X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FPoint.hs;h=685bc7ac5378841b68e1903ca27fc12be1a8f27d;hb=922f93eb2aa9d8ef1747289f5973de25bd346edc;hp=2b8d59736e28e91a5ce1cc9104e5c131305db3c6;hpb=603d9155a29bfbc353b42a6c880edce224626a16;p=spline3.git

diff --git a/src/Point.hs b/src/Point.hs
index 2b8d597..685bc7a 100644
--- a/src/Point.hs
+++ b/src/Point.hs
@@ -1,9 +1,13 @@
-{-# LANGUAGE TypeSynonymInstances #-}
+{-# LANGUAGE FlexibleInstances #-}
 
-module Point
+module Point (
+  Point,
+  dot,
+  scale
+  )
 where
 
-import Comparisons
+import Comparisons ((~=))
 
 
 type Point = (Double, Double, Double)
@@ -22,13 +26,8 @@ scale :: Point -> Double -> Point
 scale (x, y, z) d = (x*d, y*d, z*d)
 
 
--- | Returns the distance between p1 and p2.
-distance :: Point -> Point -> Double
-distance (x1, y1, z1) (x2, y2, z2) =
-    sqrt $ (x2 - x1)^(2::Int) + (y2 - y1)^(2::Int) + (z2 - z1)^(2::Int)
-
-
--- | Returns 'True' if p1 is close to (within 'epsilon' of) p2,
---   'False' otherwise.
-is_close :: Point -> Point -> Bool
-is_close p1 p2 = (distance p1 p2) ~= 0
+-- | Returns the dot product of two points (taken as three-vectors).
+{-# INLINE dot #-}
+dot :: Point -> Point -> Double
+dot (x1, y1, z1) (x2, y2, z2) =
+    (x2 - x1)^(2::Int) + (y2 - y1)^(2::Int) + (z2 - z1)^(2::Int)