X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FPoint.hs;h=49ad534385846b57e60875849a0edff87c39653f;hb=610d0f0af8a802c26d51231d6e2426a72e40fd2d;hp=e5260ae06a943505e907439a4bff81ee7bbe03b8;hpb=248880a645548e5d1910814dd9023e2af80e16ac;p=spline3.git diff --git a/src/Point.hs b/src/Point.hs index e5260ae..49ad534 100644 --- a/src/Point.hs +++ b/src/Point.hs @@ -1,9 +1,13 @@ {-# LANGUAGE FlexibleInstances #-} -module Point +module Point ( + Point, + dot, + scale + ) where -import Comparisons +import Comparisons ((~=)) type Point = (Double, Double, Double) @@ -22,13 +26,7 @@ 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). +dot :: Point -> Point -> Double +dot (x1, y1, z1) (x2, y2, z2) = + (x2 - x1)^(2::Int) + (y2 - y1)^(2::Int) + (z2 - z1)^(2::Int)