X-Git-Url: http://gitweb.michael.orlitzky.com/?a=blobdiff_plain;f=src%2FPoint.hs;h=49ad534385846b57e60875849a0edff87c39653f;hb=610d0f0af8a802c26d51231d6e2426a72e40fd2d;hp=d0859bfc54208d9b096a4f876404a79682d6423e;hpb=89b8b6e94fcc944a1f4611811265f3c6217af850;p=spline3.git diff --git a/src/Point.hs b/src/Point.hs index d0859bf..49ad534 100644 --- a/src/Point.hs +++ b/src/Point.hs @@ -1,51 +1,32 @@ -{-# LANGUAGE TypeSynonymInstances #-} +{-# LANGUAGE FlexibleInstances #-} -module Point +module Point ( + Point, + dot, + scale + ) where -type Point = (Double, Double, Double) - -x_coord :: Point -> Double -x_coord (x, _, _) = x +import Comparisons ((~=)) -y_coord :: Point -> Double -y_coord (_, y, _) = y -z_coord :: Point -> Double -z_coord (_, _, z) = z +type Point = (Double, Double, Double) instance Num Point where - p1 + p2 = (x1+x2, y1+y2, z1+z2) - where - x1 = x_coord p1 - x2 = x_coord p2 - y1 = y_coord p1 - y2 = y_coord p2 - z1 = z_coord p1 - z2 = z_coord p2 - - p1 - p2 = (x1-x2, y1-y2, z1-z2) - where - x1 = x_coord p1 - x2 = x_coord p2 - y1 = y_coord p1 - y2 = y_coord p2 - z1 = z_coord p1 - z2 = z_coord p2 - - p1 * p2 = (x1*x2, y1*y2, z1*z2) - where - x1 = x_coord p1 - x2 = x_coord p2 - y1 = y_coord p1 - y2 = y_coord p2 - z1 = z_coord p1 - z2 = z_coord p2 - + (x1,y1,z1) + (x2,y2,z2) = (x1+x2, y1+y2, z1+z2) + (x1,y1,z1) - (x2,y2,z2) = (x1-x2, y1-y2, z1-z2) + (x1,y1,z1) * (x2,y2,z2) = (x1*x2, y1*y2, z1*z2) abs (x, y, z) = (abs x, abs y, abs z) signum (x, y, z) = (signum x, signum y, signum z) fromInteger n = (fromInteger n, fromInteger n, fromInteger n) +-- | Scale a point by a constant. scale :: Point -> Double -> Point scale (x, y, z) d = (x*d, y*d, z*d) + + +-- | 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)