Files
loop/src/Geometry/ConvexPoly.hs
T

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Haskell

{-# LANGUAGE TemplateHaskell #-}
{-# LANGUAGE BangPatterns #-}
module Geometry.ConvexPoly
( ConvexPoly (..)
, cpPoints
, cpCen
, cpRad
-- , centroid
, pointsToPoly
, convexPolysOverlap
, pointInPolyPoints
) where
import Geometry.Data
import Geometry.Vector
import Geometry.LHS
import Geometry.Intersect
import Geometry.Polygon
import Control.Lens
--import qualified Control.Foldl as L
data ConvexPoly = ConvexPoly
{ _cpPoints :: [Point2]
, _cpCen :: Point2
, _cpRad :: Float
}
pointsToPoly :: [Point2] -> ConvexPoly
pointsToPoly xs = ConvexPoly
{ _cpPoints = xs
, _cpCen = cen
, _cpRad = maximum $ map (dist cen) xs
}
where
cen = centroid xs
-- | Test whether two polygons intersect or if one is contained in the other.
convexPolysOverlap :: ConvexPoly -> ConvexPoly -> Bool
convexPolysOverlap cp1 cp2 = dist (_cpCen cp1) (_cpCen cp2) < _cpRad cp1 + _cpRad cp2
&& polyPointsOverlap (_cpPoints cp1) (_cpPoints cp2)
--pointInConvexPoly :: Point2 -> ConvexPoly -> Bool
--pointInConvexPoly p cp = dist p (_cpCen cp) < _cpRad cp
-- && pointInPolyPoints p (_cpPoints cp)
-- | Test whether two polygons intersect or if one is contained in the other.
polyPointsOverlap :: [Point2] -> [Point2] -> Bool
polyPointsOverlap (p:ps) (q:qs) = pointInPolyPoints p (q:qs)
|| pointInPolyPoints q (p:ps)
|| polyPointsIntersect (p:ps) (q:qs)
polyPointsOverlap _ _ = False
-- | Test whether a point is strictly inside a polygon.
-- Supposes the points in the polygon are listed in anticlockwise order.
pointInPolyPoints :: Point2 -> [Point2] -> Bool
pointInPolyPoints !p (x:xs) = all (\l -> uncurry isLHS l p) $ zip (x:xs) (xs ++ [x])
pointInPolyPoints _ [] = False
polyPointsIntersect :: [Point2] -> [Point2] -> Bool
polyPointsIntersect (a:b:xs) ps = go a (a:b:xs) ps
where
go x' (a':b':xs') ps' = pairPolyPointsIntersect a' b' ps' || go x' (b':xs') ps'
go b' [a'] ps' = pairPolyPointsIntersect a' b' ps'
go _ _ _ = False
polyPointsIntersect _ _ = False
pairPolyPointsIntersect :: Point2 -> Point2 -> [Point2] -> Bool
pairPolyPointsIntersect a' b' (c':d':xs') = go c' a' b' (c':d':xs')
where
go x a b (c:d:xs) = intersectSegSegTest a b c d || go x a b (d:xs)
go d a b [c] = intersectSegSegTest a b c d
go _ _ _ _ = False
pairPolyPointsIntersect _ _ _ = False
makeLenses ''ConvexPoly