
+-}
 nearestAngleRep :: Float -> Float -> Float
 nearestAngleRep a b
     | b >= a && b - a <= pi = b
-    | b >= a = nearestAngleRep a (b - 2*pi)
+    | b >= a = nearestAngleRep a (b - 2 * pi)
     | a - b <= pi = b
-    | otherwise = nearestAngleRep a (b + 2*pi)
+    | otherwise = nearestAngleRep a (b + 2 * pi)
 
 {- | Find angle between two points.
  Not normalised, ranges from -2*pi to 2*pi.
@@ -170,7 +168,6 @@ doublePairSet (x, y) = S.fromList [(x, y), (y, x)]
 doubleV2 :: V2 a -> [V2 a]
 doubleV2 (V2 x y) = [V2 x y, V2 y x]
 
-
 polyToTris' :: [s] -> [s]
 {-# INLINE polyToTris' #-}
 polyToTris' [] = []
@@ -193,8 +190,6 @@ nRaysRad n x = take n $ iterate (rotateV (2 * pi / fromIntegral n)) (V2 x 0)
  This appears to sometimes fail if the angles are not normalized.
 -}
 isLeftOfA :: Float -> Float -> Bool
---isLeftOfA angle1 angle2 = (angle1 - angle2 < pi && angle1 > angle2)
---    || (angle2 - angle1 > pi && angle2 > angle1)
 isLeftOfA angle1 angle2 = normalizeAngle (angle1 - angle2) < pi
 
 {- | Test whether a vector is to the left of another, according to the smallest
@@ -204,17 +199,10 @@ isLeftOf :: Point2 -> Point2 -> Bool
 isLeftOf x y = isLeftOfA (argV x) (argV y)
 
 {- | Find the difference between two angles.
- Possibly not correct...
  TODO write tests
 -}
 diffAngles :: Float -> Float -> Float
-diffAngles x y
-    | diff > pi = diffAngles (x - 2 * pi) y
-    | diff >= 0 = diff
-    | diff > - pi = - diff
-    | otherwise = diffAngles (x + 2 * pi) y
-  where
-    diff = x - y
+diffAngles x y = nearZeroAngle $ x - y
 
 mixAngles :: Float -> Float -> Float -> Float
 mixAngles frac a1 a2